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Document And Entity Information - USD ($)	12 Months Ended
Document And Entity Information - USD ($)	Dec. 31, 2011	Feb. 01, 2012	Jun. 30, 2011
Document Information [Line Items]
Entity Registrant Name	ALLETE INC
Entity Central Index Key	0000066756
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$ 1,488,071,330
Entity Common Stock, Shares Outstanding		37,537,154
Document Fiscal Year Focus	2011
Document Fiscal Period Focus	FY
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2011

Consolidated Balance Sheet - USD ($) $ in Millions	Dec. 31, 2011	Dec. 31, 2010
Current Assets
Cash and Cash Equivalents	$ 101.1	$ 44.9
Short-Term Investments	0.0	6.7
Accounts Receivable (Less Allowance of $0.9 and $0.9)	79.7	99.5
Inventories	69.1	60.0
Prepayments and Other	27.1	28.6
Total Current Assets	277.0	239.7
Property, Plant and Equipment - Net	1,982.7	1,805.6
Regulatory Assets	345.9	310.2
Investment in ATC	98.9	93.3
Other Investments	132.3	126.0
Other Non-Current Assets	39.2	34.3
Total Assets	2,876.0	2,609.1
Current Liabilities
Accounts Payable	71.8	75.4
Accrued Taxes	26.4	22.0
Accrued Interest	12.8	13.4
Long-Term Debt Due Within One Year	5.4	13.4
Notes Payable	1.1	1.0
Other	45.6	33.7
Total Current Liabilities	163.1	158.9
Long-Term Debt	857.9	771.6
Deferred Income Taxes	373.6	325.2
Regulatory Liabilities	43.5	43.6
Defined Benefit Pension and Other Postretirement Benefit Plans	253.5	231.4
Other Non-Current Liabilities	105.1	93.4
Total Liabilities	1,796.7	1,624.1
Commitments and Contingencies (Note 11)
ALLETE's Equity
Common Stock Without Par Value, 80.0 Shares Authorized, 37.5 and 35.8 Shares Outstanding	705.6	636.1
Unearned ESOP Shares	(29.0)	(36.8)
Accumulated Other Comprehensive Loss	(28.9)	(23.2)
Retained Earnings	431.6	399.9
Total ALLETE Equity	1,079.3	976.0
Non-Controlling Interest in Subsidiaries	0.0	9.0
Total Equity	1,079.3	985.0
Total Liabilities and Equity	$ 2,876.0	$ 2,609.1

Consolidated Balance Sheet (Parenthetical) - USD ($) $ / shares in Thousands, shares in Millions, $ in Millions	Dec. 31, 2011	Dec. 31, 2010
Accounts Receivable, Allowance
Accounts Receivable, Allowance	$ 0.9	$ 0.9
Common Stock
Common Stock, Par Value	$ 0	$ 0
Common Stock, Shares Authorized	80.0	80.0
Common Stock, Shares Outstanding	37.5	35.8

Consilidated Statement of Income - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Operating Revenue
Operating Revenue	$ 928.2	$ 907.0	$ 766.7
Prior Year Rate Refunds	0.0	0.0	(7.6)
Total Operating Revenue	928.2	907.0	759.1
Operating Expenses
Fuel and Purchased Power	306.6	325.1	279.5
Operating and Maintenance	381.2	365.6	308.9
Depreciation	90.4	80.5	64.7
Total Operating Expenses	778.2	771.2	653.1
Operating Income	150.0	135.8	106.0
Other Income (Expense)
Interest Expense	(43.6)	(39.2)	(33.8)
Equity Earnings in ATC	18.4	17.9	17.5
Other	4.4	4.6	1.8
Total Other Expense	(20.8)	(16.7)	(14.5)
Income Before Non-Controlling Interest and Income Taxes	129.2	119.1	91.5
Income Tax Expense	35.6	44.3	30.8
Net Income	93.6	74.8	60.7
Less: Non-Controlling Interest in Subsidiaries	(0.2)	(0.5)	(0.3)
Net Income Attributable to ALLETE	$ 93.8	$ 75.3	$ 61.0
Average Shares of Common Stock
Basic (in shares)	35.3	34.2	32.2
Diluted (in shares)	35.4	34.3	32.2
Basic Earnings Per Share of Common Stock	$ 2.66	$ 2.20	$ 1.89
Diluted Earnings Per Share of Common Stock	2.65	2.19	1.89
Dividends Per Share of Common Stock (in dollars per share)	$ 1.78	$ 1.76	$ 1.76

Consolidated Statement of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Operating Activities
Net Income	$ 93.6	$ 74.8	$ 60.7
Allowance for Funds Used During Construction	(2.5)	(4.2)	(5.8)
Loss (Income) from Equity Investments, Net of Dividends	(3.2)	(3.1)	0.1
Gain on Real Estate Foreclosure	(0.5)	(0.7)	0.0
Gain on Sale of Assets	(0.9)	0.0	(0.2)
Loss on Impairment of Assets	1.7	0.0	3.1
Depreciation Expense	90.4	80.5	64.7
Amortization of Debt Issuance Costs	0.9	0.9	0.9
Deferred Income Tax Expense	35.8	66.0	75.2
Share-Based Compensation Expense	1.6	2.2	2.1
ESOP Compensation Expense	7.4	7.1	6.5
Defined Benefit Pension and Postretirement Benefit Expense	23.6	18.0	11.7
Bad Debt Expense	1.2	1.1	1.3
Changes in Operating Assets and Liabilities
Accounts Receivable	18.6	17.9	(43.5)
Inventories	(9.1)	(3.0)	(7.3)
Prepayments and Other	1.5	(4.3)	0.0
Accounts Payable	(9.5)	5.8	10.5
Other Current Liabilities	15.4	5.2	5.3
Cash Contributions to Defined Benefit Pension and Postretirement Plans	(24.7)	(39.3)	(30.2)
Changes in Regulatory and Other Non-Current Assets	(7.5)	4.2	(25.6)
Changes in Regulatory and Other Non-Current Liabilities	7.9	(0.4)	7.9
Cash from Operating Activities	241.7	228.7	137.4
Investing Activities
Proceeds from Sale of Available-for-sale Securities	7.8	0.6	8.9
Payments for Purchase of Available-for-sale Securities	(2.3)	(2.3)	(2.2)
Investment in ATC	(2.0)	(1.6)	(7.8)
Changes to Other Investments	(7.4)	1.3	(0.7)
Additions to Property, Plant and Equipment	(239.2)	(248.9)	(318.5)
Proceeds from Sale of Assets	2.2	0.0	0.3
Cash for Investing Activities	(240.9)	(250.9)	(320.0)
Financing Activities
Proceeds from Issuance of Common Stock	39.1	20.5	65.2
Proceeds from Issuance of Long-Term Debt	81.4	155.0	111.4
Changes in Notes Payable	0.1	(0.9)	(4.1)
Reductions of Long-Term Debt	(3.1)	(71.0)	(9.1)
Debt Issuance Costs	0.0	(1.4)	(0.6)
Dividends on Common Stock	(62.1)	(60.8)	(56.5)
Cash from Financing Activities	55.4	41.4	106.3
Change in Cash and Cash Equivalents	56.2	19.2	(76.3)
Cash and Cash Equivalents at Beginning of Period	44.9	25.7	102.0
Cash and Cash Equivalents at End of Period	$ 101.1	$ 44.9	$ 25.7

Consolidated Statement of Shareholders' Equity - USD ($) $ in Millions	Total	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Unearned ESOP Shares	Common Stock
Total Shareholders' Equity at Dec. 31, 2008	$ 827.1	$ 380.9	$ (33.0)	$ (54.9)	$ 534.1
Comprehensive Income
Net Income	60.7	60.7
Other Comprehensive Income - Net of Tax
Unrealized Gain (Loss) on Securities - Net	2.8		2.8
Unrealized Loss on Derivatives - Net	0.0
Defined Benefit Pension and Other Postretirement Plans	6.2		6.2
Total Comprehensive Income	69.7
Non-Controlling Interest in Subsidiaries	0.3	0.3
Comprehensive Income Attributable to ALLETE	70.0
Common Stock Issued - Net	79.3				79.3
Dividends Declared	(56.5)	(56.5)
ESOP Shares Earned	9.6			9.6
Total Shareholders' Equity at Dec. 31, 2009	929.5	385.4	(24.0)	(45.3)	613.4
Comprehensive Income
Net Income	74.8	74.8
Other Comprehensive Income - Net of Tax
Unrealized Gain (Loss) on Securities - Net	0.8		0.8
Unrealized Loss on Derivatives - Net	0.0
Defined Benefit Pension and Other Postretirement Plans	0.0
Total Comprehensive Income	75.6
Non-Controlling Interest in Subsidiaries	0.5	0.5
Comprehensive Income Attributable to ALLETE	76.1
Common Stock Issued - Net	22.7				22.7
Dividends Declared	(60.8)	(60.8)
ESOP Shares Earned	8.5			8.5
Total Shareholders' Equity at Dec. 31, 2010	976.0	399.9	(23.2)	(36.8)	636.1
Comprehensive Income
Net Income	93.6	93.6
Other Comprehensive Income - Net of Tax
Unrealized Gain (Loss) on Securities - Net	(0.3)		(0.3)
Unrealized Loss on Derivatives - Net	(0.3)		(0.3)
Defined Benefit Pension and Other Postretirement Plans	(5.1)		(5.1)
Total Comprehensive Income	87.9
Non-Controlling Interest in Subsidiaries	0.2	0.2
Comprehensive Income Attributable to ALLETE	88.1
Common Stock Issued - Net	69.5				69.5
Dividends Declared	(62.1)	(62.1)
ESOP Shares Earned	7.8			7.8
Total Shareholders' Equity at Dec. 31, 2011	$ 1,079.3	$ 431.6	$ (28.9)	$ (29.0)	$ 705.6

Operations and Significant Accounting Policies

12 Months Ended

Dec. 31, 2011

Operations and Significant Accounting Policies [Abstract]

Operations and Significant Accounting Policies [Text Block]

Operations and Significant Accounting Policies

Financial Statement Preparation. References in this report to “we,” “us,” and “our” are to ALLETE and its subsidiaries, collectively. We prepare our financial statements in conformity with accounting principles generally accepted in the United States of America. These principles require management to make informed judgments, best estimates, and assumptions that affect the reported amounts of assets, liabilities, revenue, and expenses. Actual results could differ from those estimates.

Subsequent Events. The Company performed an evaluation of subsequent events for potential recognition and disclosure through the time of the financial statements issuance.

Principles of Consolidation. Our consolidated financial statements include the accounts of ALLETE and all of our majority-owned subsidiary companies. All material intercompany balances and transactions have been eliminated in consolidation.

Business Segments. Our Regulated Operations and Investments and Other segments were determined in accordance with the guidance on segment reporting. Segmentation is based on the manner in which we operate, assess, and allocate resources to the business. We measure performance of our operations through budgeting and monitoring of contributions to consolidated net income by each business segment.

Regulated Operations includes our regulated utilities, Minnesota Power and SWL&P, as well as our investment in ATC, a Wisconsin-based utility that owns and maintains electric transmission assets in parts of Wisconsin, Michigan, Minnesota, and Illinois. Minnesota Power provides regulated utility electric service in northeastern Minnesota to approximately 144,000 retail customers. Minnesota Power's non-affiliated municipal customers consists of 16 municipalities in Minnesota and 1 private utility in Wisconsin. SWL&P, a wholly-owned subsidiary of ALLETE, is also a private utility in Wisconsin and a customer of Minnesota Power. SWL&P provides regulated electric, natural gas and water service in northwestern Wisconsin to approximately 15,000 electric customers, 12,000 natural gas customers and 10,000 water customers. Our regulated utility operations include retail and wholesale activities under the jurisdiction of state and federal regulatory authorities.

Investments and Other is comprised primarily of BNI Coal, our coal mining operations in North Dakota, ALLETE Properties, our Florida real estate investment, and ALLETE Clean Energy, formed in June 2011, aimed at developing or acquiring capital projects that create energy solutions via wind, solar, biomass, hydro, natural gas/liquids, shale resources, clean coal and other clean energy innovations. This segment also includes a small amount of non-rate base generation, land available-for-sale in Minnesota, and earnings on cash and investments.

BNI Coal, a wholly-owned subsidiary, mines and sells lignite coal to two North Dakota mine-mouth generating units, one of which is Square Butte. In 2011, Square Butte supplied 50 percent (227.5 MW) of its output to Minnesota Power under a long-term contract. (See Note 11. Commitments, Guarantees and Contingencies.) Coal sales are recognized when delivered at the cost of production plus a specified profit per ton of coal delivered.

ALLETE Properties represents our Florida real estate investment. Our current strategy for the assets is to complete and maintain key entitlements and infrastructure improvements without requiring significant additional investment, and sell the portfolio over time or in bulk transactions. ALLETE intends to sell its Florida land assets when opportunities arise and reinvest the proceeds in its growth initiatives. ALLETE does not intend to acquire additional Florida real estate.

Full profit recognition is recorded on sales upon closing, provided that cash collections are at least 20 percent of the contract price and the other requirements under the guidance for sales of real estate are met. In certain cases, where there are obligations to perform significant development activities after the date of sale, we recognize profit on a percentage-of-completion basis. From time to time, certain contracts with customers allow us to receive participation revenue from land sales to third parties if various formula-based criteria are achieved.

In certain cases, we pay fees or construct improvements to mitigate offsite traffic impacts. In return, we receive traffic impact fee credits as a result of some of these expenditures. We recognize revenue from the sale of traffic impact fee credits when payment is received.

ALLETE Clean Energy, a wholly owned subsidiary of ALLETE, operates independently of Minnesota Power to develop or acquire capital projects aimed at creating energy solutions via wind, solar, biomass, hydro, natural gas/liquids, shale resources, clean coal and other clean energy innovations. ALLETE Clean Energy intends to market to electric utilities, cooperatives, municipalities, independent power marketers and large end-users across North America through long-term PPAs, and will be subject to applicable state and federal regulatory approvals.

Land inventories are accounted for in accordance with the accounting standards for property, plant and equipment, and are included in Other Investments on our consolidated balance sheet. Real estate costs include the cost of land acquired, subsequent development costs and costs of improvements, capitalized development period interest, real estate taxes and payroll costs of certain employees devoted directly to the development effort. These real estate costs incurred are capitalized to the cost of real estate parcels based upon the relative sales value of parcels within each development project in accordance with the accounting standards for real estate. The cost of real estate sold includes the actual costs incurred and the estimate of future completion costs allocated to the real estate sold based upon the relative sales value method. Whenever events or circumstances indicate that the carrying value of the real estate may not be recoverable, impairments are recorded and the related assets are adjusted to their estimated fair value. (See Note 7. Investments.)

Non-Controlling Interest in Subsidiaries. In August 2011, ALLETE purchased the remaining shares of the ALLETE Properties non-controlling interest at book value for $8.8 million by issuing 0.2 million shares of ALLETE common stock. This was accounted for as an equity transaction, and no gain or loss was recognized in net income or comprehensive income.

Cash and Cash Equivalents. We consider all investments purchased with original maturities of three months or less to be cash equivalents.

Supplemental Statement of Cash Flow Information



Consolidated Statement of Cash Flows
Supplemental Disclosure
Year Ended December 31	2011		2010		2009
Millions
Cash Paid During the Period for Interest – Net of Amounts Capitalized		$43.2		$35.7		$29.8
Cash Received During the Period for Income Taxes (a)	$(11.4)		$(54.2)		$(5.6)
Noncash Investing and Financing Activities
Increase (Decrease) in Accounts Payable for Capital Additions to Property, Plant and Equipment		$5.9		$7.5	$(24.1)
AFUDC – Equity		$2.5		$4.2		$5.8
ALLETE Common Stock Contributed to the Pension Plan	$(20.0)		—		$(12.0)


(a)	Due to bonus depreciation provisions in 2009 and 2010 federal legislation, NOLs were generated which resulted in little to no estimated tax payments, and refunds were received from NOL carrybacks against prior years' taxable income.

Accounts Receivable. Accounts receivable are reported on the balance sheet net of an allowance for doubtful accounts. The allowance is based on our evaluation of the receivable portfolio under current conditions, overall portfolio quality, review of specific problems and such other factors that, in our judgment, deserve recognition in estimating losses.



Accounts Receivable
As of December 31	2011		2010
Millions
Trade Accounts Receivable
Billed		$63.7		$67.6
Unbilled	15.6		18.9
Less: Allowance for Doubtful Accounts	0.9		0.9
Total Trade Accounts Receivable	78.4		85.6
Income Taxes Receivable (a)	1.3		13.9
Total Accounts Receivable - Net		$79.7		$99.5


(a)	Income Taxes Receivable decreased from 2010 due to the collection of a 2010 NOL carryback claim. (See Note 14. Income Tax Expense.)

Concentration of Credit Risk. Financial instruments that subject us to concentrations of credit risk consist primarily of accounts receivable. Minnesota Power sells electricity to 10 Large Power Customers. Receivables from these customers totaled $9.3 million at December 31, 2011 ($17.3 million at December 31, 2010). Minnesota Power does not obtain collateral to support utility receivables, but monitors the credit standing of major customers. In addition, our taconite-producing Large Power Customers, which are a part of our Regulated Operations segment, are on a weekly billing cycle, which allows us to closely manage collection of amounts due. One of these customers accounted for 12.8 percent of consolidated revenue in 2011 (12.5 percent in 2010; 8.0 percent in 2009). In the third quarter of 2011, one of Minnesota Power's Large Power Customers, NewPage Corporation, filed for Chapter 11 bankruptcy protection. Minnesota Power had a pre-bankruptcy petition receivable of $3.2 million as of December 31, 2011. Based on our assessment of the facts and circumstances existing as of December 31, 2011, we have determined that it is not probable that the pre-petition receivable has been impaired at this time. We will continue to assess for impairment as the bankruptcy proceeds and as facts and circumstances change. The Duluth mill operations have continued without interruption and we continue to provide electric and steam service to this customer. We have received payment of scheduled post-petition receivable balances and we expect continued payment of all other post-petition receivables.

Long-Term Finance Receivables. Long-term finance receivables relating to our real estate operations are collateralized by property sold, accrue interest at market-based rates and are net of an allowance for doubtful accounts. We assess delinquent finance receivables by comparing the balance of such receivables to the estimated fair value of the collateralized property. If the fair value of the property is less than the finance receivable, we record a reserve for the difference. We estimate fair value based on recent property tax assessed values or current appraisals. (See Note 7. Investments.)

Available-for-Sale Securities. Available-for-sale securities are recorded at fair value with unrealized gains and losses included in accumulated other comprehensive income (loss), net of tax. Unrealized losses that are other than temporary are recognized in earnings. We use the specific identification method as the basis for determining the cost of securities sold. Our policy is to review available-for-sale securities for other than temporary impairment on a quarterly basis by assessing such factors as the share price trends and the impact of overall market conditions. (See Note 7. Investments.)

Inventories. Inventories are stated at the lower of cost or market. Amounts removed from inventory are recorded on an average cost basis.



Inventories
As of December 31	2011		2010
Millions
Fuel		$28.6		$22.9
Materials and Supplies	40.5		37.1
Total Inventories		$69.1		$60.0

Property, Plant and Equipment. Property, plant and equipment are recorded at original cost and are reported on the balance sheet net of accumulated depreciation. Expenditures for additions, significant replacements, improvements and major plant overhauls are capitalized; maintenance and repair costs are expensed as incurred. Gains or losses on non-rate base property, plant and equipment are recognized when they are retired or otherwise disposed. When regulated utility property, plant and equipment are retired or otherwise disposed, no gain or loss is recognized in accordance with the accounting standards for Regulated Operations. Our Regulated Operations capitalize AFUDC, which includes both an interest and equity component. AFUDC represents the cost of both debt and equity funds used to finance utility plant additions during construction periods. AFUDC amounts capitalized are included in rate base and are recovered from customers as the related property is depreciated. The MPUC has approved current cost recovery for several large capital projects recently, resulting in lower recognition of AFUDC. (See Note 3. Property, Plant and Equipment.)

Impairment of Long-Lived Assets. We review our long-lived assets for indicators of impairment in accordance with the accounting standards for property, plant and equipment on a quarterly basis. Long-lived assets that we evaluate include our real estate assets of ALLETE Properties.

In accordance with the accounting standards for property, plant and equipment, if indicators of impairment exist, we test our real estate assets for recoverability by comparing the carrying amount of the asset to the undiscounted future net cash flows expected to be generated by the asset. Cash flows are assessed at the lowest level of identifiable cash flows, which may be by each land parcel, combining various parcels into bulk sales, or other combinations thereof. Our consideration of possible impairment for our real estate assets requires us to make estimates of future cash flows on an undiscounted basis. The undiscounted future net cash flows are impacted by trends and factors known to us at the time they are calculated and our expectations related to: management's best estimate of future sales prices; holding period and timing of sales; method of disposition; and future expenditures necessary to develop and maintain the operations, including community development district assessments, property taxes and normal operation and maintenance costs. These estimates and expectations are specific to each land parcel or various bulk sales, and may vary among each land parcel or bulk sale. If the excess of undiscounted cash flows over the carrying value of a property is small, there is a greater risk of future impairment in the event of such changes and any resulting impairment charges could be material.

The poor market conditions for real estate in Florida have required us to review our land inventories for impairment. Our undiscounted cash flow analysis was estimated using management's current intent for disposition of each property, which is an estimated selling period of five to ten years based on a December 2011 asset management and disposition plan. Future selling prices have been estimated through management's best estimate of future sales prices in collaboration and consultation with outside advisors, and based on the best use of the properties over the expected period of sale. The undiscounted cash flow analysis assumes two scenarios: retail land sales followed by project bulk sales over a five year period and retail land sales over a ten year period. Our analysis assumes the most likely case of retail land sales followed by project bulk sales over a five year period; however, under both scenarios, except as noted below, the undiscounted cash flows exceeded carrying values. If our major development projects are sold in one bulk sale or if the properties are sold differently than our December 2011 plan, the actual results could be materially different from our undiscounted cash flow analysis.

The results of the impairment analysis are particularly dependent on the estimated future sales prices, method of disposition, and holding period for each property. The estimated holding period is based on management's current intent for the use and disposition of each property, which could be subject to change in future periods if the intentions of the Company as set by management and approved by the Board of Directors were to change.

In the event that projected future undiscounted cash flows are not adequate to recover the carrying value of an asset, impairment is indicated and may require a write down to the asset's fair value. Fair value is determined based on best available evidence including comparable sales, current appraised values, property tax assessed values, and discounted cash flow analysis. If fair value is less than cost, the carrying value of our investments is reduced and an impairment charge is recorded in the current period. In the fourth quarter of 2011, our impairment analysis indicated that the estimated future cash flows were not adequate to recover the carrying basis of certain properties not strategic to our three major development projects. Consequently, we reduced the cost basis to estimated fair value, resulting in a pretax impairment charge of $1.7 million. The remaining cost basis of these properties amounted to $3.0 million as of December 31, 2011.

Derivatives. ALLETE is exposed to certain risks relating to its business operations that can be managed through the use of derivative instruments. ALLETE may enter into derivative instruments to manage interest rate risk related to certain variable-rate borrowings.

Accounting for Stock-Based Compensation. We apply the fair value recognition guidance for share-based payments. Under this guidance, we recognize stock-based compensation expense for all share-based payments granted, net of an estimated forfeiture rate. (See Note 17. Employee Stock and Incentive Plans.)



Prepayments and Other Current Assets
As of December 31	2011		2010
Millions
Deferred Fuel Adjustment Clause		$17.5		$20.6
Other	9.6		8.0
Total Prepayments and Other Current Assets		$27.1		$28.6



Other Current Liabilities
As of December 31	2011		2010
Millions
Customer Deposits (a)		$16.3		$2.9
Other	29.3		30.8
Total Other Current Liabilities		$45.6		$33.7


(a)	Higher customer deposits in 2011 were primarily due to a customer security deposit for capital expenditures relating to a transmission project.



Other Non-Current Liabilities
As of December 31	2011		2010
Millions
Asset Retirement Obligation		$57.0		$50.3
Other	48.1		43.1
Total Other Non-Current Liabilities		$105.1		$93.4

Environmental Liabilities. We review environmental matters for disclosure on a quarterly basis. Accruals for environmental matters are recorded when it is probable that a liability has been incurred and the amount of the liability can be reasonably estimated, based on current law and existing technologies. These accruals are adjusted periodically as assessment and remediation efforts progress or as additional technical or legal information becomes available. Accruals for environmental liabilities are included in the balance sheet at undiscounted amounts and exclude claims for recoveries from insurance or other third parties. Costs related to environmental contamination treatment and cleanup are charged to operating expense unless recoverable in rates from customers. (See Note 11. Commitments, Guarantees and Contingencies.)

Revenue Recognition. Regulated utility rates are under the jurisdiction of Minnesota, Wisconsin and federal regulatory authorities. Customers are billed on a cycle basis. Revenue is accrued for service provided but not billed. Regulated utility electric rates include adjustment clauses that: (1) bill or credit customers for fuel and purchased energy costs above or below the base levels in rate schedules; (2) bill retail customers for the recovery of conservation improvement program expenditures not collected in base rates; and (3) bill customers for the recovery of certain transmission and renewable energy expenditures. Fuel and purchased power expense is deferred to match the period in which the revenue for fuel and purchased power expense is collected from customers pursuant to the fuel adjustment clause. BNI recognizes revenue when coal is delivered.

Unamortized Discount and Premium on Debt. Discount and premium on debt are deferred and amortized over the terms of the related debt instruments using the straight-line method.

Income Taxes. We file a consolidated federal income tax return. We account for income taxes using the liability method in accordance with the accounting standards for income taxes. Under the liability method, deferred income tax assets and liabilities are established for all temporary differences in the book and tax basis of assets and liabilities, based upon enacted tax laws and rates applicable to the periods in which the taxes become payable. Due to the effects of regulation on Minnesota Power and SWL&P, certain adjustments made to deferred income taxes are, in turn, recorded as regulatory assets or liabilities. Federal investment tax credits have been recorded as deferred credits and are being amortized to income tax expense over the service lives of the related property. In accordance with the accounting standards for uncertainty in income taxes, we are required to recognize in our financial statements the largest tax benefit of a tax position that is “more-likely-than-not” to be sustained on audit, based solely on the technical merits of the position as of the reporting date. The term “more-likely-than-not” means more than 50 percent likely. (See Note 14. Income Tax Expense.)

Excise Taxes. We collect excise taxes from our customers levied by government entities. These taxes are stated separately on the billing to the customer and recorded as a liability to be remitted to the government entity. We account for the collection and payment of these taxes on a net basis.

New Accounting Standards.

Fair Value. In May 2011, the FASB issued an accounting standards update on fair value measurement. This update requires disclosure of a sensitivity analysis for fair value measurements within Level 3 and the valuation process used. This guidance will be effective beginning with the quarter ending March 31, 2012, and is not expected to have a material impact on our consolidated financial position, results of operations or cash flows.

Statement of Comprehensive Income. In June 2011, the FASB issued an accounting standards update on the presentation of comprehensive income. This guidance will be effective beginning with the quarter ending March 31, 2012, and will modify our presentation of other comprehensive income, moving it to a separate, consecutive statement of comprehensive income immediately following the statement of income. The components of net income and other comprehensive income are unchanged and earnings per share continues to be based on net income.

Business Segments

12 Months Ended

Dec. 31, 2011

Business Segments [Abstract]

Business Segments [Text Block]

Business Segments

Regulated Operations includes our regulated utilities, Minnesota Power and SWL&P, as well as our investment in ATC, a Wisconsin-based utility that owns and maintains electric transmission assets in parts of Wisconsin, Michigan, Minnesota and Illinois. Investments and Other is comprised primarily of BNI Coal, our coal mining operations in North Dakota, ALLETE Properties, our Florida real estate investment, and ALLETE Clean Energy, formed in June 2011, aimed at developing or acquiring capital projects that create energy solutions via wind, solar, biomass, hydro, natural gas/liquids, shale resources, clean coal and other clean energy innovations. This segment also includes a small amount of non-rate base generation, approximately 5,500 acres of land available-for-sale in Minnesota, and earnings on cash and investments. For a description of our reportable business segments, see Item 1. Business.



	Consolidated			Regulated Operations			Investments and Other
Millions
2011
Operating Revenue		$928.2			$851.9			$76.3
Fuel and Purchased Power Expense	306.6			306.6			—
Operating and Maintenance Expense	381.2			301.5			79.7
Depreciation Expense	90.4			85.4			5.0
Operating Income (Loss)	150.0			158.4			(8.4		)
Interest Expense	(43.6		)	(35.8		)	(7.8		)
Equity Earnings in ATC	18.4			18.4			—
Other Income	4.4			2.6			1.8
Income (Loss) Before Non-Controlling Interest and Income Taxes	129.2			143.6			(14.4		)
Income Tax Expense (Benefit)	35.6			43.2			(7.6		)
Net Income (Loss)	93.6			100.4			(6.8		)
Less: Non-Controlling Interest in Subsidiaries	(0.2		)	—			(0.2		)
Net Income (Loss) Attributable to ALLETE		$93.8			$100.4		$(6.6)
Total Assets		$2,876.0			$2,579.8			$296.2
Capital Additions		$246.8			$228.0			$18.8

Note 2. Business Segments (Continued)



	Consolidated			Regulated Operations			Investments and Other
Millions
2010
Operating Revenue		$907.0			$835.5			$71.5
Fuel and Purchased Power Expense	325.1			325.1			—
Operating and Maintenance Expense	365.6			292.3			73.3
Depreciation Expense	80.5			76.1			4.4
Operating Income (Loss)	135.8			142.0			(6.2		)
Interest Expense	(39.2		)	(32.3		)	(6.9		)
Equity Earnings in ATC	17.9			17.9			—
Other Income	4.6			3.8			0.8
Income (Loss) Before Non-Controlling Interest and Income Taxes	119.1			131.4			(12.3		)
Income Tax Expense (Benefit)	44.3			51.6			(7.3		)
Net Income (Loss)	74.8			79.8			(5.0		)
Less: Non-Controlling Interest in Subsidiaries	(0.5		)	—			(0.5		)
Net Income (Loss) Attributable to ALLETE		$75.3			$79.8		$(4.5)
Total Assets		$2,609.1			$2,375.4			$233.7
Capital Additions		$260.0			$256.4			$3.6



	Consolidated			Regulated Operations			Investments and Other
Millions
2009
Operating Revenue		$766.7			$689.4			$77.3
Prior Year Rate Refunds	(7.6		)	(7.6		)	—
Total Operating Revenue	759.1			681.8			77.3
Fuel and Purchased Power Expense	279.5			279.5			—
Operating and Maintenance Expense	308.9			235.8			73.1
Depreciation Expense	64.7			60.2			4.5
Operating Income (Loss)	106.0			106.3			(0.3		)
Interest Expense	(33.8		)	(28.3		)	(5.5		)
Equity Earnings in ATC	17.5			17.5			—
Other Income (Expense)	1.8			5.8			(4.0		)
Income (Loss) Before Non-Controlling Interest and Income Taxes	91.5			101.3			(9.8		)
Income Tax Expense (Benefit)	30.8			35.4			(4.6		)
Net Income (Loss)	60.7			65.9			(5.2		)
Less: Non-Controlling Interest in Subsidiaries	(0.3		)	—			(0.3		)
Net Income (Loss) Attributable to ALLETE		$61.0			$65.9		$(4.9)
Total Assets		$2,393.1			$2,184.0			$209.1
Capital Additions		$303.7			$299.2			$4.5

- Definition

The entire disclosure for reporting segments including data and tables. Reportable segments include those that meet any of the following quantitative thresholds a) it's reported revenue, including sales to external customers and intersegment sales or transfers is 10 percent or more of the combined revenue, internal and external, of all operating segments b) the absolute amount of its reported profit or loss is 10 percent or more of the greater, in absolute amount of 1) the combined reported profit of all operating segments that did not report a loss or 2) the combined reported loss of all operating segments that did report a loss c) its assets are 10 percent or more of the combined assets of all operating segments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 131
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 34
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8981-108599

Reference 3: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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-Publisher FASB
-Name Accounting Standards Codification
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-Section 50
-Paragraph 40
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e9031-108599

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-Paragraph 31
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8924-108599

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 10
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Reference 8: http://www.xbrl.org/2003/role/presentationRef
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-Topic 280
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-Name Accounting Standards Codification
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-Name Accounting Standards Codification
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-Publisher FASB
-Name Accounting Standards Codification
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-Name Accounting Standards Codification
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Reference 15: http://www.xbrl.org/2003/role/presentationRef
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+ Details

Property, Plant and Equipment

12 Months Ended

Dec. 31, 2011

Property, Plant and Equipment [Abstract]

Property, Plant and Equipment [Text Block]

Property, Plant and Equipment



Property, Plant and Equipment
As of December 31	2011			2010
Millions
Regulated Utility		$2,794.8			$2,649.2
Construction Work in Progress	155.0			86.6
Accumulated Depreciation	(1,024.6		)	(975.8		)
Regulated Utility Plant - Net	1,925.2			1,760.0
Non-Rate Base Energy Operations	106.4			88.4
Construction Work-in-Progress	2.3			4.5
Accumulated Depreciation	(51.4		)	(48.0		)
Non-Rate Base Energy Operations Plant - Net	57.3			44.9
Other Plant - Net	0.2			0.7
Property, Plant and Equipment - Net		$1,982.7			$1,805.6

Depreciation is computed using the straight-line method over the estimated useful lives of the various classes of assets. The MPUC and the PSCW have approved depreciation rates for our Regulated Utility plant.



Estimated Useful Lives of Property, Plant and Equipment

Regulated Utility –	Generation	4 to 35 years	Non-Rate Base Operations	3 to 61 years
	Transmission	42 to 61 years	Other Plant	5 to 25 years
	Distribution	14 to 65 years

Asset Retirement Obligations. We recognize, at fair value, obligations associated with the retirement of certain tangible, long-lived assets that result from the acquisition, construction or development and/or normal operation of the asset. Asset retirement obligations (ARO) relate primarily to the decommissioning of our coal-fired generating facilities and land reclamation at BNI Coal, and are included in Other Non-Current Liabilities on our consolidated balance sheet. The associated retirement costs are capitalized as part of the related long-lived asset and depreciated over the useful life of the asset. Removal costs associated with certain distribution and transmission assets have not been recognized, as these facilities have indeterminate useful lives.

Conditional asset retirement obligations have been identified for treated wood poles and remaining polychlorinated biphenyl and asbestos-containing assets; however, removal costs have not been recognized because they are considered immaterial to our consolidated financial statements.

Long-standing ratemaking practices approved by applicable state and federal regulatory commissions have allowed provisions for future plant removal costs in depreciation rates. These plant removal cost recoveries were included in accumulated depreciation. These plant removal cost recoveries are classified either as AROs or as a regulatory liability for non-ARO obligations. To the extent annual accruals for plant removal costs differ from accruals under approved depreciation rates, a regulatory asset has been established in accordance with the guidance for AROs. (See Note 5. Regulatory Matters.)



Asset Retirement Obligation
Millions
Obligation as of December 31, 2009		$44.6
Accretion Expense	2.9
Additional Liabilities Incurred in 2010	2.8
Obligation as of December 31, 2010	50.3
Accretion Expense	6.4
Additional Liabilities Incurred in 2011	0.3
Obligation as of December 31, 2011		$57.0

- Definition

The entire disclosure for long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale. Examples include land, buildings, machinery and equipment, and other types of furniture and equipment including, but not limited to, office equipment, furniture and fixtures, and computer equipment and software. This disclosure may include property plant and equipment accounting policies and methodology, a schedule of property, plant and equipment gross, additions, deletions, transfers and other changes, depreciation, depletion and amortization expense, net, accumulated depreciation, depletion and amortization expense and useful lives, income statement disclosures, assets held for sale and public utility disclosures.

+ References + Details

Jointly-Owned Electric Facility

12 Months Ended

Dec. 31, 2011

Jointly-Owned Electric Facility [Abstract]

Jointly-Owned Electric Facility [Text Block]

Jointly-Owned Electric Facilities

Following are our investments in jointly-owned facilities and the related ownership percentages as of December 31, 2011:



	Plant in Service		Accumulated Depreciation		Construction Work in Progress		% Ownership
Millions
Boswell Unit 4		$406.9		$177.4		$8.8	80
CapX2020	11.9		—		15.9		9.3 - 14.7
Total		$418.8		$177.4		$24.7

We own 80 percent of the 585 MW Boswell Unit 4. While we operate the plant, certain decisions about the operations of Boswell Unit 4 are subject to the oversight of a committee on which we and WPPI Energy, the owner of the remaining 20 percent of Boswell Unit 4, have equal representation and voting rights. Each of us must provide our own financing and is obligated to pay our ownership share of operating costs. Our share of direct operating expenses of Boswell Unit 4 is included in operating expense on our consolidated statement of income. We are a participant in the CapX2020 initiative to ensure reliable electric transmission and distribution in the region surrounding our rate-regulated operations in Minnesota, along with other electric cooperatives, municipals, and investor-owned utilities. We are currently participating in three CapX2020 projects with varying ownership percentages.

Regulatory Matters

12 Months Ended

Dec. 31, 2011

Regulatory Matters [Abstract]

Regulatory Matters [Text Block]

Regulatory Matters

Electric Rates. Entities within our Regulated Operations segment file for periodic rate revisions with the MPUC, the FERC or the PSCW.

