v3.6.0.2
Capital Structure (Details) - USD ($)
$ / shares in Units, $ in Millions
 12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Class of Stock [Line Items]        
Common Stock, authorized shares (in shares) 1,400,000,000 1,400,000,000    
Common Stock, issued shares (in shares) 359,627,113 356,755,747    
Common Stock, par value (in dollars per share) $ 0.001 $ 0.001    
Common Stock, outstanding shares (in shares) 359,061,764 356,662,004 381,921,264 429,038,988
Shares issued under Calpine Equity Incentive Plans 2,422,287 1,341,908 2,566,799  
Share repurchase program (22,527) (26,601,168) (49,684,523)  
Treasury Stock, Shares, Retired   0    
Treasury Stock, Shares (in shares) 565,349 93,743    
Treasury Stock, Value $ 7 $ 1    
Shares Issued [Member]        
Class of Stock [Line Items]        
Common Stock, issued shares (in shares) 359,627,113 356,755,747 502,287,022 497,841,056
Shares issued under Calpine Equity Incentive Plans 2,871,366 2,431,236 4,445,966  
Share repurchase program 0 0 0  
Treasury Stock, Shares, Retired   (147,962,511)    
Treasury Stock, Common [Member]        
Class of Stock [Line Items]        
Treasury Stock, Shares, Retired   147,962,511    
Treasury Stock [Member]        
Class of Stock [Line Items]        
Shares issued under Calpine Equity Incentive Plans (449,079) (1,089,328) (1,879,167)  
Share repurchase program (22,527) (26,601,168) (49,684,523)  
Treasury Stock, Shares (in shares) 565,349 93,743 120,365,758 68,802,068