LOANS AND LEASES - Nonaccrual Loans by Loan Class (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans with no ACL	$ 112	$ 164
Total nonaccrual loans	569	716
Commercial portfolio | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans with no ACL	49	81
Total nonaccrual loans	288	370
Commercial portfolio | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans with no ACL	63	80
Total nonaccrual loans	92	104
Commercial portfolio | Lease financing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans with no ACL	0	3
Total nonaccrual loans	18	48
Consumer | Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans with no ACL	0	0
Total nonaccrual loans	90	111
Consumer | Automobile
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans with no ACL	0	0
Total nonaccrual loans	4	3
Consumer | Home equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans with no ACL	0	0
Total nonaccrual loans	76	79
Consumer | RV and marine
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans with no ACL	0	0
Total nonaccrual loans	$ 1	$ 1