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	$ 16,663	$ 15,752
Effect of cumulative changes in discount rate assumptions	(1,231)	(1,691)	$ (1,515)	$ (853)
Balance as of beginning-of-year, excluding shadow balance in AOCI	18,178	16,605
Effect of actual variances from expected experience			$ 22	$ 106
Adjusted balance as of beginning-of-year	18,200	16,711
Interest accrual	223	203
Net assessments collected	341	324
Benefit payments	(200)	(313)
Balance as of end-of-year, excluding shadow balance in AOCI	18,564	16,925
Balance as of end-of-period	17,333	15,234
Less: Reinsurance recoverables	11,026	9,734
Net balance as of end-of-period, net of reinsurance	$ 6,307	$ 5,500
Weighted-average duration of future policyholder benefit liability (years)	16 years	17 years