Variable Interest Entities and Unconsolidated Investments (Unconsolidated VIEs) (Details) - USD ($) $ in Millions |
Dec. 31, 2019 |
Dec. 31, 2018 |
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|---|---|---|---|---|---|---|
| Equity Method Investments Included on Balance Sheet [Abstract] | ||||||
| Equity Method Investments | $ 70 | $ 76 | ||||
| Greenfield [Member] | ||||||
| Equity Method Investments Included on Balance Sheet [Abstract] | ||||||
| Equity Method Investments | [1] | $ 66 | 55 | |||
| Equity Method Investment, Ownership Percentage | [1] | 50.00% | ||||
| Whitby [Member] | ||||||
| Equity Method Investments Included on Balance Sheet [Abstract] | ||||||
| Equity Method Investments | [2] | $ 0 | 15 | |||
| Equity Method Investment, Ownership Percentage | [2] | 0.00% | ||||
| Calpine Receivables [Member] | ||||||
| Equity Method Investments Included on Balance Sheet [Abstract] | ||||||
| Equity Method Investments | $ 4 | $ 6 | ||||
| Equity Method Investment, Ownership Percentage | 100.00% | |||||
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