Bank Premises and Equipment - Summary of Bank Premises and Equipment (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Property, Plant and Equipment [Line Items]
Accumulated depreciation and amortization	$ (3,550)	$ (3,473)
Total bank premises and equipment	2,389	2,349
Equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	2,672	2,578
Buildings
Property, Plant and Equipment [Line Items]
Property and equipment, gross	1,757	1,742
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	697	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	176	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