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Impairments (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2020 | Mar. 31, 2020 | Sep. 30, 2019 | Sep. 30, 2019
Schedule of Equity Method Investments [Line Items] |  |  |  |
Impairment losses of cost investments and intangible assets |  |  |  | $ 7
Petra Nova |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |
Impairment losses |  | $ 18 | $ 101 |
Letters of credit issued |  |  | 12 | 12
Investment in cash |  |  | 95 |
Guarantor obligations (up to) |  |  | $ 124 | $ 124
West/Other | Disposal Group, Held-for-sale, Not Discontinued Operations | Home Solar |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |
Adjustment to carrying amount of assets and liabilities | $ 29 |  |  |
Other noncurrent assets- held for sale | 88 |  |  |
Non-current liabilities - held-for-sale | $ 44 |  |  |

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