Insurance Contracts - Effect of Reinsurance on Premiums Written and Earned (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Direct Premiums Written	$ 91	$ 65	$ 265	$ 181
Assumed Reinsurance Premiums Written	22	14	60	14
Ceded Reinsurance Premiums Written	83	52	232	195
Premiums written, net of reinsurance	(31)	(27)	(92)	0
Direct Premiums Earned	89	59	243	157
Assumed Reinsurance Premiums Earned	17	3	50	3
Ceded Reinsurance Premiums Earned	$ 73	$ 45	$ 194	$ 113