Reinsurance - Rollforward of the reinsurance recoverable allowance for credit losses (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Reinsurance Recoverable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period	$ 344	$ 382
Addition to (release of) allowance for expected credit losses and disputes, net	(13)	9
Write-offs charged against the allowance for credit losses and disputes	(1)	(2)
Other changes	(3)	2
Balance, end of period	327	391
General Insurance
Reinsurance Recoverable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period	260	281
Addition to (release of) allowance for expected credit losses and disputes, net	(3)	5
Write-offs charged against the allowance for credit losses and disputes	(1)	(2)
Other changes	(3)	2
Balance, end of period	253	286
Life and Retirement
Reinsurance Recoverable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period	84	101
Addition to (release of) allowance for expected credit losses and disputes, net	(10)	4
Write-offs charged against the allowance for credit losses and disputes	0	0
Other changes	0	0
Balance, end of period	$ 74	$ 105