LOANS AND LEASES - Summary of Loans and Leases Portfolio (Details) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	$ 156,172	$ 128,163
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	81,445	60,350
Commercial | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	51,801	44,500
Commercial | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	28,070	14,264
Commercial | Leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	1,574	1,586
Retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	74,727	67,813
Retail | Residential mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	29,088	22,822
Retail | Home equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	13,122	12,015
Retail | Automobile
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	13,868	14,549
Retail | Education
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	13,141	12,997
Retail | Other retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	$ 5,508	$ 5,430