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Investments - Realized capital gains and losses by transaction type (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2020 | Sep. 30, 2019 | Sep. 30, 2020 | Sep. 30, 2019
Investments [Abstract] |  |  |  |
Sales | $ 233 | $ 147 | $ 800 | $ 359
Credit losses | 10 | (14) | (79) | (43)
Valuation of equity investments | 231 | 24 | (111) | 851
Valuation and settlements of derivative instruments | (34) | 40 | 72 | 16
Realized capital gains and losses | $ 440 | $ 197 | $ 682 | $ 1,183

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- Definition Amount of unrealized and realized gain (loss) on investment in debt security measured at amortized cost (held-to-maturity), investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale) and investment in debt security measured at fair value with change in fair value recognized in net income (trading). + References No definition available. + Details
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