Premises, Equipment and Leases - Components of Premises and Equipment (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Line Items]
Total premises and equipment, gross	$ 9,556	$ 9,355
Less: Accumulated depreciation and amortization	(5,181)	(5,004)
Total premises and equipment, net	4,375	4,351
Land
Property, Plant and Equipment [Line Items]
Total premises and equipment, gross	305	320
Buildings and improvements
Property, Plant and Equipment [Line Items]
Total premises and equipment, gross	4,297	4,345
Furniture and equipment
Property, Plant and Equipment [Line Items]
Total premises and equipment, gross	1,800	1,831
Computer software
Property, Plant and Equipment [Line Items]
Total premises and equipment, gross	2,863	2,213
In progress
Property, Plant and Equipment [Line Items]
Total premises and equipment, gross	$ 291	$ 646