2010 Rate Case. On November 2, 2010, Minnesota Power received a written order from the MPUC approving a retail rate increase of $53.5 million, a 10.38 percent return on common equity and a 54.29 percent equity ratio, subject to reconsideration. On May 24, 2011, the MPUC issued an order authorizing Minnesota Power to implement final rates of $53.5 million, effective June 1, 2011. The May 24, 2011 order authorized Minnesota Power to collect a $3.2 million differential between interim rates and final rates for the period from November 2, 2010 through May 31, 2011, all of which was recorded in 2011.

Under the terms of a stipulation and settlement agreement approved by the MPUC as part of this rate case, Minnesota Power agreed to forgo collection of $20.5 million in revenue receivable that it was entitled to under a prior rider for the Boswell Unit 3 environmental retrofit. The agreement required the Company to capitalize, as part of rate base, the $20.5 million to property, plant and equipment representing AFUDC. In conjunction with the settlement agreement, and upon receipt of the final rate order in February 2011, the Company reversed a $6.2 million deferred tax liability related to the revenue receivable Minnesota Power agreed to forgo. The $20.5 million revenue receivable was previously included in regulatory assets on the Company’s consolidated balance sheet.

On February 22, 2011, Minnesota Power appealed the MPUC’s interim rate decision in the Company’s 2010 rate case with the Minnesota Court of Appeals. The Company appealed the MPUC’s finding of exigent circumstances in the interim rate decision with the primary arguments that the MPUC exceeded its statutory authority, made its decision without the support of a body of record evidence and that the decision violated public policy. The Company desires to resolve whether the MPUC’s finding of exigent circumstances was lawful for application in future rate cases. In December 2011, the Minnesota Court of Appeals concluded that the MPUC did not err in finding exigent circumstances and properly exercised its discretion in setting interim rates. On January 4, 2012, the Company filed a petition for review at the Minnesota Supreme Court, but cannot predict the outcome at this time.


Note 5.	Regulatory Matters (Continued)

FERC-Approved Wholesale Rates. Minnesota Power’s non-affiliated municipal customers consist of 16 municipalities in Minnesota and 1 private utility in Wisconsin. SWL&P, a wholly-owned subsidiary of ALLETE, is also a private utility in Wisconsin and a customer of Minnesota Power. In 2008, Minnesota Power entered into formula-based rate contracts with these customers. In February 2011, Minnesota Power entered into a new formula-based contract with the City of Nashwauk, effective May 1, 2012, through April 30, 2022. In June 2011, Minnesota Power entered into restated contracts, effective July 1, 2011, through June 30, 2019, with the remaining 15 Minnesota municipal customers, and effective August 1, 2011, through June 30, 2019, with SWL&P. The rates included in these contracts are calculated using a cost-based formula methodology that is set each July using estimated costs and a rate of return that is equal to our authorized rate of return for Minnesota retail customers (10.38 percent). The formula-based rate methodology also provides for a monthly and yearly true-up calculation for actual costs incurred. Both the new and restated contract terms include a termination clause requiring a three-year notice to terminate. Under the City of Nashwauk contract, no termination notice may be given prior to April 30, 2019. Under the restated contracts, no termination notices may be given prior to June 30, 2016. A two-year cancellation notice is required for the one private non-affiliated utility in Wisconsin, and on December 31, 2011, this customer submitted a cancellation notice with termination effective on December 31, 2013. We are currently in negotiations to extend the contract with this customer.

2010 Wisconsin Rate Increase. SWL&P’s 2011 retail rates are based on a 2010 PSCW retail rate order, effective January 1, 2011,

that allows for a 10.9 percent return on common equity. The new rates reflect a 2.4 percent average increase in retail utility rates for SWL&P customers (a 12.8 percent increase in water rates, a 2.5 percent increase in natural gas rates and a 0.7 percent increase in electric rates). On an annualized basis, the rate increase will generate approximately $2.0 million in additional revenue.

ALLETE Clean Energy. On August 26, 2011, the Company filed with the MPUC for approval of certain affiliated interest agreements between ALLETE and ALLETE Clean Energy. These agreements relate to various relationships with ALLETE, including the accounting for certain shared services, as well as the transfer of transmission and wind development rights in North Dakota to ALLETE Clean Energy. These transmission and wind development rights are separate and distinct from those needed by Minnesota Power to meet Minnesota’s renewable energy standard requirements.

The Patient Protection and Affordable Care Act of 2010 (PPACA). In March 2010, PPACA was signed into law. One of the provisions changed the tax treatment for retiree prescription drug expenses by eliminating the tax deduction for expenses that are reimbursed under Medicare Part D, beginning January 1, 2013. Based on this provision, we are subject to additional taxes in the future and were required to reverse previously recorded tax benefits in 2010. Consequently, the reversal of previously recorded tax benefits resulted in a non-recurring charge to net income of $4.0 million in 2010. In October 2010, we submitted a filing with the MPUC requesting deferral of the retail portion of the tax charge taken in 2010 resulting from PPACA. On May 24, 2011, the MPUC approved our request for deferral until the next rate case and as a result we recorded an income tax benefit of $2.9 million and a related regulatory asset of $5.0 million. (See Note 14. Income Tax Expense.)

Pension. On December 22, 2011, the Company filed a petition with the MPUC requesting a mechanism to recover the cost of capital associated with the prepaid pension asset (or liability) created by the required contributions under the pension plan in excess of (or less than) annual pension expense. The Company further requested a mechanism to defer pension expenses in excess of (or less than) those currently being recovered in base rates. If our petition is successful the impact would be deferred in a regulatory asset (or liability) for recovery (or refund) in the Company’s next general rate case.

Regulatory Assets and Liabilities. Our regulated utility operations are subject to the accounting standards on Regulated Operations. We capitalize, as regulatory assets, incurred costs which are probable of recovery in future utility rates. Regulatory liabilities represent amounts expected to be refunded or credited to customers in rates. No regulatory assets or liabilities are currently earning a return.


Note 5.	Regulatory Matters (Continued)



Regulatory Assets and Liabilities
As of December 31	2011		2010
Millions
Current Regulatory Assets (a)
Deferred Fuel		$17.5		$20.6
Total Current Regulatory Assets	17.5		20.6
Non-Current Regulatory Assets
Future Benefit Obligations Under
Defined Benefit Pension and Other Postretirement Plans	292.8		257.9
Boswell Unit 3 Environmental Rider	—		20.5
Income Taxes	28.6		17.3
Asset Retirement Obligation	9.8		7.8
PPACA Income Tax Deferral	5.0		—
Conservation Improvement Program	4.6		0.7
Other	5.1		6.0
Total Non-Current Regulatory Assets	345.9		310.2

Total Regulatory Assets		$363.4		$330.8

Non-Current Regulatory Liabilities
Income Taxes		$21.9		$23.4
Plant Removal Obligations	15.0		16.9
Other	6.6		3.3
Total Non-Current Regulatory Liabilities		$43.5		$43.6


(a)	Current regulatory assets are included in prepayments and other on the consolidated balance sheet.

Investment in ATC

12 Months Ended

Dec. 31, 2011

Investment in ATC [Abstract]

Investment in ATC [Text Block]

Investment in ATC

Investment in ATC. Our wholly-owned subsidiary, Rainy River Energy, owns approximately 8 percent of ATC, a Wisconsin-based utility that owns and maintains electric transmission assets in parts of Wisconsin, Michigan, Minnesota, and Illinois. ATC rates are FERC approved and are based on a 12.2 percent return on common equity dedicated to utility plant. We account for our investment in ATC under the equity method of accounting. As of December 31, 2011, our equity investment in ATC was $98.9 million ($93.3 million at December 31, 2010). On January 30, 2012, we invested an additional $0.8 million in ATC. In total, we expect to invest approximately $3 million throughout 2012.



ALLETE’s Interest in ATC
Year Ended December 31	2011			2010
Millions
Equity Investment Beginning Balance		$93.3			$88.4
Cash Investments	2.0			1.6
Equity in ATC Earnings	18.4			17.9
Distributed ATC Earnings	(14.8		)	(14.6		)
Equity Investment Ending Balance		$98.9			$93.3


Note 6.	Investment in ATC (Continued)



ATC Summarized Financial Data
Balance Sheet Data
As of December 31	2011		2010
Millions
Current Assets		$58.7		$59.9
Non-Current Assets	3,053.7		2,888.4
Total Assets		$3,112.4		$2,948.3
Current Liabilities		$298.5		$428.4
Long-Term Debt	1,400.0		1,175.0
Other Non-Current Liabilities	82.6		84.9
Members’ Equity	1,331.3		1,260.0
Total Liabilities and Members’ Equity		$3,112.4		$2,948.3



Income Statement Data
Year Ended December 31	2011		2010		2009
Millions
Revenue		$567.2		$556.7		$521.5
Operating Expense	261.6		251.1		230.3
Other Expense	81.7		85.9		77.8
Net Income		$223.9		$219.7		$213.4
ALLETE’s Equity in Net Income		$18.4		$17.9		$17.5

- Definition

The entire disclosure for equity investment, or group of investments, for which combined disclosure is appropriate, including: (a) the name of each investee and percentage of ownership of common stock, (b) accounting policies for investments in common stock, (c) difference between the amount at which the investment is carried and the amount of underlying equity in net assets and the accounting treatment of the difference, (d) the total fair value of each identified investment for which a market value is available, (e) summarized information as to assets, liabilities, and results of operations of the investees (for investments in unconsolidated subsidiaries, common stock of joint ventures, or other investments using the equity method), and (f) material effects of possible conversions, exercises, or contingent issuances of the investee. Other disclosures include (a) the names of any investee in which the investor owns 20 percent or more of the voting stock and investment is not accounted for using the equity method, and the reasons why not, and (b) the names of any investee in which the investor owns less than 20 percent of the voting stock and the investment is accounted for using the equity method, and the reasons why it is.

+ References + Details

Investments

12 Months Ended

Dec. 31, 2011

Investments [Abstract]

Investments [Text Block]

Investments

Investments. At December 31, 2011, our long-term investment portfolio included the real estate assets of ALLETE Properties, debt and equity securities consisting primarily of securities held to fund employee benefits and land available-for-sale in Minnesota.



Investments
As of December 31	2011		2010
Millions
ALLETE Properties		$91.3		$94.0
Available-for-sale Securities	24.7		25.2
Other	16.3		6.8
Total Investments		$132.3		$126.0


Note 7.	Investments (Continued)



ALLETE Properties
As of December 31	2011			2010
Millions
Land Inventory Beginning Balance		$86.0			$74.9
Deeds to Collateralized Property (a)	1.8			9.9
Land Impairment (b)	(1.7		)	—
Cost of Real Estate Sold	(0.3		)	—
Capitalized Improvements and Other	0.2			1.2
Land Inventory Ending Balance	86.0			86.0
Long-Term Finance Receivables (net of allowances of $0.6 and $0.8) (a)	2.0			3.7
Other	3.3			4.3
Total Real Estate Assets		$91.3			$94.0


(a)	In 2010, the deeds to collateralized property resulted primarily from an entity which filed for Chapter 11 bankruptcy and were recorded at fair value net of estimated selling costs.


(b)	The land impairment charge was a result of an impairment analysis conducted in the fourth quarter of 2011 where the cost basis was reduced to the estimated fair value.

Land Inventory. Land inventory is accounted for as held for use and is recorded at cost, unless the carrying value is determined not to be recoverable in accordance with the accounting standards for property, plant and equipment, in which case the land inventory is written down to fair value. Land values are reviewed for impairment on a quarterly basis. In the fourth quarter of 2011, an impairment analysis of estimated future undiscounted cash flows was conducted and indicated that the cash flows were not adequate to recover the carrying basis of certain properties not strategic to our three major development projects. Consequently, we reduced the cost basis to estimated fair value resulting in a pretax impairment charge of $1.7 million. Fair value was determined based on property tax assessed values, discounted cash flow analysis, or a combination thereof. No impairments were recorded for the year ended December 31, 2010.

Long-Term Finance Receivables. As of December 31, 2011, long-term finance receivables were $2.0 million net of allowance ($3.7 million net of allowance as of December 31, 2010). The decrease is primarily the result of the transfer of properties back to ALLETE Properties by deed-in-lieu of foreclosure, in satisfaction of amounts previously owed under long-term financing receivables. Long-term finance receivables are collateralized by property sold, accrue interest at market-based rates and are net of an allowance for doubtful accounts. As of December 31, 2011, we had allowance for doubtful accounts of $0.6 million ($0.8 million as of December 31, 2010). The decrease in allowance for doubtful accounts is primarily due to recovery of real estate taxes and accrued interest on previously delinquent notes receivable.

If a purchaser defaults on a sales contract, the legal remedy is usually limited to terminating the contract and retaining the purchaser’s deposit. The property is then available for resale. In many cases, contract purchasers incur significant costs during due diligence, planning, designing and marketing the property before the contract closes, therefore they have substantially more at risk than the deposit.

Available-for-Sale Investments. We account for our available-for-sale portfolio in accordance with the guidance for certain investments in debt and equity securities. Our available-for-sale securities portfolio consisted of securities established to fund certain employee benefits and auction rate securities.



Available-For-Sale Securities
Millions			Gross Unrealized
As of December 31	Cost		Gain		(Loss)	Fair Value
2011		$27.3		$0.1	$(2.7)		$24.7
2010		$27.4		$0.2	$(2.4)		$25.2
2009		$33.1		$0.1	$(3.7)		$29.5


Note 7.	Investments (Continued)



	Net		Gross Realized		Net Unrealized Gain (Loss) in Other
Year Ended December 31	Proceeds		Gain	(Loss)	Comprehensive Income
2011		$5.5	—	—	$(0.4)
2010	$(1.7)		—	—		$1.4
2009		$6.7	—	—		$4.5

Auction Rate Securities. As of December 31, 2010, our ARS were classified as a short-term investment as the remaining balance of $6.7 million was redeemed at carrying value on January 5, 2011.

- Definition

Tabular disclosure of investments in certain debt and equity securities (and certain other trading assets) which include all debt and equity securities (other than those equity securities accounted for under the equity or cost methods of accounting) with readily determinable fair values. Other trading assets include assets that are carried on the balance sheet at fair value and held for trading purposes. A debt security represents a creditor relationship with an enterprise that is in the form of a security. Debt securities include, among other items, US Treasury securities, US government securities, municipal securities, corporate bonds, convertible debt, commercial paper, and all securitized debt instruments. An equity security represents an ownership interest in an enterprise or the right to acquire or dispose of an ownership interest in an enterprise at fixed or determinable prices. Equity securities include, among other things, common stock, certain preferred stock, warrant rights, call options, and put options, but do not include convertible debt. An entity may opt to provide the reader with additional narrative text to better understand the nature of investments in debt and equity securities (and other trading assets).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 115
-Paragraph 3, 19, 20, 21, 22, 137
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 30
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6379141&loc=d3e15032-111544

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-Name Accounting Standards Codification
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-SubTopic 10
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-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6872113&loc=d3e27161-111563

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-Name Accounting Standards Codification
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-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6957658&loc=d3e62557-112803

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Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Debt Security
-URI http://asc.fasb.org/extlink&oid=6509901
-Topic 320

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Equity Security
-URI http://asc.fasb.org/extlink&oid=6511694
-Topic 320

+ Details

Derivatives	12 Months Ended
Derivatives	Dec. 31, 2011
Derivatives [Abstract]
Derivatives [Text Block]	Derivatives During the third quarter of 2011, we entered into a variable-to-fixed interest rate swap (Swap), designated as a cash flow hedge, in order to manage the interest rate risk associated with a $75.0 million Term Loan. The Term Loan has a variable interest rate equal to the one-month LIBOR plus 1.00 percent, has a maturity of August 25, 2014, and represents approximately 9 percent of the Company’s outstanding long-term debt as of December 31, 2011. (See Note 10. Short-Term and Long-Term Debt.) The Swap agreement has a notional amount equal to the underlying debt principal and matures on August 25, 2014. The Swap agreement involves the receipt of variable rate amounts in exchange for fixed rate interest payments over the life of the agreement without an exchange of the underlying notional amount. The variable rate of the Swap is equal to the one-month LIBOR and the fixed rate is equal to 0.825 percent. Cash flows from the interest rate swap are expected to be highly effective in offsetting the variable interest expense of the debt attributable to fluctuations in the LIBOR benchmark interest rate over the life of the Swap. If it is determined that a derivative is not or has ceased to be effective as a hedge, the Company prospectively discontinues hedge accounting. The shortcut method is used to assess hedge effectiveness. At inception, all shortcut method requirements were satisfied; thus changes in value of the Swap designated as the hedging instrument will be deemed 100 percent effective. As a result, there was no ineffectiveness recorded for the year ended December 31, 2011. The mark-to-market fluctuation on the cash flow hedge was recorded in accumulated other comprehensive income on the consolidated balance sheet. As of December 31, 2011, a $0.4 million decrease in fair value was recorded and is included in other non-current liabilities on the consolidated balance sheet. Cash flows from derivative activities are presented in the same category as the item being hedged on the consolidated statement of cash flows. Amounts recorded in other comprehensive income related to cash flow hedges will be recognized in earnings when the hedged transactions occur or when it is probable that the hedged transactions will not occur. Gains or losses on interest rate hedging transactions are reflected as a component of interest expense on the consolidated statement of income.

- Definition

The entire disclosure for the entity's entire derivative instruments and hedging activities. Describes an entity's risk management strategies, derivatives in hedging activities and non-hedging derivative instruments, the assets, obligations, liabilities, revenues and expenses arising therefrom, and the amounts of and methodologies and assumptions used in determining the amounts of such items.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 133
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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
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+ Details

Fair Value

12 Months Ended

Dec. 31, 2011

Fair Value Disclosures [Abstract]

Fair Value [Text Block]

Fair Value

Fair value is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (exit price). We utilize market data or assumptions that market participants would use in pricing the asset or liability, including assumptions about risk and the risks inherent in the inputs to the valuation technique. These inputs can be readily observable, market corroborated, or generally unobservable. We primarily apply the market approach for recurring fair value measurements and endeavor to utilize the best available information. Accordingly, we utilize valuation techniques that maximize the use of observable inputs and minimize the use of unobservable inputs. These inputs, which are used to measure fair value, are prioritized through the fair value hierarchy. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 measurement) and the lowest priority to unobservable inputs (Level 3 measurement). The three levels of the fair value hierarchy are as follows:

Level 1 — Quoted prices are available in active markets for identical assets or liabilities as of the reported date. Active markets are those in which transactions for the asset or liability occur in sufficient frequency and volume to provide pricing information on an ongoing basis. This category includes primarily mutual fund investments held to fund employee benefits.

Level 2 — Pricing inputs are other than quoted prices in active markets, but are either directly or indirectly observable as of the reported date. The types of assets and liabilities included in Level 2 are typically either comparable to actively traded securities or contracts, such as treasury securities with pricing interpolated from recent trades of similar securities, or priced with models using highly observable inputs, such as commodity options priced using observable forward prices and volatilities. This category includes deferred compensation, fixed income securities, and derivative instruments consisting of cash flow hedges.

Level 3 — Significant inputs that are generally less observable from objective sources. The types of assets and liabilities included in Level 3 are those with inputs requiring significant management judgment or estimation, such as the complex and subjective models and forecasts used to determine the fair value. This category included ARS consisting of guaranteed student loans and derivative instruments consisting of financial transmission rights.

The following tables set forth by level within the fair value hierarchy, our assets and liabilities that were accounted for at fair value on a recurring basis as of December 31, 2011 and December 31, 2010. Each asset and liability is classified based on the lowest level of input that is significant to the fair value measurement. Our assessment of the significance of a particular input to the fair value measurement requires judgment, which may affect the valuation of fair value assets and liabilities and their placement within the fair value hierarchy levels.



	At Fair Value as of December 31, 2011
Recurring Fair Value Measures	Level 1		Level 2		Level 3	Total
Millions
Assets:
Equity Securities		$17.6	—		—		$17.6
Available-for-sale Securities – Corporate Debt Securities	—			$8.2	—	8.2
Money Market Funds	11.4		—		—	11.4
Total Fair Value of Assets		$29.0		$8.2	—		$37.2

Liabilities:
Deferred Compensation	—			$12.8	—		$12.8
Derivatives - Interest Rate Swap	—		0.4		—	0.4
Total Fair Value of Liabilities	—			$13.2	—		$13.2
Total Net Fair Value of Assets (Liabilities)		$29.0	$(5.0)		—		$24.0



Recurring Fair Value Measures Activity in Level 3	Debt Securities Issued by States of the United States (ARS)
Millions
Balance as of December 31, 2010		$6.7
Settled During the Period	—
Redeemed During the Period (a)	(6.7		)
Balance as of December 31, 2011	—


(a)	The ARS were redeemed at carrying value on January 5, 2011.



	At Fair Value as of December 31, 2010
Recurring Fair Value Measures	Level 1		Level 2		Level 3		Total
Millions
Assets:
Equity Securities		$19.4	—		—			$19.4
Available-for-sale Securities
Corporate Debt Securities	—			$7.5	—		7.5
Debt Securities Issued by States of the United States (ARS)	—		—			$6.7	6.7
Total Available-for-sale Securities	—		7.5		6.7		14.2
Money Market Funds	0.8		—		—		0.8
Total Fair Value of Assets		$20.2		$7.5		$6.7		$34.4

Liabilities:
Deferred Compensation	—			$13.3	—			$13.3
Total Fair Value of Liabilities	—			$13.3	—			$13.3

Total Net Fair Value of Assets (Liabilities)		$20.2	$(5.8)			$6.7		$21.1



Recurring Fair Value Measures Activity in Level 3	Derivatives			Debt Securities Issued by States of the United States (ARS)
Millions
Balance as of December 31, 2009		$0.7			$6.7
Settled During the Period (a)	(0.7		)	—
Redeemed During the Period	—			—
Balance as of December 31, 2010	—				$6.7


(a)	During the second quarter of 2010, the $0.7 million of financial transmission rights derivatives were settled.

The Company’s policy is to recognize transfers in and transfers out as of the actual date of the event or change in circumstances that caused the transfer. For the year ended December 31, 2011 and 2010, there were no transfers in or out of Levels 1, 2 or 3.

Fair Value of Financial Instruments. With the exception of the items listed below, the estimated fair value of all financial instruments approximates the carrying amount. The fair value for the items below were based on quoted market prices for the same or similar instruments.



Financial Instruments	Carrying Amount		Fair Value
Millions
Long-Term Debt, Including Current Portion
December 31, 2011		$863.3		$966.4
December 31, 2010		$785.0		$796.7

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 133
-Paragraph 44A, 44B
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 107
-Paragraph 15C, 15D
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
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-Name Statement of Financial Accounting Standard (FAS)
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+ Details

Short-term and Long-term Debt

12 Months Ended

Dec. 31, 2011

Debt Disclosure [Abstract]

Short-Term and Long-Term Debt [Text Block]

Short-Term and Long-Term Debt

Short-Term Debt. Total short-term debt outstanding as of December 31, 2011, was $6.5 million ($14.4 million at December 31, 2010) and consisted of long-term debt due within one year and notes payable.

As of December 31, 2011, we had bank lines of credit aggregating $256.4 million ($154.0 million at December 31, 2010), $250.0 million of which expires in June 2015. These bank lines of credit are available to provide short-term bank loans and liquidity support for ALLETE's commercial paper program. At December 31, 2011, $1.1 million ($1.0 million at December 31, 2010) was drawn on our lines of credit leaving a $255.3 million balance available for use ($153.0 million at December 31, 2010).

On February 1, 2012, ALLETE entered into a $150.0 million credit agreement (Agreement) with JPMorgan Chase Bank, N.A., as administrative agent, and several other lenders that are parties thereto. The Agreement is unsecured and has a maturity date of January 31, 2014, which may be extended for one year, subject to bank approvals. Advances from the Agreement may be used for general corporate purposes, to provide liquidity support for ALLETE’s commercial paper program and to issue up to $10.0 million in letters of credit.

On May 25, 2011, ALLETE entered into a $250.0 million credit agreement (Agreement) with JPMorgan Chase Bank, N.A., as administrative agent, and several other lenders that are parties thereto. The Agreement was effective July 1, 2011, and replaced our previous $150.0 million credit facility. The Agreement is unsecured and has a maturity date of June 30, 2015, which may be extended for one year. Such extension is subject to bank approvals. Advances from the Agreement may be used for general corporate purposes, to provide liquidity support for ALLETE’s commercial paper program and to issue up to $40.0 million in letters of credit.

Long-Term Debt. The aggregate amount of long-term debt maturing during 2012 is $5.4 million ($83.8 million in 2013; $94.1 million in 2014; $16.7 million in 2015; $21.0 million in 2016; and $642.3 million thereafter). Substantially all of our electric plant is subject to the lien of the mortgage collateralizing outstanding first mortgage bonds. The mortgages contain non-financial covenants customary in utility mortgages, including restrictions on our ability to incur liens, dispose of assets, and merge with other entities.

On August 25, 2011, ALLETE entered into a $75.0 million term loan agreement with JPMorgan Chase Bank, N.A., as administrative agent and a lender, and Bank of America, N.A., as a lender (Term Loan). The Term Loan is an unsecured, single-draw loan that is due on August 25, 2014. The interest rate on the Term Loan is equal to the one-month LIBOR plus 1 percent; however, we also entered into an interest rate swap agreement which effectively fixed the interest rate at 1.825 percent over the term of the loan. (See Note 8. Derivatives.) Proceeds from the Term Loan were used for general corporate purposes. As of December 31, 2011, there was $75.0 million outstanding on the Term Loan.

On November 14, 2011, ALLETE Properties renewed an $8.3 million line of credit with RBC Bank extending the maturity of the line of credit to November 2013. The previous line of credit was $10.0 million which ALLETE Properties reduced by $1.7 million million at the time of renewal.

On October 7, 2011, ALLETE Properties renewed a $3.0 million line of credit with Intracoastal Bank, extending maturity of the

line to October 2013, with all other terms remaining unchanged.

Note 10. Short-Term and Long-Term Debt (Continued)



Long-Term Debt
As of December 31	2011		2010
Millions
First Mortgage Bonds
4.86% Series Due 2013		$60.0		$60.0
6.94% Series Due 2014	18.0		18.0
7.70% Series Due 2016	20.0		20.0
8.17% Series Due 2019	42.0		42.0
5.28% Series Due 2020	35.0		35.0
4.85% Series Due 2021	15.0		15.0
4.95% Pollution Control Series F Due 2022	111.0		111.0
6.02% Series Due 2023	75.0		75.0
4.90% Series Due 2025	30.0		30.0
5.10% Series Due 2025	30.0		30.0
5.99% Series Due 2027	60.0		60.0
5.69% Series Due 2036	50.0		50.0
6.00% Series Due 2040	35.0		35.0
5.82% Series Due 2040	45.0		45.0
SWLP& First Mortgage Bonds 7.25% Series Due 2013	10.0		10.0
Senior Unsecured Notes 5.99% Due 2017	50.0		50.0
Variable Demand Revenue Refunding Bonds Series 1997 A, B, and C Due 2013 – 2020	28.2		28.3
Industrial Development Revenue Bonds 6.5% Due 2025	6.0		6.0
Industrial Development Variable Rate Demand Refunding Revenue Bonds Series 2006 Due 2025	27.8		27.8
Unsecured Term Loan Variable Rate Due 2014	75.0		—
Other Long-Term Debt, 1.0% – 8.0% Due 2012 – 2037	40.3		36.9
Total Long-Term Debt	863.3		785.0
Less: Due Within One Year	5.4		13.4
Net Long-Term Debt		$857.9		$771.6

Financial Covenants. Our long-term debt arrangements contain customary covenants. In addition, our lines of credit and letters of credit supporting certain long-term debt arrangements contain financial covenants. Our compliance with financial covenants is not dependent on debt ratings. The most restrictive covenant requires ALLETE to maintain a ratio of its Indebtedness to Total Capitalization (as the amounts are calculated in accordance with the respective long-term debt arrangements) of less than or equal to 0.65 to 1.00 measured quarterly. As of December 31, 2011, our ratio was approximately 0.44 to 1.00. Failure to meet this covenant would give rise to an event of default if not cured after notice from the lender, in which event ALLETE may need to pursue alternative sources of funding. Some of ALLETE’s debt arrangements contain “cross-default” provisions that would result in an event of default if there is a failure under other financing arrangements to meet payment terms or to observe other covenants that would result in an acceleration of payments due. As of December 31, 2011, ALLETE was in compliance with its financial covenants.

- Definition

The entire disclosure for information about short-term and long-term debt arrangements, which includes amounts of borrowings under each line of credit, note payable, commercial paper issue, bonds indenture, debenture issue, own-share lending arrangements and any other contractual agreement to repay funds, and about the underlying arrangements, rationale for a classification as long-term, including repayment terms, interest rates, collateral provided, restrictions on use of assets and activities, whether or not in compliance with debt covenants, and other matters important to users of the financial statements, such as the effects of refinancing and noncompliance with debt covenants.

+ References + Details

Commitments, Guarantees and Contingencies

12 Months Ended

Dec. 31, 2011

Commitments, Guarantees and Contingencies [Abstract]

Commitments, Guarantees and Contingencies

Power Purchase Agreements. Our long-term PPAs have been evaluated under the accounting guidance for variable interest entities. We have determined that either we have no variable interest in the PPA, or where we do have variable interests, we are not the primary beneficiary; therefore, consolidation is not required. These conclusions are based on the fact that we do not have both control over activities that are most significant to the entity and an obligation to absorb losses or receive benefits from the entity’s performance. Our financial exposure relating to these PPAs is limited to our fixed capacity and energy payments.


Note 11.	Commitments, Guarantees and Contingencies (Continued)

Power Purchase Agreements (Continued)

Square Butte PPA. Minnesota Power has a PPA with Square Butte that extends through 2026 (Agreement). It provides a long-term supply of energy to customers in our electric service territory and enables Minnesota Power to meet reserve requirements. Square Butte, a North Dakota cooperative corporation, owns a 455 MW coal-fired generating unit (Unit) near Center, North Dakota. The Unit is adjacent to a generating unit owned by Minnkota Power, a North Dakota cooperative corporation whose Class A members are also members of Square Butte. Minnkota Power serves as the operator of the Unit and also purchases power from Square Butte.

Minnesota Power is obligated to pay its pro rata share of Square Butte’s costs based on Minnesota Power’s entitlement to Unit output. Our output entitlement under the Agreement is 50 percent for the remainder of the contract, subject to the provisions of the Minnkota power sales agreement described below. Minnesota Power’s payment obligation will be suspended if Square Butte fails to deliver any power, whether produced or purchased, for a period of one year. Square Butte’s costs consist primarily of debt service, operating and maintenance, depreciation and fuel expenses. As of December 31, 2011, Square Butte had total debt outstanding of $451.4 million. Annual debt service for Square Butte is expected to be approximately $44 million in each of the five years, 2012 through 2016, of which Minnesota Power's obligation is 50 percent. Fuel expenses are recoverable through our fuel adjustment clause and include the cost of coal purchased from BNI Coal, our subsidiary, under a long-term contract.

Minnesota Power’s cost of power purchased from Square Butte during 2011 was $61.2 million ($55.2 million in 2010; $53.9 million in 2009). This reflects Minnesota Power’s pro rata share of total Square Butte costs based on the 50 percent output entitlement. Included in this amount was Minnesota Power’s pro rata share of interest expense of $11.1 million in 2011 ($10.2 million in 2010; $11.0 million in 2009). Minnesota Power’s payments to Square Butte are approved as a purchased power expense for ratemaking purposes by both the MPUC and the FERC.

Minnkota Power Sales Agreement. In conjunction with the purchase of the existing 250 kV DC transmission line from Square Butte in December 2009, Minnesota Power entered into a power sales agreement with Minnkota Power. Under the power sales agreement, Minnesota Power will sell a portion of its output from Square Butte to Minnkota Power, resulting in Minnkota Power’s net entitlement increasing and Minnesota Power’s net entitlement decreasing until Minnesota Power’s share is eliminated at the end of 2025.

No power will be sold under this agreement until Minnkota Power has placed in service a new AC transmission line, which is anticipated to occur in 2013. This new AC transmission line will allow Minnkota Power to transmit its entitlement from Square Butte directly to its customers, which, in turn, will allow Minnesota Power the ability to transmit additional wind generation on the DC transmission line.

Wind PPAs. In 2006 and 2007, Minnesota Power entered into two long-term wind PPAs with an affiliate of NextEra Energy, Inc. to purchase the output from Oliver Wind I (50 MW) and Oliver Wind II (48 MW), wind facilities located near Center, North Dakota. Each agreement is for 25 years and provides for the purchase of all output from the facilities at fixed prices. There are no fixed capacity charges, and we only pay for energy as it is delivered to us.

Hydro PPAs. Minnesota Power has a PPA with Manitoba Hydro that expires in April 2015. Under this agreement, Minnesota Power is purchasing 50 MW of capacity and the energy associated with that capacity. Both the capacity price and the energy price are adjusted annually by the change in a governmental inflationary index.

Minnesota Power has a separate PPA with Manitoba Hydro to purchase surplus energy from May 2011 through April 2022. This energy-only transaction primarily consists of surplus hydro energy on Manitoba Hydro’s system that is delivered to Minnesota Power on a non-firm basis. The pricing is based on forward market prices. Under this agreement, Minnesota Power will purchase at least one million MWh of energy over the contract term. On March 31, 2011, the MPUC approved this PPA with Manitoba Hydro.

On May 19, 2011, Minnesota Power and Manitoba Hydro signed a long-term PPA. The PPA calls for Manitoba Hydro to sell 250 MW of capacity and energy to Minnesota Power for 15 years beginning in 2020 and requires construction of additional transmission capacity between Manitoba and the U.S. The capacity price is adjusted annually until 2020 by a change in a governmental inflationary index. The energy price is based on a formula that includes an annual fixed price component adjusted for a change in a governmental inflationary index and a natural gas index, as well as market prices. On January 26, 2012, the MPUC approved this PPA with Manitoba Hydro.

North Dakota Wind Development. Minnesota Power uses the 465-mile, 250 kV DC transmission line that runs from Center, North Dakota, to Duluth, Minnesota to transport increasing amounts of wind energy from North Dakota while gradually phasing out coal-based electricity delivered to our system over this transmission line from Square Butte’s lignite coal-fired generating unit.

Bison 1 is an 82 MW wind project in North Dakota. All permitting has been received, the first phase was completed in 2010, and the second phase was completed in January 2012. Phase one included construction of a 22-mile, 230 kV transmission line and the installation of sixteen 2.3 MW wind turbines. Phase two consisted of the installation of fifteen 3.0 MW wind turbines. Bison 1 is expected to have a total project cost of $177 million, of which $171.5 million was spent through December 31, 2011. In 2009, the MPUC approved Minnesota Power’s petition seeking current cost recovery for investments and expenditures related to Bison 1, and in July 2010, the MPUC approved our petition establishing rates effective August 1, 2010. On November 3, 2011, the MPUC issued an order approving our petition to update the rates for additional investments and expenditures related to Bison 1.

Bison 2 and Bison 3 are both 105 MW wind projects in North Dakota which are expected to be completed by the end of 2012. Site preparation is currently underway for both projects and the total project costs for Bison 2 and Bison 3 are estimated to be approximately $160 million each, of which $37.0 million and $14.7 million, respectively, was spent through December 31, 2011. On September 8, 2011, and November 2, 2011, the MPUC approved Minnesota Power's petition seeking current cost recovery for investments and expenditures related to Bison 2 and Bison 3, respectively. On August 10, 2011, and October 12, 2011, the NDPSC issued a Certificate of Site Compatibility for Bison 2 and Bison 3, respectively, which authorized site construction to commence. We anticipate filing petitions with the MPUC in the first half of 2012 to establish customer billing rates for the approved cost recovery.

Leasing Agreements. BNI Coal is obligated to make lease payments for a dragline totaling $2.8 million annually for the lease term which expires in 2027. BNI Coal has the option at the end of the lease term to renew the lease at fair market value, to purchase the dragline at fair market value, or to surrender the dragline and pay a $3 million termination fee. We lease other properties and equipment under operating lease agreements with terms expiring through 2016. The aggregate amount of minimum lease payments for all operating leases is $10.9 million in 2012, $11.1 million in 2013, $11.4 million in 2014, $11.2 million in 2015, $9.2 million in 2016 and $43.0 million thereafter. Total rent and lease expense was $9.4 million in 2011 ($9.4 million in 2010; $9.3 million in 2009).

Coal, Rail and Shipping Contracts. We have coal supply agreements providing for the purchase of a significant portion of our coal requirements which expire in 2012 and 2013. We also have coal transportation agreements in place for the delivery of a significant portion of our coal requirements with expiration dates through 2015. Our minimum annual payment obligation under these supply and transportation agreements for 2012 is $55.4 million, and 2013 is $27.0 million. Our minimum annual payment obligations will increase when annual nominations are made for coal deliveries in future years. The delivered costs of fuel for Minnesota Power’s generation are recoverable from Minnesota Power’s utility customers through the fuel adjustment clause.

Transmission. We are making investments in Upper Midwest transmission opportunities that strengthen or enhance the regional transmission grid. This includes the CapX2020 initiative, investments in our own transmission assets, investments in other regional transmission assets (by ourselves or in combination with others), and our investment in ATC.

Transmission Investments. We have an approved cost recovery rider in place for certain transmission expenditures and the continued use of our 2009 billing factor was approved by the MPUC in May 2011. The billing factor allows us to charge our retail customers on a current basis for the costs of constructing certain transmission facilities plus a return on the capital invested. On June 29, 2011, we filed an updated billing factor that includes additional transmission projects and expenses, which we expect to be approved in 2012.

