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, 2024	Jun. 30, 2023	Dec. 31, 2023	Dec. 31, 2022
Present Value of Expected LFPB
Balance as of beginning-of-year	$ 15,000	$ 14,818
Effect of cumulative changes in discount rate assumptions	(3,332)	(829)	$ (2,222)	$ (905)
Balance as of beginning-of-year, excluding shadow balance in AOCI	17,222	15,723
Effect of actual variances from expected experience			$ 136	$ 6
Adjusted balance as of beginning-of-year	17,358	15,729
Interest accrual	421	376
Net assessments collected	575	609
Benefit payments	(521)	(360)
Balance as of end-of-year, excluding shadow balance in AOCI	17,833	16,354
Balance as of end-of-period	14,501	15,525
Less: reinsurance recoverables	4,880	870
Net balance as of end-of-period, net of reinsurance	$ 9,621	$ 14,655
Weighted-average duration of future policyholder benefit liability	16 years	18 years