Equity Method Investment, Summarized Financial Information, Debt

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- Definition

Power generation capacity

+ References

No definition available.

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- Definition

Prorata Share of Equity Method Investment, Summarized Financial Information, Debt

+ References

No definition available.

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- Definition

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.

+ References

Reference 1: 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(10))
-URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585

Reference 3: 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(12))
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 21D
-URI http://asc.fasb.org/extlink&oid=98514028&loc=SL94080555-108585

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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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=66011266&loc=d3e33918-111571

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- Definition

The cash inflow from the sale of long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3179-108585

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- Definition

The amount of financial or other support the reporting entity has provided (explicitly or implicitly) to the Variable Interest Entity (VIE) that it was not previously contractually required to provide or that the reporting entity intends to provide, including, for example, situations in which the reporting entity assisted the VIE in obtaining another type of support.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 5A
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=77990344&loc=SL6759159-111685

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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Variable Interest Entities and Unconsolidated Investments in Power Plants (VIE Texuals) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2018 USD ($) MW	Mar. 31, 2017 USD ($)	Dec. 31, 2017 USD ($) MW
Variable Interest Entity [Line Items]
Variable interest entity, financial or other support, amount	$ 0	$ 0
Equity method investment, ownership percentage	50.00%
Equity method investment, summarized financial information, debt	$ 244		$ 256
Prorata share of equity method investment, summarized financial information, debt	122		$ 128
Return on investments from unconsolidated subsidiaries	3	13
Proceeds from sale of Osprey Energy Center	$ 0	162
Greenfield [Member]
Variable Interest Entity [Line Items]
Power generation capacity \| MW	1,038
Equity method investment, ownership percentage	50.00%
Return on investments from unconsolidated subsidiaries	$ 0	0
Whitby [Member]
Variable Interest Entity [Line Items]
Power generation capacity \| MW	50
Equity method investment, ownership percentage	50.00%
Return on investments from unconsolidated subsidiaries	$ 3	$ 13
Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Power generation capacity \| MW	7,880		7,880
Put Option [Member]
Variable Interest Entity [Line Items]
Proceeds from sale of Osprey Energy Center	$ 280
Call Option [Member]
Variable Interest Entity [Line Items]
Proceeds from sale of Osprey Energy Center	$ 377