v2.4.0.6
Property, Plant and Equipment, Net (Details) (USD $)
 12 Months Ended
Dec. 31, 2011
Dec. 31, 2010
Dec. 31, 2009
Property, Plant and Equipment, Net [Abstract]      
Property, Plant and Equipment, Salvage Value, Percentage Rotables Change 0.15%    
Combined Cycle Power Plant, UsefulLife, Old 35    
Simple Cycle Power Plant, Useful Life, Old 40    
Combined Cycle Power Plant, Useful Life, New 37    
Simple Cycle Power Plant, Useful Life, New 47    
Depreciation $ 560,000,000 $ 568,000,000 $ 469,000,000
Rotable Parts, Useful Life, Maximum 18    
Geysers Power Plant Assets, Useful Life, New 13    
Daily Water Reinjection 18,000,000    
Increase In Depreciation Expense For Natural Gas Fired Plants     28,000,000
Decrease In Depreciation Expense For Geysers Assets     3,000,000
Decrease In Net Income Attributable To Calpine Due To Change In Accounting Estimate     25,000,000
Decrease In Basic And Diluted Earnings Per Share Due To Change In Accounting Estimate     (0.05)
Buildings, machinery and equipment 15,074,000,000 14,669,000,000  
Geothermal properties 1,163,000,000 1,102,000,000  
Other 156,000,000 182,000,000  
Property, Plant and Equipment, Gross 16,393,000,000 15,953,000,000  
Less: Accumulated depreciation 4,158,000,000 3,690,000,000  
Property, Plant and Equipment, Gross, Less Accumulated Depreciation 12,235,000,000 12,263,000,000  
Land 91,000,000 93,000,000  
Construction in progress 693,000,000 622,000,000  
Property, plant and equipment, net 13,019,000,000 12,978,000,000  
Interest Costs, Capitalized During Period $ 24,000,000 $ 15,000,000 $ 8,000,000
Geysers Steam Extraction And Gathering Assets, Useful Life, New 59    
Rotable Parts, Useful Life, Minimum 3