Reinsurance and Indemnification - Rollforward of credit loss allowance for reinsurance recoverables (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Property-Liability
Reinsurance Recoverable, Allowance for Credit Loss [Roll Forward]
Beginning balance	$ (66)	$ (60)	$ (66)	$ (59)
Increase in the provision for credit losses	0	0	0	(1)
Write-offs	0	0	0	0
Ending balance	(66)	(60)	(66)	(60)
Accident and health insurance
Reinsurance Recoverable, Allowance for Credit Loss [Roll Forward]
Beginning balance	(8)	(1)	(8)	(1)
Increase in the provision for credit losses	0	0	0	0
Write-offs	0	0	0	0
Ending balance	$ (8)	$ (1)	$ (8)	$ (1)