|
Variable Interest Entities and Unconsolidated Investments (Unconsolidated Investements) (Details) (USD $)
In Millions, unless otherwise specified |
12 Months Ended | ||
|---|---|---|---|
|
Dec. 31, 2012
|
Dec. 31, 2011
|
Dec. 31, 2010
|
|
| Income Loss from Unconsolidated Investments in Power Plants and Distributions [Line Items] | |||
| (Income) from unconsolidated investments in power plants | $ (28) | $ (21) | $ (16) |
| Return on investment in unconsolidated subsidiaries | 29 | 6 | 11 |
|
Greenfield [Member]
|
|||
| Income Loss from Unconsolidated Investments in Power Plants and Distributions [Line Items] | |||
| (Income) from unconsolidated investments in power plants | (17) | (12) | (8) |
| Return on investment in unconsolidated subsidiaries | 22 | 2 | 6 |
|
Whitby [Member]
|
|||
| Income Loss from Unconsolidated Investments in Power Plants and Distributions [Line Items] | |||
| (Income) from unconsolidated investments in power plants | (11) | (9) | (8) |
| Return on investment in unconsolidated subsidiaries | $ 7 | $ 4 | $ 5 |