Reserves for Future Policy Benefits and Claims Payable - Rollforward of Additional Liabilities, Closed Block Life (Details) - Closed Block Life - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2023	Dec. 31, 2022
Additional Liability, Long-Duration Insurance [Roll Forward]
Balance, beginning of period	$ 1,172	$ 1,159
Effect of changes in cash flow assumptions	0	6
Effect of actual variances from expected experience	25	58
Interest accrual	42	56
Net assessments collected	(123)	(107)
Balance, end of period	1,116	1,172
As Previously Reported
Additional Liability, Long-Duration Insurance [Roll Forward]
Balance, beginning of period	1,131	1,173
Balance, end of period	1,086	1,131
Cumulative effect of changes in shadow adjustments
Additional Liability, Long-Duration Insurance [Roll Forward]
Balance, beginning of period	(41)	14
Balance, end of period	$ (30)	$ (41)