CapX2020. Minnesota Power is a participant in the CapX2020 initiative which represents an effort to ensure electric transmission and distribution reliability in Minnesota and the surrounding region for the future. CapX2020, which consists of electric cooperatives, municipals and investor-owned utilities, including Minnesota’s largest transmission owners, has assessed the transmission system and projected growth in customer demand for electricity through 2020. Studies show that the region's transmission system will require major upgrades and expansion to accommodate increased electricity demand as well as support renewable energy expansion through 2020.

Note 11. Commitments, Guarantees and Contingencies (Continued)

Transmission (Continued)

Minnesota Power is currently participating in three CapX2020 projects: the Fargo, North Dakota to St. Cloud, Minnesota project, the Monticello, Minnesota to St. Cloud, Minnesota project, which together total a 238-mile, 345 kV line from Fargo, North Dakota to Monticello, Minnesota, and the 70-mile, 230 kV line between Bemidji, Minnesota and Minnesota Power’s Boswell Energy Center near Grand Rapids, Minnesota. Based on projected costs of the three transmission lines and the percentage agreements among participating utilities, Minnesota Power plans to invest between $100 million and $125 million in the CapX2020 initiative through 2015, of which $27.8 million was spent through December 31, 2011. As future CapX2020 projects are identified, Minnesota Power may elect to participate on a project-by-project basis.

In July 2010, the MPUC granted a route permit for the 28-mile 345 kV line between Monticello and St. Cloud. The project was completed and placed into service in December 2011. On June 10, 2011, the MPUC approved the route permit for the Minnesota portion of the Fargo to St. Cloud project. The North Dakota permitting process is underway. The entire 238-mile, 345 kV line from St. Cloud to Fargo is expected to be in service by 2015.

In November 2010, the MPUC approved a route permit for the Bemidji to Grand Rapids, Minnesota line and construction for the 230 kV line project commenced in January 2011. The Leech Lake Band of Ojibwe (LLBO) subsequently requested the MPUC suspend or revoke the route permit and also served the CapX2020 owners with a complaint filed in Leech Lake Tribal Court asserting adjudicatory and regulatory authority over the project. The CapX2020 owners filed a request for declaratory judgment in the United States District Court for the District of Minnesota (District Court) that the project does not require LLBO consent to cross non-tribal land within the reservation. On June 22, 2011, the federal judge issued a preliminary injunction directing the LLBO to cease and desist its claims of tribal court jurisdiction or from taking other actions to interfere with regulatory review, approval or project construction. The LLBO abandoned its motion to dismiss the declaratory action because the District Court’s injunction order had already dismissed the basis for the motion, namely, that the District Court did not have jurisdiction to hear the CapX2020 owners’ action. The parties are now proceeding with discovery and the CapX2020 owners do not anticipate any actions by the District Court until after the completion of discovery closes on May 31, 2012. The MPUC has taken no action in the matter in light of ongoing litigation in federal and tribal courts. The CapX2020 utilities are vigorously defending against the LLBO actions.

Environmental Matters

Our businesses are subject to regulation of environmental matters by various federal, state and local authorities. Currently, a number of regulatory changes to the Clean Air Act, the Clean Water Act and various waste management requirements are under consideration by both Congress and the EPA. Minnesota Power's fossil fuel facilities will likely be subject to regulation under these proposals. Our intention is to reduce our exposure to these requirements by reshaping our generation portfolio over time to reduce our reliance on coal.

We consider our businesses to be in substantial compliance with currently applicable environmental regulations and believe all necessary permits to conduct such operations have been obtained. Due to future restrictive environmental requirements through legislation and/or rulemaking, we anticipate that potential expenditures for environmental matters will be material and will require significant capital investments.

We review environmental matters on a quarterly basis. Accruals for environmental matters are recorded when it is probable that a liability has been incurred and the amount of the liability can be reasonably estimated, based on current law and existing technologies. Accruals are adjusted as assessment and remediation efforts progress or as additional technical or legal information become available. Accruals for environmental liabilities are included in the consolidated balance sheet at undiscounted amounts and exclude claims for recoveries from insurance or other third parties. Costs related to environmental contamination treatment and cleanup are charged to expense unless recoverable in rates from customers.

Air. The electric utility industry is heavily regulated both at the federal and state level to address air emissions. Minnesota Power's generating facilities mainly burn low-sulfur western sub-bituminous coal. Square Butte, located in North Dakota, burns lignite coal. All of Minnesota Power's coal-fired generating facilities are equipped with pollution control equipment such as scrubbers, bag houses and low NO_X technologies. At this time, under currently applicable environmental regulations, these facilities are substantially compliant with applicable emission requirements.

New Source Review (NSR). In August 2008, Minnesota Power received a Notice of Violation (NOV) from the EPA asserting violations of the NSR requirements of the Clean Air Act at Boswell Units 1, 2, 3 and 4 and Laskin Unit 2. The NOV asserts that seven projects undertaken at these coal-fired plants between the years 1981 and 2000 should have been reviewed under the NSR requirements and that the Boswell Unit 4 Title V permit was violated. In April 2011, Minnesota Power received a NOV alleging that two projects undertaken at Rapids Energy Center in 2004 and 2005 should have been reviewed under the NSR requirements and that the Rapids Energy Center's Title V permit was violated. Minnesota Power believes the projects specified in the NOVs were in full compliance with the Clean Air Act, NSR requirements and applicable permits. We are engaged in discussions with the EPA regarding resolution of these matters, but we are unable to predict the outcome of these discussions.

The resolution could result in civil penalties and the installation of control technology, some of which is already planned or completed for other regulatory requirements. Any costs of installing pollution control technology would likely be eligible for recovery in rates over time subject to MPUC and FERC approval in a rate proceeding.

Cross-State Air Pollution Rule (CSAPR). On July 6, 2011, the EPA issued the CSAPR, which went into effect on October 7, 2011. The final rule replaced the EPA's 2005 Clean Air Interstate Rule (CAIR). However, on December 30, 2011, the United States Court of Appeals for the District of Columbia Circuit issued a ruling staying implementation of the CSAPR, pending judicial review, and ordered that the CAIR remain in place while the CSAPR is stayed.

If the CSAPR is reinstated after judicial review, it will require states in the CSAPR region to significantly improve air quality by reducing power plant emissions that contribute to ozone and/or fine particle pollution in other states. These regulations do not directly require the installation of controls. Instead, they require facilities to have sufficient emission allowances to cover their emissions on an annual basis. These allowances would be allocated to facilities annually by the EPA and will also be able to be bought and sold.

The CAIR regulations similarly require certain states to improve air quality by reducing power plant emissions that contribute to ozone and/or fine particle pollution in other states. Minnesota participation in the CAIR was stayed by EPA administrative action while the EPA completed a review of air quality modeling issues in conjunction with the development of a final replacement rule. In its final determination, the EPA listed Minnesota as a CSAPR-affected state based on new 24-hour fine particulate NAAQS analysis. While the CAIR remains in effect, Minnesota participation in the CAIR will continue to be stayed. It is uncertain if the CSAPR-related emission restrictions will become effective for Minnesota utilities.

Since 2006, we have significantly reduced emissions at our Laskin, Taconite Harbor and Boswell generating units. Our analysis, based on our expected generation rates, indicates that these recent emission reductions would satisfy Minnesota Power's SO₂ and NO_X emission compliance obligations with respect to the EPA-allocated CSAPR allowances for 2012. We will continue to evaluate our compliance strategy under CSAPR and if any capital investments or allowance purchases are required, we would likely seek recovery of those costs. We are unable to predict any additional CSAPR compliance costs we might incur at this time if CSAPR is reinstated.

Minnesota Regional Haze. The federal regional haze rule requires states to submit state implementation plans (SIPs) to the EPA to address regional haze visibility impairment in 156 federally-protected parks and wilderness areas. Under the regional haze rule, certain large stationary sources, put in place between 1962 and 1977, with emissions contributing to visibility impairment, are required to install emission controls, known as Best Available Retrofit Technology (BART). We have two steam units, Boswell Unit 3 and Taconite Harbor Unit 3, which are subject to BART requirements.

Pursuant to the regional haze rule, Minnesota was required to develop its SIP by December 2007. As a mechanism for demonstrating progress towards meeting the long-term regional haze goal, in April 2007, the MPCA advanced a draft conceptual SIP which relied on the implementation of CAIR. However, a formal SIP was not filed at that time due to the United States Court of Appeals for the District of Columbia Circuit's remand of CAIR. Subsequently, the MPCA requested that companies with BART-eligible units complete and submit a BART emissions control retrofit study, which was completed for Taconite Harbor Unit 3 in November 2008. The retrofit work completed in 2009 at Boswell Unit 3 meets the BART requirements for that unit. In December 2009, the MPCA approved the Minnesota SIP for submittal to the EPA for its review and approval. The Minnesota SIP incorporates information from the BART emissions control retrofit studies that were completed as requested by the MPCA.

On December 30, 2011, the EPA published in the Federal Register a proposal to revise the regional haze rule. This proposal would approve the trading program in the CSAPR as an alternative to determining BART. If adopted, states in the CSAPR region could substitute participation in CSAPR for source-specific BART requirements for SO₂ and NO_Xemissions from power plants. On January 2, 2012, the MPCA submitted to the EPA a supplemental Minnesota regional haze SIP stating that it wishes to rely on the CSAPR to satisfy BART requirements for SO₂ and NO_x for electric generating units.

On January 25, 2012, the EPA published in the Federal Register a proposal to approve the Minnesota SIP, including the supplemental Minnesota SIP. If the Minnesota SIP, the supplemental Minnesota SIP, and the EPA's regional haze rule revisions are finalized as currently proposed, and the CSAPR rule is reinstated, then Minnesota Power does not foresee a need to make significant additional expenditures at Taconite Harbor Unit 3 to comply with the regional haze rule.

If controls are ultimately required, Minnesota Power will have up to five years from the final promulgation deadline to bring Taconite Harbor Unit 3 into compliance with the regional haze rule requirements. It is uncertain what controls would ultimately be required at Taconite Harbor Unit 3 under this scenario, in connection with the regional haze rule.

Mercury and Air Toxics Standards (MATS) Rule (formerly known as the Electric Generating Unit Maximum Achievable Control Technology (MACT) Rule). Under Section 112 of the Clean Air Act, the EPA is required to set emission standards for hazardous air pollutants (HAPs) for certain source categories. The EPA released a proposed MATS rule on March 16, 2011, addressing such emissions from coal-fired utility units greater than 25 MW. The final rule was issued on December 21, 2011. There are currently 188 listed HAPs which the EPA is required to evaluate for establishment of MACT standards. In the final MATS rule, the EPA established categories of HAPs, including mercury, trace metals other than mercury, acid gases, dioxin/furans, and organics other than dioxin/furans. The EPA also established emission limits for the first three categories of HAPs, and work practice standards for the remaining categories. Affected sources would have to be in compliance with the rule three years after it is published in the Federal Register. States have the authority to grant sources a one-year extension. Compliance at our Boswell Unit 4 to address the final MATS rule is expected to result in capital expenditures between $300 million to $400 million over the next five years. Some additional controls for complying with the rule at our remaining coal-fired generating units may be required, the costs of which cannot be estimated at this time.

EPA National Emission Standards for Hazardous Air Pollutants for Major Sources: Industrial, Commercial and Institutional Boilers and Process Heaters. In March 2011, a final rule was published in the Federal Register for industrial boiler maximum achievable control technology (Industrial Boiler MACT). The rule was stayed by the EPA on May 16, 2011, to allow the EPA time to consider additional comments received. The EPA re-proposed the rule in December 2011. A final rule is expected in April 2012. On January 9, 2012, the United States District Court for the District of Columbia ruled that the EPA stay of the Industrial Boiler MACT was unlawful, effectively reinstating the March 2011 rule and associated compliance deadlines. Major sources are expected to have three years to achieve compliance with the final rule. It is not known yet whether the final rule from the December 2011 proposal, expected in April 2012, will establish new compliance deadlines. This rule may result in additional control measures being required at Rapids Energy Center and Hibbard. Costs for complying with the final rule cannot be estimated at this time.

Minnesota Mercury Emission Reduction Act. Under Minnesota law, a mercury emissions reduction plan for Boswell Unit 4 is required to be submitted by July 1, 2015, with implementation no later than December 31, 2018. The statute also calls for an evaluation of a mercury control alternative which provides for environmental and public health benefits without imposing excessive costs on the utility's customers. Until Minnesota Power files its mercury emission reduction plan for Boswell Unit 4, it must file an annual report updating the MPUC and other stakeholders on the status of emission reduction planning for Boswell Unit 4. The first update was filed with the MPUC on June 30, 2011.

Mercury emission limits have also been included in the recently finalized MATS rule. We anticipate that the emission reduction plan implemented to comply with the MATS rule will satisfy the mercury emission limits under Minnesota law. Costs for the Boswell Unit 4 emission reduction plan are included in the estimated capital expenditures required for compliance with the MATS rule discussed above.

Proposed and Finalized National Ambient Air Quality Standards (NAAQS). The EPA is required to review the NAAQS every five years. If the EPA determines that a state's air quality is not in compliance with a NAAQS, the state is required to adopt plans describing how it will reduce emissions to attain the NAAQS. These state plans often include more stringent air emission limitations on sources of air pollutants than the NAAQS. Four NAAQS have either recently been revised or are currently proposed for revision, as described below.

Ozone NAAQS. The EPA has proposed to more stringently control emissions that result in ground level ozone. In January 2010, the EPA proposed to revise the 2008 eight-hour ozone standard and to adopt a secondary standard for the protection of sensitive vegetation from ozone-related damage. The EPA was scheduled to decide upon the 2008 eight-hour ozone standard in July 2011, but has announced that it is deferring revision of this standard until 2013.

Particulate Matter NAAQS.The EPA finalized the NAAQS Particulate Matter standards in September 2006. Since then, the EPA established a more stringent 24-hour average fine particulate matter (PM_2.5) standard and kept the annual average fine particulate matter standard and the 24-hour coarse particulate matter standard unchanged. The United States Court of Appeals for the District of Columbia Circuit has remanded the PM_2.5 standard to the EPA, requiring consideration of lower annual average standard values. The EPA expects to propose the new PM_2.5 standards in June 2012 with a goal to finalize the rule by June 2013. State attainment status determination will occur after the rule is finalized. It is not known when affected sources would have to take additional control measures if modeling demonstrates non-compliance at their property boundary. The EPA has indicated that ambient air quality monitoring for 2008 through 2010 will be used as a basis for states to characterize their attainment status.

SO₂ and NO₂ NAAQS. During 2010, the EPA finalized new one-hour NAAQS for SO₂ and NO₂. Monitoring data indicates that Minnesota will likely be in compliance with these new standards; however, the one-hour SO₂NAAQS also requires the EPA to evaluate modeling data to determine attainment. The MPCA intends to complete this initial modeling effort by the end of the first quarter of 2012, using facility data from sources that emit more than 100 tons per year of SO₂. Minnesota Power provided such data for all of our steam generating facilities. It is unclear what the outcome of this evaluation will be.

These NAAQS modeling efforts could result in more stringent emission limits on our coal-fired generating facilities, and possibly additional control measures on some of our units. The MPCA has informed affected sources that compliance strategies required as a result of these modeling results must be agreed to with the MPCA by February 2013. One-hour SO₂ NAAQS attainment is required by 2017.

We are unable to predict the compliance costs we might incur; however, the costs could be material. We would seek recovery of any additional costs through cost recovery riders or in a general rate case.

Climate Change. The scientific community generally accepts that emissions of GHGs are linked to global climate change. Climate change creates physical and financial risk. These physical risks could include, but are not limited to: increased or decreased precipitation and water levels in lakes and rivers; increased temperatures; and the intensity and frequency of extreme weather events. These all have the potential to affect the Company's business and operations. Minnesota Power is addressing climate change by taking the following steps that also ensure reliable and environmentally compliant generation resources to meet our customers' requirements:


•	Expand our renewable energy supply;


•	Improve the efficiency of our coal-based generation facilities, as well as other process efficiencies;


•	Provide energy conservation initiatives for our customers and engage in other demand side efforts; and


•	Support research of technologies to reduce carbon emissions from generation facilities and support carbon sequestration efforts.

EPA Regulation of GHG Emissions. In May 2010, the EPA issued the final Prevention of Significant Deterioration (PSD) and Title V Greenhouse Gas Tailoring Rule (Tailoring Rule). The Tailoring Rule establishes permitting thresholds required to address GHG emissions for new facilities, at existing facilities that undergo major modifications and at other facilities characterized as major sources under the Clean Air Act's Title V program.

For our existing facilities, the rule does not require amending our existing Title V Operating Permits to include GHG requirements. Implementation of the requirement to add GHG provisions to permits will be completed at the state level in Minnesota by the MPCA when the Title V permits are renewed. However, installation of new units or modification of existing units resulting in a significant increase in GHG emissions will require obtaining PSD permits and amending our operating permits to demonstrate that Best Available Control Technology (BACT) is being used at the facility to control GHG emissions. The EPA has defined significant emissions increase for existing sources as a GHG increase of 75,000 tons or more per year of total GHG on a CO₂ equivalent basis.

In late 2010, the EPA issued guidance to permitting authorities and affected sources to facilitate incorporation of the Tailoring Rule permitting requirements into the Title V and PSD permitting programs. The guidance stated that the project-specific top-down BACT determination process used for other pollutants will also be used to determine BACT for GHG emissions. Through sector-specific white papers, the EPA also provided examples and technical summaries of GHG emission control technologies and techniques the EPA considers available or likely to be available to sources. It is possible these control technologies could be determined to be BACT on a project-by-project basis. In the near term, one option appears to be energy efficiency maximization.

Legal challenges to the EPA's regulation of GHG emissions, including the Tailoring Rule, have been filed by others and are awaiting judicial determination. Comments to the permitting guidance were also submitted by Minnesota Power and others and may be addressed by the EPA in the form of revised guidance documents.

Water. The Clean Water Act requires NPDES permits be obtained from the EPA (or, when delegated, from individual state pollution control agencies) for any wastewater discharged into navigable waters. We have obtained all necessary NPDES permits, including NPDES storm water permits for applicable facilities, to conduct our operations. We are in substantial compliance with these permits.

Clean Water Act - Aquatic Organisms. On April 20, 2011, the EPA published in the Federal Register proposed regulations under Section 316(b) of the Clean Water Act that set standards applicable to cooling water intake structures for the protection of aquatic organisms. The proposed regulations would require existing large power plants and manufacturing facilities that withdraw greater than 25 percent of water from adjacent water bodies for cooling purposes and have a design intake flow of greater than 2 million gallons per day to limit the number of aquatic organisms that are killed when they are pinned against the facility's intake structure or that are drawn into the facility's cooling system. The Section 316(b) standards would be implemented through NPDES permits issued to the covered facilities. The Section 316(b) proposed rule comment period ended in August 2011. The EPA is obligated to finalize the rule by July 27, 2012. Minnesota Power is in the process of evaluating the potential impacts the proposed rule may have on its facilities. We are unable to predict the compliance cost we might incur; however, the costs could be material. We would seek recovery of any additional costs through cost recovery riders or in a general rate case.

EPA Steam Electric Power Generating Effluent Guidelines. In late 2009, the EPA announced that it will be reviewing and reissuing the federal effluent guidelines for steam electric stations. These are the underlying federal water discharge rules that apply to all steam electric stations. The EPA has indicated that the new rule promulgating these guidelines will be proposed in 2012 and finalized in 2014. As part of the review phase for this new rule, the EPA issued an Information Collection Request (ICR) in June 2010, to most thermal electric generating stations in the country, including all five of Minnesota Power's generating stations. The ICR was completed and submitted to the EPA in September 2010 for Boswell, Laskin, Taconite Harbor, Hibbard, and Rapids Energy Center. The ICR was designed to gather extensive information on the nature and extent of all water discharge and related wastewater handling at power plants. The information gathered through the ICR will form a basis for development of the eventual new rule, which could include more restrictive requirements on wastewater discharge, flue gas desulfurization, and wet ash handling operations. We are unable to predict the costs we might incur to comply with potential future water discharge regulations at this time.

Solid and Hazardous Waste. The Resource Conservation and Recovery Act of 1976 regulates the management and disposal of solid and hazardous wastes. We are required to notify the EPA of hazardous waste activity and, consequently, routinely submit the necessary reports to the EPA.

Coal Ash Management Facilities. Minnesota Power generates coal ash at all five of its coal-fired electric generating facilities. Two facilities store ash in onsite impoundments (ash ponds) with engineered liners and containment dikes. Another facility stores dry ash in a landfill with an engineered liner and leachate collection system. Two facilities generate a combined wood and coal ash that is either land applied as an approved beneficial use or trucked to state permitted landfills. In June 2010, the EPA proposed regulations for coal combustion residuals generated by the electric utility sector. The proposal sought comments on three general regulatory schemes for coal ash. Comments on the proposed rule were due in November 2010. It is estimated that the final rule will be published in late 2012 or early 2013. We are unable to predict the compliance cost we might incur; however, the costs could be material. We would seek recovery of any additional costs through cost recovery riders or in a general rate case.

Manufactured Gas Plant Site. We are reviewing and addressing environmental conditions at a former manufactured gas plant site in the City of Superior, Wisconsin, and formerly operated by SWL&P. We have been working with the WDNR to determine the extent of contamination and the remediation of contaminated locations. As of December 31, 2011, we have a $0.5 million liability for this site and a corresponding regulatory asset as we expect recovery of remediation costs to be allowed by the PSCW.

Other Matters

BNI Coal. As of December 31, 2011, BNI Coal had surety bonds outstanding of $29.8 million related to the reclamation liability for closing costs associated with its mine and mine facilities. Although the coal supply agreements obligate the customers to provide for the closing costs, additional assurance is required by federal and state regulations. In addition to the surety bonds, BNI Coal has secured a letter of credit with CoBANK ACB for an additional $2.6 million to provide for BNI Coal’s total reclamation liability currently estimated at $32.4 million. BNI Coal does not believe it is likely that any of these outstanding surety bonds will be drawn upon.

ALLETE Properties. As of December 31, 2011, ALLETE Properties, through its subsidiaries, had surety bonds outstanding of $10.2 million primarily related to performance and maintenance obligations to governmental entities to construct improvements in the Company's various projects. The remaining work to be completed on these improvements is estimated to be approximately $8.0 million and ALLETE Properties does not believe it is likely that any of these outstanding surety bonds will be drawn upon.

Community Development District Obligations. In March 2005, the Town Center District issued $26.4 million of tax-exempt, 6 percent capital improvement revenue bonds and in May 2006, the Palm Coast Park District issued $31.8 million of tax-exempt, 5.7 percent special assessment bonds. The capital improvement revenue bonds and the special assessment bonds are payable over 31 years (by May 1, 2036, and 2037, respectively) and secured by special assessments on the benefited land. The bond proceeds were used to pay for the construction of a portion of the major infrastructure improvements in each district and to mitigate traffic and environmental impacts. The assessments were billed to the landowners beginning in November 2006, for Town Center, and November 2007, for Palm Coast Park. To the extent that we still own land at the time of the assessment, we will incur the cost of our portion of these assessments, based upon our ownership of benefited property. At December 31, 2011, we owned 73 percent of the assessable land in the Town Center District (69 percent at December 31, 2010) and 93 percent of the assessable land in the Palm Coast Park District (93 percent at December 31, 2010). At these ownership levels, our annual assessments are $1.5 million for Town Center and $2.2 million for Palm Coast Park. As we sell property, the obligation to pay special assessments will pass to the new landowners. Under current accounting rules, these bonds are not reflected as debt on our consolidated balance sheet.

Legal Proceedings. In January 2011, the Company was named as a defendant in a lawsuit in the Sixth Judicial District for the State of Minnesota by one of our customer’s (United Taconite, LLC) property and business interruption insurers. In October 2006, United Taconite experienced a fire as a result of the failure of certain electrical protective equipment. The equipment at issue in the incident was not owned, designed, or installed by Minnesota Power, but Minnesota Power had provided testing and calibration services related to the equipment. The lawsuit alleges approximately $20 million in damages related to the fire. The Company believes that it has strong defenses to the lawsuit and intends to vigorously assert such defenses. An accrual related to any damages that may result from the lawsuit has not been recorded as of December 31, 2011, because a potential loss is not currently probable; however, the Company believes it has adequate insurance coverage for potential loss.

Other. We are involved in litigation arising in the normal course of business. Also in the normal course of business, we are involved in tax, regulatory and other governmental audits, inspections, investigations and other proceedings that involve state and federal taxes, safety, compliance with regulations, rate base and cost of service issues, among other things. While the resolution of such matters could have a material effect on earnings and cash flows in the year of resolution, none of these matters are expected to materially change our present liquidity position, or have a material adverse effect on our financial condition.

- Definition

The entire disclosure for commitments and contingencies.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Interpretation (FIN)
-Number 14
-Paragraph 3
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 5
-Paragraph 9, 10, 11, 12
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.25)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=6952336&loc=d3e14435-108349

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=6398077&loc=d3e12565-110249

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 440
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6394976&loc=d3e25287-109308

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6449706&loc=d3e16207-108621

+ Details

Common Stock and Earnings Per Share

12 Months Ended

Dec. 31, 2011

Common Stock and Earnings Per Share [Abstract]

Common Stock and Earnings Per Share [Text Block]

Common Stock and Earnings Per Share



Summary of Common Stock	Shares	Equity
	Thousands	Millions
Balance as of December 31, 2008	32,585		$534.1
Employee Stock Purchase Program	24	0.7
Invest Direct	456	13.6
Options and Stock Awards	8	1.1
Equity Issuance Program	1,685	51.9
Contributions to Pension	463	12.0
Balance as of December 31, 2009	35,221		$613.4
Employee Stock Purchase Program	19	0.6
Invest Direct	346	11.7
Options and Stock Awards	51	4.4
Equity Issuance Program	180	6.0
Balance as of December 31, 2010	35,817		$636.1
Employee Stock Purchase Program	20	0.8
Invest Direct	437	17.2
Options and Stock Awards	109	6.7
Equity Issuance Program	400	16.0
Purchase of Non-Controlling Interest	222	8.8
Contributions to Pension	508	20.0
Balance as of December 31, 2011	37,513		$705.6

Equity Issuance Program. We entered into a distribution agreement with KCCI, Inc., in February 2008, as amended, with respect to the issuance and sale of up to an aggregate of 6.6 million shares of our common stock, without par value. For the year ended December 31, 2011, 0.4 million shares of common stock were issued under this agreement resulting in net proceeds of $16.0 million. During 2010, 0.2 million shares of common stock were issued for net proceeds of $6.0 million. As of December 31, 2011, approximately 2.7 million shares of common stock remain available for issuance pursuant to the amended distribution agreement. The shares issued in 2011 and 2010 were offered for sale, from time to time, in accordance with the terms of the amended distribution agreement pursuant to Registration Statement Nos. 333-170289 and 333-147965. The remaining shares may be offered for sale, from time to time, in accordance with the terms of the amended distribution agreement pursuant to Registration Statement No. 333-170289.

Earnings Per Share. The difference between basic and diluted earnings per share, if any, arises from outstanding stock options, non-vested restricted stock, and performance share awards granted under our Executive Long-Term Incentive Compensation Plan and Director Long-Term Incentive Compensation Plan. In 2011, in accordance with accounting standards for earnings per share, 0.3 million options to purchase shares of common stock were excluded from the computation of diluted earnings per share because the option exercise prices were greater than the average market prices, and therefore, their effect would be anti-dilutive (0.5 million shares were excluded for 2010 and 0.6 million in 2009).

Purchase of Non-Controlling Interest. In the third quarter of 2011, the remaining shares of the ALLETE Properties non-controlling interest were purchased at book value for $8.8 million by issuing 0.2 million unregistered shares of ALLETE common stock. This was accounted for as an equity transaction, and no gain or loss is recognized in net income or comprehensive income.

Contributions to Pension. On December 15, 2011, ALLETE contributed approximately 507,600 shares of ALLETE common stock to its pension plan. These shares of ALLETE common stock were contributed in reliance upon an exemption available pursuant to Section 4(2) of the Securities Act of 1933 and had an aggregate value of $20.0 million when contributed. (See Item 7. Management's Discussion and Analysis of Financial Condition and Results of Operations - Liquidity and Capital Resources.)


Note 12.	Common Stock and Earnings Per Share (Continued)



Reconciliation of Basic and Diluted
Earnings Per Share			Dilutive
Year Ended December 31	Basic		Securities	Diluted
Millions Except Per Share Amounts
2011
Net Income Attributable to ALLETE		$93.8			$93.8
Common Shares	35.3		0.1	35.4
Per Share of Common Stock		$2.66			$2.65
2010
Net Income Attributable to ALLETE		$75.3			$75.3
Common Shares	34.2		0.1	34.3
Per Share of Common Stock		$2.20			$2.19
2009
Net Income Attributable to ALLETE		$61.0			$61.0
Common Shares	32.2		—	32.2
Per Share of Common Stock		$1.89			$1.89

Other Income (Expense)

12 Months Ended

Dec. 31, 2011

Other Income and Expenses [Abstract]

Other Income (Expense) [Text Block]

Other Income (Expense)



Year Ended December 31	2011		2010		2009
Millions
AFUDC - Equity		$2.5		$4.2		$5.8
Investment and Other Income (Expense)	1.9		0.4		(4.0		)
Total Other Income		$4.4		$4.6		$1.8

Income Tax Expense

12 Months Ended

Dec. 31, 2011

Income Tax Disclosure [Abstract]

Income Tax Expense [Text Block]

Income Tax Expense



Income Tax Expense
Year Ended December 31	2011			2010			2009
Millions
Current Tax Expense (Benefit)
Federal (a)		$1.4		$(23.0)			$(42.6)
State (a)	(1.6		)	1.3			(1.8		)
Total Current Tax Expense (Benefit)	(0.2		)	(21.7		)	(44.4		)
Deferred Tax Expense
Federal (b)	27.3			61.4			66.0
State (b)	9.5			5.3			10.3
Change in Valuation Allowance	(0.1		)	0.2			(0.1		)
Investment Tax Credit Amortization	(0.9		)	(0.9		)	(1.0		)
Total Deferred Tax Expense	35.8			66.0			75.2
Total Income Tax Expense		$35.6			$44.3			$30.8

(a)

For the year ended December 31, 2011, the federal and state current tax expense (benefit) of $1.4 million and $(1.6) million, respectively, was due to an NOL which resulted primarily from the bonus depreciation provision of the Tax Relief Unemployment Insurance Reauthorization and Job Creation Act of 2010. The 2011 federal and state NOLs will be carried forward to offset future taxable income. For the year ended December 31, 2010, we recorded a federal current tax benefit as a result of tax planning initiatives and the bonus depreciation provision in the Small Business Jobs Act of 2010. The 2010 federal NOL was partially utilized by carrying it back against prior years' income with the remainder carried forward to offset future years' income. The 2009 federal current tax benefit was primarily due to the bonus depreciation provision of the American Recovery and Reinvestment Act of 2009.

(b)

The year ended December 31, 2011, included an income tax benefit of $2.9 million related to the MPUC approval of our request to defer the retail portion of the tax charge taken in 2010 as a result of PPACA and a benefit for the reversal of a $6.2 million deferred tax liability related to a revenue receivable that Minnesota Power agreed to forgo as part of a stipulation and settlement agreement in its 2010 rate case. Included in the year ended December 31, 2010, was a charge of $4.0 million as a result of PPACA. (See Note 5. Regulatory Matters.)



Reconciliation of Taxes from Federal Statutory
Rate to Total Income Tax Expense
Year Ended December 31	2011			2010			2009
Millions
Income Before Non-Controlling Interest and Income Taxes		$129.2			$119.1			$91.5
Statutory Federal Income Tax Rate	35		%	35		%	35		%
Income Taxes Computed at 35 percent Statutory Federal Rate		$45.2			$41.7			$32.0
Increase (Decrease) in Tax Due to:
State Income Taxes – Net of Federal Income Tax Benefit	6.0			4.5			5.4
Impact of PPACA	—			4.0			—
Deferred Accounting for Retail Portion of PPACA	(2.9		)	—			—
2010 Rate Case Stipulation Agreement - Deferred Tax Reversal	(6.2		)	—			—
Regulatory Differences for Utility Plant	(1.2		)	(2.0		)	(2.5		)
Production Tax Credits	(4.3		)	(1.6		)	(1.2		)
Other	(1.0		)	(2.3		)	(2.9		)
Total Income Tax Expense		$35.6			$44.3			$30.8


Note 14.	Income Tax Expense (Continued)

The effective tax rate on income was 27.6 percent for 2011 (37.2 percent for 2010; 33.7 percent for 2009). The 2011 effective tax rate was primarily impacted by deductions for AFUDC-Equity (included in Regulatory Differences for Utility Plant, above), renewable tax credits, the MPUC's approval of our request to defer the retail portion of the tax charge taken in 2010 as a result of PPACA, and the reversal of a deferred tax liability related to a revenue receivable that Minnesota Power agreed to forgo as part of a stipulation and settlement agreement in its 2010 rate case. The 2010 effective tax rate was primarily impacted by deductions for AFUDC-Equity (included in Regulatory Differences for Utility Plant, above), renewable tax credits and the impact of PPACA eliminating the tax deduction for expenses that are reimbursed under Medicare Part D. The 2009 effective tax rate was impacted by deductions for AFUDC-Equity (included in Regulatory Differences for Utility Plant, above) and wind production tax credits.



Deferred Tax Assets and Liabilities
As of December 31	2011			2010
Millions
Deferred Tax Assets
Employee Benefits and Compensation		$132.7			$121.8
Property Related	56.4			51.1
NOL and Tax Credit Carryforward	78.1			28.2
Investment Tax Credits	9.0			9.7
Other	7.2			12.7
Gross Deferred Tax Assets	283.4			223.5
Deferred Tax Asset Valuation Allowance	(0.4		)	(0.5		)
Total Deferred Tax Assets		$283.0			$223.0
Deferred Tax Liabilities
Property Related		$482.7			$387.2
Regulatory Asset for Benefit Obligations	117.9			105.8
Unamortized Investment Tax Credits	12.8			13.7
Partnership Basis Differences	24.4			19.4
Other	24.0			27.3
Total Deferred Tax Liabilities		$661.8			$553.4
Net Deferred Income Taxes		$378.8			$330.4
Recorded as:
Net Current Deferred Tax Liabilities (a)		$5.2			$5.2
Net Long-Term Deferred Tax Liabilities	373.6			325.2
Net Deferred Income Taxes		$378.8			$330.4


(a)	Included in Other Current Liabilities.



NOL and Tax Credit Carryforwards
Year Ended December 31	2011		2010
Millions
Federal NOL carryforward (a)		$162.0		$62.0
Federal tax credit carryforwards	8.4		3.7
State NOL carryforwards (a, b)	73.1		71.7
State tax credit carryforwards, net of federal offset	3.8		1.7


(a)	Pretax amounts


(b)	State NOL carryforwards include Minnesota, North Dakota and Florida.

In 2011, we generated federal and various state NOLs and tax credit carryforwards primarily due to the bonus depreciation provisions of the Tax Relief, Unemployment Insurance Reauthorization and Job Creation Act of 2010. The 2011 federal NOL will be utilized by carrying it forward to offset future years' income. We expect to fully utilize the federal NOL and tax credit carryforwards; therefore a deferred tax asset has been recorded to recognize the resulting tax benefit.


Note 14.	Income Tax Expense (Continued)

The state NOLs and tax credits will be carried forward to future tax years. We have established a valuation allowance against certain state NOL and tax credits that we do not expect to utilize before their expiration.

The federal NOL and tax credit carryforward periods expire between 2019 and 2031; included in the federal NOL carryforward is $3.0 million of charitable contributions carryforward which expire between 2014 and 2015. The state NOL and tax credit carryforward periods expire between 2024 and 2031; included in the state NOL carryforwards is $2.8 million of charitable contributions carryforward which expires between 2014 and 2015.



Gross Unrecognized Income Tax Benefits	2011			2010			2009
Millions
Balance at January 1		$12.3			$9.5			$8.0
Additions for Tax Positions Related to the Current Year	—			—			0.5
Reductions for Tax Positions Related to the Current Year	—			(0.2		)	—
Additions for Tax Positions Related to Prior Years	—			4.4			1.0
Reductions for Tax Positions Related to Prior Years	(0.9		)	—			—
Settlements	—			(0.3		)	—
Lapse of Statute	—			(1.1		)	—
Balance as of December 31		$11.4			$12.3			$9.5

The gross unrecognized tax benefits as of December 31, 2011, includes $0.6 million of net unrecognized tax benefits that, if recognized, would affect the annual effective income tax rate.

As of December 31, 2011, we had $1.1 million ($0.7 million for 2010 and $0.9 million for 2009) of accrued interest related to unrecognized tax benefits included in the consolidated balance sheet. We classify interest related to unrecognized tax benefits as interest expense and tax-related penalties in operating expenses in the consolidated statement of income. In 2011, we recognized interest expense of $0.4 million (interest reduction of $0.2 million for 2010 and interest expense of $0.4 million for 2009). There were no penalties recognized for 2011, 2010 or 2009.

We file a consolidated federal income tax return in the U.S. and state income tax returns in various jurisdictions. ALLETE is currently under examination by the IRS for the tax years 2005 through 2009. ALLETE is no longer subject to federal or state examination for years before 2005.

