Debt (Letter of Credit) (Details) - USD ($) $ in Millions |
Mar. 31, 2020 |
Dec. 31, 2019 |
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|---|---|---|---|---|---|---|---|---|
| Line of Credit Facility [Line Items] | ||||||||
| Letters of Credit Outstanding, Amount | $ 1,119 | $ 1,085 | ||||||
| Revolving facilities | ||||||||
| Line of Credit Facility [Line Items] | ||||||||
| Letters of Credit Outstanding, Amount | [1] | 636 | 604 | |||||
| CDHI | ||||||||
| Line of Credit Facility [Line Items] | ||||||||
| Letters of Credit Outstanding, Amount | [2] | 3 | 3 | |||||
| Various project financing facilities | ||||||||
| Line of Credit Facility [Line Items] | ||||||||
| Letters of Credit Outstanding, Amount | 185 | 184 | ||||||
| Other corporate facilities | ||||||||
| Line of Credit Facility [Line Items] | ||||||||
| Letters of Credit Outstanding, Amount | [3] | $ 295 | $ 294 | |||||
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