Reinsurance - Life Insurance Ceded Business (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Reinsurance for Insurance Companies, by Product Segment
Insurance losses and contract holders' benefits	$ 1,398	$ 1,032
Life Insurance Segment
Reinsurance for Insurance Companies, by Product Segment
Direct earned premiums	96	93
Ceded earned premiums	(19)	(18)
Earned premiums	77	75
Direct contract holders' benefits incurred	97	103
Ceded contract holders' benefits incurred	(16)	(27)
Insurance losses and contract holders' benefits	$ 81	$ 76