PREMISES, EQUIPMENT, AND SOFTWARE - Schedule of Premises and Equipment (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024
Property, Plant and Equipment [Line Items]
Total premises and equipment, gross	$ 1,736	$ 1,685
Accumulated depreciation and amortization	(821)	(810)
Total premises and equipment, net	915	875
Land and land improvements
Property, Plant and Equipment [Line Items]
Total premises and equipment, gross	$ 143	144
Land and land improvements | Minimum
Property, Plant and Equipment [Line Items]
Useful life	10 years
Land and land improvements | Maximum
Property, Plant and Equipment [Line Items]
Useful life	75 years
Buildings and leasehold improvements
Property, Plant and Equipment [Line Items]
Total premises and equipment, gross	$ 901	887
Buildings and leasehold improvements | Minimum
Property, Plant and Equipment [Line Items]
Useful life	5 years
Buildings and leasehold improvements | Maximum
Property, Plant and Equipment [Line Items]
Useful life	60 years
Furniture, fixtures and equipment
Property, Plant and Equipment [Line Items]
Total premises and equipment, gross	$ 581	601
Furniture, fixtures and equipment | Minimum
Property, Plant and Equipment [Line Items]
Useful life	4 years
Furniture, fixtures and equipment | Maximum
Property, Plant and Equipment [Line Items]
Useful life	20 years
Construction in progress
Property, Plant and Equipment [Line Items]
Total premises and equipment, gross	$ 110	$ 53