Reinsurance - Life Insurance Ceded Business (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Reinsurance for Insurance Companies, by Product Segment
Insurance losses and contract holders' benefits	$ 1,340	$ 1,322	$ 2,738	$ 2,354
Life Insurance Segment
Reinsurance for Insurance Companies, by Product Segment
Direct earned premiums	100	96	196	189
Ceded earned premiums	(20)	(20)	(39)	(38)
Earned premiums	80	76	157	151
Direct contract holders' benefits incurred	100	109	197	212
Ceded contract holders' benefits incurred	(22)	(27)	(38)	(54)
Insurance losses and contract holders' benefits	$ 78	$ 82	$ 159	$ 158