Insurance Contracts - Effect of Reinsurance on Premiums Written and Earned (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Direct Premiums Written	$ 65	$ 16	$ 181	$ 83
Assumed Reinsurance Premiums Written	14	0	14	0
Ceded Reinsurance Premiums Written	52	17	195	63
Premiums written, net of reinsurance	(27)	0	0	(21)
Direct Premiums Earned	59	30	157	83
Assumed Reinsurance Premiums Earned	3	0	3	0
Ceded Reinsurance Premiums Earned	$ 45	$ 19	$ 113	$ 43