Reinsurance (Components of Reinsurance Receivables) (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Reinsurance receivables related to insurance reserves
Ceded claim and claim adjustment expenses	$ 5,982	$ 5,713	$ 5,141	$ 5,191
Reinsurance receivables related to paid losses	426	359
Reinsurance receivables	6,408	6,072	$ 5,434
Allowance for uncollectible reinsurance	(27)	(21)
Reinsurance receivables, net of allowance for uncollectible reinsurance	$ 6,381	$ 6,051