Reinsurance - Rollforward of the Reinsurance Recoverable Allowance for Credit Losses (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Reinsurance Recoverable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period	$ 279	$ 255	$ 269	$ 255
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	(1)	0	(1)	(1)
Other changes	2	6	9	6
Balance, end of period	$ 276	$ 260	$ 276	$ 260