Reinsurance and Indemnification - Schedule of Rollforward of Credit Loss Allowance for Reinsurance Recoverables (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Reinsurance
Beginning balance	$ (65)
Ending balance	(65)	$ (65)
Property and casualty
Reinsurance
Beginning balance	(62)	(66)
Decrease/(Increase) in the provision for credit losses	(1)	(5)
Write-offs	1	9
Ending balance	(62)	(62)
Accident and health insurance
Reinsurance
Beginning balance	(3)	(8)
Decrease/(Increase) in the provision for credit losses	0	5
Write-offs	0	0
Ending balance	$ (3)	$ (3)