Future Contract Benefits - 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	298	301	597	599
Interest accretion	$ 35	$ 34	$ 69	$ 67