Future Policy Benefit Reserves - Summary of Balances and Changes (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024	Dec. 31, 2024	Dec. 31, 2023
Present value of future net premiums
Balance, January 1			$ 3,425	$ 3,710
Effect of changes in discount rate	$ (83)	$ (147)	(83)	(147)	$ (7)	$ (125)
Balance, January 1, at original locked in discount rate			3,418	3,585
Effect of changes in cash flow assumptions					114	111
Expect of actual variances from expected experience					(2)	(40)
Adjusted balance, January 1					3,530	3,656
Interest accrual			133	139
Net premiums: earned during period			(306)	(317)
Balance, end of period at original locked in discount rate	3,357	3,478	3,357	3,478
Effect of changes in discount rate	83	147	83	147	7	125
Balance, September 30	3,440	3,625	3,440	3,625
Present value of future benefits & expenses
Balance, January 1			16,583	17,669
Effect of changes in discount rate	26	(612)	26	(612)	440	(578)
Balance, January 1, at original locked in discount rate			17,023	17,091
Effect of change in cash flow assumptions					121	126
Effect of actual variances from expected experience					50	33
Adjusted balance, January 1					17,194	17,250
Interest accrual			688	693
Benefit & expense payments			(870)	(883)
Balance, end of period at original locked in discount rate	17,012	17,060	17,012	17,060
Effect of changes in discount rate	(26)	612	(26)	612	(440)	$ 578
Balance, September 30	16,986	17,672	16,986	17,672
Net LFPB	13,546	14,047	13,546	14,047	$ 13,158
Insurance claims and policyholders benefits, including policyholders' dividends, remeasurement impact	$ (36)	$ (48)	$ (59)	$ (88)