Insurance (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Statutory Accounting Practices [Line Items]
Cash and cash equivalents	$ 85	$ 82
Marketable securities	644	649
Total cash, cash equivalents, and marketable securities	729	731
Assets Held by Insurance Regulators	11	10
Prepaid reinsurance premiums and other reinsurance recoverables	876	818
Related party transaction, prepaid reinsurance premiums and other reinsurance recoverables	98	98
Earned insurance premiums	259	249	$ 241
Insurance loss and loss adjustment expenses	224	161	107
Liability for reported insurance claims and estimate of unreported claims	35	26
Unearned insurance premiums and fees	995	930
Related Party Transactions Unearned Premiums and Fees	863	808
Premiums Written and Earned [Abstract]
Direct premiums written	472	394	337
Assumed premiums written	0	0	0
Ceded premiums written	(300)	(275)	(264)
Net premiums written	172	119	73
Direct premiums earned	415	359	306
Assumed premiums earned	0	0	0
Ceded premiums earned	(244)	(240)	(231)
Premiums Earned, Net	171	119	75
Insurance Expenses [Abstract]
Insurance losses	181	90	34
Loss adjustment expenses	5	4	2
Reinsurance Income and Other Expenses, Net	(40)	(41)	(40)
Insurance expenses	146	53	(4)
Liability for reported insurance claims and estimate of unreported claims	35	26
Ceded insurance expenses	$ 233	$ 198	$ 156