Claim and Claim Adjustment Expense Reserves (International - Net prior year claim and allocated claim adjustment expense reserve development) (Details) - International - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Liability for Claims and Claims Adjustment Expense [Line Items]
Commercial	$ (2)	$ 0
Specialty	19	0
Other	(2)	0
Total pretax (favorable) unfavorable development	$ 15	$ 0