Property, Plant and Equipment, Net (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Property, Plant and Equipment [Line Items]
Depreciation	$ 557	$ 560	$ 568
Buildings, machinery and equipment	14,774	15,074
Geothermal properties	1,243	1,163
Other	142	156
Property, Plant and Equipment, Gross	16,159	16,393
Less: Accumulated depreciation	4,390	4,158
Property, Plant and Equipment, Gross, Less Accumulated Depreciation	11,769	12,235
Land	98	91
Construction in progress	1,138	693
Property, plant and equipment, net	13,005	13,019
Interest Costs, Capitalized During Period	$ 38	$ 24	$ 15
Building, Machinery and Equipment, Gross [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Estimated Useful Lives	P3Y
Building, Machinery and Equipment, Gross [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Estimated Useful Lives	P47Y
Geothermal Properties, Gross [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Estimated Useful Lives	P13Y
Geothermal Properties, Gross [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Estimated Useful Lives	P59Y
Property, Plant and Equipment, Other Types [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Estimated Useful Lives	P3Y
Property, Plant and Equipment, Other Types [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Estimated Useful Lives	P47Y