Reinsurance and Indemnification - Schedule of Rollforward of Credit Loss Allowance for Reinsurance Recoverables (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Reinsurance
Beginning balance	$ (65)
Ending balance	(63)	$ (65)
Property and casualty
Reinsurance
Beginning balance	(62)	(62)
Increase (Decrease) in the provision for credit losses	(1)	(1)
Write-offs	0	1
Ending balance	(63)	(62)
Accident and health insurance
Reinsurance
Beginning balance	(3)	(3)
Increase (Decrease) in the provision for credit losses	2	0
Write-offs	0	0
Reinsurance recoverables allowance reclassified to held for sale	1	0
Ending balance	$ 0	$ (3)