Future Policy Benefits Reserves - Summary of Balances and Changes (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023	Dec. 31, 2022
Present value of future net premiums
Balance, January 1			$ 3,710	$ 3,993
Effect of changes in discount rate	$ (147)	$ 67	(147)	67	$ (125)	$ (74)
Balance, January 1, at original locked in discount rate			3,585	3,919
Effect of changes in cash flow assumptions					111	28
Expect of actual variances from expected experience					(40)	(112)
Adjusted balance, January 1					3,656	3,835
Interest accrual			139	153
Net premiums: earned during period			(317)	(332)
Balance, end of period at original locked in discount rate	3,478	3,656	3,478	3,656
Balance, September 30	3,625	3,589	3,625	3,589
Present value of future benefits & expenses
Balance, January 1			17,669	17,472
Effect of changes in discount rate	612	(873)	612	(873)	578	125
Balance, January 1, at original locked in discount rate			17,091	17,347
Effect of change in cash flow assumptions					126	36
Effect of actual variances from expected experience					33	(45)
Adjusted balance, January 1					17,250	$ 17,338
Interest accrual			693	723
Benefit & expense payments			(883)	(945)
Balance, end of period at original locked in discount rate	17,060	17,116	17,060	17,116
Balance, September 30	17,672	16,243	17,672	16,243
Net LFPB	14,047	12,654	14,047	12,654	$ 13,959
Insurance claims and policyholders benefits, including policyholders' dividends, remeasurement impact	$ (48)	$ (41)	$ (88)	$ (75)