During the next 12 months it is reasonably possible the amount of unrecognized tax benefits could be reduced by $5.0 million due to statute expirations and anticipated audit settlements. This amount is primarily due to timing issues.

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 08
-Paragraph h
-Article 4

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 109
-Paragraph 136, 172
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 109
-Paragraph 43, 44, 45, 46, 47, 48, 49
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 15
-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32718-109319

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 9
-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32639-109319

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(h))
-URI http://asc.fasb.org/extlink&oid=6881521&loc=d3e23780-122690

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32537-109319

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32559-109319

+ Details

Comprehensive Income

12 Months Ended

Dec. 31, 2011

Comprehensive Income (Loss) [Abstract]

Comprehensive Income (Loss) [Text Block]

Comprehensive Income (Loss)



Comprehensive Income (Loss)
Year Ended December 31	2011			2010			2009
Millions
Net Income		$93.6			$74.8			$60.7
Other Comprehensive Income
Unrealized Gain (Loss) on Securities Net of income taxes of $(0.1), $0.6, and $1.7	(0.3		)	0.8			2.8
Unrealized Loss on Derivatives Net of income taxes of $(0.2), $-, and $-	(0.3		)	—			—
Defined Benefit Pension and Other Postretirement Plans Net of income taxes of $(3.6), $-, and $4.1	(5.1		)	—			6.2
Total Other Comprehensive Income (Loss)	(5.7		)	0.8			9.0
Total Comprehensive Income		$87.9			$75.6			$69.7
Less: Non-Controlling Interest in Subsidiaries	(0.2		)	(0.5		)	(0.3		)
Comprehensive Income Attributable to ALLETE		$88.1			$76.1			$70.0


Note 15.	Comprehensive Income (Loss) (Continued)



Accumulated Other Comprehensive Income (Loss)
As of December 31	2011		2010
Millions
Unrealized Loss on Securities	$(1.3)		$(1.0)
Unrealized Loss on Derivatives	(0.3	)	—
Defined Benefit Pension and Other Postretirement Plans	(27.3	)	(22.2	)
Total Accumulated Other Comprehensive Loss	$(28.9)		$(23.2)

- Definition

The entire disclosure for comprehensive income. Includes, but is not limited to, the following: 1) the amount of income tax expense or benefit allocated to each component of other comprehensive income, including reclassification adjustments, 2) the reclassification adjustments for each classification of other comprehensive income and 3) the ending accumulated balances for each component of comprehensive income. Components of comprehensive income include: (1) foreign currency translation adjustments; (2) gains (losses) on foreign currency transactions that are designated as, and are effective as, economic hedges of a net investment in a foreign entity; (3) gains (losses) on intercompany foreign currency transactions that are of a long-term-investment nature, when the entities to the transaction are consolidated, combined, or accounted for by the equity method in the reporting enterprise's financial statements; (4) change in the market value of a futures contract that qualifies as a hedge of an asset reported at fair value; (5) unrealized holding gains (losses) on available-for-sale securities and that resulting from transfers of debt securities from the held-to-maturity category to the available-for-sale category; (6) a net loss recognized as an additional pension liability not yet recognized as net periodic pension cost; and (7) the net gain (loss) and net prior service cost or credit for pension plans and other postretirement benefit plans.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 130
-Paragraph 14-26
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Reference 2: http://www.xbrl.org/2003/role/presentationRef
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+ Details

Pension and Other Postretirement Benefit Plans

12 Months Ended

Dec. 31, 2011

Pension and Other Postretirement Benefit Plans [Abstract]

Pension and Other Postretirement Benefit Plans [Text Block]

Pension and Other Postretirement Benefit Plans

We have noncontributory union and non-union defined benefit pension plans covering eligible employees. The plans provide defined benefits based on years of service and final average pay. In 2011, we made total contributions of $33.8 million, of which $20.0 million was contributed in shares of ALLETE common stock (total contributions of $26.5 million in 2010). We also have a defined contribution pension plan covering substantially all employees. The 2011 plan year employer contributions, which are made through the employee stock ownership plan portion of the RSOP, totaled $7.3 million ($7.2 million for the 2010 plan year.) (See Note 12. Common Stock and Earnings Per Share and Note 17. Employee Stock and Incentive Plans).

In 2006, the non-union defined benefit pension plan was amended to suspend further crediting of service to the plan and to close the plan to new participants. In conjunction with those amendments, contributions were increased to the RSOP. In 2010, the Minnesota Power union defined benefit pension plan was amended to close the plan to new participants beginning February 1, 2011.

We have postretirement health care and life insurance plans covering eligible employees. In 2010, our postretirement health plan was amended to close the plan to employees hired after January 31, 2011. The full eligibility requirement was also amended in 2010, to age 55 with 10 years of participation in the plan. The postretirement health plans are contributory with participant contributions adjusted annually. Postretirement health and life benefits are funded through a combination of Voluntary Employee Benefit Association trusts (VEBAs), established under section 501(c)(9) of the Internal Revenue Code, and an irrevocable grantor trust. In 2011, $10.9 million was contributed to the VEBAs. In 2010, we contributed $12.8 million to the VEBAs. There were no contributions made to the grantor trust in 2011 and 2010.

Management considers various factors when making funding decisions such as regulatory requirements, actuarially determined minimum contribution requirements, and contributions required to avoid benefit restrictions for the pension plans. Estimated defined benefit pension and postretirement health and life contributions for 2012 are expected to be $1.0 million and $13.9 million, respectively. Contributions are based on estimates and assumptions which are subject to change.

Accounting for defined benefit pension and postretirement benefit plans requires that employers recognize on a prospective basis the funded status of their defined benefit pension and other postretirement plans on their consolidated balance sheet and recognize as a component of other comprehensive income, net of tax, the gains or losses and prior service costs or credits that arise during the period but are not recognized as components of net periodic benefit cost.

The defined benefit pension and postretirement health and life benefit costs recognized annually by our regulated companies are expected to be recovered through rates filed with our regulatory jurisdictions. As a result, these amounts that are required to otherwise be recognized in accumulated other comprehensive income have been recognized as a long-term regulatory asset on our consolidated balance sheet, in accordance with the accounting standards for Regulated Operations. The defined benefit pension and postretirement health and life benefit costs associated with our other non-rate base operations are recognized in accumulated other comprehensive income.



Pension Obligation and Funded Status
Year Ended December 31	2011			2010
Millions
Accumulated Benefit Obligation		$550.6			$485.6
Change in Benefit Obligation
Obligation, Beginning of Year		$525.6			$465.2
Service Cost	7.6			6.2
Interest Cost	27.4			26.2
Actuarial Loss	54.6			47.1
Benefits Paid	(28.6		)	(27.2		)
Participant Contributions	10.9			8.1
Obligation, End of Year		$597.5			$525.6
Change in Plan Assets
Fair Value, Beginning of Year		$382.0			$327.6
Actual Return on Plan Assets	33.1			45.6
Employer Contribution	45.8			36.0
Benefits Paid	(28.5		)	(27.2		)
Fair Value, End of Year		$432.4			$382.0
Funded Status, End of Year	$(165.1)			$(143.6)

Net Pension Amounts Recognized in Consolidated Balance Sheet Consist of:
Current Liabilities	$(1.1)			$(0.8)
Non-Current Liabilities	$(164.0)			$(142.8)

The pension costs that are reported as a component within our consolidated balance sheet, reflected in long-term regulatory assets and accumulated other comprehensive income, consist of the following:



Unrecognized Pension Costs
Year Ended December 31	2011		2010
Millions
Net Loss		$269.0		$225.1
Prior Service Cost	1.1		1.4
Total Unrecognized Pension Costs		$270.1		$226.5



Components of Net Periodic Pension Expense
Year Ended December 31	2011			2010			2009
Millions
Service Cost		$7.6			$6.2			$5.7
Interest Cost	27.4			26.2			26.2
Expected Return on Plan Assets	(34.6		)	(33.7		)	(33.8		)
Amortization of Loss	12.1			6.6			3.4
Amortization of Prior Service Costs	0.3			0.5			0.6
Net Pension Expense		$12.8			$5.8			$2.1



Other Changes in Pension Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income and Regulatory Assets
Year Ended December 31	2011			2010
Millions
Net Loss		$56.1			$35.2
Amortization of Prior Service Cost	(0.3		)	(0.5		)
Amortization of Gain	(12.2		)	(6.6		)
Total Recognized in Other Comprehensive Income and Regulatory Assets		$43.6			$28.1



Information for Pension Plans with an Accumulated Benefit Obligation in Excess of Plan Assets
Year Ended December 31	2011		2010
Millions
Projected Benefit Obligation		$597.5		$525.6
Accumulated Benefit Obligation		$550.6		$485.6
Fair Value of Plan Assets		$432.4		$382.0



Postretirement Health and Life Obligation and Funded Status
Year Ended December 31	2011			2010
Millions
Change in Benefit Obligation
Obligation, Beginning of Year		$204.1			$192.1
Service Cost	3.8			4.8
Interest Cost	10.8			10.9
Actuarial Loss (Gain)	(2.9		)	17.6
Participant Contributions	2.5			2.1
Plan Amendments	—			(14.2		)
Benefits Paid	(7.7		)	(9.2		)
Obligation, End of Year		$210.6			$204.1
Change in Plan Assets
Fair Value, Beginning of Year		$114.7			$96.4
Actual Return on Plan Assets	—			12.0
Employer Contribution	11.4			13.4
Participant Contributions	2.5			2.0
Benefits Paid	(7.6		)	(9.1		)
Fair Value, End of Year		$121.0			$114.7
Funded Status, End of Year	$(89.6)			$(89.4)

Net Postretirement Health and Life Amounts Recognized in Consolidated Balance Sheet Consist of:
Current Liabilities	$(0.9)			$(0.8)
Non-Current Liabilities	$(88.7)			$(88.6)

According to the accounting standards for retirement benefits, only assets in the VEBAs are treated as plan assets in the above table for the purpose of determining funded status. In addition to the postretirement health and life assets reported in the previous table, we had $20.3 million in irrevocable grantor trusts included in Other Investments on our consolidated balance sheet at December 31, 2011 ($19.8 million at December 31, 2010).

The postretirement health and life costs that are reported as a component within our consolidated balance sheet, reflected in regulatory long-term assets and accumulated other comprehensive income, consist of the following:



Unrecognized Postretirement Health and Life Costs
Year Ended December 31	2011			2010
Millions
Net Loss		$78.5			$80.1
Prior Service Cost	(9.5		)	(11.2		)
Transition Obligation	0.1			0.2
Total Unrecognized Postretirement Health and Life Costs		$69.1			$69.1



Components of Net Periodic Postretirement Health and Life Expense
Year Ended December 31	2011			2010			2009
Millions
Service Cost		$3.8			$4.8			$4.1
Interest Cost	10.8			10.9			10.0
Expected Return on Plan Assets	(9.7		)	(9.5		)	(8.3		)
Amortization of Prior Service Cost	(1.7		)	(0.1		)	—
Amortization of Loss	8.5			4.8			2.5
Amortization of Transition Obligation	0.1			2.5			2.5
Net Postretirement Health and Life Expense		$11.8			$13.4			$10.8



Other Changes in Postretirement Benefit Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income and Regulatory Assets
Year Ended December 31	2011			2010
Millions
Net Loss		$6.9			$15.3
Prior Service Cost (Credit) Arising During the Period	—			(14.2		)
Amortization of Prior Service Cost	1.7			0.1
Amortization of Transition Obligation	(0.1		)	(2.5		)
Amortization of Loss	(8.5		)	(4.8		)
Total Recognized in Other Comprehensive Income and Regulatory Assets	—			$(6.1)



Estimated Future Benefit Payments
			Postretirement
	Pension		Health and Life
Millions
2012		$29.2		$8.3
2013		$30.0		$9.2
2014		$31.2		$10.2
2015		$32.3		$11.2
2016		$33.4		$11.9
Years 2017 – 2021		$181.4		$66.6

The pension and postretirement health and life costs recorded in regulatory long-term assets and accumulated other comprehensive income expected to be recognized as a component of net pension and postretirement benefit costs for the year ending December 31, 2012, are as follows:



	Pension		Postretirement Health and Life
Millions
Net Loss		$17.5		$7.5
Prior Service Costs		$0.3		($1.7	)
Transition Obligations	—			$0.1
Total Pension and Postretirement Health and Life Costs		$17.8		$5.9



Weighted-Average Assumptions Used to Determine Benefit Obligation
Year Ended December 31	2011		2010
Discount Rate
Pension	4.54	%	5.36	%
Postretirement Health and Life	4.56	%	5.40	%
Rate of Compensation Increase	4.3 - 4.6%		4.3 - 4.6%
Health Care Trend Rates
Trend Rate	10	%	10	%
Ultimate Trend Rate	5	%	5	%
Year Ultimate Trend Rate Effective	2018		2018



Weighted-Average Assumptions Used to Determine Net Periodic Benefit Costs
Year Ended December 31	2011		2010		2009
Discount Rate	5.36 - 5.40%		5.81	%	6.12	%
Expected Long-Term Return on Plan Assets (a)
Pension	8.5	%	8.5	%	8.5	%
Postretirement Health and Life	6.8 - 8.5%		6.8 - 8.5%		6.8 - 8.5%
Rate of Compensation Increase	4.3 - 4.6%		4.3 - 4.6%		4.3 - 4.6%

(a) The expected long-term rate of return used to determine net periodic benefit expenses for 2012 has been reduced to 8.25 percent.

In establishing the expected long-term return on plan assets, we take into account the actual long-term historical performance of our plan assets, the actual long-term historical performance for the type of securities we are invested in, and apply the historical performance utilizing the target allocation of our plan assets to forecast an expected long-term return. Our expected rate of return is then selected after considering the results of each of those factors, in addition to considering the impact of current economic conditions, if applicable, on long-term historical returns.

The discount rate is computed using a yield curve adjusted for ALLETE’s projected cash flows to match our plan characteristics. The yield curve is determined using high-quality long-term corporate bond rates at the valuation date. We believe the adjusted discount curve used in this comparison does not materially differ in duration and cash flows from our pension obligation.



Sensitivity of a One-Percentage-Point Change in Health Care Trend Rates
	One Percent		One Percent
	Increase		Decrease
Millions
Effect on Total of Postretirement Health and Life Service and Interest Cost		$2.0	$(1.6)
Effect on Postretirement Health and Life Obligation		$25.1	$(20.7)



Actual Plan Asset Allocations
	Pension				Postretirement Health and Life (a)
	2011		2010		2011		2010
Equity Securities	52	%	52	%	51	%	58	%
Debt Securities	27	%	29	%	39	%	33	%
Real Estate	5	%	5	%	—		—
Private Equity	16	%	14	%	10	%	9	%
	100	%	100	%	100	%	100	%


(a)	Includes VEBAs and irrevocable grantor trusts.

There was $20.0 million (approximately 507,600 shares) of ALLETE common stock included in pension plan equity securities at December 31, 2011 (none in 2010).

To achieve strong returns within managed risk, we diversify our asset portfolio to approximate the target allocations in the table below. Equity securities are diversified among domestic companies with large, mid and small market capitalizations, as well as investments in international companies. The majority of debt securities are made up of investment grade bonds.



Plan Asset Target Allocations
			Postretirement
	Pension		Health and Life (a)
Equity Securities	52	%	48	%
Debt Securities	30	%	34	%
Real Estate	9	%	9	%
Private Equity	9	%	9	%
	100	%	100	%


(a)	Includes VEBAs and irrevocable grantor trusts.

Fair Value

Level 1 — Quoted prices are available in active markets for identical assets or liabilities as of the reported date. Active markets are those in which transactions for the asset or liability occur in sufficient frequency and volume to provide pricing information on an ongoing basis. This category includes various U.S. equity securities, public mutual funds, and futures. These instruments are valued using the closing price from the applicable exchange or whose value is quoted and readily traded daily.

Level 2 — Pricing inputs are other than quoted prices in active markets, but are either directly or indirectly observable as of the reported date. The types of assets and liabilities included in Level 2 are typically either comparable to actively traded securities or contracts, such as treasury securities with pricing interpolated from recent trades of similar securities, or priced with models using highly observable inputs. This category includes various bonds and non-public funds whose underlying investments may be level 1 or level 2 securities.

Level 3 — Significant inputs that are generally less observable from objective sources. The types of assets and liabilities included in Level 3 are those with inputs requiring significant management judgment or estimation, such as the complex and subjective models and forecasts used to determine the fair value. This category includes private equity funds and real estate valued through external appraisal processes. Valuation methodologies incorporate pricing models, discounted cash flow models, and similar techniques which utilize capitalization rates, discount rates, cash flows and other factors.

Pension Fair Value



	At Fair Value as of December 31, 2011
Recurring Fair Value Measures	Level 1		Level 2		Level 3		Total
Millions
Assets:
Equity Securities:
U.S. Large-cap (a)		$32.1		$37.3	—			$69.4
U.S. Mid-cap Growth (a)	13.5		15.8		—		29.3
U.S. Small-cap (a)	13.1		15.2		—		28.3
International	—		75.1		—		75.1
ALLETE	21.3		—		—		21.3
Debt Securities:
Mutual Funds	72.8		—		—		72.8
Fixed Income	—		45.5		—		45.5
Other Types of Investments:
Private Equity Funds	—		—			$69.0	69.0
Real Estate	—		—		21.7		21.7
Total Fair Value of Assets		$152.8		$188.9		$90.7		$432.4

(a)

The underlying investments classified under U.S. Equity Securities consist of Money Market Funds and U.S. Government Bonds (Level 1), and Funds (Level 2), which are combined with futures, which settle daily, in a portable alpha program to achieve the returns of the U.S. Equity Securities Large-cap, Mid-cap Growth, and Small-cap funds. Our exposure with respect to these investments includes both the futures and the underlying investments.



Recurring Fair Value Measures	Equity Securities
Activity in Level 3	(Auction Rate Securities)			Private Equity Funds			Real Estate
Millions
Balance as of December 31, 2010		$6.7			$50.7			$20.1
Actual Return on Plan Assets	—			30.9			3.5
Purchases, sales, and settlements, net	(6.7		)	(12.6		)	(1.9		)
Balance as of December 31, 2011	—				$69.0			$21.7



	At Fair Value as of December 31, 2010
Recurring Fair Value Measures	Level 1		Level 2		Level 3		Total
Millions
Assets:
Equity Securities:
U.S. Large-cap (a)		$30.4		$29.9		$3.5		$63.8
U.S. Mid-cap Growth (a)	14.0		13.7		1.6		29.3
U.S. Small-cap (a)	13.7		13.5		1.6		28.8
International	—		77.1		—		77.1
Debt Securities:
Mutual Funds	46.5		—		—		46.5
Fixed Income	—		65.7		—		65.7
Other Types of Investments:
Private Equity Funds	—		—		50.7		50.7
Real Estate	—		—		20.1		20.1
Total Fair Value of Assets		$104.6		$199.9		$77.5		$382.0

(a)

The underlying investments classified under U.S. Equity Securities consist of Money Market Funds and U.S. Government Bonds (Level 1), Funds (Level 2), and Auction Rate Securities (Level 3), which are combined with futures, which settle daily, in a portable alpha program to achieve the returns of the U.S. Equity Securities Large-cap, Mid-cap Growth, and Small-cap funds. Our exposure with respect to these investments includes both the futures and the underlying investments.



Recurring Fair Value Measures	Equity Securities
Activity in Level 3	(Auction Rate Securities)			Private Equity Funds			Real Estate
Millions
Balance as of December 31, 2009		$9.1			$44.7			$17.3
Actual Return on Plan Assets	—			(4.1		)	(6.1		)
Purchases, sales, and settlements, net	(2.4		)	10.1			8.9
Balance as of December 31, 2010		$6.7			$50.7			$20.1

Postretirement Health and Life Fair Value



	At Fair Value as of December 31, 2011
Recurring Fair Value Measures	Level 1		Level 2		Level 3		Total
Millions
Assets:
Equity Securities:
U.S. Large-cap		$15.9	—		—			$15.9
U.S. Mid-cap Growth	11.5		—		—		11.5
U.S. Small-cap	11.2		—		—		11.2
International	25.1		—		—		25.1
Debt Securities:
Mutual Funds	24.1		—		—		24.1
Fixed Income	0.3			$18.9	—		19.2
Other Types of Investments:
Private Equity Funds	—		—			$14.0	14.0
Total Fair Value of Assets		$88.1		$18.9		$14.0		$121.0



Recurring Fair Value Measures
Activity in Level 3	Private Equity Funds
Millions
Balance as of December 31, 2010		$12.4
Actual Return on Plan Assets	1.1
Purchases, sales, and settlements, net	0.5
Balance as of December 31, 2011		$14.0



	At Fair Value as of December 31, 2010
Recurring Fair Value Measures	Level 1		Level 2		Level 3		Total
Millions
Assets:
Equity Securities:
U.S. Large-cap		$15.7	—		—			$15.7
U.S. Mid-cap Growth	11.4		—		—		11.4
U.S. Small-cap	11.5		—		—		11.5
International	26.8		—		—		26.8
Debt Securities:
Mutual Funds	9.0		—		—		9.0
Fixed Income	—			$27.9	—		27.9
Other Types of Investments:
Private Equity Funds	—		—			$12.4	12.4
Total Fair Value of Assets		$74.4		$27.9		$12.4		$114.7



Recurring Fair Value Measures
Activity in Level 3	Private Equity Funds
Millions
Balance as of December 31, 2009		$9.4
Actual Return on Plan Assets	1.4
Purchases, sales, and settlements, net	1.6
Balance as of December 31, 2010		$12.4

Accounting and disclosure requirements for the Medicare Prescription Drug, Improvement and Modernization Act of 2003 (Act) provide guidance for employers that sponsor postretirement health care plans that provide prescription drug benefits. We provide postretirement health benefits that include prescription drug benefits, which qualify us for the federal subsidy under the Act.

- Definition

The entire disclosure for pension and other postretirement benefits.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
-Paragraph 5
-Subparagraph a
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
-Paragraph 5
-Subparagraph b
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
-Paragraph 5
-Subparagraph h
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
-Paragraph 5
-Subparagraph q
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
-Paragraph 8
-Subparagraph m
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 106
-Paragraph 518
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 87
-Paragraph 264
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Emerging Issues Task Force (EITF)
-Number 03-2
-Paragraph 8
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Principles Board Opinion (APB)
-Number 30
-Paragraph 26
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Staff Position (FSP)
-Number FAS106-2
-Paragraph 20, 21, 22
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 158
-Paragraph 7, 21, 22
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
-Paragraph 5, 6, 7, 8
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 13: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Implementation Guide (Q and A)
-Number FAS88
-Paragraph 63
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 14: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-URI http://asc.fasb.org/topic&trid=2235017

+ Details

Employee Stock and Incentive Plans

12 Months Ended

Dec. 31, 2011

Employee Stock and Incentive Plans [Abstract]

Employee Stock and Incentive Plans [Text Block]

Employee Stock and Incentive Plans

Employee Stock Ownership Plan. We sponsor a leveraged ESOP within the RSOP. As of their date of hire, eligible employees may contribute to the RSOP plan. In 1990, the ESOP issued a $75.0 million note (term not to exceed 25 years at 10.25 percent) to use as consideration for 2.8 million shares (1.9 million shares adjusted for stock splits) of our newly issued common stock. The note was refinanced in 2006 at 6 percent. We make annual contributions to the ESOP equal to the ESOP’s debt service less available dividends received by the ESOP. The majority of dividends received by the ESOP are used to pay debt service, with the balance distributed to participants. The ESOP shares were initially pledged as collateral for its debt. As the debt is repaid, shares are released from collateral and allocated to participants based on the proportion of debt service paid in the year. As shares are released from collateral, we report compensation expense equal to the current market price of the shares less dividends on allocated shares. Dividends on allocated ESOP shares are recorded as a reduction of retained earnings; available dividends on unallocated ESOP shares are recorded as a reduction of debt and accrued interest. ESOP compensation expense was $7.4 million in 2011 ($7.1 million in 2010; $6.5 million in 2009).

According to the accounting standards for stock compensation, unallocated shares of ALLETE common stock currently held and purchased by the ESOP will be treated as unearned ESOP shares and not considered outstanding for earnings per share computations. ESOP shares are included in earnings per share computations after they are allocated to participants.



Year Ended December 31	2011		2010		2009
Millions
ESOP Shares
Allocated	2.2		2.2		2.2
Unallocated	1.0		1.3		1.5
Total	3.2		3.5		3.7
Fair Value of Unallocated Shares		$42.0		$48.4		$49.0

Stock-Based Compensation. Stock Incentive Plan. Under our Executive Long-Term Incentive Compensation Plan (Executive Plan), share-based awards may be issued to key employees through a broad range of methods, including non-qualified and incentive stock options, performance shares, performance units, restricted stock, stock appreciation rights and other awards. There are 1.3 million shares of common stock reserved for issuance under the Executive Plan, with 0.6 million of these shares available for issuance as of December 31, 2011.

We had a Director Long-Term Stock Incentive Plan (Director Plan) which expired on January 1, 2006. No grants have been made since 2003 under the Director Plan. Approximately 1,293 options were outstanding under the Director Plan at December 31, 2011.

We currently have the following types of share-based awards outstanding:

Non-Qualified Stock Options. The options allow for the purchase of shares of common stock at a price equal to the market value of our common stock at the date of grant. Options become exercisable beginning one year after the grant date, with one-third vesting each year over three years. Options may be exercised up to ten years following the date of grant. In the case of qualified retirement, death or disability, options vest immediately and the period over which the options can be exercised is three years. Employees have up to three months to exercise vested options upon voluntary termination or involuntary termination without cause. All options are canceled upon termination for cause. All options vest immediately upon retirement, death, disability or a change of control, as defined in the award agreement. We determine the fair value of options using the Black-Scholes option-pricing model. The estimated fair value of options, including the effect of estimated forfeitures, is recognized as expense on the straight-line basis over the options’ vesting periods, or the accelerated vesting period if the employee is retirement eligible. Stock options have not been granted under our Executive Plan since 2008.

The risk-free interest rate for periods within the contractual life of the option is based on the U.S. Treasury yield curve in effect at the grant date. Expected volatility is estimated based on the historic volatility of our stock and the stock of our peer group companies. We utilize historical option exercise and employee pre-vesting termination data to estimate the option life. The dividend growth rate is based upon historical growth rates in our dividends.


Note 17.	Employee Stock and Incentive Plans (Continued)

Performance Shares. Under the performance share awards plan, the number of shares earned is contingent upon attaining specific market goals over a three-year performance period. Market goals are measured by total shareholder return relative to a group of peer companies. In the case of qualified retirement, death or disability during a performance period, a pro rata portion of the award will be earned at the conclusion of the performance period based on the market goals achieved. In the case of termination of employment for any reason other than qualified retirement, death or disability, no award will be earned. If there is a change in control, a pro rata portion of the award will be paid based on the greater of actual performance up to the date of the change in control or target performance. The fair value of these awards is determined by the probability of meeting the total shareholder return goals. Compensation cost is recognized over the three-year performance period based on our estimate of the number of shares which will be earned by the award recipients.

Restricted Stock Units. Under the restricted stock units plan, shares vest monthly over a three-year period. In the case of qualified retirement, death or disability, a pro rata portion of the award will be earned. In the case of termination of employment for any other reason other than qualified retirement, death or disability, no award will be earned. If there is a change in control, a pro rata portion of the award will be paid. The fair value of these awards is equal to the grant date fair value. Compensation cost is recognized over the three-year vesting period based on our estimate of the number of shares which will be earned by the award recipients.

Employee Stock Purchase Plan (ESPP). Under our ESPP, eligible employees may purchase ALLETE common stock at a 5 percent discount from the market price. Because the discount is not greater than 5 percent, we are not required to apply fair value accounting to these awards.

RSOP. The RSOP is a contributory defined contribution plan subject to the provisions of the Employee Retirement Income Security Act of 1974, as amended, and qualifies as an employee stock ownership plan and profit sharing plan. The RSOP provides eligible employees an opportunity to save for retirement.

The following share-based compensation expense amounts were recognized in our consolidated statement of income for the periods presented.



Share-Based Compensation Expense
Year Ended December 31	2011		2010		2009
Millions
Stock Options	—			$0.1		$0.3
Performance Shares		$1.1	1.5		1.5
Restricted Stock Units	0.5		0.6		0.3
Total Share-Based Compensation Expense		$1.6		$2.2		$2.1
Income Tax Benefit		$0.7		$0.9		$0.8

There were no capitalized stock-based compensation costs at December 31, 2011, 2010, or 2009.

As of December 31, 2011, the total unrecognized compensation cost for the performance share awards and restricted stock units not yet recognized in our consolidated statements of income was $1.3 million and $0.6 million, respectively. These amounts are expected to be recognized over a weighted-average period of 1.7 years and 1.6 years for performance share awards and restricted stock units, respectively.

Non-Qualified Stock Options. The following table presents information regarding our outstanding stock options as of December 31, 2011.


Note 17.	Employee Stock and Incentive Plans (Continued)



	2011			2010			2009
	Number of Options	Weighted-Average Exercise Price		Number of Options	Weighted-Average Exercise Price		Number of Options	Weighted-Average Exercise Price
Outstanding as of January 1,	560,887		$40.69	646,235		$40.05	672,419		$39.99
Granted (a)	—	—		—	—		—	—
Exercised	80,798		$34.25	40,769		$27.76	4,508		$18.85
Forfeited	19,855		$43.96	44,579		$43.16	21,676		$42.62
Outstanding as of December 31,	460,234		$41.68	560,887		$40.69	646,235		$40.05
Exercisable as of December 31,	460,234		$41.59	523,491		$39.76	512,743		$37.34


(a)	Stock options have not been granted since 2008. The weighted-average grant-date intrinsic value of options granted in 2008 was $6.18.

Cash received from non-qualified stock options exercised was less than $0.1 million in 2011. The intrinsic value of a stock award is the amount by which the fair value of the underlying stock exceeds the exercise price of the award. The total intrinsic value of options exercised was $0.5 million during 2011 ($0.3 million in 2010; $0.1 million in 2009).



	Range of Exercise Price
As of December 31, 2011	$18.85 to $29.79		$37.76 to $41.35		$44.15 to $48.65
Options Outstanding and Exercisable:
Number Outstanding and Exercisable	11,672		279,133		169,429
Weighted Average Remaining Contractual Life (Years)	1.1		4.5		4.5
Weighted Average Exercise Price		$24.14		$39.57		$46.37

Performance Shares. The following table presents information regarding our non-vested performance shares as of December 31, 2011.



	2011				2010				2009
	Number of Shares		Weighted- Average Grant Date Fair Value		Number of Shares		Weighted- Average Grant Date Fair Value		Number of Shares		Weighted- Average Grant Date Fair Value
Non-vested as of January 1,	122,489			$38.15	121,825			$41.96	79,238			$47.94
Granted (a)	39,312			$41.00	49,302			$35.44	69,800			$35.06
Awarded	(32,368	)		$48.10	—		—		—		—
Unearned Grant Award	—		—		(22,909	)		$54.50	(24,615	)		$41.97
Forfeited	(1,100	)		$34.35	(25,729	)		$36.45	(2,598	)		$38.78
Non-vested as of December 31,	128,333			$28.00	122,489			$38.15	121,825			$41.96

(a) Shares granted includes accrued dividends.

Less than 0.1 million performance shares were granted in January 2011 for the three-year performance period ending in 2013. The ultimate issuance is contingent upon the attainment of certain future market goals of ALLETE during the performance periods. The grant date fair value of the performance shares granted was $1.4 million.

Less than 0.1 million performance shares were awarded in February 2011 for the three-year performance period ending in 2010. The grant date fair value of the shares awarded was $1.6 million.

Less than 0.1 million performance shares were awarded in February 2012 for the three-year performance period ending in 2011. The grant date fair value of the shares awarded was $1.4 million.


Note 17.	Employee Stock and Incentive Plans (Continued)

Restricted Stock Units. The following table presents information regarding our available restricted stock units as of December 31, 2011.



	2011				2010				2009
	Number of Shares		Weighted- Average Grant Date Fair Value		Number of Shares		Weighted- Average Grant Date Fair Value		Number of Shares		Weighted- Average Grant Date Fair Value
Available as of January 1,	43,803			$30.61	28,983			$29.41	—		—
Granted (a)	20,136			$36.74	26,589			$31.83	30,465			$29.41
Awarded	(215	)		$30.30	(3,091	)		$29.75	—		—
Forfeited	(260	)		$29.41	(8,678	)		$30.62	(1,482	)		$29.41
Available as of December 31,	63,464			$22.88	43,803			$30.61	28,983			$29.41

(a) Shares granted includes accrued dividends.

Less than 0.1 million restricted stock units were granted in January 2011 for the vesting period ending in 2013. The grant date fair value of the restricted stock units granted was $0.6 million.

Less than 0.1 million restricted stock units were awarded in February 2011. The grant date fair value of the shares awarded was less than $0.1 million.

Less than 0.1 million restricted stock units were awarded in February 2012. The grant date fair value of the shares awarded was $0.8 million.

- Definition

The entire disclosure for compensation-related costs for equity-based compensation, which may include disclosure of policies, compensation plan details, allocation of equity compensation, incentive distributions, equity-based arrangements to obtain goods and services, deferred compensation arrangements, employee stock ownership plan details and employee stock purchase plan details.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 123R
-Paragraph 64, 65, A240
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Statement of Position (SOP)
-Number 93-6
-Paragraph 53
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 14

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 50
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6406099&loc=d3e25284-112666

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5047-113901

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5444-113901

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 40
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6418621&loc=d3e17540-113929

+ Details

Quarterly Financial Data (Unaudited)

12 Months Ended

Dec. 31, 2011

Quarterly Financial Data (Unaudited) [Abstract]

Quarterly Financial Data (Unaudited) [Text Block]

Quarterly Financial Data (Unaudited)

Information for any one quarterly period is not necessarily indicative of the results which may be expected for the year.



Quarter Ended	Mar. 31		Jun. 30		Sept. 30		Dec. 31
Millions Except Earnings Per Share
2011
Operating Revenue		$242.2		$219.9		$226.9		$239.2
Operating Income		$50.8		$26.1		$38.9		$34.2
Net Income Attributable to ALLETE		$37.2		$17.0		$20.5		$19.1
Earnings Per Share of Common Stock
Basic		$1.07		$0.49		$0.57		$0.53
Diluted		$1.07		$0.48		$0.57		$0.53
2010
Operating Revenue		$233.6		$211.2		$224.1		$238.1
Operating Income		$46.1		$31.7		$35.3		$22.7
Net Income Attributable to ALLETE		$23.0		$19.4		$19.6		$13.3
Earnings Per Share of Common Stock
Basic		$0.68		$0.57		$0.57		$0.38
Diluted		$0.68		$0.57		$0.56		$0.38

- Definition

The entire disclosure for the quarterly financial data in the annual financial statements. The disclosure may include a tabular presentation of financial information for each fiscal quarter for the current and previous year, including revenues, gross profit, income or loss before extraordinary items and earnings per share data. It also includes an indication if the information in the note is unaudited, comments on the aggregate effect of year-end adjustments, and an explanation of matters or transactions that affect comparability or are pertinent to an understanding of the information furnished.

+ References + Details

Schedule II

12 Months Ended

Dec. 31, 2011

Schedule II [Abstract]

Valuation and Qualifying Accounts and Reserves [Text Block]

Schedule II

ALLETE

Valuation and Qualifying Accounts and Reserves



	Balance at Beginning of Period		Additions Charged Other to Income Charges			Deductions from Reserves (a)		Balance at End of Period
	Balance at Beginning of Period		Additions Charged Other to Income Charges			Deductions from Reserves (a)		Balance at End of Period
Millions
Reserve Deducted from Related Assets
Reserve For Uncollectible Accounts
2009 Trade Accounts Receivable		$0.7		$1.3	—		$1.1		$0.9
Finance Receivables – Long-Term		$0.1		$0.3	—	—			$0.4
2010 Trade Accounts Receivable		$0.9		$1.1	—		$1.1		$0.9
Finance Receivables – Long-Term		$0.4		$0.8	—		$0.4		$0.8
2011 Trade Accounts Receivable		$0.9		$1.3	—		$1.3		$0.9
Finance Receivables – Long-Term		$0.8		$0.1	—		$0.3		$0.6
Deferred Asset Valuation Allowance
2009 Deferred Tax Assets		$0.4	$(0.1)		—	—			$0.3
2010 Deferred Tax Assets		$0.3		$0.2	—	—			$0.5
2011 Deferred Tax Assets		$0.5	$(0.1)		—	—			$0.4


(a)	Includes uncollectible accounts written off.

