Investments - Schedule of Net Gains (Losses) on Derivatives and Investments (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2026	Mar. 31, 2025
Available-for-sale securities
Realized gains on sale	$ 7	$ 3
Realized losses on sale	(9)	(12)
Credit loss income (expense)	(8)	0
Credit loss income (expense) on mortgage loans	(26)	(11)
Other	(11)	(46)
Net gains (losses) excluding derivatives and funds withheld assets	(47)	(66)
Net gains (losses) on derivatives and investments	283	1,343
Net gains (losses) on funds withheld reinsurance treaties (see Note 8)	(159)	(388)
Total net gains (losses) on derivatives and investments	124	955
Derivatives excluding funds withheld under reinsurance treaties and non-qualified voluntary deferred compensation plan
Available-for-sale securities
Net gains (losses) on derivative instruments (see Note 5)	330	1,409
Derivatives related to funds withheld under reinsurance treaties
Available-for-sale securities
Net gains (losses) on derivative instruments (see Note 5)	18	(218)
Net gains (losses) on funds withheld reinsurance treaties (see Note 8)	$ (159)	$ (388)

Debt Securities, Available For Sale, Credit Loss Expense (Reversal)

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Financing Receivable, Credit Loss, Expense (Reversal) And Other (Gain) Loss

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Gain (Loss) On Funds Withheld, Reinsurance Treaties

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Gain (Loss) On Investments And Derivative Instruments

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Gain (Loss) On Investments And Derivative Instruments, Net

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Other Operating Gain (Loss)

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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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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-9

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

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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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-SubTopic 10
-Name Accounting Standards Codification
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Amount of realized and unrealized gain (loss) on investment.

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Reference 3: http://www.xbrl.org/2003/role/recommendedDisclosureRef
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