v2.4.0.8

Variable Interest Entities and Unconsolidated Investments in Power Plants (Unconsolidated VIEs) (Details) (USD $) In Millions, unless otherwise specified | Sep. 30, 2014 | Dec. 31, 2013
--- | --- | ---
Schedule of Equity Method Investments [Line Items] |  |
Equity Method Investments | $ 92 | $ 93
Greenfield [Member] |  |
Schedule of Equity Method Investments [Line Items] |  |
Equity Method Investments | 78 | 76
Equity Method Investment, Ownership Percentage | 50.00% |
Whitby [Member] |  |
Schedule of Equity Method Investments [Line Items] |  |
Equity Method Investments | $ 14 | $ 17
Equity Method Investment, Ownership Percentage | 50.00% |

X
- 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=6382943&loc=d3e33918-111571 + Details
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