v2.4.1.9
Basis of Presentation and Summary of Significant Accounting Policies Property, Plant and Equipment, Net (Details) (USD $)
In Millions, unless otherwise specified
3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Dec. 31, 2014
Property, Plant and Equipment [Line Items]      
Interest Costs Capitalized $ 5us-gaap_InterestCostsCapitalized $ 6us-gaap_InterestCostsCapitalized  
Buildings, machinery and equipment 16,092cpn_BuildingsMachineryAndEquipmentGross   16,059cpn_BuildingsMachineryAndEquipmentGross
Geothermal properties 1,314cpn_GeothermalPropertiesGross   1,294cpn_GeothermalPropertiesGross
Other 205us-gaap_PropertyPlantAndEquipmentOther   203us-gaap_PropertyPlantAndEquipmentOther
Property, Plant and Equipment, Gross 17,611us-gaap_PropertyPlantAndEquipmentGross   17,556us-gaap_PropertyPlantAndEquipmentGross
Less: Accumulated depreciation 5,122us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment   4,984us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment
Property, Plant and Equipment, Gross, Less Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment 12,489cpn_PropertyPlantAndEquipmentGrossLessAccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment   12,572cpn_PropertyPlantAndEquipmentGrossLessAccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment
Land 119us-gaap_Land   120us-gaap_Land
Construction in progress 570us-gaap_ConstructionInProgressGross   498us-gaap_ConstructionInProgressGross
Property, plant and equipment, net $ 13,178us-gaap_PropertyPlantAndEquipmentNet   $ 13,190us-gaap_PropertyPlantAndEquipmentNet