Insurance (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Statutory Accounting Practices [Line Items]
Cash and cash equivalents	$ 28	$ 22
Marketable securities	696	703
Total cash, cash equivalents, and marketable securities	724	725
Assets Held by Insurance Regulators	12	12
Prepaid reinsurance premiums and other reinsurance recoverables	743	708
Related party transaction, prepaid reinsurance premiums and other reinsurance recoverables	103	97
Earned insurance premiums	223	213	$ 207
Insurance loss and loss adjustment expenses	92	88	84
Liability for reported insurance claims and estimate of unreported claims	15	12
Unearned insurance premiums and fees	857	822
Related Party Transactions Unearned Premiums and Fees	742	711
Premiums Written and Earned [Abstract]
Direct premiums written	324	366	406
Assumed premiums written	0	0	0
Ceded premiums written	(252)	(229)	(223)
Net premiums written	72	137	183
Direct premiums earned	293	350	377
Assumed premiums earned	0	0	0
Ceded premiums earned	(218)	(207)	(195)
Premiums Earned, Net	75	143	182
Insurance Expenses [Abstract]
Insurance losses	45	110	128
Loss adjustment expenses	2	5	7
Reinsurance Income and Other Expenses, Net	(37)	(33)	(32)
Insurance expenses	10	82	103
Liability for reported insurance claims and estimate of unreported claims	15	12
Ceded insurance expenses	$ 150	$ 130	$ 127