Premises and Equipment - Summary of Premises and Equipment (Detail) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 2,462	$ 2,343
Less: accumulated depreciation and amortization	1,326	1,220
Right-of-use assets — operating leases	$ 569	$ 616
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Premises and equipment, net	Premises and equipment, net
Premises and equipment, net	$ 1,705	$ 1,739
Land
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	146	148
Buildings
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	703	685
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	423	413
Furniture and equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 1,190	$ 1,097