Basis of Presentation and Summary of Significant Accounting Policies (Details) (USD $) In Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010	Dec. 31, 2010
Restricted Cash and Cash Equivalents Items [Line Items]
Current	$ 175		$ 175		$ 195
Non-current	42		42		53
Total	217		217		248
Property, Plant and Equipment [Abstract]
Buildings, machinery and equipment	14,966		14,966		14,578
Geothermal Properties	1,143		1,143		1,102
Other	265		265		273
Subtotal - gross	16,374		16,374		15,953
Accumulated depreciation	3,931		3,931		3,690
Subtotal - net	12,443		12,443		12,263
Land	94		94		93
Construction in Progress	496		496		622
Property, plant and equipment, net	13,033		13,033		12,978
Prior period reclassifications [Abstract]
(Gain) loss on interest rate derivatives, net	37	(8)	146	3
Depreciation expense on corporate assets reclassification		3		6
Reclassification of Cash Settlement on Interest Rate Swaps in Statement of Cash Flows				14
Cash and cash equivalents subject to project finance facilities and lease agreements	301		301		269
Inventory balance	246		246		262
Capitalized Interest	4	1	11	2
Debt Service
Restricted Cash and Cash Equivalents Items [Line Items]
Current	48		48		44
Non-current	28		28		25
Total	76		76		69
Rent Reserve
Restricted Cash and Cash Equivalents Items [Line Items]
Current	5		5		22
Non-current					5
Total	5		5		27
Construction Major Maintenance
Restricted Cash and Cash Equivalents Items [Line Items]
Current	56		56		35
Non-current	3		3		14
Total	59		59		49
Security Project Insurance
Restricted Cash and Cash Equivalents Items [Line Items]
Current	51		51		75
Non-current	7		7		7
Total	58		58		82
Other
Restricted Cash and Cash Equivalents Items [Line Items]
Current	15		15		19
Non-current	4		4		2
Total	$ 19		$ 19		$ 21