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Debt and Finance Leases - Non-Recourse Debt (Details) - USD ($) | Oct. 21, 2019 | Jan. 04, 2019 | Apr. 07, 2016 | Dec. 31, 2019
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Agua Caliente Borrower 1, due 2038 |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Redemption percentage of principal | 102.00% |  |  |
Non Recourse Debt | Agua Caliente Borrower 1, due 2038 |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Interest rate, stated percentage |  |  |  | 5.43%
Non Recourse Debt | Credit Agreement 2019 | Letter of Credit |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Credit facility |  | $ 80,000,000 |  |
Annual facility fees, percentage |  | 1.33% |  |
Letter of credit |  |  |  | $ 80,000,000
Midwest Generation | Non Recourse Debt |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Proceeds from sale of unforced capacity |  |  | $ 253,000,000 |
Interest rate, stated percentage |  |  | 4.39% |

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