LOANS AND LEASES - NALs Past Due (Details) - USD ($) $ in Millions	Sep. 30, 2025	Dec. 31, 2024
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	$ 137,956	$ 130,042
Loans Accounted for Under FVO	171	173
90 or more days past due and accruing	234	239
Total
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	1,446	1,485
30-59 Days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	562	603
60-89  Days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	230	238
90 or  more days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	654	644
Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	136,339	128,384
Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	62,978	56,809
Loans Accounted for Under FVO	0	0
90 or more days past due and accruing	1	3
Commercial and industrial | Total
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	413	374
Commercial and industrial | 30-59 Days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	104	96
Commercial and industrial | 60-89  Days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	59	46
Commercial and industrial | 90 or  more days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	250	232
Commercial and industrial | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	62,565	56,435
Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	10,732	11,078
Loans Accounted for Under FVO	0	0
90 or more days past due and accruing	0	0
Commercial real estate | Total
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	36	74
Commercial real estate | 30-59 Days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	1	35
Commercial real estate | 60-89  Days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	0	0
Commercial real estate | 90 or  more days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	35	39
Commercial real estate | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	10,696	11,004
Lease financing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	5,515	5,454
Loans Accounted for Under FVO	0	0
90 or more days past due and accruing	6	11
Lease financing | Total
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	57	93
Lease financing | 30-59 Days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	37	56
Lease financing | 60-89  Days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	11	23
Lease financing | 90 or  more days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	9	14
Lease financing | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	5,458	5,361
Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	24,502	24,242
Loans Accounted for Under FVO	171	173
90 or more days past due and accruing	187	185
Residential mortgage | Total
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	550	536
Residential mortgage | 30-59 Days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	216	196
Residential mortgage | 60-89  Days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	86	98
Residential mortgage | 90 or  more days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	248	242
Residential mortgage | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	23,781	23,533
Automobile
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	15,996	14,564
Loans Accounted for Under FVO	0	0
90 or more days past due and accruing	12	12
Automobile | Total
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	157	160
Automobile | 30-59 Days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	114	117
Automobile | 60-89  Days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	28	27
Automobile | 90 or  more days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	15	16
Automobile | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	15,839	14,404
Home equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	10,314	10,142
Loans Accounted for Under FVO	0	0
90 or more days past due and accruing	20	20
Home equity | Total
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	175	188
Home equity | 30-59 Days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	53	64
Home equity | 60-89  Days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	33	32
Home equity | 90 or  more days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	89	92
Home equity | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	10,139	9,954
RV and marine
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	5,805	5,982
Loans Accounted for Under FVO	0	0
90 or more days past due and accruing	3	4
RV and marine | Total
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	30	38
RV and marine | 30-59 Days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	21	26
RV and marine | 60-89  Days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	6	7
RV and marine | 90 or  more days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	3	5
RV and marine | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	5,775	5,944
Other consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	2,114	1,771
Loans Accounted for Under FVO	0	0
90 or more days past due and accruing	5	4
Other consumer | Total
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	28	22
Other consumer | 30-59 Days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	16	13
Other consumer | 60-89  Days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	7	5
Other consumer | 90 or  more days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	5	4
Other consumer | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	$ 2,086	$ 1,749