Operations and Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2011
Operations and Significant Accounting Policies [Abstract]
Principles of Consolidation [Policy Text Block]	Principles of Consolidation. Our consolidated financial statements include the accounts of ALLETE and all of our majority-owned subsidiary companies. All material intercompany balances and transactions have been eliminated in consolidation.
Cash and Cash Equivalents [Policy Text Block]	Cash and Cash Equivalents. We consider all investments purchased with original maturities of three months or less to be cash equivalents.
Accounts Receivable [Policy Text Block]	Accounts Receivable. Accounts receivable are reported on the balance sheet net of an allowance for doubtful accounts. The allowance is based on our evaluation of the receivable portfolio under current conditions, overall portfolio quality, review of specific problems and such other factors that, in our judgment, deserve recognition in estimating losses.
Long-Term Finance Receivables [Policy Text Block]	Long-Term Finance Receivables. Long-term finance receivables relating to our real estate operations are collateralized by property sold, accrue interest at market-based rates and are net of an allowance for doubtful accounts. We assess delinquent finance receivables by comparing the balance of such receivables to the estimated fair value of the collateralized property. If the fair value of the property is less than the finance receivable, we record a reserve for the difference. We estimate fair value based on recent property tax assessed values or current appraisals. (See Note 7. Investments.) Long-term finance receivables are collateralized by property sold, accrue interest at market-based rates and are net of an allowance for doubtful accounts.
Available-for-sale Securities [Policy Text Block]	Available-for-Sale Securities. Available-for-sale securities are recorded at fair value with unrealized gains and losses included in accumulated other comprehensive income (loss), net of tax. Unrealized losses that are other than temporary are recognized in earnings. We use the specific identification method as the basis for determining the cost of securities sold. Our policy is to review available-for-sale securities for other than temporary impairment on a quarterly basis by assessing such factors as the share price trends and the impact of overall market conditions. (See Note 7. Investments.)
Inventories [Policy Text Block]	Inventories. Inventories are stated at the lower of cost or market. Amounts removed from inventory are recorded on an average cost basis.
Property, Plant and Equipment [Policy Text Block]	Property, Plant and Equipment. Property, plant and equipment are recorded at original cost and are reported on the balance sheet net of accumulated depreciation. Expenditures for additions, significant replacements, improvements and major plant overhauls are capitalized; maintenance and repair costs are expensed as incurred. Gains or losses on non-rate base property, plant and equipment are recognized when they are retired or otherwise disposed. When regulated utility property, plant and equipment are retired or otherwise disposed, no gain or loss is recognized in accordance with the accounting standards for Regulated Operations. Our Regulated Operations capitalize AFUDC, which includes both an interest and equity component. AFUDC represents the cost of both debt and equity funds used to finance utility plant additions during construction periods. AFUDC amounts capitalized are included in rate base and are recovered from customers as the related property is depreciated. The MPUC has approved current cost recovery for several large capital projects recently, resulting in lower recognition of AFUDC. (See Note 3. Property, Plant and Equipment.) Depreciation is computed using the straight-line method over the estimated useful lives of the various classes of assets.
Long-Lived Asset Impairments [Policy Text Block]	Impairment of Long-Lived Assets. We review our long-lived assets for indicators of impairment in accordance with the accounting standards for property, plant and equipment on a quarterly basis. Long-lived assets that we evaluate include our real estate assets of ALLETE Properties. In accordance with the accounting standards for property, plant and equipment, if indicators of impairment exist, we test our real estate assets for recoverability by comparing the carrying amount of the asset to the undiscounted future net cash flows expected to be generated by the asset. Cash flows are assessed at the lowest level of identifiable cash flows, which may be by each land parcel, combining various parcels into bulk sales, or other combinations thereof. Our consideration of possible impairment for our real estate assets requires us to make estimates of future cash flows on an undiscounted basis. The undiscounted future net cash flows are impacted by trends and factors known to us at the time they are calculated and our expectations related to: management's best estimate of future sales prices; holding period and timing of sales; method of disposition; and future expenditures necessary to develop and maintain the operations, including community development district assessments, property taxes and normal operation and maintenance costs. These estimates and expectations are specific to each land parcel or various bulk sales, and may vary among each land parcel or bulk sale. If the excess of undiscounted cash flows over the carrying value of a property is small, there is a greater risk of future impairment in the event of such changes and any resulting impairment charges could be material.
Derivatives [Policy Text Block]	Derivatives. ALLETE is exposed to certain risks relating to its business operations that can be managed through the use of derivative instruments. ALLETE may enter into derivative instruments to manage interest rate risk related to certain variable-rate borrowings.
Accounting for Stock-Based Compensation [Policy Text Block]	Accounting for Stock-Based Compensation. We apply the fair value recognition guidance for share-based payments. Under this guidance, we recognize stock-based compensation expense for all share-based payments granted, net of an estimated forfeiture rate. (See Note 17. Employee Stock and Incentive Plans.)
Environmental Liabilities [Policy Text Block]	Environmental Liabilities. We review environmental matters for disclosure on a quarterly basis. Accruals for environmental matters are recorded when it is probable that a liability has been incurred and the amount of the liability can be reasonably estimated, based on current law and existing technologies. These accruals are adjusted periodically as assessment and remediation efforts progress or as additional technical or legal information becomes available. Accruals for environmental liabilities are included in the balance sheet at undiscounted amounts and exclude claims for recoveries from insurance or other third parties. Costs related to environmental contamination treatment and cleanup are charged to operating expense unless recoverable in rates from customers. (See Note 11. Commitments, Guarantees and Contingencies.)
Revenue Recognition [Policy Text Block]	Revenue Recognition. Regulated utility rates are under the jurisdiction of Minnesota, Wisconsin and federal regulatory authorities. Customers are billed on a cycle basis. Revenue is accrued for service provided but not billed. Regulated utility electric rates include adjustment clauses that: (1) bill or credit customers for fuel and purchased energy costs above or below the base levels in rate schedules; (2) bill retail customers for the recovery of conservation improvement program expenditures not collected in base rates; and (3) bill customers for the recovery of certain transmission and renewable energy expenditures. Fuel and purchased power expense is deferred to match the period in which the revenue for fuel and purchased power expense is collected from customers pursuant to the fuel adjustment clause. BNI recognizes revenue when coal is delivered.
Unamortized Discount and Premium on Debt [Policy Text Block]	Unamortized Discount and Premium on Debt. Discount and premium on debt are deferred and amortized over the terms of the related debt instruments using the straight-line method.
Income Taxes [Policy Text Block]	Income Taxes. We file a consolidated federal income tax return. We account for income taxes using the liability method in accordance with the accounting standards for income taxes. Under the liability method, deferred income tax assets and liabilities are established for all temporary differences in the book and tax basis of assets and liabilities, based upon enacted tax laws and rates applicable to the periods in which the taxes become payable. Due to the effects of regulation on Minnesota Power and SWL&P, certain adjustments made to deferred income taxes are, in turn, recorded as regulatory assets or liabilities. Federal investment tax credits have been recorded as deferred credits and are being amortized to income tax expense over the service lives of the related property. In accordance with the accounting standards for uncertainty in income taxes, we are required to recognize in our financial statements the largest tax benefit of a tax position that is “more-likely-than-not” to be sustained on audit, based solely on the technical merits of the position as of the reporting date. The term “more-likely-than-not” means more than 50 percent likely. (See Note 14. Income Tax Expense.)
Excise Taxes [Policy Text Block]	Excise Taxes. We collect excise taxes from our customers levied by government entities. These taxes are stated separately on the billing to the customer and recorded as a liability to be remitted to the government entity. We account for the collection and payment of these taxes on a net basis.

Property, Plant and Equipment (Policies)	12 Months Ended
Property, Plant and Equipment (Policies)	Dec. 31, 2011
Property, Plant and Equipment [Abstract]
Depreciation [Policy Text Block]	Property, Plant and Equipment. Property, plant and equipment are recorded at original cost and are reported on the balance sheet net of accumulated depreciation. Expenditures for additions, significant replacements, improvements and major plant overhauls are capitalized; maintenance and repair costs are expensed as incurred. Gains or losses on non-rate base property, plant and equipment are recognized when they are retired or otherwise disposed. When regulated utility property, plant and equipment are retired or otherwise disposed, no gain or loss is recognized in accordance with the accounting standards for Regulated Operations. Our Regulated Operations capitalize AFUDC, which includes both an interest and equity component. AFUDC represents the cost of both debt and equity funds used to finance utility plant additions during construction periods. AFUDC amounts capitalized are included in rate base and are recovered from customers as the related property is depreciated. The MPUC has approved current cost recovery for several large capital projects recently, resulting in lower recognition of AFUDC. (See Note 3. Property, Plant and Equipment.) Depreciation is computed using the straight-line method over the estimated useful lives of the various classes of assets.
Asset Retirement Obligations [Policy Text Block]	Asset Retirement Obligations. We recognize, at fair value, obligations associated with the retirement of certain tangible, long-lived assets that result from the acquisition, construction or development and/or normal operation of the asset.

- Definition

Disclosure of accounting policy for determining amounts to accrue and charge against earnings so as to satisfy legal obligations associated with the retirement (through sale, abandonment, recycling, or disposal in some other manner) of a tangible long-lived asset that result from the acquisition, construction, or development and (or) the normal operation of a long-lived asset. This accounting policy disclosure excludes obligations arising 1) in connection with leased property, whether imposed by a lease agreement or by a party other than the lessor, that meet the definition of either minimum lease payments or contingent rentals; 2) solely from a plan to sell or otherwise dispose of a long-lived asset and 3) from certain environmental remediation liabilities.

+ References + Details

- Definition

Disclosure of accounting policy for property, plant and equipment which may include the basis of such assets, depreciation methods used and estimated useful lives, the entity's capitalization policy, including its accounting treatment for costs incurred for repairs and maintenance activities, whether such asset balances include capitalized interest and the method by which such is calculated, how disposals of such assets are accounted for and how impairment of such assets is assessed and recognized.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Principles Board Opinion (APB)
-Number 22
-Paragraph 12, 13
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 13
-Subparagraph a
-Article 5

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Principles Board Opinion (APB)
-Number 12
-Paragraph 5
-Subparagraph d
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 43
-Chapter 9
-Section C
-Paragraph 5
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 144
-Paragraph 7
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 34
-Paragraph 8, 9
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6367646&loc=d3e18780-107790

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-URI http://asc.fasb.org/subtopic&trid=2155824

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.13(a))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Regulatory Matters (Policies)	12 Months Ended
Regulatory Matters (Policies)	Dec. 31, 2011
Regulatory Matters [Abstract]
Regulatory Assets and Liabilities [Policy Text Block]	Our regulated utility operations are subject to the accounting standards on Regulated Operations. We capitalize, as regulatory assets, incurred costs which are probable of recovery in future utility rates. Regulatory liabilities represent amounts expected to be refunded or credited to customers in rates.

- Definition

Disclosure of accounting policy for public utilities. Examples include a discussion about the scope criteria and appropriateness for and extent of the application of generally accepted accounting principles related to accounting for the effects of certain types of regulation (may include identification of specific business units). Other examples of the disclosures may include: descriptions of the form and economic effects of regulation (for example, but not limited to, recording of regulatory assets and liabilities to the rate setting process); statement about periodic assessments of periodic assessments of generally accepted accounting principles related to accounting for the effects of certain types of regulation; information regarding amortization of and return on regulatory assets and liabilities, including the remaining amounts and recovery or settlement periods; accounting for changes to recovery estimates; AFUDC, plant abandonment's and plant disallowances.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 71
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 90
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 92
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 101
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6367646&loc=d3e18780-107790

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 980
-SubTopic 10
-URI http://asc.fasb.org/subtopic&trid=2156579

+ Details

Investments (Policies)	12 Months Ended
Investments (Policies)	Dec. 31, 2011
Investments [Abstract]
Land Held-for-Sale [Policy Text Block]	Land inventory is accounted for as held for use and is recorded at cost, unless the carrying value is determined not to be recoverable in accordance with the accounting standards for property, plant and equipment, in which case the land inventory is written down to fair value. Land values are reviewed for impairment on a quarterly basis.
Long-Term Finance Receivables [Policy Text Block]	Long-Term Finance Receivables. Long-term finance receivables relating to our real estate operations are collateralized by property sold, accrue interest at market-based rates and are net of an allowance for doubtful accounts. We assess delinquent finance receivables by comparing the balance of such receivables to the estimated fair value of the collateralized property. If the fair value of the property is less than the finance receivable, we record a reserve for the difference. We estimate fair value based on recent property tax assessed values or current appraisals. (See Note 7. Investments.) Long-term finance receivables are collateralized by property sold, accrue interest at market-based rates and are net of an allowance for doubtful accounts.

- Definition

Disclosure of accounting policy for finance, loan and lease receivables, including those held for investment and those held for sale. This disclosure may include (1) the basis at which such receivables are carried in the entity's statements of financial position (2) how the level of the allowance for loan and lease losses is determined (3) when impairments, charge-offs or recoveries are recognized for such receivables (4) the treatment of origination fees and costs, including the amortization method for net deferred fees or costs (5) the treatment of any premiums or discounts or unearned income (6) the entity's income recognition (revenues, expenses and gains and losses arising from committing to issue, issuing, granting, collecting, terminating, modifying and holding loans) policies for such receivables, including those that are impaired, past due or placed on nonaccrual status and (7) the treatment of foreclosures or repossessions.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Principles Board Opinion (APB)
-Number 22
-Paragraph 12
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 114
-Paragraph 20
-Subparagraph b
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Statement of Position (SOP)
-Number 01-6
-Paragraph 13
-Subparagraph b
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 3-5
-Article 5

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 9
-URI http://asc.fasb.org/extlink&oid=6965416&loc=d3e5144-111524

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6367646&loc=d3e18780-107790

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6378556&loc=d3e10133-111534

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=6965416&loc=d3e5093-111524

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (b,d)
-URI http://asc.fasb.org/extlink&oid=6965416&loc=d3e5212-111524

+ Details

Fair Value (Policies)	12 Months Ended
Fair Value (Policies)	Dec. 31, 2011
Fair Value Disclosures [Abstract]
Fair Value Transfers [Policy Text Block]	The Company’s policy is to recognize transfers in and transfers out as of the actual date of the event or change in circumstances that caused the transfer.

Pension and Other Postretirement Benefit Plans (Policies)	12 Months Ended
	Dec. 31, 2011
Pension and Other Postretirement Benefit Plans [Abstract]
Pension and Other Postretirement Plans, Policy [Policy Text Block]	Accounting for defined benefit pension and postretirement benefit plans requires that employers recognize on a prospective basis the funded status of their defined benefit pension and other postretirement plans on their consolidated balance sheet and recognize as a component of other comprehensive income, net of tax, the gains or losses and prior service costs or credits that arise during the period but are not recognized as components of net periodic benefit cost. The defined benefit pension and postretirement health and life benefit costs recognized annually by our regulated companies are expected to be recovered through rates filed with our regulatory jurisdictions. As a result, these amounts that are required to otherwise be recognized in accumulated other comprehensive income have been recognized as a long-term regulatory asset on our consolidated balance sheet, in accordance with the accounting standards for Regulated Operations. The defined benefit pension and postretirement health and life benefit costs associated with our other non-rate base operations are recognized in accumulated other comprehensive income.

- Definition

Disclosure of accounting policy for pension and other postretirement benefit plans. This accounting policy may address (1) the types of plans sponsored by the entity, and the benefits provided by each plan (2) groups that participate in (or are covered by) each plan (3) how plan assets, liabilities and expenses are measured, including the use of any actuaries and (4) significant assumptions used by the entity to value plan assets and liabilities and how such assumptions are derived.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 106
-Paragraph 19, 20, 21, 22
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
-Paragraph 5, 6, 7, 9, 11, 12, 13
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 158
-Paragraph 4, 5, 6, 7
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 87
-Paragraph 15-19, 63, 64
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
-Paragraph 5
-Subparagraph a
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
-Paragraph 5
-Subparagraph b
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
-Paragraph 5
-Subparagraph h
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
-Paragraph 5
-Subparagraph q
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
-Paragraph 8
-Subparagraph m
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6367646&loc=d3e18780-107790

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 70
-URI http://asc.fasb.org/subtopic&trid=2235116

Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 60
-URI http://asc.fasb.org/subtopic&trid=2235172

Reference 13: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 80
-URI http://asc.fasb.org/subtopic&trid=2235144

Reference 14: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 30
-URI http://asc.fasb.org/subtopic&trid=2235074

+ Details

Employee Stock and Incentive Plans (Policies)	12 Months Ended
Employee Stock and Incentive Plans (Policies)	Dec. 31, 2011
Employee Stock and Incentive Plans [Abstract]
Executive Option and Incentive Plans [Policy Text Block]	Stock Incentive Plan. Under our Executive Long-Term Incentive Compensation Plan (Executive Plan), share-based awards may be issued to key employees through a broad range of methods, including non-qualified and incentive stock options, performance shares, performance units, restricted stock, stock appreciation rights and other awards.
Employee Stock Ownership Plan [Policy Text Block]	According to the accounting standards for stock compensation, unallocated shares of ALLETE common stock currently held and purchased by the ESOP will be treated as unearned ESOP shares and not considered outstanding for earnings per share computations. ESOP shares are included in earnings per share computations after they are allocated to participants.
Performance Shares, RSU's, ESPP, and RSOP [Policy Text Block]	Performance Shares. Under the performance share awards plan, the number of shares earned is contingent upon attaining specific market goals over a three-year performance period. Market goals are measured by total shareholder return relative to a group of peer companies. In the case of qualified retirement, death or disability during a performance period, a pro rata portion of the award will be earned at the conclusion of the performance period based on the market goals achieved. In the case of termination of employment for any reason other than qualified retirement, death or disability, no award will be earned. If there is a change in control, a pro rata portion of the award will be paid based on the greater of actual performance up to the date of the change in control or target performance. The fair value of these awards is determined by the probability of meeting the total shareholder return goals. Compensation cost is recognized over the three-year performance period based on our estimate of the number of shares which will be earned by the award recipients. Restricted Stock Units. Under the restricted stock units plan, shares vest monthly over a three-year period. In the case of qualified retirement, death or disability, a pro rata portion of the award will be earned. In the case of termination of employment for any other reason other than qualified retirement, death or disability, no award will be earned. If there is a change in control, a pro rata portion of the award will be paid. The fair value of these awards is equal to the grant date fair value. Compensation cost is recognized over the three-year vesting period based on our estimate of the number of shares which will be earned by the award recipients. Employee Stock Purchase Plan (ESPP). Under our ESPP, eligible employees may purchase ALLETE common stock at a 5 percent discount from the market price. Because the discount is not greater than 5 percent, we are not required to apply fair value accounting to these awards. RSOP. The RSOP is a contributory defined contribution plan subject to the provisions of the Employee Retirement Income Security Act of 1974, as amended, and qualifies as an employee stock ownership plan and profit sharing plan. The RSOP provides eligible employees an opportunity to save for retirement.

Operations and Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2011

Operations and Significant Accounting Policies [Abstract]

Supplemental Statement of Cash Flow Information [Table Text Block]

Supplemental Statement of Cash Flow Information



Consolidated Statement of Cash Flows
Supplemental Disclosure
Year Ended December 31	2011		2010		2009
Millions
Cash Paid During the Period for Interest – Net of Amounts Capitalized		$43.2		$35.7		$29.8
Cash Received During the Period for Income Taxes (a)	$(11.4)		$(54.2)		$(5.6)
Noncash Investing and Financing Activities
Increase (Decrease) in Accounts Payable for Capital Additions to Property, Plant and Equipment		$5.9		$7.5	$(24.1)
AFUDC – Equity		$2.5		$4.2		$5.8
ALLETE Common Stock Contributed to the Pension Plan	$(20.0)		—		$(12.0)


(a)	Due to bonus depreciation provisions in 2009 and 2010 federal legislation, NOLs were generated which resulted in little to no estimated tax payments, and refunds were received from NOL carrybacks against prior years' taxable income.

Accounts Receivable [Table Text Block]



Accounts Receivable
As of December 31	2011		2010
Millions
Trade Accounts Receivable
Billed		$63.7		$67.6
Unbilled	15.6		18.9
Less: Allowance for Doubtful Accounts	0.9		0.9
Total Trade Accounts Receivable	78.4		85.6
Income Taxes Receivable (a)	1.3		13.9
Total Accounts Receivable - Net		$79.7		$99.5


(a)	Income Taxes Receivable decreased from 2010 due to the collection of a 2010 NOL carryback claim. (See Note 14. Income Tax Expense.)

Inventories [Table Text Block]



Inventories
As of December 31	2011		2010
Millions
Fuel		$28.6		$22.9
Materials and Supplies	40.5		37.1
Total Inventories		$69.1		$60.0

Prepayments and Other Current Assets [Table Text Block]



Prepayments and Other Current Assets
As of December 31	2011		2010
Millions
Deferred Fuel Adjustment Clause		$17.5		$20.6
Other	9.6		8.0
Total Prepayments and Other Current Assets		$27.1		$28.6

Other Liabilities [Table Text Block]



Other Current Liabilities
As of December 31	2011		2010
Millions
Customer Deposits (a)		$16.3		$2.9
Other	29.3		30.8
Total Other Current Liabilities		$45.6		$33.7


(a)	Higher customer deposits in 2011 were primarily due to a customer security deposit for capital expenditures relating to a transmission project.



Other Non-Current Liabilities
As of December 31	2011		2010
Millions
Asset Retirement Obligation		$57.0		$50.3
Other	48.1		43.1
Total Other Non-Current Liabilities		$105.1		$93.4

Business Segments (Tables)

12 Months Ended

Dec. 31, 2011

Dec. 31, 2010

Dec. 31, 2009

Business Segments [Abstract]

Business Segments [Table Text Block]



	Consolidated			Regulated Operations			Investments and Other
Millions
2011
Operating Revenue		$928.2			$851.9			$76.3
Fuel and Purchased Power Expense	306.6			306.6			—
Operating and Maintenance Expense	381.2			301.5			79.7
Depreciation Expense	90.4			85.4			5.0
Operating Income (Loss)	150.0			158.4			(8.4		)
Interest Expense	(43.6		)	(35.8		)	(7.8		)
Equity Earnings in ATC	18.4			18.4			—
Other Income	4.4			2.6			1.8
Income (Loss) Before Non-Controlling Interest and Income Taxes	129.2			143.6			(14.4		)
Income Tax Expense (Benefit)	35.6			43.2			(7.6		)
Net Income (Loss)	93.6			100.4			(6.8		)
Less: Non-Controlling Interest in Subsidiaries	(0.2		)	—			(0.2		)
Net Income (Loss) Attributable to ALLETE		$93.8			$100.4		$(6.6)
Total Assets		$2,876.0			$2,579.8			$296.2
Capital Additions		$246.8			$228.0			$18.8



	Consolidated			Regulated Operations			Investments and Other
Millions
2010
Operating Revenue		$907.0			$835.5			$71.5
Fuel and Purchased Power Expense	325.1			325.1			—
Operating and Maintenance Expense	365.6			292.3			73.3
Depreciation Expense	80.5			76.1			4.4
Operating Income (Loss)	135.8			142.0			(6.2		)
Interest Expense	(39.2		)	(32.3		)	(6.9		)
Equity Earnings in ATC	17.9			17.9			—
Other Income	4.6			3.8			0.8
Income (Loss) Before Non-Controlling Interest and Income Taxes	119.1			131.4			(12.3		)
Income Tax Expense (Benefit)	44.3			51.6			(7.3		)
Net Income (Loss)	74.8			79.8			(5.0		)
Less: Non-Controlling Interest in Subsidiaries	(0.5		)	—			(0.5		)
Net Income (Loss) Attributable to ALLETE		$75.3			$79.8		$(4.5)
Total Assets		$2,609.1			$2,375.4			$233.7
Capital Additions		$260.0			$256.4			$3.6



	Consolidated			Regulated Operations			Investments and Other
Millions
2009
Operating Revenue		$766.7			$689.4			$77.3
Prior Year Rate Refunds	(7.6		)	(7.6		)	—
Total Operating Revenue	759.1			681.8			77.3
Fuel and Purchased Power Expense	279.5			279.5			—
Operating and Maintenance Expense	308.9			235.8			73.1
Depreciation Expense	64.7			60.2			4.5
Operating Income (Loss)	106.0			106.3			(0.3		)
Interest Expense	(33.8		)	(28.3		)	(5.5		)
Equity Earnings in ATC	17.5			17.5			—
Other Income (Expense)	1.8			5.8			(4.0		)
Income (Loss) Before Non-Controlling Interest and Income Taxes	91.5			101.3			(9.8		)
Income Tax Expense (Benefit)	30.8			35.4			(4.6		)
Net Income (Loss)	60.7			65.9			(5.2		)
Less: Non-Controlling Interest in Subsidiaries	(0.3		)	—			(0.3		)
Net Income (Loss) Attributable to ALLETE		$61.0			$65.9		$(4.9)
Total Assets		$2,393.1			$2,184.0			$209.1
Capital Additions		$303.7			$299.2			$4.5

- Definition

Tabular disclosure of the profit or loss and total assets for each reportable segment. An entity discloses certain information on each reportable segment if the amounts (a) are included in the measure of segment profit or loss reviewed by the chief operating decision maker or (b) are otherwise regularly provided to the chief operating decision maker, even if not included in that measure of segment profit or loss.

+ References + Details

Property, Plant and Equipment (Tables)

12 Months Ended

Dec. 31, 2011

Property, Plant and Equipment [Abstract]

Property, Plant, and Equipment [Table Text Block]



Property, Plant and Equipment
As of December 31	2011			2010
Millions
Regulated Utility		$2,794.8			$2,649.2
Construction Work in Progress	155.0			86.6
Accumulated Depreciation	(1,024.6		)	(975.8		)
Regulated Utility Plant - Net	1,925.2			1,760.0
Non-Rate Base Energy Operations	106.4			88.4
Construction Work-in-Progress	2.3			4.5
Accumulated Depreciation	(51.4		)	(48.0		)
Non-Rate Base Energy Operations Plant - Net	57.3			44.9
Other Plant - Net	0.2			0.7
Property, Plant and Equipment - Net		$1,982.7			$1,805.6

Estimated Useful Lives of Property, Plant and Equipment [Table Text Block]



Estimated Useful Lives of Property, Plant and Equipment

Regulated Utility –	Generation	4 to 35 years	Non-Rate Base Operations	3 to 61 years
	Transmission	42 to 61 years	Other Plant	5 to 25 years
	Distribution	14 to 65 years

Asset Retirement Obligation [Table Text Block]



Asset Retirement Obligation
Millions
Obligation as of December 31, 2009		$44.6
Accretion Expense	2.9
Additional Liabilities Incurred in 2010	2.8
Obligation as of December 31, 2010	50.3
Accretion Expense	6.4
Additional Liabilities Incurred in 2011	0.3
Obligation as of December 31, 2011		$57.0

Jointly-Owned Electric Facility (Tables)

12 Months Ended

Dec. 31, 2011

Jointly-Owned Electric Facility [Abstract]

Jointly Owned Electric Facility [Table Text Block]



	Plant in Service		Accumulated Depreciation		Construction Work in Progress		% Ownership
Millions
Boswell Unit 4		$406.9		$177.4		$8.8	80
CapX2020	11.9		—		15.9		9.3 - 14.7
Total		$418.8		$177.4		$24.7

Regulatory Matters (Tables)

12 Months Ended

Dec. 31, 2011

Regulatory Matters [Abstract]

Regulatory Assets and Liabilities [Text Block]


Note 5.	Regulatory Matters (Continued)



Regulatory Assets and Liabilities
As of December 31	2011		2010
Millions
Current Regulatory Assets (a)
Deferred Fuel		$17.5		$20.6
Total Current Regulatory Assets	17.5		20.6
Non-Current Regulatory Assets
Future Benefit Obligations Under
Defined Benefit Pension and Other Postretirement Plans	292.8		257.9
Boswell Unit 3 Environmental Rider	—		20.5
Income Taxes	28.6		17.3
Asset Retirement Obligation	9.8		7.8
PPACA Income Tax Deferral	5.0		—
Conservation Improvement Program	4.6		0.7
Other	5.1		6.0
Total Non-Current Regulatory Assets	345.9		310.2

Total Regulatory Assets		$363.4		$330.8

Non-Current Regulatory Liabilities
Income Taxes		$21.9		$23.4
Plant Removal Obligations	15.0		16.9
Other	6.6		3.3
Total Non-Current Regulatory Liabilities		$43.5		$43.6


(a)	Current regulatory assets are included in prepayments and other on the consolidated balance sheet.

Investment in ATC (Tables)

12 Months Ended

Dec. 31, 2011

Investment in ATC [Abstract]

ALLETE's Interest in ATC [Table Text Block]



ALLETE’s Interest in ATC
Year Ended December 31	2011			2010
Millions
Equity Investment Beginning Balance		$93.3			$88.4
Cash Investments	2.0			1.6
Equity in ATC Earnings	18.4			17.9
Distributed ATC Earnings	(14.8		)	(14.6		)
Equity Investment Ending Balance		$98.9			$93.3

ATC Summarized Financial Data [Table Text Block]



ATC Summarized Financial Data
Balance Sheet Data
As of December 31	2011		2010
Millions
Current Assets		$58.7		$59.9
Non-Current Assets	3,053.7		2,888.4
Total Assets		$3,112.4		$2,948.3
Current Liabilities		$298.5		$428.4
Long-Term Debt	1,400.0		1,175.0
Other Non-Current Liabilities	82.6		84.9
Members’ Equity	1,331.3		1,260.0
Total Liabilities and Members’ Equity		$3,112.4		$2,948.3



Income Statement Data
Year Ended December 31	2011		2010		2009
Millions
Revenue		$567.2		$556.7		$521.5
Operating Expense	261.6		251.1		230.3
Other Expense	81.7		85.9		77.8
Net Income		$223.9		$219.7		$213.4
ALLETE’s Equity in Net Income		$18.4		$17.9		$17.5

Investments (Tables)

12 Months Ended

Dec. 31, 2011

Investments [Abstract]

Other Investments and ALLETE Properties [Table Text Block]



Investments
As of December 31	2011		2010
Millions
ALLETE Properties		$91.3		$94.0
Available-for-sale Securities	24.7		25.2
Other	16.3		6.8
Total Investments		$132.3		$126.0


Note 7.	Investments (Continued)



ALLETE Properties
As of December 31	2011			2010
Millions
Land Inventory Beginning Balance		$86.0			$74.9
Deeds to Collateralized Property (a)	1.8			9.9
Land Impairment (b)	(1.7		)	—
Cost of Real Estate Sold	(0.3		)	—
Capitalized Improvements and Other	0.2			1.2
Land Inventory Ending Balance	86.0			86.0
Long-Term Finance Receivables (net of allowances of $0.6 and $0.8) (a)	2.0			3.7
Other	3.3			4.3
Total Real Estate Assets		$91.3			$94.0


(a)	In 2010, the deeds to collateralized property resulted primarily from an entity which filed for Chapter 11 bankruptcy and were recorded at fair value net of estimated selling costs.


(b)	The land impairment charge was a result of an impairment analysis conducted in the fourth quarter of 2011 where the cost basis was reduced to the estimated fair value.

Available-for-sale Securities Reconciliation [Table Text Block]



Available-For-Sale Securities
Millions			Gross Unrealized
As of December 31	Cost		Gain		(Loss)	Fair Value
2011		$27.3		$0.1	$(2.7)		$24.7
2010		$27.4		$0.2	$(2.4)		$25.2
2009		$33.1		$0.1	$(3.7)		$29.5

Available-for-sale Securities [Table Text Block]



	Net		Gross Realized		Net Unrealized Gain (Loss) in Other
Year Ended December 31	Proceeds		Gain	(Loss)	Comprehensive Income
2011		$5.5	—	—	$(0.4)
2010	$(1.7)		—	—		$1.4
2009		$6.7	—	—		$4.5

- Definition

Tabular disclosure of available-for-sale securities which consist of all investments in certain debt and equity securities neither classified as trading or held-to-maturity securities. A debt security represents a creditor relationship with an enterprise. Debt securities include, among other items, US Treasury securities, US government securities, municipal securities, corporate bonds, convertible debt, commercial paper, and all securitized debt instruments. An equity security represents an ownership interest in an enterprise or the right to acquire or dispose of an ownership interest in an enterprise at fixed or determinable prices. Equity securities include, among other things, common stock, certain preferred stock, warrant rights, call options, and put options, but do not include convertible debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Emerging Issues Task Force (EITF)
-Number 03-1
-Paragraph 21
-Subparagraph a, b
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Staff Position (FSP)
-Number FAS115-1/124-1
-Paragraph 17
-Subparagraph a, b
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 115
-Paragraph 19, 20, 21
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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-SubTopic 10
-Section 50
-Paragraph 7
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Reference 5: http://www.xbrl.org/2003/role/presentationRef
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-Topic 942
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+ Details

Fair Value (Tables)

12 Months Ended

Dec. 31, 2011

Dec. 31, 2010

Fair Value Disclosures [Abstract]

Recurring Fair Value Measures [Table Text Block]



	At Fair Value as of December 31, 2011
Recurring Fair Value Measures	Level 1		Level 2		Level 3	Total
Millions
Assets:
Equity Securities		$17.6	—		—		$17.6
Available-for-sale Securities – Corporate Debt Securities	—			$8.2	—	8.2
Money Market Funds	11.4		—		—	11.4
Total Fair Value of Assets		$29.0		$8.2	—		$37.2

Liabilities:
Deferred Compensation	—			$12.8	—		$12.8
Derivatives - Interest Rate Swap	—		0.4		—	0.4
Total Fair Value of Liabilities	—			$13.2	—		$13.2
Total Net Fair Value of Assets (Liabilities)		$29.0	$(5.0)		—		$24.0



	At Fair Value as of December 31, 2010
Recurring Fair Value Measures	Level 1		Level 2		Level 3		Total
Millions
Assets:
Equity Securities		$19.4	—		—			$19.4
Available-for-sale Securities
Corporate Debt Securities	—			$7.5	—		7.5
Debt Securities Issued by States of the United States (ARS)	—		—			$6.7	6.7
Total Available-for-sale Securities	—		7.5		6.7		14.2
Money Market Funds	0.8		—		—		0.8
Total Fair Value of Assets		$20.2		$7.5		$6.7		$34.4

Liabilities:
Deferred Compensation	—			$13.3	—			$13.3
Total Fair Value of Liabilities	—			$13.3	—			$13.3

Total Net Fair Value of Assets (Liabilities)		$20.2	$(5.8)			$6.7		$21.1

Recurring Fair Value Measures Activity in Level 3 [Table Text Block]



Recurring Fair Value Measures Activity in Level 3	Debt Securities Issued by States of the United States (ARS)
Millions
Balance as of December 31, 2010		$6.7
Settled During the Period	—
Redeemed During the Period (a)	(6.7		)
Balance as of December 31, 2011	—


(a)	The ARS were redeemed at carrying value on January 5, 2011.



Recurring Fair Value Measures Activity in Level 3	Derivatives			Debt Securities Issued by States of the United States (ARS)
Millions
Balance as of December 31, 2009		$0.7			$6.7
Settled During the Period (a)	(0.7		)	—
Redeemed During the Period	—			—
Balance as of December 31, 2010	—				$6.7


(a)	During the second quarter of 2010, the $0.7 million of financial transmission rights derivatives were settled.

Financial Instruments [Table Text Block]



Financial Instruments	Carrying Amount		Fair Value
Millions
Long-Term Debt, Including Current Portion
December 31, 2011		$863.3		$966.4
December 31, 2010		$785.0		$796.7

- Definition

Tabular disclosure of the fair value measurement of assets using significant unobservable inputs (Level 3), a reconciliation of the beginning and ending balances, separately presenting changes during the period attributable to the following: (1) total gains or losses for the period (realized and unrealized), segregating those gains or losses included in earnings (or changes in net assets) and gains or losses recognized in other comprehensive income, and a description of where those gains or losses included in earnings (or changes in net assets) are reported in the statement of income (or activities); (2) purchases, sales, issuances, and settlements (each type disclosed separately); and (3) transfers in and transfers out of Level 3 (for example, transfers due to changes in the observability of significant inputs), by class of asset.

