Variable Interest Entities and Unconsolidated Investments in Power Plants (Unconsolidated VIEs) (Details) - USD ($) $ in Millions |
Sep. 30, 2019 |
Dec. 31, 2018 |
||
|---|---|---|---|---|
| Schedule of Equity Method Investments [Line Items] | ||||
| Equity method investments | $ 73 | $ 76 | ||
| Equity method investment, ownership percentage | 50.00% | |||
| Greenfield [Member] | ||||
| Schedule of Equity Method Investments [Line Items] | ||||
| Equity method investments | [1] | $ 59 | 55 | |
| Equity method investment, ownership percentage | 50.00% | |||
| Whitby [Member] | ||||
| Schedule of Equity Method Investments [Line Items] | ||||
| Equity method investments | $ 9 | 15 | ||
| Equity method investment, ownership percentage | 50.00% | |||
| Calpine Receivables [Member] | ||||
| Schedule of Equity Method Investments [Line Items] | ||||
| Equity method investments | $ 5 | $ 6 | ||
| Equity method investment, ownership percentage | 100.00% | |||
| ||||