Investments - Net Investment Income (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024	Dec. 31, 2024
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income	$ 455	$ 379	$ 1,342	$ 1,160
Less: investment expense	20	18	60	50
Net investment income	435	361	1,282	1,110
Financing Receivable, Excluding Accrued Interest, Nonaccrual	71		71		$ 24
Fixed maturities
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income	351	305	1,054	912
Financing Receivable, Excluding Accrued Interest, Nonaccrual	3		3		$ 9
Equity securities
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income	2	2	5	5
Mortgage loans on real estate
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income	57	45	168	140
Policy loans
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income	2	2	6	6
Short-term investments and cash equivalents
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income	4	3	11	8
Other
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income	$ 39	$ 22	$ 98	$ 89