v2.4.0.8
Capital Structure (Details) (USD $)
 3 Months Ended 12 Months Ended
Dec. 31, 2013
Sep. 30, 2013
Mar. 31, 2013
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2011
Class of Stock [Line Items]            
Shares Of New, Reorganized Common Stock       485,000,000    
Common Stock, authorized shares (in shares) (1,400,000,000)     (1,400,000,000) (1,400,000,000)  
Common Stock, issued shares (in shares) (497,841,056)     (497,841,056) (492,495,100)  
Common Stock, par value (in dollars per share) $ (0.001)     $ (0.001) $ (0.001)  
Common Stock, outstanding shares (in shares) (429,038,988)     (429,038,988) (457,048,970)  
Treasury Stock, Shares (in shares) 68,802,068     68,802,068 35,446,130  
Treasury Stock, Value $ 1,230,000,000     $ 1,230,000,000 $ 594,000,000  
Treasury Stock, Value, Acquired, Cost Method 239,000,000     636,000,000 469,000,000 120,000,000
Common Stock Activity [Roll Forward]            
Total common shares outstanding, beginning balance     (457,048,970) (457,048,970) (481,743,738) (488,693,630)
Resolution of claims/inter-creditor disputes           0
Shares issued under Calpine Equity Incentive Plans       3,022,128 1,741,909.000000 1,187,181
Share repurchase program       (31,032,110.00000) (26,436,677.000000) (8,137,073)
Total common shares outstanding, ending balance (429,038,988)     (429,038,988) (457,048,970) (481,743,738)
Stock Repurchase Program, Authorized Amount   100,000,000 400,000,000   600,000,000  
Shares Issued [Member]
            
Common Stock Activity [Roll Forward]            
Total common shares outstanding, beginning balance     (492,495,100) (492,495,100) (490,468,815) (444,883,356)
Resolution of claims/inter-creditor disputes           44,258,432
Shares issued under Calpine Equity Incentive Plans       5,345,956 2,026,285 1,327,027
Share repurchase program       0 0 0
Total common shares outstanding, ending balance (497,841,056)     (497,841,056) (492,495,100) (490,468,815)
Shares Held inTreasury [Member]
            
Common Stock Activity [Roll Forward]            
Total common shares outstanding, beginning balance     (35,446,130) (35,446,130) (8,725,077) (448,158)
Resolution of claims/inter-creditor disputes           0
Shares issued under Calpine Equity Incentive Plans       2,323,828 284,376 139,846
Share repurchase program       (31,032,110) (26,436,677) (8,137,073)
Total common shares outstanding, ending balance (68,802,068)     (68,802,068) (35,446,130) (8,725,077)
Shares Held in Reserve [Member]
            
Common Stock Activity [Roll Forward]            
Total common shares outstanding, beginning balance     0 0 0 (44,258,432)
Resolution of claims/inter-creditor disputes           44,258,432
Shares issued under Calpine Equity Incentive Plans       0 0 0
Share repurchase program       0 0 0
Total common shares outstanding, ending balance 0     0 0 0
Unfinished Program [Member]
            
Common Stock Activity [Roll Forward]            
Share repurchase program       (12,459,919)    
Treasury Stock Acquired, Average Cost Per Share       $ 19.15    
Stock Repurchase Program, Cumulative Authorized Amount       1,000,000,000    
Finished Program [Member]
            
Common Stock Activity [Roll Forward]            
Share repurchase program       (60,139,816)    
Treasury Stock Acquired, Average Cost Per Share       $ 18.29    
Stock Repurchase Program, Cumulative Authorized Amount       $ 1,100,000,000