Reinsurance - Rollforward of the reinsurance recoverable allowance for credit losses (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Reinsurance Recoverable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period	$ 107	$ 87	$ 101	$ 83
Current period provision for expected credit losses and disputes	1	15	7	19
Write-offs charged against the allowance for credit losses and disputes	0	0	0	0
Balance, end of period	$ 108	$ 102	$ 108	$ 102