Future Contract Benefits - Summary of Changes in Present Values of LFPB (UL and Other) (Details) - UL and Other - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2024	Sep. 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 shadow balance in AOCI	(1,863)	(897)	$ (2,222)	$ (905)
Balance as of beginning-of-year, excluding shadow balance in AOCI	17,222	15,723
Effect of changes in cash flow assumptions			244	173
Effect of actual variances from expected experience			$ 170	$ (28)
Adjusted balance as of beginning-of-year	17,636	15,868
Interest accrual	639	573
Net assessments collected	860	895
Benefit payments	(718)	(473)
Balance as of end-of-year, excluding shadow balance in AOCI	18,417	16,863
Balance as of end-of-period	16,554	15,965
Less: reinsurance recoverables	5,139	654
Net balance as of end-of-period, net of reinsurance	$ 11,415	$ 15,311
Weighted-average duration of future policyholder benefit liability	16 years	17 years