PREMISES, EQUIPMENT, AND SOFTWARE - Schedule of Premises and Equipment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Total premises and equipment, gross	$ 1,572	$ 1,596
Accumulated depreciation	(804)	(837)
Total premises and equipment, net	768	759
Land and land improvements
Property, Plant and Equipment [Line Items]
Total premises and equipment, gross	$ 101	102
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	$ 805	800
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	$ 589	644
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	$ 77	$ 50