Amount of distribution received from equity method investee for return on investment, classified as operating activities. Excludes distribution for return of investment, classified as investing activities.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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This item represents an other than temporary decline in value that has been recognized against an investment accounted for under the equity method of accounting. The excess of the carrying amount over the fair value of the investment represents the amount of the write down which is or was reflected in earnings. The written down value is a new cost basis with the adjusted value of the investment becoming its new carrying value subject to the equity accounting method. Evidence of a loss in value might include, but would not necessarily be limited to, absence of an ability to recover the carrying amount of the investment or inability of the investee to sustain an earnings capacity which would justify the carrying amount of the investment.

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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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This item represents the aggregate value of each identified investment accounted for under the equity method of accounting based on the quoted market price for those investments in common stock for which a quoted market price is available.

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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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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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Equity method investments in unconsolidated affiliates - impairments (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended		30 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016	Dec. 31, 2015	Jun. 30, 2017
Equity in earnings of unconsolidated affiliates
Equity in (loss) earnings of unconsolidated affiliates	$ 9.2	$ 9.6	$ (36.1)	$ 27.9
Equity Method Investments.	199.8		199.8		$ 266.8
Distributions from unconsolidated affiliates	$ 13.7	$ 13.0	$ 30.9	$ 36.5
Chambers Cogen, LP
Equity in earnings of unconsolidated affiliates
Percentage of ownership interest	40.00%		40.00%
Equity in (loss) earnings of unconsolidated affiliates			$ 3.4		$ 5.5	$ 6.5
Equity impairment other than temporary	$ 47.1
Equity Method Investments.	124.0		124.0
Distributions from unconsolidated affiliates							$ 33.6
Estimated fair value of equity investment	$ 77.2		$ 77.2
Selkirk Cogen Partners, LP
Equity in earnings of unconsolidated affiliates
Percentage of ownership interest	17.70%		17.70%
Equity in (loss) earnings of unconsolidated affiliates			$ 1.2
Equity impairment other than temporary	$ 10.6