Insurance Contracts - Effect of Reinsurance on Premiums Written and Earned (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2024	Mar. 31, 2023
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Direct Premiums Written	$ 81	$ 61
Assumed Reinsurance Premiums Written	17	0
Ceded Reinsurance Premiums Written	70	43
Premiums written, net of reinsurance	(28)	(18)
Direct Premiums Earned	75	46
Assumed Reinsurance Premiums Earned	16	0
Ceded Reinsurance Premiums Earned	$ 57	$ 32

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