Reinsurance - Rollforward of the reinsurance recoverable allowance for credit losses (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Reinsurance Recoverable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period	$ 391	$ 378	$ 382	$ 375
Addition to (release of) allowance for expected credit losses and disputes, net	(2)	(1)	7	4
Write-offs charged against the allowance for credit losses and disputes	0	(3)	(2)	(7)
Recoveries of amounts previously written off	2	0	2	0
Other changes	0	0	2	2
Balance, end of period	391	374	391	374
General Insurance
Reinsurance Recoverable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period	286	291	281	292
Addition to (release of) allowance for expected credit losses and disputes, net	(4)	(1)	1	0
Write-offs charged against the allowance for credit losses and disputes	0	(3)	(2)	(7)
Recoveries of amounts previously written off	2	0	2	0
Other changes	0	0	2	2
Balance, end of period	284	287	284	287
Life and Retirement
Reinsurance Recoverable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period	105	87	101	83
Addition to (release of) allowance for expected credit losses and disputes, net	2	0	6	4
Write-offs charged against the allowance for credit losses and disputes	0	0	0	0
Recoveries of amounts previously written off	0	0	0	0
Other changes	0	0	0	0
Balance, end of period	$ 107	$ 87	$ 107	$ 87