Investments - Net Investment Income (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income	$ 557	$ 432	$ 1,537	$ 1,264
Investment expenses	(26)	(13)	(50)	(34)
Net investment income (excluding net realized capital gains or losses)	531	419	1,487	1,230
Net realized capital gains (losses)	19	(142)	(89)	(345)
Net investment income	550	277	1,398	885
Yield-related impairment losses	12	47	51	108
Credit-related impairment losses (reversal of losses)	0	0	0	(3)
Supporting experience-rated products
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Net investment income	8	8	24	25
Debt securities
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income	307	217	816	612
Mortgage loans
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income	20	16	56	43
Other investments
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income	$ 230	$ 199	$ 665	$ 609