+ References + Details

- Definition

Tabular disclosure of the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments, assets, and liabilities. Such certain disclosures about the financial instruments, assets, and liabilities include: (1) the fair value of the required items together with their carrying amounts (as appropriate) and (2) the methodology and assumptions used in developing such estimates of fair value.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 107
-Paragraph 10
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
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-Name Statement of Financial Accounting Standard (FAS)
-Number 107
-Paragraph 15
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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef
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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef
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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 6: http://www.xbrl.org/2003/role/presentationRef
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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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+ Details

Short-Term and Long-Term Debt (Tables)

12 Months Ended

Dec. 31, 2011

Long-term Debt, Current and Noncurrent [Abstract]

Long-term Debt [Table Text Block]



Long-Term Debt
As of December 31	2011		2010
Millions
First Mortgage Bonds
4.86% Series Due 2013		$60.0		$60.0
6.94% Series Due 2014	18.0		18.0
7.70% Series Due 2016	20.0		20.0
8.17% Series Due 2019	42.0		42.0
5.28% Series Due 2020	35.0		35.0
4.85% Series Due 2021	15.0		15.0
4.95% Pollution Control Series F Due 2022	111.0		111.0
6.02% Series Due 2023	75.0		75.0
4.90% Series Due 2025	30.0		30.0
5.10% Series Due 2025	30.0		30.0
5.99% Series Due 2027	60.0		60.0
5.69% Series Due 2036	50.0		50.0
6.00% Series Due 2040	35.0		35.0
5.82% Series Due 2040	45.0		45.0
SWLP& First Mortgage Bonds 7.25% Series Due 2013	10.0		10.0
Senior Unsecured Notes 5.99% Due 2017	50.0		50.0
Variable Demand Revenue Refunding Bonds Series 1997 A, B, and C Due 2013 – 2020	28.2		28.3
Industrial Development Revenue Bonds 6.5% Due 2025	6.0		6.0
Industrial Development Variable Rate Demand Refunding Revenue Bonds Series 2006 Due 2025	27.8		27.8
Unsecured Term Loan Variable Rate Due 2014	75.0		—
Other Long-Term Debt, 1.0% – 8.0% Due 2012 – 2037	40.3		36.9
Total Long-Term Debt	863.3		785.0
Less: Due Within One Year	5.4		13.4
Net Long-Term Debt		$857.9		$771.6

- Definition

Tabular disclosure of long-debt instruments or arrangements, including identification, terms, features, collateral requirements and other information necessary to a fair presentation. These are debt arrangements that originally required repayment more than twelve months after issuance or greater than the normal operating cycle of the entity, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 22
-Article 5

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+ Details

Common Stock and Earnings Per Share (Tables)

12 Months Ended

Dec. 31, 2011

Common Stock and Earnings Per Share [Abstract]

Summary of Common Stock [Table Text Block]



Summary of Common Stock	Shares	Equity
	Thousands	Millions
Balance as of December 31, 2008	32,585		$534.1
Employee Stock Purchase Program	24	0.7
Invest Direct	456	13.6
Options and Stock Awards	8	1.1
Equity Issuance Program	1,685	51.9
Contributions to Pension	463	12.0
Balance as of December 31, 2009	35,221		$613.4
Employee Stock Purchase Program	19	0.6
Invest Direct	346	11.7
Options and Stock Awards	51	4.4
Equity Issuance Program	180	6.0
Balance as of December 31, 2010	35,817		$636.1
Employee Stock Purchase Program	20	0.8
Invest Direct	437	17.2
Options and Stock Awards	109	6.7
Equity Issuance Program	400	16.0
Purchase of Non-Controlling Interest	222	8.8
Contributions to Pension	508	20.0
Balance as of December 31, 2011	37,513		$705.6

Reconciliation of Basic and Diluted Earnings Per Share [Table Text Block]



Reconciliation of Basic and Diluted
Earnings Per Share			Dilutive
Year Ended December 31	Basic		Securities	Diluted
Millions Except Per Share Amounts
2011
Net Income Attributable to ALLETE		$93.8			$93.8
Common Shares	35.3		0.1	35.4
Per Share of Common Stock		$2.66			$2.65
2010
Net Income Attributable to ALLETE		$75.3			$75.3
Common Shares	34.2		0.1	34.3
Per Share of Common Stock		$2.20			$2.19
2009
Net Income Attributable to ALLETE		$61.0			$61.0
Common Shares	32.2		—	32.2
Per Share of Common Stock		$1.89			$1.89

- Definition

Tabular disclosure of an entity's stock, including par or stated value per share, number and dollar amount of share subscriptions, shares authorized, shares issued, shares outstanding, number and dollar amount of shares held in an employee trust, dividend per share, total dividends, share conversion features, par value plus additional paid in capital, the value of treasury stock and other information necessary to a fair presentation, and EPS information. Stock by class includes common, convertible, and preferred stocks which are not redeemable or redeemable solely at the option of the issuer. Includes preferred stock with redemption features that are solely within the control of the issuer and mandatorily redeemable stock if redemption is required to occur only upon liquidation or termination of the reporting entity. If more than one issue is outstanding, state the title of each issue and the corresponding dollar amount; dollar amount of any shares subscribed but unissued and the deduction of subscriptions receivable there from; number of shares authorized, issued, and outstanding.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 30
-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 5
-Section 02
-Paragraph 29

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 150
-Paragraph 9
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21475-112644

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21484-112644

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21488-112644

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(d),(e))
-URI http://asc.fasb.org/extlink&oid=6881521&loc=d3e23780-122690

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21506-112644

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21538-112644

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21521-112644

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21553-112644

Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6403732&loc=d3e21300-112643

Reference 13: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6959260&loc=d3e187085-122770

Reference 14: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.28,29)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 15: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 480
-SubTopic 10
-Section S99
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6802392&loc=d3e177068-122764

+ Details

Other Income (Expense) (Tables)

12 Months Ended

Dec. 31, 2011

Other Income and Expenses [Abstract]

Other Income (Expense) [Table Text Block]



Year Ended December 31	2011		2010		2009
Millions
AFUDC - Equity		$2.5		$4.2		$5.8
Investment and Other Income (Expense)	1.9		0.4		(4.0		)
Total Other Income		$4.4		$4.6		$1.8

Income Tax Expense (Tables)

12 Months Ended

Dec. 31, 2011

Income Tax Disclosure [Abstract]

Income Tax Expense [Table Text Block]



Income Tax Expense
Year Ended December 31	2011			2010			2009
Millions
Current Tax Expense (Benefit)
Federal (a)		$1.4		$(23.0)			$(42.6)
State (a)	(1.6		)	1.3			(1.8		)
Total Current Tax Expense (Benefit)	(0.2		)	(21.7		)	(44.4		)
Deferred Tax Expense
Federal (b)	27.3			61.4			66.0
State (b)	9.5			5.3			10.3
Change in Valuation Allowance	(0.1		)	0.2			(0.1		)
Investment Tax Credit Amortization	(0.9		)	(0.9		)	(1.0		)
Total Deferred Tax Expense	35.8			66.0			75.2
Total Income Tax Expense		$35.6			$44.3			$30.8

(a)

(b)

Reconciliation of Taxes from Federal Statutory Rate to Total Income Tax Expense [Table Text Block]



Reconciliation of Taxes from Federal Statutory
Rate to Total Income Tax Expense
Year Ended December 31	2011			2010			2009
Millions
Income Before Non-Controlling Interest and Income Taxes		$129.2			$119.1			$91.5
Statutory Federal Income Tax Rate	35		%	35		%	35		%
Income Taxes Computed at 35 percent Statutory Federal Rate		$45.2			$41.7			$32.0
Increase (Decrease) in Tax Due to:
State Income Taxes – Net of Federal Income Tax Benefit	6.0			4.5			5.4
Impact of PPACA	—			4.0			—
Deferred Accounting for Retail Portion of PPACA	(2.9		)	—			—
2010 Rate Case Stipulation Agreement - Deferred Tax Reversal	(6.2		)	—			—
Regulatory Differences for Utility Plant	(1.2		)	(2.0		)	(2.5		)
Production Tax Credits	(4.3		)	(1.6		)	(1.2		)
Other	(1.0		)	(2.3		)	(2.9		)
Total Income Tax Expense		$35.6			$44.3			$30.8

Deferred Tax Assets and Liabilities [Table Text Block]



Deferred Tax Assets and Liabilities
As of December 31	2011			2010
Millions
Deferred Tax Assets
Employee Benefits and Compensation		$132.7			$121.8
Property Related	56.4			51.1
NOL and Tax Credit Carryforward	78.1			28.2
Investment Tax Credits	9.0			9.7
Other	7.2			12.7
Gross Deferred Tax Assets	283.4			223.5
Deferred Tax Asset Valuation Allowance	(0.4		)	(0.5		)
Total Deferred Tax Assets		$283.0			$223.0
Deferred Tax Liabilities
Property Related		$482.7			$387.2
Regulatory Asset for Benefit Obligations	117.9			105.8
Unamortized Investment Tax Credits	12.8			13.7
Partnership Basis Differences	24.4			19.4
Other	24.0			27.3
Total Deferred Tax Liabilities		$661.8			$553.4
Net Deferred Income Taxes		$378.8			$330.4
Recorded as:
Net Current Deferred Tax Liabilities (a)		$5.2			$5.2
Net Long-Term Deferred Tax Liabilities	373.6			325.2
Net Deferred Income Taxes		$378.8			$330.4


(a)	Included in Other Current Liabilities.

NOL and Tax Credit Carryforwards [Table Text Block]



NOL and Tax Credit Carryforwards
Year Ended December 31	2011		2010
Millions
Federal NOL carryforward (a)		$162.0		$62.0
Federal tax credit carryforwards	8.4		3.7
State NOL carryforwards (a, b)	73.1		71.7
State tax credit carryforwards, net of federal offset	3.8		1.7


(a)	Pretax amounts


(b)	State NOL carryforwards include Minnesota, North Dakota and Florida.

Gross Unrecognized Income Tax Benefits [Table Text Block]



Gross Unrecognized Income Tax Benefits	2011			2010			2009
Millions
Balance at January 1		$12.3			$9.5			$8.0
Additions for Tax Positions Related to the Current Year	—			—			0.5
Reductions for Tax Positions Related to the Current Year	—			(0.2		)	—
Additions for Tax Positions Related to Prior Years	—			4.4			1.0
Reductions for Tax Positions Related to Prior Years	(0.9		)	—			—
Settlements	—			(0.3		)	—
Lapse of Statute	—			(1.1		)	—
Balance as of December 31		$11.4			$12.3			$9.5

- Definition

Tabular disclosure of tax positions taken in the tax returns filed or to be filed for which it is more likely than not that the tax position will not be sustained upon examination by taxing authorities (i.e., uncertain tax positions) and other types of income tax contingencies, including: (1) the policy on classification of interest and penalties; (2) a tabular reconciliation of the total amounts of unrecognized tax benefits at the beginning and end of the period; the total amount(s) of: (3) unrecognized tax benefits that, if recognized, would affect the effective tax rate, and (4) interest and penalties recognized in each of the income statement and balance sheet; (5) for positions for which it is reasonably possible that the total amounts unrecognized will significantly change within 12 months of the reporting date the: (i) nature of the uncertainty, (ii) nature of the event that could occur that would cause the change, and (iii) an estimate of the range of the reasonably possible change or a statement that an estimate of the range cannot be made; and (6) a description of tax years that remain subject to examination by major tax jurisdictions.

+ References + Details

Comprehensive Income (Tables)

12 Months Ended

Dec. 31, 2011

Comprehensive Income (Loss) [Abstract]

Comprehensive Income (Loss) [Table Text Block]



Comprehensive Income (Loss)
Year Ended December 31	2011			2010			2009
Millions
Net Income		$93.6			$74.8			$60.7
Other Comprehensive Income
Unrealized Gain (Loss) on Securities Net of income taxes of $(0.1), $0.6, and $1.7	(0.3		)	0.8			2.8
Unrealized Loss on Derivatives Net of income taxes of $(0.2), $-, and $-	(0.3		)	—			—
Defined Benefit Pension and Other Postretirement Plans Net of income taxes of $(3.6), $-, and $4.1	(5.1		)	—			6.2
Total Other Comprehensive Income (Loss)	(5.7		)	0.8			9.0
Total Comprehensive Income		$87.9			$75.6			$69.7
Less: Non-Controlling Interest in Subsidiaries	(0.2		)	(0.5		)	(0.3		)
Comprehensive Income Attributable to ALLETE		$88.1			$76.1			$70.0

Accumulated Other Comprehensive Income (Loss) [Table Text Block]



Accumulated Other Comprehensive Income (Loss)
As of December 31	2011		2010
Millions
Unrealized Loss on Securities	$(1.3)		$(1.0)
Unrealized Loss on Derivatives	(0.3	)	—
Defined Benefit Pension and Other Postretirement Plans	(27.3	)	(22.2	)
Total Accumulated Other Comprehensive Loss	$(28.9)		$(23.2)

Pension and Other Postretirement Benefit Plans (Tables)

12 Months Ended

Dec. 31, 2011

Dec. 31, 2010

Defined Benefit Plan Disclosure [Line Items]

Estimated Future Benefit Payments [Table Text Block]



Estimated Future Benefit Payments
			Postretirement
	Pension		Health and Life
Millions
2012		$29.2		$8.3
2013		$30.0		$9.2
2014		$31.2		$10.2
2015		$32.3		$11.2
2016		$33.4		$11.9
Years 2017 – 2021		$181.4		$66.6

Pension and Postretirement Health and Life Costs Recorded in Other Long-Term Assets and Accumulated Other Comprehensive Income Expected to be Recognized over the Next Fiscal Year [Table Text Block]



	Pension		Postretirement Health and Life
Millions
Net Loss		$17.5		$7.5
Prior Service Costs		$0.3		($1.7	)
Transition Obligations	—			$0.1
Total Pension and Postretirement Health and Life Costs		$17.8		$5.9

Weighted-Average Assumptions Used to Determine Benefit Obligation and Net Periodic Benefit Costs [Table Text Block]



Weighted-Average Assumptions Used to Determine Benefit Obligation
Year Ended December 31	2011		2010
Discount Rate
Pension	4.54	%	5.36	%
Postretirement Health and Life	4.56	%	5.40	%
Rate of Compensation Increase	4.3 - 4.6%		4.3 - 4.6%
Health Care Trend Rates
Trend Rate	10	%	10	%
Ultimate Trend Rate	5	%	5	%
Year Ultimate Trend Rate Effective	2018		2018



Weighted-Average Assumptions Used to Determine Net Periodic Benefit Costs
Year Ended December 31	2011		2010		2009
Discount Rate	5.36 - 5.40%		5.81	%	6.12	%
Expected Long-Term Return on Plan Assets (a)
Pension	8.5	%	8.5	%	8.5	%
Postretirement Health and Life	6.8 - 8.5%		6.8 - 8.5%		6.8 - 8.5%
Rate of Compensation Increase	4.3 - 4.6%		4.3 - 4.6%		4.3 - 4.6%

(a) The expected long-term rate of return used to determine net periodic benefit expenses for 2012 has been reduced to 8.25 percent.

Sensitivity of a One-Percentage-Point Change in Health Care Trend Rates [Table Text Block]



Sensitivity of a One-Percentage-Point Change in Health Care Trend Rates
	One Percent		One Percent
	Increase		Decrease
Millions
Effect on Total of Postretirement Health and Life Service and Interest Cost		$2.0	$(1.6)
Effect on Postretirement Health and Life Obligation		$25.1	$(20.7)

Actual Plan Asset Allocations [Table Text Block]



Actual Plan Asset Allocations
	Pension				Postretirement Health and Life (a)
	2011		2010		2011		2010
Equity Securities	52	%	52	%	51	%	58	%
Debt Securities	27	%	29	%	39	%	33	%
Real Estate	5	%	5	%	—		—
Private Equity	16	%	14	%	10	%	9	%
	100	%	100	%	100	%	100	%


(a)	Includes VEBAs and irrevocable grantor trusts.

Plan Asset Target Allocations [Table Text Block]



Plan Asset Target Allocations
			Postretirement
	Pension		Health and Life (a)
Equity Securities	52	%	48	%
Debt Securities	30	%	34	%
Real Estate	9	%	9	%
Private Equity	9	%	9	%
	100	%	100	%


(a)	Includes VEBAs and irrevocable grantor trusts.

Recurring Fair Value Measures [Table Text Block]



	At Fair Value as of December 31, 2011
Recurring Fair Value Measures	Level 1		Level 2		Level 3	Total
Millions
Assets:
Equity Securities		$17.6	—		—		$17.6
Available-for-sale Securities – Corporate Debt Securities	—			$8.2	—	8.2
Money Market Funds	11.4		—		—	11.4
Total Fair Value of Assets		$29.0		$8.2	—		$37.2

Liabilities:
Deferred Compensation	—			$12.8	—		$12.8
Derivatives - Interest Rate Swap	—		0.4		—	0.4
Total Fair Value of Liabilities	—			$13.2	—		$13.2
Total Net Fair Value of Assets (Liabilities)		$29.0	$(5.0)		—		$24.0



	At Fair Value as of December 31, 2010
Recurring Fair Value Measures	Level 1		Level 2		Level 3		Total
Millions
Assets:
Equity Securities		$19.4	—		—			$19.4
Available-for-sale Securities
Corporate Debt Securities	—			$7.5	—		7.5
Debt Securities Issued by States of the United States (ARS)	—		—			$6.7	6.7
Total Available-for-sale Securities	—		7.5		6.7		14.2
Money Market Funds	0.8		—		—		0.8
Total Fair Value of Assets		$20.2		$7.5		$6.7		$34.4

Liabilities:
Deferred Compensation	—			$13.3	—			$13.3
Total Fair Value of Liabilities	—			$13.3	—			$13.3

Total Net Fair Value of Assets (Liabilities)		$20.2	$(5.8)			$6.7		$21.1

Activity in Level 3 [Table Text Block]



Recurring Fair Value Measures Activity in Level 3	Debt Securities Issued by States of the United States (ARS)
Millions
Balance as of December 31, 2010		$6.7
Settled During the Period	—
Redeemed During the Period (a)	(6.7		)
Balance as of December 31, 2011	—


(a)	The ARS were redeemed at carrying value on January 5, 2011.



Recurring Fair Value Measures Activity in Level 3	Derivatives			Debt Securities Issued by States of the United States (ARS)
Millions
Balance as of December 31, 2009		$0.7			$6.7
Settled During the Period (a)	(0.7		)	—
Redeemed During the Period	—			—
Balance as of December 31, 2010	—				$6.7


(a)	During the second quarter of 2010, the $0.7 million of financial transmission rights derivatives were settled.

Pension [Member]

Defined Benefit Plan Disclosure [Line Items]

Obligation and Funded Status [Table Text Block]



Pension Obligation and Funded Status
Year Ended December 31	2011			2010
Millions
Accumulated Benefit Obligation		$550.6			$485.6
Change in Benefit Obligation
Obligation, Beginning of Year		$525.6			$465.2
Service Cost	7.6			6.2
Interest Cost	27.4			26.2
Actuarial Loss	54.6			47.1
Benefits Paid	(28.6		)	(27.2		)
Participant Contributions	10.9			8.1
Obligation, End of Year		$597.5			$525.6
Change in Plan Assets
Fair Value, Beginning of Year		$382.0			$327.6
Actual Return on Plan Assets	33.1			45.6
Employer Contribution	45.8			36.0
Benefits Paid	(28.5		)	(27.2		)
Fair Value, End of Year		$432.4			$382.0
Funded Status, End of Year	$(165.1)			$(143.6)

Net Pension Amounts Recognized in Consolidated Balance Sheet Consist of:
Current Liabilities	$(1.1)			$(0.8)
Non-Current Liabilities	$(164.0)			$(142.8)

Unrecognized Pension and Other Postretirement Costs [Table Text Block]



Unrecognized Pension Costs
Year Ended December 31	2011		2010
Millions
Net Loss		$269.0		$225.1
Prior Service Cost	1.1		1.4
Total Unrecognized Pension Costs		$270.1		$226.5

Components of Net Periodic Expense [Table Text Block]



Components of Net Periodic Pension Expense
Year Ended December 31	2011			2010			2009
Millions
Service Cost		$7.6			$6.2			$5.7
Interest Cost	27.4			26.2			26.2
Expected Return on Plan Assets	(34.6		)	(33.7		)	(33.8		)
Amortization of Loss	12.1			6.6			3.4
Amortization of Prior Service Costs	0.3			0.5			0.6
Net Pension Expense		$12.8			$5.8			$2.1

Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income and Regulatory Assets [Table Text Block]



Other Changes in Pension Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income and Regulatory Assets
Year Ended December 31	2011			2010
Millions
Net Loss		$56.1			$35.2
Amortization of Prior Service Cost	(0.3		)	(0.5		)
Amortization of Gain	(12.2		)	(6.6		)
Total Recognized in Other Comprehensive Income and Regulatory Assets		$43.6			$28.1

Information for Pension Plans with an Accumulated Benefit Obligation in Excess of Plan Assets [Table Text Block]



Information for Pension Plans with an Accumulated Benefit Obligation in Excess of Plan Assets
Year Ended December 31	2011		2010
Millions
Projected Benefit Obligation		$597.5		$525.6
Accumulated Benefit Obligation		$550.6		$485.6
Fair Value of Plan Assets		$432.4		$382.0

Recurring Fair Value Measures [Table Text Block]



	At Fair Value as of December 31, 2011
Recurring Fair Value Measures	Level 1		Level 2		Level 3		Total
Millions
Assets:
Equity Securities:
U.S. Large-cap (a)		$32.1		$37.3	—			$69.4
U.S. Mid-cap Growth (a)	13.5		15.8		—		29.3
U.S. Small-cap (a)	13.1		15.2		—		28.3
International	—		75.1		—		75.1
ALLETE	21.3		—		—		21.3
Debt Securities:
Mutual Funds	72.8		—		—		72.8
Fixed Income	—		45.5		—		45.5
Other Types of Investments:
Private Equity Funds	—		—			$69.0	69.0
Real Estate	—		—		21.7		21.7
Total Fair Value of Assets		$152.8		$188.9		$90.7		$432.4

(a)



	At Fair Value as of December 31, 2010
Recurring Fair Value Measures	Level 1		Level 2		Level 3		Total
Millions
Assets:
Equity Securities:
U.S. Large-cap (a)		$30.4		$29.9		$3.5		$63.8
U.S. Mid-cap Growth (a)	14.0		13.7		1.6		29.3
U.S. Small-cap (a)	13.7		13.5		1.6		28.8
International	—		77.1		—		77.1
Debt Securities:
Mutual Funds	46.5		—		—		46.5
Fixed Income	—		65.7		—		65.7
Other Types of Investments:
Private Equity Funds	—		—		50.7		50.7
Real Estate	—		—		20.1		20.1
Total Fair Value of Assets		$104.6		$199.9		$77.5		$382.0

(a)

Activity in Level 3 [Table Text Block]



Recurring Fair Value Measures	Equity Securities
Activity in Level 3	(Auction Rate Securities)			Private Equity Funds			Real Estate
Millions
Balance as of December 31, 2010		$6.7			$50.7			$20.1
Actual Return on Plan Assets	—			30.9			3.5
Purchases, sales, and settlements, net	(6.7		)	(12.6		)	(1.9		)
Balance as of December 31, 2011	—				$69.0			$21.7



Recurring Fair Value Measures	Equity Securities
Activity in Level 3	(Auction Rate Securities)			Private Equity Funds			Real Estate
Millions
Balance as of December 31, 2009		$9.1			$44.7			$17.3
Actual Return on Plan Assets	—			(4.1		)	(6.1		)
Purchases, sales, and settlements, net	(2.4		)	10.1			8.9
Balance as of December 31, 2010		$6.7			$50.7			$20.1

Postretirement Health and Life [Member]

Defined Benefit Plan Disclosure [Line Items]

Obligation and Funded Status [Table Text Block]



Postretirement Health and Life Obligation and Funded Status
Year Ended December 31	2011			2010
Millions
Change in Benefit Obligation
Obligation, Beginning of Year		$204.1			$192.1
Service Cost	3.8			4.8
Interest Cost	10.8			10.9
Actuarial Loss (Gain)	(2.9		)	17.6
Participant Contributions	2.5			2.1
Plan Amendments	—			(14.2		)
Benefits Paid	(7.7		)	(9.2		)
Obligation, End of Year		$210.6			$204.1
Change in Plan Assets
Fair Value, Beginning of Year		$114.7			$96.4
Actual Return on Plan Assets	—			12.0
Employer Contribution	11.4			13.4
Participant Contributions	2.5			2.0
Benefits Paid	(7.6		)	(9.1		)
Fair Value, End of Year		$121.0			$114.7
Funded Status, End of Year	$(89.6)			$(89.4)

Net Postretirement Health and Life Amounts Recognized in Consolidated Balance Sheet Consist of:
Current Liabilities	$(0.9)			$(0.8)
Non-Current Liabilities	$(88.7)			$(88.6)

Unrecognized Pension and Other Postretirement Costs [Table Text Block]



Unrecognized Postretirement Health and Life Costs
Year Ended December 31	2011			2010
Millions
Net Loss		$78.5			$80.1
Prior Service Cost	(9.5		)	(11.2		)
Transition Obligation	0.1			0.2
Total Unrecognized Postretirement Health and Life Costs		$69.1			$69.1

Components of Net Periodic Expense [Table Text Block]



Components of Net Periodic Postretirement Health and Life Expense
Year Ended December 31	2011			2010			2009
Millions
Service Cost		$3.8			$4.8			$4.1
Interest Cost	10.8			10.9			10.0
Expected Return on Plan Assets	(9.7		)	(9.5		)	(8.3		)
Amortization of Prior Service Cost	(1.7		)	(0.1		)	—
Amortization of Loss	8.5			4.8			2.5
Amortization of Transition Obligation	0.1			2.5			2.5
Net Postretirement Health and Life Expense		$11.8			$13.4			$10.8

Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income and Regulatory Assets [Table Text Block]



Other Changes in Postretirement Benefit Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income and Regulatory Assets
Year Ended December 31	2011			2010
Millions
Net Loss		$6.9			$15.3
Prior Service Cost (Credit) Arising During the Period	—			(14.2		)
Amortization of Prior Service Cost	1.7			0.1
Amortization of Transition Obligation	(0.1		)	(2.5		)
Amortization of Loss	(8.5		)	(4.8		)
Total Recognized in Other Comprehensive Income and Regulatory Assets	—			$(6.1)

Recurring Fair Value Measures [Table Text Block]



	At Fair Value as of December 31, 2011
Recurring Fair Value Measures	Level 1		Level 2		Level 3		Total
Millions
Assets:
Equity Securities:
U.S. Large-cap		$15.9	—		—			$15.9
U.S. Mid-cap Growth	11.5		—		—		11.5
U.S. Small-cap	11.2		—		—		11.2
International	25.1		—		—		25.1
Debt Securities:
Mutual Funds	24.1		—		—		24.1
Fixed Income	0.3			$18.9	—		19.2
Other Types of Investments:
Private Equity Funds	—		—			$14.0	14.0
Total Fair Value of Assets		$88.1		$18.9		$14.0		$121.0



	At Fair Value as of December 31, 2010
Recurring Fair Value Measures	Level 1		Level 2		Level 3		Total
Millions
Assets:
Equity Securities:
U.S. Large-cap		$15.7	—		—			$15.7
U.S. Mid-cap Growth	11.4		—		—		11.4
U.S. Small-cap	11.5		—		—		11.5
International	26.8		—		—		26.8
Debt Securities:
Mutual Funds	9.0		—		—		9.0
Fixed Income	—			$27.9	—		27.9
Other Types of Investments:
Private Equity Funds	—		—			$12.4	12.4
Total Fair Value of Assets		$74.4		$27.9		$12.4		$114.7

Activity in Level 3 [Table Text Block]



Recurring Fair Value Measures
Activity in Level 3	Private Equity Funds
Millions
Balance as of December 31, 2010		$12.4
Actual Return on Plan Assets	1.1
Purchases, sales, and settlements, net	0.5
Balance as of December 31, 2011		$14.0



Recurring Fair Value Measures
Activity in Level 3	Private Equity Funds
Millions
Balance as of December 31, 2009		$9.4
Actual Return on Plan Assets	1.4
Purchases, sales, and settlements, net	1.6
Balance as of December 31, 2010		$12.4

Employee Stock and Incentive Plans (Tables)

12 Months Ended

Dec. 31, 2011

Employee Stock and Incentive Plans [Abstract]

Employee Stock Ownership Plan [Table Text Block]



Year Ended December 31	2011		2010		2009
Millions
ESOP Shares
Allocated	2.2		2.2		2.2
Unallocated	1.0		1.3		1.5
Total	3.2		3.5		3.7
Fair Value of Unallocated Shares		$42.0		$48.4		$49.0

Share-Based Compensation Expense [Table Text Block]



Share-Based Compensation Expense
Year Ended December 31	2011		2010		2009
Millions
Stock Options	—			$0.1		$0.3
Performance Shares		$1.1	1.5		1.5
Restricted Stock Units	0.5		0.6		0.3
Total Share-Based Compensation Expense		$1.6		$2.2		$2.1
Income Tax Benefit		$0.7		$0.9		$0.8

Non-Qualified Stock Options [Table Text Block]



	2011			2010			2009
	Number of Options	Weighted-Average Exercise Price		Number of Options	Weighted-Average Exercise Price		Number of Options	Weighted-Average Exercise Price
Outstanding as of January 1,	560,887		$40.69	646,235		$40.05	672,419		$39.99
Granted (a)	—	—		—	—		—	—
Exercised	80,798		$34.25	40,769		$27.76	4,508		$18.85
Forfeited	19,855		$43.96	44,579		$43.16	21,676		$42.62
Outstanding as of December 31,	460,234		$41.68	560,887		$40.69	646,235		$40.05
Exercisable as of December 31,	460,234		$41.59	523,491		$39.76	512,743		$37.34


(a)	Stock options have not been granted since 2008. The weighted-average grant-date intrinsic value of options granted in 2008 was $6.18.

Stock Options, by Exercise Price Range [Table Text Block]



	Range of Exercise Price
As of December 31, 2011	$18.85 to $29.79		$37.76 to $41.35		$44.15 to $48.65
Options Outstanding and Exercisable:
Number Outstanding and Exercisable	11,672		279,133		169,429
Weighted Average Remaining Contractual Life (Years)	1.1		4.5		4.5
Weighted Average Exercise Price		$24.14		$39.57		$46.37

Non-Vested Performance Shares [Table Text Block]



	2011				2010				2009
	Number of Shares		Weighted- Average Grant Date Fair Value		Number of Shares		Weighted- Average Grant Date Fair Value		Number of Shares		Weighted- Average Grant Date Fair Value
Non-vested as of January 1,	122,489			$38.15	121,825			$41.96	79,238			$47.94
Granted (a)	39,312			$41.00	49,302			$35.44	69,800			$35.06
Awarded	(32,368	)		$48.10	—		—		—		—
Unearned Grant Award	—		—		(22,909	)		$54.50	(24,615	)		$41.97
Forfeited	(1,100	)		$34.35	(25,729	)		$36.45	(2,598	)		$38.78
Non-vested as of December 31,	128,333			$28.00	122,489			$38.15	121,825			$41.96

(a) Shares granted includes accrued dividends.

Restricted Stock Units [Table Text Block]



	2011				2010				2009
	Number of Shares		Weighted- Average Grant Date Fair Value		Number of Shares		Weighted- Average Grant Date Fair Value		Number of Shares		Weighted- Average Grant Date Fair Value
Available as of January 1,	43,803			$30.61	28,983			$29.41	—		—
Granted (a)	20,136			$36.74	26,589			$31.83	30,465			$29.41
Awarded	(215	)		$30.30	(3,091	)		$29.75	—		—
Forfeited	(260	)		$29.41	(8,678	)		$30.62	(1,482	)		$29.41
Available as of December 31,	63,464			$22.88	43,803			$30.61	28,983			$29.41

(a) Shares granted includes accrued dividends.

- Definition

Tabular disclosure of the description of the plan, the basis for determining contributions, including the employee groups covered, and the nature and effect of significant matters affecting comparability of information for all periods presented. For leveraged ESOPs and pension reversion ESOPs, the disclosure may include the basis for releasing shares and how dividends on allocated and unallocated shares are used. Disclosure may also include a description of the accounting policies followed for ESOP transactions, including the method of measuring compensation, the classification of dividends on ESOP shares, and the treatment of ESOP shares for EPS computations. If the employer has both old ESOP shares for which it does not adopt the latest guidance and new ESOP shares for which the new guidance is required, the accounting policies for both blocks of shares may be described. Disclosure may also include he amount of compensation cost recognized during the period, the number of allocated shares, committed-to-be-released shares, and suspense shares held by the ESOP at the balance-sheet date, the fair value of unearned ESOP shares at the balance-sheet date for shares accounted for under the latest guidance, the existence and nature of any repurchase obligation, including disclosure of the fair value of the shares allocated as of the balance sheet date, which are subject to a repurchase obligation.

+ References + Details

Quarterly Financial Data (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2011

Quarterly Financial Data (Unaudited) [Abstract]

Quarterly Financial Data (Unaudited) [Table Text Block]



Quarter Ended	Mar. 31		Jun. 30		Sept. 30		Dec. 31
Millions Except Earnings Per Share
2011
Operating Revenue		$242.2		$219.9		$226.9		$239.2
Operating Income		$50.8		$26.1		$38.9		$34.2
Net Income Attributable to ALLETE		$37.2		$17.0		$20.5		$19.1
Earnings Per Share of Common Stock
Basic		$1.07		$0.49		$0.57		$0.53
Diluted		$1.07		$0.48		$0.57		$0.53
2010
Operating Revenue		$233.6		$211.2		$224.1		$238.1
Operating Income		$46.1		$31.7		$35.3		$22.7
Net Income Attributable to ALLETE		$23.0		$19.4		$19.6		$13.3
Earnings Per Share of Common Stock
Basic		$0.68		$0.57		$0.57		$0.38
Diluted		$0.68		$0.57		$0.56		$0.38

Operations and Significant Accounting Policies (Details)
shares in Millions, $ in Millions

12 Months Ended

Dec. 31, 2011

USD ($)

Customers

Dec. 31, 2010

USD ($)

Dec. 31, 2009

USD ($)

Trade Accounts Receivable [Abstract]

Billed

$ 63.7

$ 67.6

Unbilled

15.6

18.9

Less: Allowance for Doubtful Accounts

0.9

Total Trade Accounts Receivable

78.4

85.6

Income Taxes Receivable

^[1]

1.3

13.9

Total Accounts Receivable - Net

79.7

99.5

Impairement of Long-Lived Assets [Abstract]

Land Impairment

^[2]

1.7

0.0

Remaining Cost Basis

$ 3.0

Income Tax Disclosure [Abstract]

More Likely Than Not Definition

50.00%

Inventory Disclosure [Abstract]

Fuel

$ 28.6

22.9

Materials and Supplies

40.5

37.1

Total Inventories

69.1

60.0

Noncontrolling Interest [Abstract]

Purchase of Non-Controlling Interest at Book Value

$ 8.8

Purchase of Non-Controlling Interest, Shares Issued | shares

0.2

Other Liabilities, Current [Abstract]

Customer Deposits

^[3]

$ 16.3

2.9

Other

29.3

30.8

Total Other Current Liabilities

45.6

33.7

Other Liabilities, Noncurrent [Abstract]

Asset Retirement Obligation

57.0

50.3

$ 44.6

Other

48.1

43.1

Total Other Non-Current Liabilities

105.1

93.4

Prepaid Expense and Other Assets, Current [Abstract]

Deferred Fuel Adjustment Clause

17.5

20.6

Other

9.6

8.0

Total Prepayments and Other Current Assets

27.1

28.6

Supplemental Cash Flow Information [Abstract]

Cash Paid During the Period for Interest - Net of Amounts Capitalized

43.2

35.7

29.8

Cash Received During the Period for Income Taxes

^[4]

(11.4)

(54.2)

(5.6)

Noncash Investing and Financing Activities [Abstract]

Increase (Decrease) in Accounts Payable for Capital Additions to Property, Plant and Equipment

5.9

7.5

(24.1)

AFUDC-Equity

2.5

4.2

5.8

ALLETE Common Stock Contributed to the Pension Plan

$ (20.0)

$ 0.0

$ (12.0)

Retail [Member]

Customer Information [Line Items]

Number of Customers | Customers

144,000

Electric [Member]

Customer Information [Line Items]

Number of Customers | Customers

15,000

Natural Gas [Member]

Customer Information [Line Items]

Number of Customers | Customers

12,000

Water [Member]

Customer Information [Line Items]

Number of Customers | Customers

10,000

Non-Affiliated Municipal Customers, Municpalities [Member]

Customer Information [Line Items]

Number of Customers | Customers

Non-Affiliated Municipal Customers, Private Utilities [Member]

Customer Information [Line Items]

Number of Customers | Customers

[1]	(a)Income Taxes Receivable decreased from 2010 due to the collection of a 2010 NOL carryback claim. (See Note 14. Income Tax Expense.)
[2]	(b)The land impairment charge was a result of an impairment analysis conducted in the fourth quarter of 2011 where the cost basis was reduced to the estimated fair value.
[3]	(a)Higher customer deposits in 2011 were primarily due to a customer security deposit for capital expenditures relating to a transmission project.
[4]	(a)Due to bonus depreciation provisions in 2009 and 2010 federal legislation, NOLs were generated which resulted in little to no estimated tax payments, and refunds were received from NOL carrybacks against prior years' taxable income.

