Investments - Schedule of Sources of Net Investment Income (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Net Investment Income [Line Items]
Investment expenses	$ (93)	$ (106)	$ (259)	$ (309)
Net investment income excluding funds withheld assets	715	653	1,983	1,672
Net investment income	886	856	2,554	2,329
Variable Interest Entity, Primary Beneficiary
Net Investment Income [Line Items]
Decrease in fair value of notes issued	(44)	(46)	(116)	(120)
Debt securities
Net Investment Income [Line Items]
Total investment income excluding funds withheld assets	582	520	1,672	1,366
Equity securities
Net Investment Income [Line Items]
Total investment income excluding funds withheld assets	7	2	(44)	8
Mortgage loans
Net Investment Income [Line Items]
Total investment income excluding funds withheld assets	114	90	317	261
Policy loans
Net Investment Income [Line Items]
Total investment income excluding funds withheld assets	16	17	46	50
Limited partnerships
Net Investment Income [Line Items]
Total investment income excluding funds withheld assets	38	69	85	129
Other investment income
Net Investment Income [Line Items]
Total investment income excluding funds withheld assets	51	61	166	167
Total investment income excluding funds withheld assets
Net Investment Income [Line Items]
Total investment income excluding funds withheld assets	808	759	2,242	1,981
Funds Withheld Reinsurance Assets
Net Investment Income [Line Items]
Investment expenses	(10)	(12)	(32)	(37)
Net investment income	171	203	571	657
Debt securities, at fair value under the fair value option
Net Investment Income [Line Items]
Net investment income	$ (66)	$ 14	$ (112)	$ (60)