Investments (Net realized investment gains (losses)) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Fixed maturity securities:
Gross gains	$ 44	$ 34	$ 175	$ 98
Gross losses	(18)	(31)	(207)	(104)
Net investment gains (losses) on fixed maturity securities	26	3	(32)	(6)
Equity securities	25	7	(45)	60
Derivatives	(2)	(2)	(7)	(13)
Mortgage loans	(3)	0	(16)	0
Short term investments and other	(19)	(1)	(20)	(21)
Net investment gains (losses)	$ 27	$ 7	$ (120)	$ 20

Investments and Derivatives, Realized Gain (Loss)

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Realized Gain (Loss) on Short Term Investments

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Amount of realized gain on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount of realized gain (loss) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount of realized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount of realized gain (loss) from sale of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

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The difference between the book value and the sale price of options, swaps, futures, forward contracts, and other derivative instruments. This element refers to the gain (loss) included in earnings.

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Amount of credit loss expense (reversal of expense) for financing receivable.

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