Future Contract Benefit - Summary of Gross Premiums and Interest Accretion (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Payout Annuities
Liability for Future Policy Benefit, Activity [Line Items]
Gross premiums	$ 25	$ 24	$ 48	$ 45
Interest accretion	22	22	44	43
Traditional Life
Liability for Future Policy Benefit, Activity [Line Items]
Gross premiums	312	316	626	631
Interest accretion	38	37	75	74
Group Protection
Liability for Future Policy Benefit, Activity [Line Items]
Gross premiums	926	893	1,859	1,789
Interest accretion	$ 50	$ 45	$ 100	$ 93