|
Variable Interest Entities and Unconsolidated Investments (VIE Texuals) (Details)
In Millions, unless otherwise specified |
3 Months Ended | 3 Months Ended | 3 Months Ended | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
|
Mar. 31, 2013
USD ($)
MW
|
Mar. 31, 2012
USD ($)
|
Dec. 31, 2012
USD ($)
MW
|
Mar. 31, 2013
Greenfield [Member]
USD ($)
|
Mar. 31, 2012
Greenfield [Member]
USD ($)
|
Mar. 31, 2013
Greenfield [Member]
CAD
MW
|
Mar. 31, 2013
Whitby [Member]
USD ($)
MW
|
Mar. 31, 2012
Whitby [Member]
USD ($)
|
Mar. 31, 2013
Inland Empire Energy Center [Member]
Y
MW
|
Mar. 31, 2013
Inland Empire Energy Center [Member]
Minimum [Member]
Y
|
Mar. 31, 2013
Inland Empire Energy Center [Member]
Maximum [Member]
Y
|
|
| Variable Interest Entity [Line Items] | |||||||||||
| Power generation capacity | 8,255 | 8,255 | 1,038 | 50 | 775 | ||||||
| Variable Interest Entity, Financial or Other Support, Amount | $ 0 | $ 0 | |||||||||
| Equity Method Investment, Ownership Percentage | 50.00% | 50.00% | |||||||||
| Equity Method Investment, Summarized Financial Information, Debt | 432 | 448 | |||||||||
| Prorata Share of Equity Method Investment, Summarized Financial Information, Debt | 216 | 224 | |||||||||
| Equity Method Investment, Summarized Financial Information, Term Loan Period | 18 years | ||||||||||
| Equity Method Investment, Summarized Financial Information, Term Loan | 648 | ||||||||||
| Project financing interest rate spread - Canadian LIBOR | 1.125% | ||||||||||
| Project financing interest rate spread - Canadian Prime Rate | 0.125% | ||||||||||
| Distribution from equity method investee | $ 0 | $ 0 | $ 0 | $ 0 | |||||||
| Call Option Exercise Period | 2,017 | 2,024 | |||||||||
| Put Option Exercise Period | 2,025 | ||||||||||