Basis of Presentation and Summary of Significant Accounting Policies (Details) (USD $) In Millions	3 Months Ended	9 Months Ended
Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010	Dec. 31, 2010
Restricted Cash and Cash Equivalents Items [Line Items]
Current	$ 195		$ 195		$ 195
Non-current	43		43		53
Total	238		238		248
Property, Plant and Equipment [Abstract]
Buildings, machinery and equipment	14,972		14,972		14,578
Geothermal Properties	1,146		1,146		1,102
Other	259		259		273
Subtotal - gross	16,377		16,377		15,953
Accumulated depreciation	4,046		4,046		3,690
Subtotal - net	12,331		12,331		12,263
Land	93		93		93
Construction in Progress	586		586		622
Property, plant and equipment, net	13,010		13,010		12,978
Prior period reclassifications [Abstract]
(Gain) loss on interest rate derivatives, net	3	84	149	87
Depreciation expense on corporate assets reclassification		3		9
Reclassification of Cash Settlement on Interest Rate Swaps in Statement of Cash Flows				27
Cash and cash equivalents subject to project finance facilities and lease agreements	308		308		269
Inventory balance	251		251		262
Capitalized Interest	6	6	17	8
Debt Service
Restricted Cash and Cash Equivalents Items [Line Items]
Current	22		22		44
Non-current	27		27		25
Total	49		49		69
Rent Reserve
Restricted Cash and Cash Equivalents Items [Line Items]
Current	2		2		22
Non-current					5
Total	2		2		27
Construction Major Maintenance
Restricted Cash and Cash Equivalents Items [Line Items]
Current	46		46		35
Non-current	4		4		14
Total	50		50		49
Security Project Insurance
Restricted Cash and Cash Equivalents Items [Line Items]
Current	112		112		75
Non-current	8		8		7
Total	120		120		82
Other
Restricted Cash and Cash Equivalents Items [Line Items]
Current	13		13		19
Non-current	4		4		2
Total	$ 17		$ 17		$ 21

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