Reinsurance and Indemnification - Rollforward of Credit Loss Allowance for Reinsurance Recoverables (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Reinsurance
Beginning balance	$ (60)
Ending balance	(74)	$ (60)
Property and casualty
Reinsurance
Beginning balance	(59)	(60)
Increase (decrease) in the provision for credit losses	(8)	1
Write-offs	1	0
Ending balance	(66)	(59)
Accident and health insurance
Reinsurance
Beginning balance	(1)	(1)
Increase (decrease) in the provision for credit losses	7	0
Write-offs	0	0
Ending balance	$ (8)	$ (1)