Future Contract Benefit - Summary of Gross Premiums and Interest Accretion (UL and Other) (Details) - UL and Other - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Liability for Future Policy Benefit, Activity [Line Items]
Gross premiums	$ 774	$ 751	$ 2,371	$ 2,290
Interest accretion	$ 234	$ 213	$ 686	$ 623