Reinsurance - Rollforward of the Reinsurance Recoverable Allowance for Credit Losses (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Reinsurance Recoverable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period	$ 255	$ 260	$ 281
Addition to (release of) allowance for expected credit losses and disputes, net	11	(5)	(22)
Write-offs charged against the allowance for credit losses and disputes	(1)	0	(5)
Recoveries of amounts previously written off	0	0	2
Other changes	4	0	4
Balance, end of year	$ 269	$ 255	$ 260