Reinsurance - Schedule of Gains and Losses on Funds Withheld Reinsurance Treaties (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Available-for-sale securities
Realized gains on sale	$ 34	$ 10	$ 45	$ 17
Realized losses on sale	(60)	(8)	(79)	(31)
Net gains (losses) on hedging instruments			(3,666)	(2,538)
Net gains (losses) on funds withheld payable under reinsurance treaties			(290)	(1,094)
Funds Withheld Reinsurance Assets
Available-for-sale securities
Realized gains on sale	8	1	11	9
Realized losses on sale	(16)	(11)	(83)	(85)
Credit loss expense	(4)	(11)	(19)	(38)
Credit loss expense on mortgage loans	0	(9)	(7)	(12)
Other	(1)	(9)	(7)	13
Net gains (losses) on non-derivative investments	(13)	(39)	(105)	(113)
Net gains (losses) on hedging instruments	(2)	13	0	(53)
Net gains (losses) on funds withheld payable under reinsurance treaties	181	(353)	(185)	(928)
Total net gains (losses) on derivatives and investments	166	(379)	(290)	(1,094)
Derivatives related to funds withheld under reinsurance treaties
Available-for-sale securities
Embedded derivative gain (loss)	330	(182)	231	(579)
Derivatives related to funds withheld under reinsurance treaties \| Funds withheld embedded derivative
Available-for-sale securities
Embedded derivative gain (loss)	$ 332	$ (195)	$ 231	$ (526)

Net Gains (Losses) On Funds Withheld Payable Under Reinsurance Treaties

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Nonoperating Gains (Losses), Non-Derivative Instruments

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Amount of expense for credit loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), for which no credit loss was previously recorded.

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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 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 increase (decrease) in the fair value of derivatives recognized in the income statement.

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Aggregate net gain (loss) on all derivative instruments recognized in earnings during the period, before tax effects.

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The aggregate amount of gains or losses resulting from nonoperating activities (for example, interest and dividend revenue, property, plant and equipment impairment loss, and so forth).

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Amount of gain (loss) related to nonoperating activities, classified as other.

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

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