Investments - Schedule of Sources of Net Investment Income (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Net Investment Income [Line Items]
Investment expenses	$ (63)	$ (94)
Net investment income excluding funds withheld assets	541	528
Net investment income	740	755
Variable Interest Entity, Primary Beneficiary
Net Investment Income [Line Items]
Increase (decrease) in fair value of notes issued	(16)	(32)
Debt Securities
Net Investment Income [Line Items]
Total investment income excluding funds withheld assets	472	431
Equity securities
Net Investment Income [Line Items]
Total investment income excluding funds withheld assets	(59)	1
Net investment income excluding funds withheld assets	(58)	0
Mortgage loans
Net Investment Income [Line Items]
Total investment income excluding funds withheld assets	99	83
Policy loans
Net Investment Income [Line Items]
Total investment income excluding funds withheld assets	16	17
Limited partnerships
Net Investment Income [Line Items]
Total investment income excluding funds withheld assets	19	38
Other investment income
Net Investment Income [Line Items]
Total investment income excluding funds withheld assets	57	52
Total investment income excluding funds withheld assets
Net Investment Income [Line Items]
Total investment income excluding funds withheld assets	604	622
Funds withheld assets
Net Investment Income [Line Items]
Investment expenses	(11)	(13)
Net investment income	199	227
Debt securities, at fair value under the fair value option
Net Investment Income [Line Items]
Net investment income	$ (72)	$ (10)