Insurance (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Statutory Accounting Practices [Line Items]
Cash and cash equivalents	$ 82	$ 55
Marketable securities	649	607
Total cash, cash equivalents, and marketable securities	731	662
Assets Held by Insurance Regulators	10	11
Prepaid reinsurance premiums and other reinsurance recoverables	818	779
Related party transaction, prepaid reinsurance premiums and other reinsurance recoverables	98	99
Earned insurance premiums	249	241	$ 223
Insurance loss and loss adjustment expenses	161	107	92
Liability for reported insurance claims and estimate of unreported claims	26	18
Unearned insurance premiums and fees	930	891
Related Party Transactions Unearned Premiums and Fees	808	773
Premiums Written and Earned [Abstract]
Direct premiums written	394	337	324
Assumed premiums written	0	0	0
Ceded premiums written	(275)	(264)	(252)
Net premiums written	119	73	72
Direct premiums earned	359	306	293
Assumed premiums earned	0	0	0
Ceded premiums earned	(240)	(231)	(218)
Premiums Earned, Net	119	75	75
Insurance Expenses [Abstract]
Insurance losses	90	34	45
Loss adjustment expenses	4	2	2
Reinsurance Income and Other Expenses, Net	(41)	(40)	(37)
Insurance expenses	53	(4)	10
Liability for reported insurance claims and estimate of unreported claims	26	18
Ceded insurance expenses	$ 198	$ 156	$ 150