Reinsurance - Rollforward of the Reinsurance Recoverable Allowance for Credit Losses (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Reinsurance Recoverable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period	$ 285	$ 344
Addition to (release of) allowance for expected credit losses and disputes, net	(9)	(13)
Write-offs charged against the allowance for credit losses and disputes	(3)	(1)
Other changes	0	(3)
Balance, end of period	273	327
General Insurance
Reinsurance Recoverable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period	255	260
Addition to (release of) allowance for expected credit losses and disputes, net	1	(3)
Write-offs charged against the allowance for credit losses and disputes	(1)	(1)
Other changes	0	(3)
Balance, end of period	255	253
Life and Retirement
Reinsurance Recoverable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period	30	84
Addition to (release of) allowance for expected credit losses and disputes, net	(10)	(10)
Write-offs charged against the allowance for credit losses and disputes	(2)	0
Other changes	0	0
Balance, end of period	$ 18	$ 74