Bank Premises and Equipment - Summary of Bank Premises and Equipment (Details) - USD ($) $ in Millions		Mar. 31, 2024	Dec. 31, 2023
Property, Plant and Equipment [Line Items]
Accumulated depreciation and amortization		$ (3,485)	$ (3,473)
Total bank premises and equipment	[1]	2,376	2,349
Equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross		2,641	2,578
Buildings
Property, Plant and Equipment [Line Items]
Property and equipment, gross		1,743	1,742
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross		692	685
Land and and improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross		621	618
Construction in progress
Property, Plant and Equipment [Line Items]
Property and equipment, gross		148	180
Land and improvements held for sale
Property, Plant and Equipment [Line Items]
Property and equipment, gross		12	15
Buildings held for sale
Property, Plant and Equipment [Line Items]
Property and equipment, gross		4	4
Other property
Property, Plant and Equipment [Line Items]
Land improvements		$ 9	$ 9

[1] Includes $16 and $19 of bank premises and equipment held for sale at March 31, 2024 and December 31, 2023, respectively.