Bank Premises and Equipment - Summary of Bank Premises and Equipment (Details) - USD ($) $ in Millions		Mar. 31, 2022	Dec. 31, 2021
Property, Plant and Equipment [Line Items]
Accumulated depreciation and amortization		$ (3,212)	$ (3,210)
Total bank premises and equipment	[1]	2,102	2,120
Equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross		2,401	2,392
Buildings
Property, Plant and Equipment [Line Items]
Property and equipment, gross		1,653	1,668
Land and and improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross		638	645
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross		519	517
Construction in progress
Property, Plant and Equipment [Line Items]
Property and equipment, gross		78	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		7	6
Other property
Property, Plant and Equipment [Line Items]
Land improvements		$ 35	$ 39

[1] Includes $25 and $24 of bank premises and equipment held for sale at March 31, 2022 and December 31, 2021, respectively.