Debt (Project Financing, Notes Payable and Others) (Details) - USD ($) $ in Millions |
Dec. 31, 2018 |
Dec. 31, 2017 |
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|---|---|---|---|---|---|---|---|---|---|---|---|
| Debt Instrument [Line Items] | |||||||||||
| Long-term Debt | $ 10,156 | $ 11,213 | |||||||||
| Russell City Project [Member] | |||||||||||
| Debt Instrument [Line Items] | |||||||||||
| Long-term Debt | $ 341 | $ 401 | |||||||||
| Debt Instrument, Interest Rate, Effective Percentage | [1] | 6.50% | 6.40% | ||||||||
| Steamboat [Member] | |||||||||||
| Debt Instrument [Line Items] | |||||||||||
| Long-term Debt | $ 384 | $ 414 | |||||||||
| Debt Instrument, Interest Rate, Effective Percentage | [1] | 4.50% | 4.70% | ||||||||
| OMEC [Member] | |||||||||||
| Debt Instrument [Line Items] | |||||||||||
| Long-term Debt | [2] | $ 218 | $ 294 | ||||||||
| Debt Instrument, Interest Rate, Effective Percentage | [1] | 7.10% | 7.20% | ||||||||
| Los Esteros Project [Member] | |||||||||||
| Debt Instrument [Line Items] | |||||||||||
| Long-term Debt | $ 163 | $ 191 | |||||||||
| Debt Instrument, Interest Rate, Effective Percentage | [1] | 4.70% | 5.30% | ||||||||
| Pasadena [Member] | |||||||||||
| Debt Instrument [Line Items] | |||||||||||
| Long-term Debt | [3] | $ 76 | $ 89 | ||||||||
| Debt Instrument, Interest Rate, Effective Percentage | [1] | 8.90% | 8.90% | ||||||||
| Bethpage [Member] | |||||||||||
| Debt Instrument [Line Items] | |||||||||||
| Long-term Debt | [4] | $ 53 | $ 60 | ||||||||
| Debt Instrument, Interest Rate, Effective Percentage | [1] | 7.10% | 7.10% | ||||||||
| Other Debt Obligations [Member] | |||||||||||
| Debt Instrument [Line Items] | |||||||||||
| Long-term Debt | $ 29 | $ 49 | |||||||||
| Debt Instrument, Interest Rate, Effective Percentage | [1] | 0.00% | 0.00% | ||||||||
| Project Financing Total [Member] | |||||||||||
| Debt Instrument [Line Items] | |||||||||||
| Long-term Debt | $ 1,264 | $ 1,498 | |||||||||
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