Operations and Significant Accounting Policies - Concentraion of Credit Risk (Details) $ in Millions	12 Months Ended
	Dec. 31, 2011 USD ($) Customers	Dec. 31, 2010 USD ($)	Dec. 31, 2009
Customer Information [Line Items]
LP Major Customer, Percent of Total Revenue	12.80%	12.50%	8.00%
NewPage Bankruptcy Pre-Petition Receivable	$ 3.2
Large Power Customer [Member]
Customer Information [Line Items]
Number of Customers \| Customers	10
Accounts Receivable	$ 9.3	$ 17.3

Operations and Significant Accounting Policies- Investments (Details)	12 Months Ended
	Dec. 31, 2011 MW
Long-term Contract for Purchase of Electric Power [Line Items]
Real Estate Sales Revenue Recognition, Minimum Contract Price Cash Collections Requirement	20.00%
Square Butte PPA [Member]
Long-term Contract for Purchase of Electric Power [Line Items]
Output Purchased (Percent)	50.00%
Output Purchased (MW)	227.5

Business Segments (Details) $ in Millions	3 Months Ended								12 Months Ended
Business Segments (Details) $ in Millions	Dec. 31, 2011 USD ($)	Sep. 30, 2011 USD ($)	Jun. 30, 2011 USD ($)	Mar. 31, 2011 USD ($)	Dec. 31, 2010 USD ($)	Sep. 30, 2010 USD ($)	Jun. 30, 2010 USD ($)	Mar. 31, 2010 USD ($)	Dec. 31, 2011 USD ($)	Dec. 31, 2010 USD ($)	Dec. 31, 2009 USD ($)
Business Segments [Abstract]
Number of acres of land available-for-sale (in acres)	5,500								5,500
Business Segments [Line Items]
Operating and Maintenance Expense									$ 381.2	$ 365.6	$ 308.9
Depreciation Expense									90.4	80.5	64.7
Operating Income	$ 34.2	$ 38.9	$ 26.1	$ 50.8	$ 22.7	$ 35.3	$ 31.7	$ 46.1	150.0	135.8	106.0
Interest Expense									(43.6)	(39.2)	(33.8)
Equity Earnings in ATC									18.4	17.9	17.5
Other Income (Expense)									4.4	4.6	1.8
Income (Loss) Before Non-Controlling Interest and Income Taxes									129.2	119.1	91.5
Income Tax Expense (Benefit)									35.6	44.3	30.8
Net Income (Loss)									93.6	74.8	60.7
Less: Non-Controlling Interest in Subsidiaries									(0.2)	(0.5)	(0.3)
Net Income (Loss) Attributable to ALLETE	19.1	$ 20.5	$ 17.0	$ 37.2	13.3	$ 19.6	$ 19.4	$ 23.0	93.8	75.3	61.0
Total Assets	2,876.0				2,609.1				2,876.0	2,609.1
Consolidated [Member]
Business Segments [Line Items]
Operating Revenue											766.7
Prior Year Rate Refunds											(7.6)
Operating Revenue									928.2	907.0	759.1
Total Operating Revenue									928.2	907.0	759.1
Fuel and Purchased Power Expense									306.6	325.1	279.5
Operating and Maintenance Expense									381.2	365.6	308.9
Depreciation Expense									90.4	80.5	64.7
Operating Income									150.0	135.8	106.0
Interest Expense									(43.6)	(39.2)	(33.8)
Equity Earnings in ATC									18.4	17.9	17.5
Other Income (Expense)									4.4	4.6	1.8
Income (Loss) Before Non-Controlling Interest and Income Taxes									129.2	119.1	91.5
Income Tax Expense (Benefit)									35.6	44.3	30.8
Net Income (Loss)									93.6	74.8	60.7
Less: Non-Controlling Interest in Subsidiaries									(0.2)	(0.5)	(0.3)
Net Income (Loss) Attributable to ALLETE									93.8	75.3	61.0
Total Assets	2,876.0				2,609.1				2,876.0	2,609.1	2,393.1
Capital Additions									246.8	260.0	303.7
Regulated Operations [Member]
Business Segments [Line Items]
Operating Revenue											689.4
Prior Year Rate Refunds											(7.6)
Operating Revenue									851.9	835.5	681.8
Total Operating Revenue									851.9	835.5	681.8
Fuel and Purchased Power Expense									306.6	325.1	279.5
Operating and Maintenance Expense									301.5	292.3	235.8
Depreciation Expense									85.4	76.1	60.2
Operating Income									158.4	142.0	106.3
Interest Expense									(35.8)	(32.3)	(28.3)
Equity Earnings in ATC									18.4	17.9	17.5
Other Income (Expense)									2.6	3.8	5.8
Income (Loss) Before Non-Controlling Interest and Income Taxes									143.6	131.4	101.3
Income Tax Expense (Benefit)									43.2	51.6	35.4
Net Income (Loss)									100.4	79.8	65.9
Less: Non-Controlling Interest in Subsidiaries									0.0	0.0	0.0
Net Income (Loss) Attributable to ALLETE									100.4	79.8	65.9
Total Assets	2,579.8				2,375.4				2,579.8	2,375.4	2,184.0
Capital Additions									228.0	256.4	299.2
Investments and Other [Member]
Business Segments [Line Items]
Operating Revenue											77.3
Prior Year Rate Refunds											0.0
Operating Revenue									76.3	71.5	77.3
Total Operating Revenue									76.3	71.5	77.3
Fuel and Purchased Power Expense									0.0	0.0	0.0
Operating and Maintenance Expense									79.7	73.3	73.1
Depreciation Expense									5.0	4.4	4.5
Operating Income									(8.4)	(6.2)	(0.3)
Interest Expense									(7.8)	(6.9)	(5.5)
Equity Earnings in ATC									0.0	0.0	0.0
Other Income (Expense)									1.8	0.8	(4.0)
Income (Loss) Before Non-Controlling Interest and Income Taxes									(14.4)	(12.3)	(9.8)
Income Tax Expense (Benefit)									(7.6)	(7.3)	(4.6)
Net Income (Loss)									(6.8)	(5.0)	(5.2)
Less: Non-Controlling Interest in Subsidiaries									(0.2)	(0.5)	(0.3)
Net Income (Loss) Attributable to ALLETE									(6.6)	(4.5)	(4.9)
Total Assets	$ 296.2				$ 233.7				296.2	233.7	209.1
Capital Additions									$ 18.8	$ 3.6	$ 4.5

Property, Plant and Equipment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment - Net	$ 1,982.7	$ 1,805.6
Asset Retirement Obligation [Roll Forward]
Beginning Obligation	50.3	44.6
Accretion Expense	6.4	2.9
Additional Liabilities Incurred	0.3	2.8
Ending Obligation	57.0	50.3
Regulated Utiity [Member]
Property, Plant and Equipment [Line Items]
Segment Property, Plant and Equipment	2,794.8	2,649.2
Construction Work in Progress	155.0	86.6
Accumulated Depreciation	(1,024.6)	(975.8)
Segment Property, Plant and Equipment - Net	$ 1,925.2	1,760.0
Estimated Useful Life - Generation	4 to 35 years
Estimated Useful Life - Transmission	42 to 61 years
Estimated Useful Life - Distribution	14 to 65 years
Unregulated Non-Rate Base Energy Operations and Other Plant [Member]
Property, Plant and Equipment [Line Items]
Segment Property, Plant and Equipment	$ 106.4	88.4
Construction Work in Progress	2.3	4.5
Accumulated Depreciation	(51.4)	(48.0)
Segment Property, Plant and Equipment - Net	57.3	44.9
Other Plant - Net	$ 0.2	$ 0.7
Estimated Useful Life - Non-Rate Base Operations	3 to 61 years
Estimated Useful Life - Other Plant	5 to 25 years

Jointly-Owned Electric Facility (Details) $ in Millions	12 Months Ended
Jointly-Owned Electric Facility (Details) $ in Millions	Dec. 31, 2011 USD ($) MW
Jointly Owned Electric Facility [Line Items]
Plant in Service	$ 418.8
Accumulated Depreciation	177.4
Construction Work in Progress	24.7
Boswell Unit 4 [Member]
Jointly Owned Electric Facility [Line Items]
Plant in Service	406.9
Accumulated Depreciation	177.4
Construction Work in Progress	$ 8.8
% Ownership	80.00%
Coal-fired generating unit capacity \| MW	585
Jointly-Owned Electric Facility Percentage Not Owned	20.00%
CapX2020 [Member]
Jointly Owned Electric Facility [Line Items]
Plant in Service	$ 11.9
Accumulated Depreciation	0.0
Construction Work in Progress	$ 15.9
% Ownership Range	9.3 - 14.7

Regulatory Matters (Details)
$ in Millions

3 Months Ended

Jun. 30, 2011

USD ($)

Mar. 31, 2011

USD ($)

Mar. 31, 2010

USD ($)

Dec. 31, 2011

USD ($)

Customers

Sep. 30, 2011

USD ($)

Jun. 01, 2011

May 24, 2011

USD ($)

Dec. 31, 2010

USD ($)

Nov. 02, 2010

USD ($)

Regulatory Matters [Line Items]

Regulatory Assets, Current

$ 17.5

$ 20.6

Regulatory Assets, Noncurrent

345.9

310.2

Regulatory Assets

363.4

330.8

Regulatory Liability, Noncurrent

$ 43.5

43.6

2010 Rate Case [Member]

Regulatory Matters [Line Items]

Approved Retail Rate Increase

$ 53.5

Approved Rate of Return on Common Equity

10.38%

Approved Percentage of Capital Structure Related to Equity

54.29%

MPUC, Rates, Effective Date

June 1, 2011

Amount of Rate Differential Authorized for Collection

$ 3.2

Amount of Revenue Receivable Capitalized

$ 20.5

FERC-Approved Wholesale Rates [Member]

Regulatory Matters [Line Items]

Non-Affiliated Municipal Customers, Municipalities | Customers

Non-Affiliated Municipal Customers, Private Utilities | Customers

Length of Notice Required to Terminate (Years)

Non-Affiliated Municipal Customers, Private Utilities [Member]

Regulatory Matters [Line Items]

Length of Notice Required to Terminate (Years)

2010 Wisconsin Rate Increase [Member]

Regulatory Matters [Line Items]

Approved Rate of Return on Common Equity

10.90%

Approved Retail Rate Increase (Percent)

2.40%

Amount Of Estimated Additional Revenue

$ 2.0

DTL Reversal, Revenue Receivable Forgone [Member]

Regulatory Matters [Line Items]

Tax Adjustments, Settlements, and Unusual Provisions

$ 6.2

DTA Tax Charge, Elimination of Medicare Part D [Member]

Regulatory Matters [Line Items]

Tax Adjustments, Settlements, and Unusual Provisions

$ 4.0

Income Tax Benefit, MPUC Approval of Deferral of PPACA [Member]

Regulatory Matters [Line Items]

Tax Adjustments, Settlements, and Unusual Provisions

$ 2.9

Water Rates [Member] | 2010 Wisconsin Rate Increase [Member]

Regulatory Matters [Line Items]

Approved Retail Rate Increase (Percent)

12.80%

Natural Gas Rates [Member] | 2010 Wisconsin Rate Increase [Member]

Regulatory Matters [Line Items]

Approved Retail Rate Increase (Percent)

2.50%

Electric Rates [Member] | 2010 Wisconsin Rate Increase [Member]

Regulatory Matters [Line Items]

Approved Retail Rate Increase (Percent)

0.70%

Deferred Income Tax Charges [Member]

Regulatory Matters [Line Items]

Regulatory Liability, Noncurrent

$ 21.9

$ 23.4

Plant Removal Obligations Costs [Member]

Regulatory Matters [Line Items]

Regulatory Liability, Noncurrent

15.0

16.9

Other Regulatory Liabilities [Member]

Regulatory Matters [Line Items]

Regulatory Liability, Noncurrent

6.6

3.3

Deferred Fuel Costs [Member]

Regulatory Matters [Line Items]

Regulatory Assets, Current

^[1]

17.5

20.6

Pension Costs [Member]

Regulatory Matters [Line Items]

Regulatory Assets, Noncurrent

292.8

257.9

Environmental Restoration Costs [Member]

Regulatory Matters [Line Items]

Regulatory Assets, Noncurrent

0.0

20.5

Deferred Income Tax Charges [Member]

Regulatory Matters [Line Items]

Regulatory Assets, Noncurrent

28.6

17.3

Asset Retirement Obligation Costs [Member]

Regulatory Matters [Line Items]

Regulatory Assets, Noncurrent

9.8

7.8

Medicare Part D Regulatory Asset [Member]

Regulatory Matters [Line Items]

Regulatory Assets, Noncurrent

5.0

0.0

CIP Financial Incentive [Member]

Regulatory Matters [Line Items]

Regulatory Assets, Noncurrent

4.6

0.7

Other Regulatory Assets [Member]

Regulatory Matters [Line Items]

Regulatory Assets, Noncurrent

$ 5.1

$ 6.0

[1]	(a)Current regulatory assets are included in prepayments and other on the consolidated balance sheet.

Investment in ATC (Details) - USD ($) $ in Millions	12 Months Ended
Investment in ATC (Details) - USD ($) $ in Millions	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Jan. 31, 2012
ALLETE's Investment in ATC [Roll Forward]
Equity Investment Beginning Balance	$ 93.3	$ 88.4
Cash Investments	2.0	1.6
Equity Earnings in ATC	18.4	17.9	$ 17.5
Distributed ATC Earnings	(14.8)	(14.6)
Equity Investment Ending Balance	98.9	93.3	88.4
Balance Sheet Data [Abstract]
Current Assets	58.7	59.9
Non-Current Assets	3,053.7	2,888.4
Total Assets	3,112.4	2,948.3
Current Liabilities	298.5	428.4
Long-Term Debt	1,400.0	1,175.0
Other Non-Current Liabilities	82.6	84.9
Members' Equity	1,331.3	1,260.0
Total Liabilities and Members' Equity	3,112.4	2,948.3
Income Statement Data [Abstract]
Revenue	567.2	556.7	521.5
Operating Expense	261.6	251.1	230.3
Other Expense	81.7	85.9	77.8
Net Income	223.9	219.7	213.4
ALLETE's Equity in Net Income	18.4	$ 17.9	$ 17.5
Investment in ATC [Abstract]
Equity Method Investment, Expected Future Investment	$ 3.0
Equity Method Investment - Additional Investment Amount				$ 0.8
Equity Method Investment, Approved Return on Common Equity	12.20%
Equity Method Investment, Ownership Percentage	8.00%

Investments (Details) - USD ($)
$ in Millions

12 Months Ended

Dec. 31, 2011

Dec. 31, 2010

Dec. 31, 2009

Jan. 05, 2011

Available-for-sale Securities [Abstract]

Cost

$ 27.3

$ 27.4

$ 33.1

Gross Unrealized Gain

0.1

0.2

0.1

Gross Unrealized (Loss)

(2.7)

(2.4)

(3.7)

Fair Value

24.7

25.2

29.5

Net Proceeds

5.5

(1.7)

6.7

Gross Realized Gain

0.0

Gross Realized (Loss)

0.0

Net Unrealized Gain (Loss) in Other Comprehensive Income

(0.4)

1.4

4.5

Available for sale securities, Issued by States of the United States (ARS)

$ 6.7

Investments [Abstract]

ALLETE Properties

91.3

94.0

Available-for-sale Securities

24.7

25.2

Other

16.3

6.8

Total Investments

132.3

126.0

Notes, Loans and Financing Receivable, Net, Noncurrent [Abstract]

Notes, Loans and Financing Receivable, Net, Noncurrent

2.0

3.7

Financing Receivable, Allowance for Credit Losses, Provisions

0.6

0.8

Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]

Land Inventory Beginning Balance

86.0

74.9

Deeds to Collateralized Property

^[1]

1.8

9.9

Land Impairment

^[2]

(1.7)

0.0

Cost of Real Estate Sold

(0.3)

0.0

Capitalized Improvements and Other

0.2

1.2

Land Inventory Ending Balance

86.0

$ 74.9

Long-Term Finance Receivables (net of allowances of $0.6 and $0.8)

^[1]

2.0

3.7

Other

3.3

4.3

Total Real Estate Assets

91.3

94.0

Long-Term Finance Receivable Allowance

$ 0.6

$ 0.8

[1]	(a)In 2010, the deeds to collateralized property resulted primarily from an entity which filed for Chapter 11 bankruptcy and were recorded at fair value net of estimated selling costs.
[2]	(b)The land impairment charge was a result of an impairment analysis conducted in the fourth quarter of 2011 where the cost basis was reduced to the estimated fair value.

Derivatives (Details) - USD ($) $ in Millions	12 Months Ended
Derivatives (Details) - USD ($) $ in Millions	Dec. 31, 2011	Aug. 25, 2011
Interest Rate Swap [Abstract]
Term Loan, Face Amount		$ 75.0
Term Loan, Description of Variable Rate Basis	one-month LIBOR
Term Loan, Basis Spread on Variable Rate	1.00%
Percentage of Debt Hedged by Interest Rate Derivatives	9.00%
Derivative, Fixed Interest Rate	0.825%
Discussion of Interest Rate Cash Flow Hedge Effectiveness Assessment and Measurement	The shortcut method is used to assess hedge effectiveness. At inception, all shortcut method requirements were satisfied; thus changes in value of the Swap designated as the hedging instrument will be deemed 100 percent effective. As a result, there was no ineffectiveness recorded for the year ended December 31, 2011.
Interest Rate Cash Flow Hedge Liability at Fair Value	$ 0.4

Recurring Fair Value Measures (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Available-for-sale Securities [Abstract]
Available-for-sale Securities	$ 24.7	$ 25.2	$ 29.5
Liabilities [Abstract]
Derivatives - Interest Rate Swap	(0.4)
Fair Value Hierarchy Transfers, All Levels	0.0
Recurring [Member] \| Fair Value, Inputs, Level 1 [Member]
Assets [Abstract]
Equity Securities	17.6	19.4
Available-for-sale Securities [Abstract]
Available-for-sale Securities		0.0
Money Market Funds	11.4	0.8
Total Fair Value of Assets	29.0	20.2
Liabilities [Abstract]
Deferred Compensation	0.0	0.0
Derivatives - Interest Rate Swap	0.0
Total Fair Value of Liabilities	0.0	0.0
Total Net Fair Value of Assets (Liabilities)	29.0	20.2
Recurring [Member] \| Fair Value, Inputs, Level 2 [Member]
Assets [Abstract]
Equity Securities	0.0	0.0
Available-for-sale Securities [Abstract]
Available-for-sale Securities		7.5
Money Market Funds	0.0	0.0
Total Fair Value of Assets	8.2	7.5
Liabilities [Abstract]
Deferred Compensation	12.8	13.3
Derivatives - Interest Rate Swap	0.4
Total Fair Value of Liabilities	13.2	13.3
Total Net Fair Value of Assets (Liabilities)	(5.0)	(5.8)
Recurring [Member] \| Fair Value, Inputs, Level 3 [Member]
Assets [Abstract]
Equity Securities	0.0	0.0
Available-for-sale Securities [Abstract]
Available-for-sale Securities		6.7
Money Market Funds	0.0	0.0
Total Fair Value of Assets	0.0	6.7
Liabilities [Abstract]
Deferred Compensation	0.0	0.0
Derivatives - Interest Rate Swap	0.0
Total Fair Value of Liabilities	0.0	0.0
Total Net Fair Value of Assets (Liabilities)	0.0	6.7
Recurring [Member] \| Total [Member]
Assets [Abstract]
Equity Securities	17.6	19.4
Available-for-sale Securities [Abstract]
Available-for-sale Securities		14.2
Money Market Funds	11.4	0.8
Total Fair Value of Assets	37.2	34.4
Liabilities [Abstract]
Deferred Compensation	12.8	13.3
Derivatives - Interest Rate Swap	0.4
Total Fair Value of Liabilities	13.2	13.3
Total Net Fair Value of Assets (Liabilities)	24.0	21.1
Corporate Debt Securities [Member] \| Recurring [Member] \| Fair Value, Inputs, Level 1 [Member]
Available-for-sale Securities [Abstract]
Available-for-sale Securities	0.0	0.0
Corporate Debt Securities [Member] \| Recurring [Member] \| Fair Value, Inputs, Level 2 [Member]
Available-for-sale Securities [Abstract]
Available-for-sale Securities	8.2	7.5
Corporate Debt Securities [Member] \| Recurring [Member] \| Fair Value, Inputs, Level 3 [Member]
Available-for-sale Securities [Abstract]
Available-for-sale Securities	0.0	0.0
Corporate Debt Securities [Member] \| Recurring [Member] \| Total [Member]
Available-for-sale Securities [Abstract]
Available-for-sale Securities	$ 8.2	7.5
Debt Securities Issued by the United States (ARS) [Member] \| Recurring [Member] \| Fair Value, Inputs, Level 1 [Member]
Available-for-sale Securities [Abstract]
Available-for-sale Securities		0.0
Debt Securities Issued by the United States (ARS) [Member] \| Recurring [Member] \| Fair Value, Inputs, Level 2 [Member]
Available-for-sale Securities [Abstract]
Available-for-sale Securities		0.0
Debt Securities Issued by the United States (ARS) [Member] \| Recurring [Member] \| Fair Value, Inputs, Level 3 [Member]
Available-for-sale Securities [Abstract]
Available-for-sale Securities		6.7
Debt Securities Issued by the United States (ARS) [Member] \| Recurring [Member] \| Total [Member]
Available-for-sale Securities [Abstract]
Available-for-sale Securities		$ 6.7

Recurring Fair Value Measures, Activity in Level 3 (Details) - USD ($)
$ in Millions

12 Months Ended

Dec. 31, 2011

Dec. 31, 2010

Derivatives [Member]

Recurring Fair Value Measures, Activity in Level 3 [Line Items]

Beginning Balance

$ 0.0

$ 0.7

Settled During the Period

^[1]

(0.7)

Redeemed During the Period

0.0

Ending Balance

0.0

Debt Securities Issued by States of the United States (ARS) [Member]

Recurring Fair Value Measures, Activity in Level 3 [Line Items]

Beginning Balance

6.7

Settled During the Period

0.0

Redeemed During the Period

(6.7)

^[2]

0.0

Ending Balance

$ 0.0

$ 6.7

[1]	(a)During the second quarter of 2010, the $0.7 million of financial transmission rights derivatives were settled.
[2]	(a)The ARS were redeemed at carrying value on January 5, 2011.

Fair Value - Financial Instruments (Details) - USD ($) $ in Millions	Dec. 31, 2011	Dec. 31, 2010
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Long-Term Debt, Including Current Portion - Carrying Amount	$ 863.3	$ 785.0
Long-Term Debt, Including Current Portion - Fair Value	$ 966.4	$ 796.7

Short-Term and Long-Term Debt (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2011	Feb. 01, 2012	Nov. 14, 2011	Oct. 07, 2011	Sep. 30, 2011	Aug. 25, 2011	Jun. 30, 2011	Dec. 31, 2010
Financial Covenants [Abstract]
Debt Instrument, Required Indebtedness to Total Capital Ratio	0.65 to 1.00
Debt Instrument, Actual Indebtedness to Total Capital Ratio	0.44 to 1.00
Maturities of Long-term Debt [Abstract]
Long-term Debt, Current Maturities	$ 5.4							$ 13.4
Long-term Debt, Maturities, Repayments of Principal in Year Two	83.8
Long-term Debt, Maturities, Repayments of Principal in Year Three	94.1
Long-term Debt, Maturities, Repayments of Principal in Year Four	16.7
Long-term Debt, Maturities, Repayments of Principal in Year Five	21.0
Long-term Debt, Maturities, Repayments of Principal after Year Five	$ 642.3
Debt Instrument [Line Items]
Debt Instrument, Face Amount						$ 75.0
Debt Instrument, Description of Variable Rate Basis	one-month LIBOR
Debt Instrument, Basis Spread on Variable Rate	1.00%
Short-term Debt [Abstract]
Short-term Debt	$ 6.5							14.4
Aggregate Lines of Credit, Total Borrowing Capacity	256.4							154.0
Aggregate Lines of Credit, Used Borrowing Capacity	1.1							1.0
Aggregate Lines of Credit, Available Borrowing Capacity	255.3							$ 153.0
Credit Agreement Feb 2012 [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		$ 150.0
Letter of Credit Maximum Issuances		$ 10.0
Credit Agreement July 2011 [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	250.0						$ 150.0
Letter of Credit Maximum Issuances	$ 40.0
Term Loan Agreement [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount						$ 75.0
Debt Instrument, Description of Variable Rate Basis	LIBOR
Debt Instrument, Basis Spread on Variable Rate	1.00%
Debt Instrument, Interest Rate, Effective Percentage	1.825%
Debt Instrument, Carrying Amount at Period End	$ 75.0
ALLETE Properties LOC Nov 2011 [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity			$ 8.3		$ 10.0
Line of Credit Borrowing Capacity Reduction	$ 1.7
ALLETE Properties LOC Oct 2011 [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity				$ 3.0

Schedule of Long-Term Debt (Details) - USD ($) $ in Millions	Dec. 31, 2011	Dec. 31, 2010
Debt Instrument [Line Items]
Long-term Debt	$ 863.3	$ 785.0
Long-term Debt, Current Maturities	5.4	13.4
Long-term Debt, Excluding Current Maturities	857.9	771.6
4.86% Series Due 2013 [Member]
Debt Instrument [Line Items]
Long-term Debt	60.0	60.0
6.94% Series Due 2014 [Member]
Debt Instrument [Line Items]
Long-term Debt	18.0	18.0
7.70% Series Due 2016 [Member]
Debt Instrument [Line Items]
Long-term Debt	20.0	20.0
8.17% Series Due 2019 [Member]
Debt Instrument [Line Items]
Long-term Debt	42.0	42.0
5.28% Series Due 2020 [Member]
Debt Instrument [Line Items]
Long-term Debt	35.0	35.0
4.85% Series Due 2021 [Member]
Debt Instrument [Line Items]
Long-term Debt	15.0	15.0
4.95% Pollution Control Series F Due 2022 [Member]
Debt Instrument [Line Items]
Long-term Debt	111.0	111.0
6.02% Series Due 2023 [Member]
Debt Instrument [Line Items]
Long-term Debt	75.0	75.0
4.90% Series Due 2025 [Member]
Debt Instrument [Line Items]
Long-term Debt	30.0	30.0
5.10% Series Due 2025 [Member]
Debt Instrument [Line Items]
Long-term Debt	30.0	30.0
5.99% Series Due 2027 [Member]
Debt Instrument [Line Items]
Long-term Debt	60.0	60.0
5.69% Series Due 2036 [Member]
Debt Instrument [Line Items]
Long-term Debt	50.0	50.0
6.00% Series Due 2040 [Member]
Debt Instrument [Line Items]
Long-term Debt	35.0	35.0
5.82% Series Due 2040 [Member]
Debt Instrument [Line Items]
Long-term Debt	45.0	45.0
7.25% Series Due 2013 [Member]
Debt Instrument [Line Items]
Long-term Debt	10.0	10.0
Senior Unsecured Notes 5.99% Due 2017 [Member]
Debt Instrument [Line Items]
Long-term Debt	50.0	50.0
Variable Demand Revenue Refunding Bonds Series 1997 A, B, and C Due 2013-2020 [Member]
Debt Instrument [Line Items]
Long-term Debt	28.2	28.3
Industrial Development Revenue Bonds 6.5% Due 2025 [Member]
Debt Instrument [Line Items]
Long-term Debt	6.0	6.0
Industrial Development Variable Rate Demand Refunding Revenue Bonds Series 2006 Due 2025 [Member]
Debt Instrument [Line Items]
Long-term Debt	27.8	27.8
Unsecured Term Loan Variable Rate Due 2014 [Member] [Domain]
Debt Instrument [Line Items]
Long-term Debt	75.0	0.0
Other Long-Term Debt, 1.0%-8.0% Due 2012-2037 [Member]
Debt Instrument [Line Items]
Long-term Debt	$ 40.3	$ 36.9

Commitments, Guarantees and Contingencies - Power Purchase Agreements (Details) MWh in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2011 USD ($) MW MWh Years shares	Dec. 31, 2010 USD ($)	Dec. 31, 2009 USD ($)
Power Purchase Agreements [Line Items]
Long-term Contract for Purchase of Electric Power, Number of Wind PPAs	2
Interest Expense	$ 43.6	$ 39.2	$ 33.8
Minnkota Power Sales Agreement [Member]
Power Purchase Agreements [Line Items]
Long-term Contract for Purchase of Electric Power, Date of Contract Expiration	2025
Long-term Contract for Purchase of Electric Power, Anticipated Date of New Transmission Line	2013
Oliver Wind I PPA [Member]
Power Purchase Agreements [Line Items]
Long-term Contract for Purchase of Electric Power, Share of Plant Output Being Purchased (MW) \| MW	50
Long-term Contract for Purchase of Electric Power, Start Date of Contract	2006
Oliver Wind II PPA [Member]
Power Purchase Agreements [Line Items]
Long-term Contract for Purchase of Electric Power, Share of Plant Output Being Purchased (MW) \| MW	48
Long-term Contract for Purchase of Electric Power, Start Date of Contract	2007
Oliver Wind I and II PPA [Member]
Power Purchase Agreements [Line Items]
Long-term Contract for Purchase of Electric Power, Term of Contract (Years) \| Years	25
fixed capacity charge	$ 0.0
Manitoba Hydro PPA (expires April 2015) [Member]
Power Purchase Agreements [Line Items]
Long-term Contract for Purchase of Electric Power, Share of Plant Output Being Purchased (MW) \| MW	50
Long-term Contract for Purchase of Electric Power, Date of Contract Expiration	April 2015
Manitoba Hydro PPA (expires April 2022) [Member]
Power Purchase Agreements [Line Items]
Long-term Contract for Purchase of Electric Power, Start Date of Contract	May 2011
Long-term Contract for Purchase of Electric Power, Date of Contract Expiration	April 2022
Long-term Contract for Purchase of Electric Power, Share of Plant Output Being Purchased (MWh) \| MWh	1
Long-term Contract for Purchase of Electric Power, Date of MPUC Approval	March 31, 2011
Manitoba Hydro PPA (expires 2035) [Member]
Power Purchase Agreements [Line Items]
Long Term Contract For Purchase Of Electric Power Date Agreement Was Executed	May 19, 2011
Long-term Contract for Purchase of Electric Power, Term of Contract (Years) \| Years	15
Long-term Contract for Purchase of Electric Power, Start Date of Contract	2020
Long-term Contract for Purchase of Electric Power, Generating Unit Capacity (MW) \| MW	250
Long-term Contract for Purchase of Electric Power, Date of MPUC Approval	January 26, 2012
Square Butte PPA [Member]
Power Purchase Agreements [Line Items]
Cost of Purchased Power	$ 61.2	55.2	53.9
Long-term Contract for Purchase of Electric Power, Date of Contract Expiration	2026
Long-term Contract for Purchase of Electric Power, Generating Unit Capacity (MW) \| shares	455
Long-term Contract for Purchase of Electric Power, Amount of Long-term Debt or Lease Obligation Outstanding	$ 451.4
Long-term Contract for Purchase of Electric Power, Share of Plant Output Being Purchased	50.00%
Long-term Contract for Purchase of Electric Power, Annual Minimum Debt Service Payment Required	$ 44.0
Interest Expense	$ 11.1	$ 10.2	$ 11.0
DC Transmission Line from Square Butte [Member]
Power Purchase Agreements [Line Items]
Transmission Line Purchase Date	December 2009

Commitments, Guarantees and Contingencies - North Dakota Wind Development (Details) $ in Millions	Dec. 31, 2011 USD ($) MW Miles kV
DC Transmission Line from Square Butte [Member]
North Dakota Wind Development [Line Items]
Transmission Line Length (Miles) \| Miles	465
Transmission Line Capacity (kV) \| kV	250
Bison 1 Wind Project [Member]
North Dakota Wind Development [Line Items]
Generating Unit Capacity (MW) \| MW	82
Expected Capital Cost	$ 177.0
Capital Cost Spent to Date	$ 171.5
MPUC, Current Cost Recovery, Approval Date	2009
MPUC, Rates, Approval Date	July 2010
MPUC, Rates, Effective Date	August 1, 2010
MPUC Updated Approval Date	November 3, 2011
Bison 1 Wind Project, Phase 1 [Member]
North Dakota Wind Development [Line Items]
Transmission Line Length (Miles) \| Miles	22
Transmission Line Capacity (kV) \| kV	230
Project Completion Date	2010
Number of Turbines	16
Capacity of Turbines (MW) \| MW	2.3
Bison 1 Wind Project, Phase 2 [Member]
North Dakota Wind Development [Line Items]
Project Completion Date	January 2012
Number of Turbines	15
Capacity of Turbines (MW) \| MW	3.0
Bison 2 and 3 Wind Projects [Member]
North Dakota Wind Development [Line Items]
Generating Unit Capacity (MW) \| MW	105
Project Completion Date	2012
Expected Capital Cost	$ 160.0
Bison 2 Wind Project [Member]
North Dakota Wind Development [Line Items]
Capital Cost Spent to Date	$ 37.0
MPUC, Project, Approval Date	September 8, 2011
NDPSC, Site Permit, Approval Date	August 10, 2011
Bison 3 Wind Project [Member]
North Dakota Wind Development [Line Items]
Capital Cost Spent to Date	$ 14.7
MPUC, Project, Approval Date	November 2, 2011
NDPSC, Site Permit, Approval Date	October 12, 2011

Commitments, Guarantees and Contingencies - Leasing Agreements (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Leasing Agreements [Line Items]
Operating Leases, Future Minimum Payments Due, Current	$ 10.9
Operating Leases, Future Minimum Payments, Due in Two Years	11.1
Operating Leases, Future Minimum Payments, Due in Three Years	11.4
Operating Leases, Future Minimum Payments, Due in Four Years	11.2
Operating Leases, Future Minimum Payments, Due in Five Years	9.2
Operating Leases, Future Minimum Payments, Due Thereafter	43.0
Operating Leases, Rent Expense	9.4	$ 9.4	$ 9.3
Exploration and Production Equipment [Member]
Leasing Agreements [Line Items]
Annual Lease Payment	$ 2.8
Leasing Agreement Expiration Date	2027
Termination Fee	$ 3.0

Commitments, Guarantees and Contingencies - Coal Rail and Shipping Contracts (Details) - Public Utilities, Inventory, Coal [Member] $ in Millions	Dec. 31, 2011 USD ($)
Coal Rail and Shipping Contracts [Line Items]
Recorded Unconditional Purchase Obligation Due within One Year	$ 55.4
Recorded Unconditional Purchase Obligation Due in Second Year	$ 27.0

Commitments, Guarantees and Contingencies - Transmission (Details) $ in Millions	Dec. 31, 2011 USD ($) Miles kV
Transmission [Line Items]
MPUC, Billing Factor, Approval Date	May 2011
MPUC, Updated Billing Factor, Filing Date	June 29, 2011
MPUC, Updated Billing Factor, Expected Approval Date	2012
CapX2020 Bemidji to Grand Rapids Project [Member]
Transmission [Line Items]
Transmission Line Length (Miles) \| Miles	70
Transmission Line Capacity (kV) \| kV	230
CapX2020 Monticello to St. Cloud Project [Member]
Transmission [Line Items]
Transmission Line Length (Miles) \| Miles	28
Transmission Line Capacity (kV) \| kV	345
Project Completion Date	December 2011
MPUC, Route Permit, Approval Date	July 2010
CapX2020 Fargo to St. Cloud Project [Member]
Transmission [Line Items]
MPUC, Route Permit, Approval Date	June 10, 2011
CapX2020 Fargo to Monticello Projects [Member]
Transmission [Line Items]
Transmission Line Length (Miles) \| Miles	238
Transmission Line Capacity (kV) \| kV	345
Projected In Service Date	2015
CapX2020 [Member]
Transmission [Line Items]
Number of Projects	3
Minimum Amount Expected to be Invested in Transmission Projects \| $	$ 100.0
Maximum Amount Expected to be Invested in Transmission Projects \| $	125.0
Capital Cost Spent to Date \| $	$ 27.8

Commitments, Guarantees and Contingencies - Environmental Matters (Details) $ in Millions	Dec. 31, 2011 USD ($)
Boswell Unit 4 [Member]
Environmental Matters [Line Items]
minimum amount expected to be invested for compliance costs	$ 300.0
maximum amount expected to be invested for compliance costs	400.0
Manufactured Gas Plant Site [Member]
Environmental Matters [Line Items]
Liability for Remediation of Manufactured Gas Plant Site	$ 0.5

Commitments, Guarantees and Contingencies - Other Matters (Details) $ in Millions	Dec. 31, 2011 USD ($) Years	Dec. 31, 2010
BNI Coal Reclamation Liability [Member]
Guarantor Obligations [Line Items]
Surety Bonds Outstanding	$ 29.8
Total amount of letter of credit secured in addition to surety bonds for reclamation liability	2.6
Total current estimated reclamation liability	32.4
ALLETE Properties Performance and Maintenance Obligations [Member]
Guarantor Obligations [Line Items]
Surety Bonds Outstanding	10.2
Performance and Maintenance Obligations	$ 8.0
Town Center Community Development District [Member]
Guarantor Obligations [Line Items]
Capital Improvement Revenue/Special Assessment Bonds, Date Issued	March 2005
Special Assessment Bond	$ 26.4
Capital Improvement Revenue/Special Assessment Bonds, Interest Rate	6.00%
Capital Improvement Revenue/Special Assessment Bonds, Ownership Percentage of Benefited Property	73.00%	69.00%
Capital Improvement Revenue/Special Assessment Bonds, Annual Assessments Based on Ownership Percentage	$ 1.5
Palm Coast Park Community Development District [Member]
Guarantor Obligations [Line Items]
Capital Improvement Revenue/Special Assessment Bonds, Date Issued	May 2006
Special Assessment Bond	$ 31.8
Capital Improvement Revenue/Special Assessment Bonds, Interest Rate	5.70%
Capital Improvement Revenue/Special Assessment Bonds, Ownership Percentage of Benefited Property	93.00%	93.00%
Capital Improvement Revenue/Special Assessment Bonds, Annual Assessments Based on Ownership Percentage	$ 2.2
Community Development Districts [Member]
Guarantor Obligations [Line Items]
Capital Improvement Revenue/Special Assessment Bonds, Term (Years) \| Years	31

Commitments, Guarantees and Contingencies - Legal Proceedings (Details) $ in Millions	12 Months Ended
	Dec. 31, 2011 USD ($)
Pending or Threatened Litigation [Member]
Loss Contingencies [Line Items]
Loss Contingency, Damages Sought, Value	$ 20

- Definition

The value (monetary amount) of the award the plaintiff seeks in the legal matter.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 5
-Paragraph 9
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 5
-Paragraph 11
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 5
-Paragraph 10
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6952336&loc=d3e14326-108349

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6952336&loc=d3e14435-108349

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 9
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6952336&loc=d3e14557-108349

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 5
-Paragraph 12
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

Common Stock and Earnings Per Share - Summary of Common Stock (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Class of Stock [Line Items]
Common Stock Outstanding, Shares	37,500,000	35,800,000
Purchase of Non-Controlling Interest, Shares	200,000
Contributions to Pension, Shares	507,600
Contributions to Pension, Value	$ 20.0
Common Stock [Member]
Class of Stock [Line Items]
Common Stock Outstanding, Shares	37,513,000	35,817,000	35,221,000	32,585,000
Common Stock Outstanding, Value	$ 705.6	$ 636.1	$ 613.4	$ 534.1
Employee Stock Purchase Program, Shares	20,000	19,000	24,000
Employee Stock Purchase Program, Value	$ 0.8	$ 0.6	$ 0.7
Invest Direct, Shares	437,000	346,000	456,000
Invest Direct, Value	$ 17.2	$ 11.7	$ 13.6
Options and Stock Awards, Shares	109,000	51,000	8,000
Options and Stock Awards, Value	$ 6.7	$ 4.4	$ 1.1
Equity Issuance Program, Shares	400,000	180,000	1,685,000
Equity Issuance Program, Value	$ 16.0	$ 6.0	$ 51.9
Purchase of Non-Controlling Interest, Shares	222,000
Purchase of Non-Controlling Interest, Value	$ 8.8
Contributions to Pension, Shares	507,600		463,000
Contributions to Pension, Value	$ 20.0		$ 12.0
Equity Issuance Program Shares Authorized	6,600,000
Equity Issuance Program Shares Available for Issuance	2,700,000

Common Stock and Earnings Per Share - Reconciliation of Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Earnings Per Share [Abstract]
Antidilutive Options to Purchase Shares of Common Stock Excluded from the Computation of Earnings Per Share									0.3	0.5	0.6
Earnings Per Share, Basic [Abstract]
Net Income Attributable to ALLETE	$ 19.1	$ 20.5	$ 17.0	$ 37.2	$ 13.3	$ 19.6	$ 19.4	$ 23.0	$ 93.8	$ 75.3	$ 61.0
Common Shares									35.3	34.2	32.2
Per Share of Common Stock	$ 0.53	$ 0.57	$ 0.49	$ 1.07	$ 0.38	$ 0.57	$ 0.57	$ 0.68	$ 2.66	$ 2.20	$ 1.89
Dilutive Securities (Shares)									0.1	0.1	0.0
Earnings Per Share, Diluted [Abstract]
Net Income Attributable to ALLETE									$ 93.8	$ 75.3	$ 61.0
Common Shares									35.4	34.3	32.2
Per Share of Common Stock	$ 0.53	$ 0.57	$ 0.48	$ 1.07	$ 0.38	$ 0.56	$ 0.57	$ 0.68	$ 2.65	$ 2.19	$ 1.89

Other Income (Expense) (Details) - USD ($) $ in Millions	12 Months Ended
Other Income (Expense) (Details) - USD ($) $ in Millions	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Other Income and Expenses [Abstract]
AFUDC - Equity	$ 2.5	$ 4.2	$ 5.8
Investment and Other Income (Expense)	1.9	0.4	(4.0)
Total Other Income	$ 4.4	$ 4.6	$ 1.8

Income Tax Expense (Details) - USD ($)
$ in Millions

12 Months Ended

Dec. 31, 2011

Dec. 31, 2010

Dec. 31, 2009

Income Tax Disclosure [Abstract]

Current Federal Tax Expense (Benefit)

^[1]

$ 1.4

$ (23.0)

$ (42.6)

Current State Tax Expense (Benefit)

^[1]

(1.6)

1.3

(1.8)

Total Current Tax Expense (Benefit)

(0.2)

(21.7)

(44.4)

Deferred Federal Tax Expense (Benefit)

^[2]

27.3

61.4

66.0

Deferred State Tax Expense (Benefit)

^[2]

9.5

5.3

10.3

Change in Valuation Allowance

(0.1)

0.2

(0.1)

Investment Tax Credit Amortization

(0.9)

(1.0)

Total Deferred Tax Expense

35.8

66.0

75.2

Total Income Tax Expense

35.6

44.3

30.8

DTA Tax Charge, Elimination of Medicare Part D [Member]

Income Tax Contingency [Line Items]

Tax Adjustments, Settlements, and Unusual Provisions

0.0

4.0

0.0

Income Tax Benefit, MPUC Approval of Deferral of PPACA [Member]

Income Tax Contingency [Line Items]

Tax Adjustments, Settlements, and Unusual Provisions

(2.9)

0.0

DTL Reversal, Revenue Receivable Forgone [Member]

Income Tax Contingency [Line Items]

Tax Adjustments, Settlements, and Unusual Provisions

$ (6.2)

$ 0.0

[1]

(a)For the year ended December 31, 2011, the federal and state current tax expense (benefit) of $1.4 million and $(1.6) million, respectively, was due to an NOL which resulted primarily from the bonus depreciation provision of the Tax Relief Unemployment Insurance Reauthorization and Job Creation Act of 2010. The 2011 federal and state NOLs will be carried forward to offset future taxable income. For the year ended December 31, 2010, we recorded a federal current tax benefit as a result of tax planning initiatives and the bonus depreciation provision in the Small Business Jobs Act of 2010. The 2010 federal NOL was partially utilized by carrying it back against prior years' income with the remainder carried forward to offset future years' income. The 2009 federal current tax benefit was primarily due to the bonus depreciation provision of the American Recovery and Reinvestment Act of 2009.

