v3.19.3.a.u2

Capital Structure (Details) - USD ($) $ / shares in Units, $ in Billions | 3 Months Ended | 12 Months Ended |  |
--- | --- | --- | --- | ---
Mar. 31, 2018 | Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017 | Mar. 08, 2018 | Dec. 31, 2016
Class of Stock [Line Items] |  |  |  |  |  |
Sale of Stock, Price Per Share |  |  |  |  | $ 15.25 |
Sale of Stock, Consideration Received on Transaction | $ 5.6 |  |  |  |  |
Common Stock, authorized shares (in shares) |  | 5,000 | 5,000 |  |  |
Common Stock, issued shares (in shares) |  | 105.2 | 105.2 |  |  |
Treasury Stock, Shares |  |  |  |  |  |
Common Stock, par value (in dollars per share) |  | $ 0.001 | $ 0.001 |  |  |
Common Stock, outstanding shares (in shares) |  | 105.2 | 105.2 | 360,516,091 |  | 359,061,764
Shares issued under Calpine Equity Incentive Plans |  | 0 | (121,906) | 1,454,327 |  |
Stock Canceled During the Period, Shares |  |  | (360,394,185) |  |  |
Stock Issued During Period, Shares, New Issues |  |  | 105.2 |  |  |
Shares Issued [Member] |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |
Common Stock, issued shares (in shares) |  | 105.2 | 105.2 | 361,677,891 |  | 359,627,113
Shares issued under Calpine Equity Incentive Plans |  | 0 | 355,805 | 2,050,778 |  |
Stock Canceled During the Period, Shares |  |  | (362,033,696) |  |  |
Stock Issued During Period, Shares, New Issues |  |  | 105.2 |  |  |
Treasury Stock [Member] |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |
Treasury Stock, Shares |  | 0 | 0 | 1,161,800 |  | 565,349
Shares issued under Calpine Equity Incentive Plans |  | 0 | (477,711) | (596,451) |  |
Stock Canceled During the Period, Shares |  |  | 1,639,511 |  |  |
Stock Issued During Period, Shares, New Issues |  |  | 0 |  |  |

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