LOANS AND LEASES - Net of Unearned Income (Detail) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost loans and leases, carrying amount	$ 26,162	$ 23,289
Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost loans and leases, carrying amount	9,305	8,960
Commercial and Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost loans and leases, carrying amount	7,709	5,308
Commercial Leases [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost loans and leases, carrying amount	497	432
Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost loans and leases, carrying amount	40	21
Total Commercial Loans and Leases [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost loans and leases, carrying amount	17,551	14,721
Direct Installment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost loans and leases, carrying amount	1,947	1,821
Residential Mortgages [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost loans and leases, carrying amount	3,520	3,374
Indirect Installment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost loans and leases, carrying amount	1,767	1,922
Consumer Lines of Credit [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost loans and leases, carrying amount	1,377	1,451
Consumer Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost loans and leases, carrying amount	$ 8,611	$ 8,568