LOANS AND LEASES - Summary of Loans and Leases Portfolio (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	$ 154,688	$ 156,662
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	80,866	82,180
Commercial | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	50,450	51,836
Commercial | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	28,999	28,865
Commercial | Leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	1,417	1,479
Retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	73,822	74,482
Retail | Residential mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	30,362	29,921
Retail | Home equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	14,135	14,043
Retail | Automobile
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	11,535	12,292
Retail | Education
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	12,634	12,808
Retail | Other retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	$ 5,156	$ 5,418