Future Contract Benefits - Summary of Gross Premiums and Interest Accretion (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Payout Annuities
Liability for Future Policy Benefit, Activity [Line Items]
Gross premiums	$ 17	$ 23
Interest accretion	22	22
Traditional Life
Liability for Future Policy Benefit, Activity [Line Items]
Gross premiums	303	314
Interest accretion	36	37
Group Protection
Liability for Future Policy Benefit, Activity [Line Items]
Gross premiums	914	933
Interest accretion	$ 55	$ 50