v3.19.1

Variable Interest Entities and Unconsolidated Investments (VIE Textuals) (Details) | 12 Months Ended
--- | ---
Dec. 31, 2018 USD ($) yr MW | Dec. 31, 2017 USD ($) MW | Dec. 31, 2016 USD ($)
Schedule of Equity Method Investments [Line Items] |  |  |  |
Proceeds from sale of power plants and other(2) | [1] | $ 11,000,000 | $ 162,000,000 | $ 179,000,000
Variable Interest Entity, Financial or Other Support, Amount |  | 0 | 0 | $ 115,000,000
Equity Method Investment, Summarized Financial Information, Debt |  | 301,000,000 | 256,000,000 |
Prorata Share of Equity Method Investment, Summarized Financial Information, Debt |  | 151,000,000 | 128,000,000 |
Long-term Debt |  | 10,156,000,000 | $ 11,213,000,000 |
Put Option [Member] |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |
Proceeds from sale of power plants and other(2) |  | 280,000,000 |  |
Call Option [Member] |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |
Proceeds from sale of power plants and other(2) |  | $ 377,000,000 |  |
Russell City Energy [Member] |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |
Minority Interest Ownership Percentage By Noncontrolling Third Party Owners |  | 25.00% |  |
Equity Method Investment, Ownership Percentage |  | 75.00% |  |
Variable Interest Entity, Primary Beneficiary [Member] |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |
Power generation capacity | MW |  | 7,880 | 7,880 |
Inland Empire Energy Center [Member] |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |
Power generation capacity | MW |  | 775 |  |
Put Option Exercise Period | yr |  | 2,025 |  |
Minimum [Member] | Inland Empire Energy Center [Member] |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |
Call Option Exercise Period | yr |  | 2,017 |  |
Maximum [Member] | Inland Empire Energy Center [Member] |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |
Call Option Exercise Period | yr |  | 2,024 |  |
Calpine Receivables [Member] |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount |  | $ 44,000,000 |  |
Equity Method Investment, Ownership Percentage |  | 100.00% |  |
Greenfield [Member] |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |
Power generation capacity | MW |  | 1,038 |  |
Equity Method Investment, Ownership Percentage |  | 50.00% |  |
Whitby [Member] |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |
Power generation capacity | MW |  | 50 |  |
Equity Method Investment, Ownership Percentage |  | 50.00% |  |
OMEC [Member] |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |
Debt Instrument, Face Amount |  | $ 220,000,000 |  |
Long-term Debt | [2] | $ 218,000,000 | $ 294,000,000 |
[1] | On October 26, 2016, we completed the sale of Mankato Power Plant for $407 million, including working capital and other adjustments. We received net proceeds of $164 million after the non-cash reduction of Steamboat project debt of $243 million as the funds were provided directly to the lender in conjunction with the sale of the power plant.
[2] | On December 19, 2018, we refinanced the project debt associated with OMEC which lowered the aggregate debt balance to $220 million and extended the maturity to August 2024. In the event that the OMEC put option is exercised, the debt will become payable on November 3, 2019. See Note 7 for further information related to the OMEC put option.

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