Future Contract Benefits - Summary of Gross Premiums and Interest Accretion (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Payout Annuities
Liability for Future Policy Benefit, Activity [Line Items]
Gross assessments	$ 21	$ 28
Interest accretion	22	21
Traditional Life
Liability for Future Policy Benefit, Activity [Line Items]
Gross assessments	298	295
Interest accretion	33	32
Group Protection
Liability for Future Policy Benefit, Activity [Line Items]
Gross assessments	896	885
Interest accretion	48	42
UL and Other
Liability for Future Policy Benefit, Activity [Line Items]
Gross assessments	766	915
Interest accretion	$ 203	$ 186