Claim and Claim Adjustment Expense Reserves (International - Net prior year claim and allocated claim adjustment expense reserve development) (Details) - International - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Liability for Claims and Claims Adjustment Expense [Line Items]
Commercial	$ (26)	$ (12)	$ (18)
Specialty	5	6	35
Other	(4)	0	(4)
Total pretax (favorable) unfavorable development	$ (25)	$ (6)	$ 13