Debt (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012
Nonrecourse Debt Default [Line Items]
Default	$ 1,377
Sonel [Member]
Nonrecourse Debt Default [Line Items]
Net Assets	359
Kelanitissa [Member]
Nonrecourse Debt Default [Line Items]
Net Assets	56
Maritza [Member]
Nonrecourse Debt Default [Line Items]
Net Assets	534
Saurashtra [Member]
Nonrecourse Debt Default [Line Items]
Net Assets	16
Kavarna [Member]
Nonrecourse Debt Default [Line Items]
Net Assets	72
Covenant Violation [Member] | Sonel [Member]
Nonrecourse Debt Default [Line Items]
Default	285
Covenant Violation [Member] | Kelanitissa [Member]
Nonrecourse Debt Default [Line Items]
Default	10
Covenant Violation [Member] | Maritza [Member]
Nonrecourse Debt Default [Line Items]
Default	850
Covenant Violation [Member] | Saurashtra [Member]
Nonrecourse Debt Default [Line Items]
Default	28
Payment Default [Member] | Kavarna [Member]
Nonrecourse Debt Default [Line Items]
Default	$ 204