Investments - Schedule of Sources of Net Investment Income (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Net Investment Income [Line Items]
Investment expenses	$ (103)	$ (109)	$ (166)	$ (203)
Net investment income excluding funds withheld assets	727	491	1,268	1,019
Net investment income	928	718	1,668	1,473
Variable Interest Entity, Primary Beneficiary
Net Investment Income [Line Items]
Increase (decrease) in fair value of notes issued	(56)	(42)	(72)	(74)
Debt Securities
Net Investment Income [Line Items]
Total investment income excluding funds withheld assets	618	415	1,090	846
Equity securities
Net Investment Income [Line Items]
Total investment income excluding funds withheld assets	8	5	(51)	6
Mortgage loans
Net Investment Income [Line Items]
Total investment income excluding funds withheld assets	104	88	203	171
Policy loans
Net Investment Income [Line Items]
Total investment income excluding funds withheld assets	14	16	30	33
Limited partnerships
Net Investment Income [Line Items]
Total investment income excluding funds withheld assets	28	22	47	60
Other investment income
Net Investment Income [Line Items]
Total investment income excluding funds withheld assets	58	54	115	106
Total investment income excluding funds withheld assets
Net Investment Income [Line Items]
Total investment income excluding funds withheld assets	830	600	1,434	1,222
Funds withheld assets
Net Investment Income [Line Items]
Investment expenses	(11)	(12)	(22)	(25)
Net investment income	201	227	400	454
Debt securities, at fair value under the fair value option
Net Investment Income [Line Items]
Net investment income	$ (46)	$ (64)	$ 26	$ (74)