Future Contract Benefits - Summary of Changes in Present Values of LFPB (UL and Other) (Details) - UL and Other - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024	Dec. 31, 2024	Dec. 31, 2023
Present Value of Expected LFPB
Balance as of beginning-of-year	$ 16,062	$ 15,000
Effect of cumulative changes in shadow balance in AOCI	(2,377)	(3,083)	$ (2,673)	$ (2,222)
Balance as of beginning-of-year, excluding shadow balance in AOCI	18,735	17,222
Effect of actual variances from expected experience			$ 23	$ 106
Adjusted balance as of beginning-of-year	18,758	17,328
Interest accrual	228	209
Net assessments collected	293	303
Benefit payments	(200)	(313)
Balance as of end-of-year, excluding shadow balance in AOCI	19,079	17,527
Balance as of end-of-period	16,702	14,444
Less: Reinsurance recoverables	5,316	4,776
Net balance as of end-of-period, net of reinsurance	$ 11,386	$ 9,668
Weighted-average duration of future policyholder benefit liability	16 years	17 years