Undiscounted and Discounted Future Benefit Payments and Gross Premiums (Details) - Life policy reserves: - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022	Dec. 31, 2021
Term Life Insurance
Liability for Future Policy Benefit, Activity [Line Items]
Undiscounted expected future benefit payments	$ 4,696		$ 4,128
Undiscounted expected future gross premiums	4,470		4,000
Discounted expected future benefit payments	2,691	$ 2,584	2,745	$ 2,993
Discounted expected future gross premiums	2,674		2,754
Whole Life Insurance
Liability for Future Policy Benefit, Activity [Line Items]
Undiscounted expected future benefit payments	1,586		1,511
Undiscounted expected future gross premiums	618		580
Discounted expected future benefit payments	644	$ 614	736	$ 826
Discounted expected future gross premiums	$ 384		$ 400