v2.4.0.6

Capital Structure (Details) (USD $) | 1 Months Ended | 3 Months Ended | 12 Months Ended
--- | --- | --- | ---
Feb. 12, 2013 | Mar. 31, 2013 | Jun. 30, 2012 | Sep. 30, 2011 | Dec. 31, 2012 | Dec. 31, 2011 | Dec. 31, 2010
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) |
Common Stock, issued shares (in shares) |  |  |  |  | (492,495,100) | (490,468,815) |
Common Stock, par value (in dollars per share) |  |  |  |  | $ (0.001) | $ (0.001) |
Common Stock, outstanding shares (in shares) |  |  |  |  | (457,048,970) | (481,743,738) |
Treasury Stock, Shares (in shares) |  |  |  |  | 35,446,130 | 8,725,077 |
Treasury Stock, Value |  |  |  |  | $ 594,000,000 | $ 125,000,000 |
Stock Repurchase Program, Authorized Amount |  | 400,000,000 | 600,000,000 | 300,000,000 |  |  |
Treasury Stock, Value, Acquired, Cost Method |  |  |  |  | 469,000,000 | 120,000,000 | 2,000,000
Treasury Stock Acquired, Average Cost Per Share | $ 16.87 |  |  |  |  |  |
Common Stock Activity [Roll Forward] |  |  |  |  |  |  |
Total common shares outstanding, beginning balance | (457,048,970) | (457,048,970) |  |  | (481,743,738) | (488,693,630) | (487,745,299)
Resolution of claims/inter-creditor disputes |  |  |  |  |  | 0 | 0
Shares issued under Calpine Equity Incentive Plans |  |  |  |  | 1,741,909 | 1,187,181 | 948,331
Share repurchase program | (35,568,833) |  |  |  | (26,436,677) | (8,137,073) |
Total common shares outstanding, ending balance |  |  |  |  | (457,048,970) | (481,743,738) | (488,693,630)
Stock Repurchase Program, Cumulative Authorized Amount |  |  |  |  | $ 1,000,000,000 |  |
Shares Issued [Member] |  |  |  |  |  |  |
Common Stock Activity [Roll Forward] |  |  |  |  |  |  |
Total common shares outstanding, beginning balance |  |  |  |  | (490,468,815) | (444,883,356) | (443,325,827)
Resolution of claims/inter-creditor disputes |  |  |  |  |  | 44,258,432 | 488,612
Shares issued under Calpine Equity Incentive Plans |  |  |  |  | 2,026,285 | 1,327,027 | 1,068,917
Share repurchase program |  |  |  |  | 0 | 0 |
Total common shares outstanding, ending balance |  |  |  |  | (492,495,100) | (490,468,815) | (444,883,356)
Shares Held inTreasury [Member] |  |  |  |  |  |  |
Common Stock Activity [Roll Forward] |  |  |  |  |  |  |
Total common shares outstanding, beginning balance |  |  |  |  | (8,725,077) | (448,158) | (327,572)
Resolution of claims/inter-creditor disputes |  |  |  |  |  | 0 | 0
Shares issued under Calpine Equity Incentive Plans |  |  |  |  | 284,376 | 139,846 | 120,586
Share repurchase program |  |  |  |  | (26,436,677) | (8,137,073) |
Total common shares outstanding, ending balance |  |  |  |  | (35,446,130) | (8,725,077) | (448,158)
Shares Held in Reserve [Member] |  |  |  |  |  |  |
Common Stock Activity [Roll Forward] |  |  |  |  |  |  |
Total common shares outstanding, beginning balance |  |  |  |  | 0 | (44,258,432) | (44,747,044)
Resolution of claims/inter-creditor disputes |  |  |  |  |  | 44,258,432 | 488,612
Shares issued under Calpine Equity Incentive Plans |  |  |  |  | 0 | 0 | 0
Share repurchase program |  |  |  |  | 0 | 0 |
Total common shares outstanding, ending balance |  |  |  |  | 0 | 0 | (44,258,432)

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