Future Contract Benefit - Summary of Gross Premiums and Interest Accretion (UL and Other) (Details) - UL and Other - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Liability for Future Policy Benefit, Activity [Line Items]
Gross assessments	$ 700	$ 766
Interest accretion	$ 228	$ 209