Non-Recourse Debt (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Nonrecourse Debt Default [Line Items]
Default	$ 1,304
Gains Losses On Extinguishment Of Debt	(47)	0
Sonel [Member]
Nonrecourse Debt Default [Line Items]
Net Assets	361
Maritza [Member]
Nonrecourse Debt Default [Line Items]
Net Assets	576
Saurashtra [Member]
Nonrecourse Debt Default [Line Items]
Net Assets	15
Kavarna [Member]
Nonrecourse Debt Default [Line Items]
Net Assets	82
Tiete [Member]
Nonrecourse Debt Default [Line Items]
Debt Instrument, Increase, Additional Borrowings	251
Debt Instrument, Decrease, Repayments	60
El Salvador [Member]
Nonrecourse Debt Default [Line Items]
Debt Instrument, Increase, Additional Borrowings	310
Debt Instrument, Decrease, Repayments	150
Sul [Member]
Nonrecourse Debt Default [Line Items]
Debt Instrument, Increase, Additional Borrowings	150
Debt Instrument, Decrease, Repayments	34
Mong Duong [Member]
Nonrecourse Debt Default [Line Items]
Debt Instrument, Increase, Additional Borrowings	119
Masinloc [Member]
Nonrecourse Debt Default [Line Items]
Debt Instrument, Increase, Additional Borrowings	500
Gains Losses On Extinguishment Of Debt	(43)
Extinguishment of Debt, Amount	500
Covenant Violation [Member] | Sonel [Member]
Nonrecourse Debt Default [Line Items]
Default	264
Covenant Violation [Member] | Maritza [Member]
Nonrecourse Debt Default [Line Items]
Default	819
Covenant Violation [Member] | Kavarna [Member]
Nonrecourse Debt Default [Line Items]
Default	196
Payment Default [Member] | Saurashtra [Member]
Nonrecourse Debt Default [Line Items]
Default	$ 25