Basis of Presentation and Summary of Significant Accounting Policies Property, Plant and Equipment, Net (Details) - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Buildings, machinery and equipment	$ 16,712	$ 16,294
Geothermal properties	1,368	1,319
Other	230	208
Property, plant and equipment, gross	18,310	17,821
Less: Accumulated depreciation	5,652	5,377
Property, plant and equipment, gross, less accumulated depreciation, depletion and amortization	12,658	12,444
Land	121	120
Construction in progress	562	448
Property, plant and equipment, net	$ 13,341	$ 13,012