Future Contract Benefits - Summary of Changes in Present Values of Expected Net Premiums and LFPB (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024	Dec. 31, 2024	Dec. 31, 2023
Present Value of Expected LFPB
Net balance as of end-of-period	$ 40,908		$ 40,002
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	2,008	2,084
Beginning balance of original discount rate	2,259	2,271
Effect of actual variances from expected experience			(1)	1
Adjusted balance as of beginning-of-year	2,258	2,272
Issuances	22	15
Interest accrual	22	22
Benefit payments	(49)	(49)
Ending balance at original discount rate	2,253	2,260
Effect of cumulative changes in discount rate assumptions	(221)	(226)
Balance as of end-of-period	2,032	2,034
Net balance as of end-of-period	2,032	2,034	2,008
Less: Reinsurance recoverables	1,491	1,572
Net balance as of end-of-period, net of reinsurance	$ 541	$ 462
Weighted-average duration of future policyholder benefit liability (years)	9 years	9 years
Deferred profit liability	$ 65	$ 60
Payout Annuities | Cumulative effect from adoption of new accounting standards
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	(251)	(187)
Traditional Life
Present Value of Expected Net Premiums
Balance as of beginning-of-year	5,751	6,084
Beginning balance at original discount rate	6,028	6,236
Effect of actual variances from expected experience			(18)	23
Adjusted balance as of beginning-of-year			6,010	6,259
Issuances	64	109
Interest accrual	61	61
Net premiums collected	(189)	(199)
Flooring impact of LFPB	(3)	1
Ending balance at original discount rate	5,943	6,231
Effect of cumulative changes in discount rate assumptions	(197)	(257)
Balance as of end-of-period	5,746	5,974
Present Value of Expected LFPB
Balance as of beginning-of-year	9,255	9,637
Beginning balance of original discount rate	9,701	9,839
Effect of actual variances from expected experience			(13)	27
Adjusted balance as of beginning-of-year	9,688	9,866
Issuances	64	109
Interest accrual	95	94
Benefit payments	(221)	(191)
Ending balance at original discount rate	9,626	9,878
Effect of cumulative changes in discount rate assumptions	(314)	(386)
Balance as of end-of-period	9,312	9,492
Net balance as of end-of-period	3,566	3,518	3,504
Less: Reinsurance recoverables	210	244
Net balance as of end-of-period, net of reinsurance	$ 3,356	$ 3,274
Weighted-average duration of future policyholder benefit liability (years)	9 years	10 years
Traditional Life | Cumulative effect from adoption of new accounting standards
Present Value of Expected Net Premiums
Balance as of beginning-of-year	$ (277)	$ (152)
Present Value of Expected LFPB
Balance as of beginning-of-year	(446)	(202)
Group Protection
Present Value of Expected Net Premiums
Effect of cumulative changes in discount rate assumptions			(550)	(490)
Present Value of Expected LFPB
Balance as of beginning-of-year	5,628	5,689
Beginning balance of original discount rate	6,178	6,179
Effect of actual variances from expected experience			(72)	$ (67)
Adjusted balance as of beginning-of-year	6,106	6,112
Issuances	402	408
Interest accrual	50	48
Benefit payments	(371)	(382)
Ending balance at original discount rate	6,187	6,186
Effect of cumulative changes in discount rate assumptions	(475)	(546)
Balance as of end-of-period	5,712	5,640
Net balance as of end-of-period	5,712		$ 5,628
Less: Reinsurance recoverables	3,600	123
Net balance as of end-of-period, net of reinsurance	$ 2,112	$ 5,517
Weighted-average duration of future policyholder benefit liability (years)	5 years	5 years