Contracts Accounted for as Insurance - Effect of Reinsurance on Premiums Written, Premiums Earned and Loss and LAE (Benefit) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Premiums Written:
Direct	$ 377	$ 355	$ 453
Assumed	(17)	22	1
Ceded	0	0	13
Net	360	377	467
Premiums Earned:
Direct	469	385	448
Assumed	28	32	41
Ceded	(3)	(3)	(4)
Net earned premiums	494	414	485
Loss and LAE (benefit):
Direct	32	(203)	182
Assumed	(17)	5	24
Ceded	1	(22)	(3)
Loss and LAE (benefit)	$ 16	$ (220)	$ 203

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