LOANS AND LEASES - Schedule of Loans by Class (Details) - USD ($) $ in Millions	Mar. 31, 2026	Dec. 31, 2025	Mar. 31, 2025
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	$ 148,692	$ 147,930	$ 141,358
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	121,950	120,734
Commercial \| Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	45,753	44,721
Commercial \| Capital call lines
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	32,274	31,791
Commercial \| Owner occupied commercial mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	17,502	17,660
Commercial \| Investor dependent
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	2,714	2,778
Commercial \| Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	23,707	23,784
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	26,742	27,196
Consumer \| Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	21,698	21,861
Consumer \| Revolving mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	2,863	2,863
Consumer \| Auto
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	1,332	1,416
Consumer \| Other consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	$ 849	$ 1,056