Investments - Investments - ACL on Fixed Maturities (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Debt Securities, Available-for-sale, Allowance for Credit Loss [Line Items]
Debt Securities, Available-for-sale, Allowance for Credit Loss, Beginning Balance	$ 14	$ 19	$ 16	$ 21
Credit losses on fixed maturities where credit losses were not previously recorded			0	1
Reduction due to sales	0	(3)	0	(3)
Net increases (decreases) in allowance on fixed maturities that had an allowance in a previous period			(2)	1
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Writeoff			0	4
Corporate
Debt Securities, Available-for-sale, Allowance for Credit Loss [Line Items]
Debt Securities, Available-for-sale, Allowance for Credit Loss, Beginning Balance		6	3	9
Credit losses on fixed maturities where credit losses were not previously recorded			0	0
Reduction due to sales		(3)	0	(3)
Net increases (decreases) in allowance on fixed maturities that had an allowance in a previous period			(3)	1
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Writeoff			0	4
CMBS
Debt Securities, Available-for-sale, Allowance for Credit Loss [Line Items]
Debt Securities, Available-for-sale, Allowance for Credit Loss, Beginning Balance	14	13	13	12
Credit losses on fixed maturities where credit losses were not previously recorded			0	1
Reduction due to sales	$ 0	$ 0	0	0
Net increases (decreases) in allowance on fixed maturities that had an allowance in a previous period			1	0
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Writeoff			$ 0	$ 0

Amount of allowance 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).

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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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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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Amount of writeoff of allowance 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).

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