Undiscounted and Discounted Future Benefit Payments and Gross Premiums (Details) - Life Policy Reserves - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Term Life Insurance
Liability for Future Policy Benefit, Activity
Undiscounted expected future benefit payments	$ 4,791	$ 4,655
Undiscounted expected future gross premiums	4,374	4,436
Liability for Future Policy Benefit, Expected Future Policy Benefit, before Reinsurance, after Discount Rate Change	2,751	2,584	$ 2,993	$ 3,222
Discounted expected future gross premiums	2,652	2,582
Whole Life Insurance
Liability for Future Policy Benefit, Activity
Undiscounted expected future benefit payments	1,648	1,562
Undiscounted expected future gross premiums	659	606
Liability for Future Policy Benefit, Expected Future Policy Benefit, before Reinsurance, after Discount Rate Change	657	614	$ 826	$ 843
Discounted expected future gross premiums	$ 409	$ 368