Bank Premises and Equipment - Summary of Bank Premises and Equipment (Details) - USD ($) $ in Millions		Dec. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Line Items]
Accumulated depreciation and amortization		$ (3,473)	$ (3,360)
Total bank premises and equipment	[1]	2,349	2,187
Equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross		$ 2,578	2,492
Equipment | Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Life		1 year
Equipment | Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Life		20 years
Buildings
Property, Plant and Equipment [Line Items]
Property and equipment, gross		$ 1,742	1,699
Buildings | Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Life		1 year
Buildings | Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Life		30 years
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross		$ 685	568
Leasehold improvements | Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Life		1 year
Leasehold improvements | Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Life		30 years
Land and and improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross		$ 618	640
Construction in progress
Property, Plant and Equipment [Line Items]
Property and equipment, gross		180	124
Land and improvements held for sale
Property, Plant and Equipment [Line Items]
Property and equipment, gross		15	17
Buildings held for sale
Property, Plant and Equipment [Line Items]
Property and equipment, gross		4	7
Other property
Property, Plant and Equipment [Line Items]
Land improvements		$ 9	$ 27

[1] Includes $19 and $24 of bank premises and equipment held for sale at both December 31, 2023 and 2022. For further information, refer to Note 7.