Future Contract Benefits - Summary of Changes in Present Values of LFPB (UL and Other) (Details) - UL and Other - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Dec. 31, 2024	Dec. 31, 2023
Present Value of Expected Future Policy Benefits
Balance as of beginning-of-year	$ 16,062	$ 15,000
Effect of cumulative changes in shadow balance in AOCI	(2,408)	(3,332)	$ (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			$ 117	$ 136
Adjusted balance as of beginning-of-year	18,852	17,358
Interest accrual	461	421
Net assessments collected	616	575
Benefit payments	(532)	(521)
Balance as of end-of-year, excluding shadow balance in AOCI	19,397	17,833
Balance as of end-of-period	16,989	14,501
Less: Reinsurance recoverables	5,385	4,880
Net balance as of end-of-period, net of reinsurance	$ 11,604	$ 9,621
Weighted-average duration of future policyholder benefit liability	16 years	16 years
Unfavorable impact to the liability due to mortality	$ (116)	$ (138)
Effect of actual variances from expected experience, net of reinsurance	$ 35	$ 80