Reinsurance and Indemnification - Schedule of Rollforward of Credit Loss Allowance for Reinsurance Recoverables (Details) - Property and casualty - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Reinsurance Recoverable, Allowance for Credit Loss [Roll Forward]
Beginning balance	$ (54)	$ (63)
Decrease (increase) in the provision for credit losses	(1)	0
Write-offs	0	0
Ending balance	$ (55)	$ (63)