Bank Premises and Equipment - Summary of Bank Premises and Equipment (Details) - USD ($) $ in Millions		Jun. 30, 2022	Dec. 31, 2021
Property, Plant and Equipment [Line Items]
Accumulated depreciation and amortization		$ (3,255)	$ (3,210)
Total bank premises and equipment	[1]	2,118	2,120
Equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross		2,422	2,392
Buildings
Property, Plant and Equipment [Line Items]
Property and equipment, gross		1,660	1,668
Land and and improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross		648	645
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross		526	517
Construction in progress
Property, Plant and Equipment [Line Items]
Property and equipment, gross		93	84
Land and improvements held for sale
Property, Plant and Equipment [Line Items]
Property and equipment, gross		18	18
Buildings
Property, Plant and Equipment [Line Items]
Property and equipment, gross		6	6
Other property
Property, Plant and Equipment [Line Items]
Land improvements		$ 33	$ 39

[1] Includes $24 of bank premises and equipment held for sale at both June 30, 2022 and December 31, 2021.