[2]

(b)The year ended December 31, 2011, included an income tax benefit of $2.9 million related to the MPUC approval of our request to defer the retail portion of the tax charge taken in 2010 as a result of PPACA and a benefit for the reversal of a $6.2 million deferred tax liability related to a revenue receivable that Minnesota Power agreed to forgo as part of a stipulation and settlement agreement in its 2010 rate case. Included in the year ended December 31, 2010, was a charge of $4.0 million as a result of PPACA. (See Note 5. Regulatory Matters.)

Income Tax Expense - Reconciliation of Taxes from Federal Statutory Rate to Total Income Tax Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Unusual or Infrequent Item [Line Items]
Income Before Non-Controlling Interest and Income Taxes	$ 129.2	$ 119.1	$ 91.5
Statutory Federal Income Tax Rate	35.00%	35.00%	35.00%
Income Taxes Computed at 35 Percent Statutory Federal Rate	$ 45.2	$ 41.7	$ 32.0
State Income Taxes - Net of Federal Income Tax Benefit	6.0	4.5	5.4
Regulatory Differences for Utility Plant	(1.2)	(2.0)	(2.5)
Production Tax Credit	(4.3)	(1.6)	(1.2)
Other	(1.0)	(2.3)	(2.9)
Income Tax Expense	$ 35.6	$ 44.3	$ 30.8
Effective Income Tax Rate	27.60%	37.20%	33.70%
DTA Tax Charge, Elimination of Medicare Part D [Member]
Unusual or Infrequent Item [Line Items]
Tax Adjustments, Settlements, and Unusual Provisions	$ 0.0	$ 4.0	$ 0.0
DTL Reversal, Revenue Receivable Forgone [Member]
Unusual or Infrequent Item [Line Items]
Tax Adjustments, Settlements, and Unusual Provisions	(6.2)	0.0	0.0
Income Tax Benefit, MPUC Approval of Deferral of PPACA [Member]
Unusual or Infrequent Item [Line Items]
Tax Adjustments, Settlements, and Unusual Provisions	$ (2.9)	$ 0.0	$ 0.0

Income Tax Expense - Deferred Tax Assets and Liabilities (Details) - USD ($)
$ in Millions

Dec. 31, 2011

Dec. 31, 2010

Deferred Tax Assets [Abstract]

Employee Benefits and Compensation

$ 132.7

$ 121.8

Property Related

56.4

51.1

NOL and Tax Credit Carryforward

78.1

28.2

Investment Tax Credits

9.0

9.7

Other

7.2

12.7

Gross Deferred Tax Assets

283.4

223.5

Deferred Tax Asset Valuation Allowance

(0.4)

(0.5)

Total Deferred Tax Assets

283.0

223.0

Deferred Tax Liabilities [Abstract]

Property Related

482.7

387.2

Regulatory Asset for Benefit Obligations

117.9

105.8

Unamortized Investment Tax Credits

12.8

13.7

Partnership Basis Differences

24.4

19.4

Other

24.0

27.3

Total Deferred Tax Liabilities

661.8

553.4

Net Deferred Income Taxes

378.8

330.4

Net Current Deferred Tax Liabilities

^[1]

5.2

Net Long-Term Deferred Tax Liabilities

$ 373.6

$ 325.2

[1]	(a)Included in Other Current Liabilities.

Income Tax Expense - NOL and Tax Credit Carryforwards (Details) - USD ($)
$ in Millions

Dec. 31, 2011

Dec. 31, 2010

Federal [Member]

NOL and Tax Credit Carryforwards [Line Items]

NOL Carryforward

^[1]

$ 162.0

$ 62.0

Tax Credit Carryforwards

8.4

3.7

Charitable Contributions Carryforward

3.0

State [Member]

NOL and Tax Credit Carryforwards [Line Items]

NOL Carryforward

^[1],[2]

73.1

71.7

Tax Credit Carryforwards

3.8

$ 1.7

Charitable Contributions Carryforward

$ 2.8

[1]	(a)Pretax amounts
[2]	(b)State NOL carryforwards include Minnesota, North Dakota and Florida.

Income Tax Expense - Gross Unrecognized Income Tax Benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Gross Unrecognized Income Tax Benefits [Abstract]
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	$ 0.6
Accrued Interest	1.1	$ 0.7	$ 0.9
Interest Expense	0.4	0.2	0.4
Penalties	0.0
Reasonably Possible Change in Unrecognized Tax Benefits in Next 12 Months	5.0
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at January 1	12.3	9.5	8.0
Additions for Tax Positions Related to the Current Year	0.0	0.0	0.5
Reductions for Tax Positions Related to the Current Year	0.0	(0.2)	0.0
Additions for Tax Positions Related to Prior Years	0.0	4.4	1.0
Reduction for Tax Positions Related to Prior Years	(0.9)	0.0	0.0
Settlements	0.0	(0.3)	0.0
Lapse of Statute	0.0	(1.1)	0.0
Balance as of December 31	$ 11.4	$ 12.3	$ 9.5

Comprehensive Income (Details) - USD ($) $ in Millions	12 Months Ended
Comprehensive Income (Details) - USD ($) $ in Millions	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Accumulated Other Comprehensive Income (Loss) [Abstract]
Unrealized Loss on Securities	$ (1.3)	$ (1.0)
Unrealized Loss on Derivatives	(0.3)	0.0
Defined Benefit Pension and Other Postretirement Plans	(27.3)	(22.2)
Total Accumulated Other Comprehensive Loss	(28.9)	(23.2)
Comprehensive Income (Loss) [Abstract]
Net Income	93.6	74.8	$ 60.7
Other Comprehensive Income (Loss) [Abstract]
Unrealized Gain (Loss) on Securities Net of income taxes of $(0.1), $0.6, and $1.7	(0.3)	0.8	2.8
Unrealized Loss on Derivatives Net of income taxes of $(0.2) $-, and $-	(0.3)	0.0	0.0
Defined Benefit Pension and Other Postretirement Plans Net of income taxes of $(3.6), $-, and $4.1	(5.1)	0.0	6.2
Total Other Comprehensive Income (Loss)	(5.7)	0.8	9.0
Total Comprehensive Income	87.9	75.6	69.7
Less: Non-Controlling Interest in Subsidiaries	(0.2)	(0.5)	(0.3)
Comprehensive Income Attributable to ALLETE	88.1	76.1	70.0
Unrealized Gain (Loss) on Securities, Income Taxes	(0.1)	0.6	1.7
Unrealized Loss on Derivatives, Income Taxes	(0.2)	0.0	0.0
Defined Benefit Pension and Other Postretirement Plans, Income Taxes	$ (3.6)	$ 0.0	$ 4.1

Pension and Other Postretirement Benefit Plan Contributions (Details) - USD ($) $ in Millions	12 Months Ended		24 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2011
Defined Benefit Plan Disclosure [Line Items]
Stock Issued During Period, Value, Employee Benefit Plan	$ 20.0
Pension [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension and Other Postretirement Benefit Contributions	33.8	$ 26.5
Contributions by Employer through ESOP	7.3	7.2
Estimated Employer Contributions in Next Fiscal Year	1.0		$ 1.0
Postretirement Health and Life [Member]
Defined Benefit Plan Disclosure [Line Items]
Estimated Employer Contributions in Next Fiscal Year	13.9		13.9
VEBA [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension and Other Postretirement Benefit Contributions	$ 10.9	$ 12.8
Grantor Trust [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension and Other Postretirement Benefit Contributions			$ 0.0

Pension and Postretirement Health and Life Obligation and Funded Status (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Change in Plan Assets [Roll Forward]
Non-Current Liabilities	$ 253.5	$ 231.4
Pension [Member]
Defined Benefit Plan Disclosure [Line Items]
Accumulated Benefit Obligation	550.6	485.6
Change in Benefit Obligation [Roll Forward]
Obligation, Beginning of Year	525.6	465.2
Service Cost	7.6	6.2	$ 5.7
Interest Cost	27.4	26.2	26.2
Actuarial Loss (Gain)	54.6	47.1
Benefits Paid	(28.6)	(27.2)
Participant Contributions	10.9	8.1
Obligation, End of Year	597.5	525.6	465.2
Change in Plan Assets [Roll Forward]
Fair Value, Beginning of Year	382.0	327.6
Actual Return on Plan Assets	33.1	45.6
Employer Contribution	45.8	36.0
Benefits Paid	(28.5)	(27.2)
Fair Value, End of Year	432.4	382.0	327.6
Funded Status, End of Year	(165.1)	(143.6)
Current Liabilities	(1.1)	(0.8)
Non-Current Liabilities	(164.0)	(142.8)
Postretirement Health and Life [Member]
Change in Benefit Obligation [Roll Forward]
Obligation, Beginning of Year	204.1	192.1
Service Cost	3.8	4.8	4.1
Interest Cost	10.8	10.9	10.0
Actuarial Loss (Gain)	(2.9)	17.6
Benefits Paid	(7.7)	(9.2)
Participant Contributions	2.5	2.1
Plan Amendments	0.0	(14.2)
Obligation, End of Year	210.6	204.1	192.1
Change in Plan Assets [Roll Forward]
Fair Value, Beginning of Year	114.7	96.4
Actual Return on Plan Assets	0.0	12.0
Employer Contribution	11.4	13.4
Participant Contributions	2.5	2.0
Benefits Paid	(7.6)	(9.1)
Fair Value, End of Year	121.0	114.7	$ 96.4
Funded Status, End of Year	(89.6)	(89.4)
Current Liabilities	(0.9)	(0.8)
Non-Current Liabilities	(88.7)	(88.6)
Grantor Trust [Member]
Change in Plan Assets [Roll Forward]
Other Investments	$ 20.3	$ 19.8

Unrecognized Pension and Postretirement Health and Life Costs (Details) - USD ($) $ in Millions	Dec. 31, 2011	Dec. 31, 2010
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Total Unrecognized Costs	$ 27.3	$ 22.2
Pension [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Net Loss	269.0	225.1
Prior Service Cost	1.1	1.4
Total Unrecognized Costs	270.1	226.5
Postretirement Health and Life [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Net Loss	78.5	80.1
Prior Service Cost	(9.5)	(11.2)
Transition Obligation	0.1	0.2
Total Unrecognized Costs	$ 69.1	$ 69.1

- Definition

The total of net gain (loss), prior service cost (credit), and transition assets (obligations), as well as minimum pension liability if still remaining, included in accumulated other comprehensive income associated with a defined benefit pension or other postretirement plan(s) because they have yet to be recognized as components of net periodic benefit cost.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 130
-Paragraph 26
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
-Paragraph 5
-Subparagraph i
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 158
-Paragraph 7
-Subparagraph c
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=6920043&loc=d3e637-108580

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 14
-URI http://asc.fasb.org/extlink&oid=6920043&loc=d3e681-108580

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=6920043&loc=d3e653-108580

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (i)
-URI http://asc.fasb.org/extlink&oid=6962843&loc=d3e1928-114920

+ Details

- Definition

Amount related to the pretax cost of benefit changes attributable to plan participants' prior service pursuant to a plan amendment or a plan initiation, which has not yet been recognized as components of net periodic benefit cost.

+ References

+ Details

- Definition

Of the original amount of transition assets as of the date FAS 87 or 106 was initially applied, (a) the fair value of plan assets plus any recognized accrued pension or other postretirement benefit cost or less any recognized prepaid pension or other postretirement benefit cost in excess of (b) the benefit obligation, the portion of which has yet to be recognized as components of net periodic benefit cost. Of the original amount of transition obligations as of the date FAS 87 or 106 was initially applied, (a) the benefit obligation in excess of (b) the fair value of plan assets plus any recognized accrued pension or other postretirement benefit cost or less any recognized prepaid pension or other postretirement benefit cost, the portion of which has yet to be recognized as components of net periodic benefit cost. This amount is pretax.

+ References

+ Details

Components of Net Periodic Pension and Postretirement Health and Life Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Pension [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Service Cost	$ 7.6	$ 6.2	$ 5.7
Interest Cost	27.4	26.2	26.2
Expected Return on Plan Assets	(34.6)	(33.7)	(33.8)
Amortization of Loss	12.1	6.6	3.4
Amortization of Prior Service Costs	0.3	0.5	0.6
Net Expense	12.8	5.8	2.1
Postretirement Health and Life [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Service Cost	3.8	4.8	4.1
Interest Cost	10.8	10.9	10.0
Expected Return on Plan Assets	(9.7)	(9.5)	(8.3)
Amortization of Loss	8.5	4.8	2.5
Amortization of Prior Service Costs	(1.7)	(0.1)	0.0
Amortization of Transition Obligation	0.1	2.5	2.5
Net Expense	$ 11.8	$ 13.4	$ 10.8

Other Changes in Pension and Postretirement Health and Life Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income and Regulatory Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010
Pension [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Net Loss	$ 56.1	$ 35.2
Amortization of Prior Service Cost	(0.3)	(0.5)
Amortization of Gain (Loss)	(12.2)	(6.6)
Total Recognized in Other Comprehensive Income and Regulatory Assets	43.6	28.1
Postretirement Health and Life [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Net Loss	6.9	15.3
Prior Service Cost (Credit) Arising During Period	0.0	(14.2)
Amortization of Prior Service Cost	1.7	0.1
Amortization of Transition Obligation	(0.1)	(2.5)
Amortization of Gain (Loss)	(8.5)	(4.8)
Total Recognized in Other Comprehensive Income and Regulatory Assets	$ 0.0	$ (6.1)

- Definition

The change in other comprehensive income due to the amortization of the net prior service costs (credit) into net periodic pension costs.

+ References

+ Details

- Definition

The pretax cost (credit) of benefit changes attributable to plan participants' prior service resulting from a plan amendment or plan initiation that occurred during the period. The cost has not yet been recognized in net periodic benefit cost. A plan amendment includes provisions that grant increased (decreased) benefits based on service rendered in prior periods.

+ References

+ Details

- Definition

Amounts recognized in other comprehensive income (but not yet recognized in net periodic benefit cost), including the net gain (loss) and net prior service cost (credit) arising during the period. Also includes reclassification adjustments out of other comprehensive income as a result of being recognized as components of net periodic benefit cost for the period. While for technical reasons this element has no balance attribute, the default assumption is a credit balance consistent with its label.

+ References

+ Details

- Definition

Pretax change in the value of either the benefit obligation or the plan assets resulting from experience different from that assumed or from a change in an actuarial assumption, or the consequence of a decision to temporarily deviate from the substantive plan, that has not been recognized in net periodic benefit cost.

+ References

+ Details

- Definition

The net transition asset or obligation recognized, before tax, as a reclassification adjustment of other comprehensive income as a result of being recognized as a component of net periodic benefit cost for the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
-Article 3

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
-Paragraph 5
-Subparagraph i
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 158
-Paragraph 7
-Subparagraph a
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 158
-Paragraph 4
-Subparagraph c, d
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=6920043&loc=d3e637-108580

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=6959260&loc=d3e187085-122770

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 16
-URI http://asc.fasb.org/extlink&oid=6920043&loc=d3e709-108580

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=6920043&loc=d3e716-108580

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 15
-URI http://asc.fasb.org/extlink&oid=6920043&loc=d3e689-108580

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (j)
-URI http://asc.fasb.org/extlink&oid=6962843&loc=d3e1928-114920

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 55
-Paragraph 2
-Subparagraph (j)
-URI http://asc.fasb.org/extlink&oid=6920433&loc=d3e998-108581

Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 51
-Paragraph 38
-Subparagraph c(3)
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

- Definition

The net gain (loss) previously recognized in other comprehensive income that is a reclassification adjustment of other comprehensive income as a result of being recognized as a component of net periodic benefit cost for the period.

+ References

+ Details

Information for Pension Plans with an Accumulated Benefit Obligation in Excess of Plan Assets (Details) - Pension [Member] - USD ($) $ in Millions	Dec. 31, 2011	Dec. 31, 2010
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Projected Benefit Obligation	$ 597.5	$ 525.6
Accumulated Benefit Obligation	550.6	485.6
Fair Value of Plan Assets	$ 432.4	$ 382.0

Estimated Future Benefit Payments (Details) $ in Millions	Dec. 31, 2011 USD ($)
Pension [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
2012	$ 29.2
2013	30.0
2014	31.2
2015	32.3
2016	33.4
Years 2017 - 2021	181.4
Postretirement Health and Life [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
2012	8.3
2013	9.2
2014	10.2
2015	11.2
2016	11.9
Years 2017 - 2021	$ 66.6

Pension and Postretirement Health and Life Costs Recorded in Other Long-Term Assets and AOCI Expected to be Recognized as a Component of Net Pension and Postretirement Benefit Costs in the Next Fiscal Year (Details) $ in Millions	12 Months Ended
	Dec. 31, 2012 USD ($)
Pension [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Net Loss	$ 17.5
Prior Service Costs	0.3
Transition Obligations	0.0
Total Pension and Postretirement Health and Life Costs	17.8
Postretirement Health and Life [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Net Loss	7.5
Prior Service Costs	(1.7)
Transition Obligations	0.1
Total Pension and Postretirement Health and Life Costs	$ 5.9

Weighted-Average Assumptions Used to Determine Benefit Obligation and Net Periodic Benefit Costs (Details)

12 Months Ended

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2010

Dec. 31, 2009

Weighted-Average Assumptions Used to Determine Benefit Obligation [Abstract]

Rate of Compensation Increase

4.3 - 4.6%

Trend Rate

10.00%

Ultimate Trend Rate

5.00%

Year Ultimate Trend Rate Effective

2018

Weighted-Average Assumptions Used to Determine Net Periodic Benefit Costs [Abstract]

Discount Rate (Range)

5.36 - 5.40%

Discount Rate

5.81%

6.12%

Rate of Compensation Increase

4.3 - 4.6%

Revised Expected Long-term Rate of Return

8.25%

Pension [Member]

Weighted-Average Assumptions Used to Determine Benefit Obligation [Abstract]

Discount Rate

4.54%

5.36%

Weighted-Average Assumptions Used to Determine Net Periodic Benefit Costs [Abstract]

Revised Expected Long-term Rate of Return

^[1]

8.50%

Postretirement Health and Life [Member]

Weighted-Average Assumptions Used to Determine Benefit Obligation [Abstract]

Discount Rate

4.56%

5.40%

Weighted-Average Assumptions Used to Determine Net Periodic Benefit Costs [Abstract]

Expected Long-Term Return on Plan Assets

^[1]

6.8 - 8.5%

[1]	(a) The expected long-term rate of return used to determine net periodic benefit expenses for 2012 has been reduced to 8.25 percent.

Sensitivity of a One-Percentage-Point Change in Health Care Trend Rates (Details) - Postretirement Health and Life [Member] $ in Millions	12 Months Ended
	Dec. 31, 2011 USD ($)
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Effect of One Percent Increase on Total of Postretirement Health and Life Service and Interest Cost	$ 2.0
Effect of One Percent Decrease on Total of Postretirement Health and Life Service and Interest Cost	(1.6)
Effect of One Percent Increase on Postretirement Health and Life Obligation	25.1
Effect of One Percent Decrease on Postretirement Health and Life Obligation	$ (20.7)

Plan Asset Allocations (Details) - shares

12 Months Ended

Dec. 31, 2011

Dec. 31, 2010

Plan Asset Target Allocations [Abstract]

ALLETE Common Stock Included in Pension Plan Equity Securities

20,000,000

Stock Issued During Period, Shares, Employee Benefit Plan

507,600

Pension [Member]

Plan Asset Target Allocations [Abstract]

Equity Securities Target Allocation

52.00%

Debt Securities Target Allocation

30.00%

Real Estate Target Allocation

9.00%

Private Equity Target Allocation

9.00%

Pension [Member] | Equity Securities [Member]

Actual Plan Asset Allocations [Abstract]

Actual Plan Asset Allocation

52.00%

Pension [Member] | Debt Securities [Member]

Actual Plan Asset Allocations [Abstract]

Actual Plan Asset Allocation

27.00%

29.00%

Pension [Member] | Real Estate [Member]

Actual Plan Asset Allocations [Abstract]

Actual Plan Asset Allocation

5.00%

Pension [Member] | Private Equity [Member]

Actual Plan Asset Allocations [Abstract]

Actual Plan Asset Allocation

16.00%

14.00%

Postretirement Health and Life [Member]

Plan Asset Target Allocations [Abstract]

Equity Securities Target Allocation

^[1]

48.00%

Debt Securities Target Allocation

^[1]

34.00%

Real Estate Target Allocation

^[1]

9.00%

Private Equity Target Allocation

^[1]

9.00%

Postretirement Health and Life [Member] | Equity Securities [Member]

Actual Plan Asset Allocations [Abstract]

Actual Plan Asset Allocation

^[2]

51.00%

58.00%

Postretirement Health and Life [Member] | Debt Securities [Member]

Actual Plan Asset Allocations [Abstract]

Actual Plan Asset Allocation

^[2]

39.00%

33.00%

Postretirement Health and Life [Member] | Real Estate [Member]

Actual Plan Asset Allocations [Abstract]

Actual Plan Asset Allocation

^[2]

0.00%

Postretirement Health and Life [Member] | Private Equity [Member]

Actual Plan Asset Allocations [Abstract]

Actual Plan Asset Allocation

^[2]

10.00%

9.00%

[1]	(a)Includes VEBAs and irrevocable grantor trusts.
[2]	(a)Includes VEBAs and irrevocable grantor trusts.

Pension and Other Postretirement Benefit Plans Activity in Level 3 (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010
Pension [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Actual Return on Plan Assets	$ 33.1	$ 45.6
Pension [Member] \| Equity Securities (Auction Rate Securities) [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	6.7	9.1
Actual Return on Plan Assets	0.0	0.0
Purchases, Sales and Settlements, Net	(6.7)	(2.4)
Ending Balance	0.0	6.7
Pension [Member] \| Private Equity Funds [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	50.7	44.7
Actual Return on Plan Assets	30.9	(4.1)
Purchases, Sales and Settlements, Net	(12.6)	10.1
Ending Balance	69.0	50.7
Pension [Member] \| Real Estate [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	20.1	17.3
Actual Return on Plan Assets	3.5	(6.1)
Purchases, Sales and Settlements, Net	(1.9)	8.9
Ending Balance	21.7	20.1
Postretirement Health and Life [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Actual Return on Plan Assets	0.0	12.0
Postretirement Health and Life [Member] \| Private Equity Funds [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	12.4	9.4
Actual Return on Plan Assets	1.1	1.4
Purchases, Sales and Settlements, Net	0.5	1.6
Ending Balance	$ 14.0	$ 12.4

- Definition

The difference between fair value of plan assets at the end of the period and the fair value at the beginning of the period, adjusted for contributions and payments of benefits during the period, and after adjusting for taxes and other expenses, as applicable.

+ References

+ Details

Employee Stock and Incentive Plans - Employee Stock Ownership Plan (Details) - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Employee Stock and Incentive Plans [Abstract]
ESOP Employer Loan, Description	In 1990, the ESOP issued a $75.0 million note (term not to exceed 25 years at 10.25 percent) to use as consideration for 2.8 million shares (1.9 million shares adjusted for stock splits) of our newly issued common stock. The note was refinanced in 2006 at 6 percent.
ESOP Compensation Expense	$ 7.4	$ 7.1	$ 6.5
Allocated	2.2	2.2	2.2
Unallocated	1.0	1.3	1.5
Total	3.2	3.5	3.7
Fair Value of Unallocated Shares	$ 42.0	$ 48.4	$ 49.0

Employee Stock and Incentive Plans - Stock-Based Compensation (Details)

12 Months Ended

Dec. 31, 2011

Years

Dec. 31, 2010

Dec. 31, 2009

Dec. 31, 2008

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Grants under Director Plan

^[1]

Options Outstanding

460,234

560,887

646,235

672,419

PSA Performance Period | Years

RSU Vesting Period

ESPP Discount

5.00%

Long-Term Incentive Compensation, Director Plan [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Grants under Director Plan

Options Outstanding

1,293

Long-Term Incentive Compensation, Executive Plan [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Common Stock Reserved

1,300,000

Shares Available for Issuance

600,000

[1]	(a)Stock options have not been granted since 2008. The weighted-average grant-date intrinsic value of options granted in 2008 was $6.18.

Employee Stock and Incentive Plans - Share-Based Compensation Expense (Details) $ in Millions	12 Months Ended
	Dec. 31, 2011 USD ($)	Dec. 31, 2010 USD ($)	Dec. 31, 2009 USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-Based Compensation Expense	$ 1.6	$ 2.2	$ 2.1
Income Tax Benefit	0.7	0.9	0.8
Capitalized Stock-Based Compensation Expense	0.0
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-Based Compensation Expense	0.0	0.1	0.3
Performance Shares Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-Based Compensation Expense	1.1	1.5	1.5
Unrecognized Compensation Cost	$ 1.3
Weighted Average Period for Recognition	1.7
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-Based Compensation Expense	$ 0.5	$ 0.6	$ 0.3
Unrecognized Compensation Cost	$ 0.6
Weighted Average Period for Recognition	1.6

Employee Stock and Incentive Plans - Non-Qualified Stock Options (Details) - USD ($)
$ / shares in Units, $ in Millions

12 Months Ended

Dec. 31, 2011

Dec. 31, 2010

Dec. 31, 2009

Dec. 31, 2008

Number of Options [Abstract]

Outstanding as of January 1,

560,887

646,235

672,419

Granted

^[1]

Exercised

80,798

40,769

4,508

Forfeited

19,855

44,579

21,676

Outstanding as of December 31,

460,234

560,887

646,235

672,419

Exercisable as of December 31,

460,234

523,491

512,743

Weighted Average Exercise Price [Abstract]

Outstanding as of January 1,

$ 40.69

$ 40.05

$ 39.99

Granted

^[1]

0.00

Exercised

34.25

27.76

18.85

Forfeited

43.96

43.16

42.62

Outstanding as of December 31,

41.68

40.69

40.05

$ 39.99

Exercisable as of December 31,

$ 41.59

$ 39.76

$ 37.34

Proceeds from Stock Options Exercised

$ 0.1

Weighted Average Grant Date Intrinsic Value of Options Granted

$ 6.18

Total Intrinsic Value of Options Exercised

$ 0.5

$ 0.3

$ 0.1

[1]	(a)Stock options have not been granted since 2008. The weighted-average grant-date intrinsic value of options granted in 2008 was $6.18.

Employee Stock and Incentive Plans - Stock Options, Range of Exercise Price (Details)	12 Months Ended
	Dec. 31, 2011 Years $ / shares shares	Dec. 31, 2010 shares	Dec. 31, 2009 shares
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number Outstanding and Exercisable	460,234	523,491	512,743
$18.85 to $29.79 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number Outstanding and Exercisable	11,672
Weighted Average Remaining Contracutal Life (Years) \| Years	1.1
Weighted Average Exercise Price \| $ / shares	$ 24.14
$37.76 to $41.35 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number Outstanding and Exercisable	279,133
Weighted Average Remaining Contracutal Life (Years) \| Years	4.5
Weighted Average Exercise Price \| $ / shares	$ 39.57
$44.15 to $48.65 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number Outstanding and Exercisable	169,429
Weighted Average Remaining Contracutal Life (Years) \| Years	4.5
Weighted Average Exercise Price \| $ / shares	$ 46.37

Employee Stock and Incentive Plans - Performance Shares (Details)
$ / shares in Units, $ in Millions

3 Months Ended

12 Months Ended

Mar. 31, 2010

USD ($)

$ / shares

Dec. 31, 2012

$ / shares

Dec. 31, 2011

USD ($)

Years

$ / shares

Dec. 31, 2010

$ / shares

Dec. 31, 2009

$ / shares

Number of Shares [Abstract]

Awarded

100,000

Weighted Average Grant Date Fair Value [Abstract]

Performance Share Grants, Grant Date Fair Value | $

$ 1.4

Performance Share Awards, Grant Date Fair Value | $

$ 1.4

$ 1.6

Performance Period | Years

Performance Shares Awards [Member]

Number of Shares [Abstract]

Non-vested as of January 1,

121,825

128,333

122,489

121,825

79,238

Granted

^[1]

39,312

49,302

69,800

Awarded

(32,368)

Unearned Grant Award

(22,909)

(24,615)

Forfeited

(1,100)

(25,729)

(2,598)

Non-vested as of December 31,

128,333

122,489

121,825

Weighted Average Grant Date Fair Value [Abstract]

As of January 1, | $ / shares

$ 41.96

$ 28.00

$ 38.15

$ 41.96

$ 47.94

Granted | $ / shares

^[1]

41.00

35.44

35.06

Awarded | $ / shares

48.10

0.00

Unearned Grant Award | $ / shares

0.00

54.50

41.97

Forfeited | $ / shares

34.35

36.45

38.78

As of December 31, | $ / shares

$ 28.00

$ 38.15

$ 41.96

[1]	(a) Shares granted includes accrued dividends.

Employee Stock and Incentive Plans - Restricted Stock Units (Details) - USD ($)
$ / shares in Units, $ in Millions

12 Months Ended

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2010

Dec. 31, 2009

Weighted Average Grant Date Fair Value [Abstract]

Restricted Stock Units Granted, Grant Date Fair Value

$ 0.6

Restricted Stock Units Awarded, Shares

100,000

Restricted Stock Units Awarded, Grant Date Fair Value

$ 0.8

$ 0.1

Restricted Stock Units (RSUs) [Member]

Number of Shares [Abstract]

Available as of January 1,

63,464

43,803

28,983

Granted

20,136

26,589

^[1]

30,465

^[1]

Awarded

(3,091)

Forfeited

(260)

(8,678)

(1,482)

Available as of December 31,

63,464

43,803

28,983

Weighted Average Grant Date Fair Value [Abstract]

As of January 1,

$ 22.88

$ 30.61

$ 29.41

$ 0.00

Granted

^[1]

36.74

31.83

29.41

Awarded

30.30

29.75

0.00

Forfeited

29.41

30.62

29.41

As of December 31,

$ 22.88

$ 30.61

$ 29.41

Restricted Stock Units Awarded, Shares

(215)

[1]	(a) Shares granted includes accrued dividends.

Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Quarterly Financial Data (Unaudited) [Abstract]
Operating Revenue	$ 239.2	$ 226.9	$ 219.9	$ 242.2	$ 238.1	$ 224.1	$ 211.2	$ 233.6	$ 928.2	$ 907.0	$ 759.1
Operating Income	34.2	38.9	26.1	50.8	22.7	35.3	31.7	46.1	150.0	135.8	106.0
Net Income Attributable to ALLETE	$ 19.1	$ 20.5	$ 17.0	$ 37.2	$ 13.3	$ 19.6	$ 19.4	$ 23.0	$ 93.8	$ 75.3	$ 61.0
Basic Earnings Per Share of Common Stock	$ 0.53	$ 0.57	$ 0.49	$ 1.07	$ 0.38	$ 0.57	$ 0.57	$ 0.68	$ 2.66	$ 2.20	$ 1.89
Diluted Earnings Per Share of Common Stock	$ 0.53	$ 0.57	$ 0.48	$ 1.07	$ 0.38	$ 0.56	$ 0.57	$ 0.68	$ 2.65	$ 2.19	$ 1.89

- Definition

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 128
-Paragraph 36, 37, 38
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 5
-Section 03
-Paragraph 20

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
-Article 7
-Paragraph 18

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
-Paragraph 21
-Article 9

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.21)
-URI http://asc.fasb.org/extlink&oid=6880815&loc=d3e20235-122688

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6920599&loc=d3e1252-109256

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 55
-Paragraph 52
-URI http://asc.fasb.org/extlink&oid=6945512&loc=d3e4984-109258

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.23)
-URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04.19)
-URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Emerging Issues Task Force (EITF)
-Number 07-4
-Paragraph 4
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

- Definition

The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

+ References + Details

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Emerging Issues Task Force (EITF)
-Number 87-21
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 51
-Paragraph 38
-Subparagraph a
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 130
-Paragraph 10, 15
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 95
-Paragraph 28, 29, 30
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Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
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-Section 03
-Paragraph 19

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
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Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
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-Section 45
-Paragraph 28
-URI http://asc.fasb.org/extlink&oid=6943989&loc=d3e3602-108585

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Net Income
-URI http://asc.fasb.org/extlink&oid=6518256

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Other Comprehensive Income
-URI http://asc.fasb.org/extlink&oid=6519514

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
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-URI http://asc.fasb.org/extlink&oid=6880815&loc=d3e20235-122688

Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-Subparagraph (SX 210.7-04.19)
-URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913

Reference 13: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
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-Section 45
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-URI http://asc.fasb.org/extlink&oid=6920043&loc=d3e565-108580

Reference 14: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
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-URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913

Reference 15: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 51
-Paragraph 38
-Subparagraph d
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 16: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 51
-Paragraph A7
-Appendix A