Undiscounted and Discounted Future Benefit Payments and Gross Premiums (Details) - Life policy reserves: - USD ($) $ in Millions	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021
Term Life Insurance
Liability for Future Policy Benefit, Activity [Line Items]
Undiscounted expected future benefit payments	$ 4,738			$ 4,589
Undiscounted expected future gross premiums	4,345			4,378
Discounted expected future benefit payments	2,662	$ 2,691	$ 2,584	2,702	$ 2,745	$ 2,993
Discounted expected future gross premiums	2,583			2,690
Whole Life Insurance
Liability for Future Policy Benefit, Activity [Line Items]
Undiscounted expected future benefit payments	1,610			1,517
Undiscounted expected future gross premiums	641			583
Discounted expected future benefit payments	633	$ 644	$ 614	646	$ 736	$ 826
Discounted expected future gross premiums	$ 390			$ 372