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The amount of additional or anticipated investments in the investee accounted for under the equity method of accounting.

+ References

No definition available.

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- Definition

Equity Method Investment - Additional Investment Amount

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No definition available.

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- Definition

The approved percentage return on common equity dedicated to the utility plant in the investee accounted for under the equity method of accounting.

+ References

No definition available.

+ Details

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- Definition

The amount of the operating expense reported by an equity method investment of the entity.

+ References

No definition available.

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- Definition

The amount of other expense reported by an equity method investment of the entity.

+ References

No definition available.

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- Definition

This item represents disclosure of the amount of dividends or other distributions received from unconsolidated subsidiaries, certain corporate joint ventures, and certain noncontrolled corporation; these investments are accounted for under the equity method of accounting. This element excludes distributions that constitute a return of investment, which are classified as investing activities.

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-Publisher FASB

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- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

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-Name Statement of Financial Accounting Standard (FAS)

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This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized.

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- Definition

The amount of net income (loss) reported by an equity method investment of the entity.

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- Definition

The amount of revenue from sale of goods and services reduced by sales returns, allowances, and discounts reported by an equity method investment of the entity.

+ References

No definition available.

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This item represents the entity's proportionate share for the period of the net income (loss) of its investee (such as unconsolidated subsidiaries and joint ventures) to which the equity method of accounting is applied. This item includes income or expense related to stock-based compensation based on the investor's grant of stock to employees of an equity method investee.

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The cash outflow associated with the purchase of or advances to an equity method investments, which are investments in joint ventures and entities in which the entity has an equity ownership interest normally of 20 to 50 percent and exercises significant influence.

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Investment in ATC (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Dec. 31, 2012	Apr. 30, 2012
Investment in ATC [Abstract]
Ownership Percentage	8.00%
Approved Return on Common Equity	12.20%
Equity Method Investment - Anticipated Investment for Year			$ 3.0
Equity Method Investment - Investments Made During Year	0.8			1.2
ALLETE's Investment in ATC [Roll Forward]
Equity Investment Balance as of December 31, 2011	98.9		98.9
Cash Investments	0.8
Equity Earnings in ATC	4.6	4.4
Distributed ATC Earnings	(3.8)
Equity Investment Balance as of March 31, 2012	100.5
ATC Summarized Financial Data [Abstract]
Revenue	147.7	139.6
Operating Expense	69.6	63.1
Other Expense	20.0	22.3
Net Income	58.1	54.2
ALLETE's Equity in Net Income	$ 4.6	$ 4.4