Future Contract Benefits - Summary of Changes in Present Values of Expected Net Premiums and LFPB (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023	Dec. 31, 2022
Present Value of Expected LFPB
Net balance as of end-of-period	$ 38,848		$ 39,864
Payout Annuities
Present Value of Expected Net Premiums
Balance as of beginning-of-year	0	$ 0
Beginning balance at original discount rate	0	0
Effect of actual variances from expected experience			0	$ 0
Adjusted balance as of beginning-of-year	0	0
Issuances	0	0
Interest accrual	0	0
Net premiums collected	0	0
Flooring impact of LFPB	0	0
Ending balance at original discount rate	0	0
Effect of cumulative changes in discount rate assumptions	0	0
Balance as of end-of-period	0	0
Present Value of Expected LFPB
Balance as of beginning-of-year	2,085	2,004
Beginning balance of original discount rate	2,272	2,267
Effect of actual variances from expected experience			1	(1)
Adjusted balance as of beginning-of-year	2,273	2,266
Issuances	15	27
Interest accrual	22	21
Benefit payments	(49)	(46)
Ending balance of original discount rate	2,261	2,268
Effect of cumulative changes in discount rate assumptions	(227)	(200)
Balance as of end-of-period	2,034	2,068
Net balance as of end-of-period	2,034	2,068	2,085
Less: reinsurance recoverables	1,562	3
Net balance as of end-of-period, net of reinsurance	$ 472	$ 2,065
Weighted-average duration of future policyholder benefit liability	9 years	9 years
Deferred profit liability	$ 60	$ 43
Payout Annuities | Cumulative Effect, Period of Adoption, Adjustment
Present Value of Expected Net Premiums
Balance as of beginning-of-year	0	0
Present Value of Expected LFPB
Balance as of beginning-of-year	(187)	(263)
Traditional Life
Present Value of Expected Net Premiums
Balance as of beginning-of-year	6,200	6,063
Beginning balance at original discount rate	6,348	6,645
Effect of actual variances from expected experience			2	(241)
Adjusted balance as of beginning-of-year	6,350	6,404
Issuances	108	176
Interest accrual	63	60
Net premiums collected	(202)	(203)
Flooring impact of LFPB	3	2
Ending balance at original discount rate	6,322	6,439
Effect of cumulative changes in discount rate assumptions	(254)	(230)
Balance as of end-of-period	6,068	6,209
Present Value of Expected LFPB
Balance as of beginning-of-year	10,041	9,572
Beginning balance of original discount rate	10,230	10,357
Effect of actual variances from expected experience			7	(251)
Adjusted balance as of beginning-of-year	10,237	10,106
Issuances	108	177
Interest accrual	100	95
Benefit payments	(206)	(186)
Ending balance of original discount rate	10,239	10,192
Effect of cumulative changes in discount rate assumptions	(378)	(302)
Balance as of end-of-period	9,861	9,890
Net balance as of end-of-period	3,793	3,681	3,841
Less: reinsurance recoverables	421	520
Net balance as of end-of-period, net of reinsurance	$ 3,372	$ 3,161
Weighted-average duration of future policyholder benefit liability	9 years	10 years
Traditional Life | Cumulative Effect, Period of Adoption, Adjustment
Present Value of Expected Net Premiums
Balance as of beginning-of-year	$ (148)	$ (582)
Present Value of Expected LFPB
Balance as of beginning-of-year	(189)	(785)
Group Protection
Present Value of Expected Net Premiums
Effect of cumulative changes in discount rate assumptions			(490)	(597)
Present Value of Expected LFPB
Balance as of beginning-of-year	5,689	5,462
Beginning balance of original discount rate	6,179	6,059
Effect of actual variances from expected experience			(67)	(100)
Adjusted balance as of beginning-of-year	6,112	5,959
Issuances	408	437
Interest accrual	48	42
Benefit payments	(382)	(377)
Ending balance of original discount rate	6,186	6,061
Effect of cumulative changes in discount rate assumptions	(546)	(569)
Balance as of end-of-period	5,640	5,492
Net balance as of end-of-period	5,640		5,689
Less: reinsurance recoverables	123	126
Net balance as of end-of-period, net of reinsurance	$ 5,517	$ 5,366
Weighted-average duration of future policyholder benefit liability	5 years	4 years
UL and Other
Present Value of Expected Net Premiums
Effect of cumulative changes in discount rate assumptions	$ (3,083)	$ (669)	(2,222)	(905)
Present Value of Expected LFPB
Balance as of beginning-of-year	15,000	14,818
Balance as of beginning-of-year, excluding shadow balance in AOCI	17,222	15,723
Effect of actual variances from expected experience			106	$ (9)
Adjusted balance as of beginning-of-year	17,328	15,714
Interest accrual	209	186
Net assessments collected	303	336
Benefit payments	(313)	(183)
Balance as of end-of-year, excluding shadow balance in AOCI	17,527	16,053
Balance as of end-of-period	14,444	15,384
Net balance as of end-of-period	14,444		$ 15,000
Less: reinsurance recoverables	4,776	862
Net balance as of end-of-period, net of reinsurance	$ 9,668	$ 14,522
Weighted-average duration of future policyholder benefit liability	17 years	17 years