LOANS, LEASES, AND ALLOWANCE FOR CREDIT LOSSES (Summary of Nonaccrual Loans) (Details) - USD ($) $ in Millions	Sep. 30, 2026	Dec. 31, 2025
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized cost basis with no allowance	$ 86	$ 95
Amortized cost basis with allowance	225	220
Nonaccrual loans that are current	311	315
Related allowance	45	36
Commercial:
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized cost basis with no allowance	46	77
Amortized cost basis with allowance	130	69
Nonaccrual loans that are current	176	146
Related allowance	24	20
Commercial: \| Commercial and industrial
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized cost basis with no allowance	16	44
Amortized cost basis with allowance	114	49
Nonaccrual loans that are current	130	93
Related allowance	23	19
Commercial: \| Owner-occupied
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized cost basis with no allowance	30	33
Amortized cost basis with allowance	16	18
Nonaccrual loans that are current	46	51
Related allowance	1	1
Commercial: \| Municipal
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized cost basis with no allowance		0
Amortized cost basis with allowance		2
Nonaccrual loans that are current		2
Related allowance		0
Commercial real estate:
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized cost basis with no allowance		4
Amortized cost basis with allowance		69
Nonaccrual loans that are current		73
Related allowance		2
Commercial real estate: \| Term
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized cost basis with no allowance	32	4
Amortized cost basis with allowance	8	68
Nonaccrual loans that are current	40	72
Related allowance	0	2
Commercial real estate: \| Construction and land development
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized cost basis with no allowance		0
Amortized cost basis with allowance		1
Nonaccrual loans that are current		1
Related allowance		0
Consumer:
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized cost basis with no allowance	8	14
Amortized cost basis with allowance	87	82
Nonaccrual loans that are current	95	96
Related allowance	21	14
Consumer: \| 1-4 family residential
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized cost basis with no allowance	7	14
Amortized cost basis with allowance	51	51
Nonaccrual loans that are current	58	65
Related allowance	6	5
Consumer: \| Home equity credit line
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized cost basis with no allowance	1	0
Amortized cost basis with allowance	34	30
Nonaccrual loans that are current	35	30
Related allowance	13	8
Consumer: \| Bankcard and other revolving plans
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized cost basis with no allowance	0	0
Amortized cost basis with allowance	1	1
Nonaccrual loans that are current	1	1
Related allowance	1	$ 1
Consumer: \| Other
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized cost basis with no allowance	0
Amortized cost basis with allowance	1
Nonaccrual loans that are current	1
Related allowance	$ 1

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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