Reinsurance (Reinsurance Recoverables - Narrative) (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024
Ceded Credit Risk [Line Items]
Reinsurance Recoverables, Ceded	$ 19,600	$ 19,600
Premiums, reinsurance and other, allowance for credit losses	3	3
Five Largest Ceded Reinsurers [Member]
Ceded Credit Risk [Line Items]
Ceded Credit Risk, Reinsurance Recoverables, Net	$ 16,400	$ 16,900
Ceded Credit Risk, Reinsurance Recoverables, Percentage	84.00%	86.00%
Ceded Credit Risk, Unsecured [Member]
Ceded Credit Risk [Line Items]
Reinsurance Recoverables, Ceded	$ 6,300	$ 6,100
Ceded Credit Risk, Unsecured [Member] | Five Largest Ceded Reinsurers [Member]
Ceded Credit Risk [Line Items]
Ceded Credit Risk, Reinsurance Recoverables, Net	$ 3,800	$ 4,300