v3.19.1
Acquisitions, Divestitures and Discontinued Operations (Textuals) (Details)
$ in Millions
 3 Months Ended 12 Months Ended
Mar. 31, 2017
USD ($)
Dec. 31, 2016
USD ($)
Dec. 31, 2018
USD ($)
Dec. 31, 2017
USD ($)
Dec. 31, 2016
USD ($)
Jan. 17, 2017
USD ($)
Dec. 01, 2016
USD ($)
Oct. 26, 2016
MW
Feb. 05, 2016
USD ($)
MW
Business Acquisition [Line Items]                  
Business Acquisition, Pro Forma Revenue         $ 8,324        
Business Acquisition, Pro Forma Net Income (Loss)         105        
(Gain) on sale of power plants, net     $ 0 $ 27 157        
Calpine Solutions [Member]                  
Business Acquisition [Line Items]                  
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net             $ 1,150    
Working Capital Adjustment to Sale price         350        
Recovered collateral subsequent to closing         250        
Expected recovery through collateral synergies             $ 200    
Number of States in which Entity Operates             20    
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets             $ 141    
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Prepaid Expense and Other Assets             518    
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Derivative assets [1]             365    
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment             7    
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles [2]             360    
Business Acquisition, Goodwill, Expected Tax Deductible Amount             162    
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Long-term derivative asset [1]             359    
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets             1,912    
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities             276    
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Derivative liabilities, current [1]             270    
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Long-term derivative liabilities [1]             216    
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities             $ 762    
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net   $ 800     $ 800        
North American Power [Member]                  
Business Acquisition [Line Items]                  
Ownership Percentage of Acquiree           100.00%      
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net           $ 105      
Granite Ridge Energy Center [Member]                  
Business Acquisition [Line Items]                  
Summer peaking capacity | MW                 695
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net                 $ 500
Power generation capacity | MW                 745
Osprey Energy Center [Member]                  
Business Acquisition [Line Items]                  
Proceeds from Sale of Productive Assets $ 166                
(Gain) on sale of power plants, net $ 27                
Mankato [Member]                  
Business Acquisition [Line Items]                  
Proceeds from Sale of Productive Assets   396              
Gain (Loss) on Sale of Assets and Asset Impairment Charges   $ 157              
Power generation capacity | MW               375  
Expansion generation capacity | MW               345  
Acquired contracts [Member] | Calpine Solutions [Member]                  
Business Acquisition [Line Items]                  
Finite-Lived Intangible Asset, Useful Life   5 years              
Customer Relationships [Member] | Calpine Solutions [Member]                  
Business Acquisition [Line Items]                  
Finite-Lived Intangible Asset, Useful Life   14 years              
[1] Consists of acquired customer and wholesale contracts which will be substantially amortized over 5 years.
[2] Consists primarily of customer relationships that are being amortized over 14 years. See Note 3 for a further description of our intangible assets.