LOANS, LEASES, AND ALLOWANCE FOR CREDIT LOSSES (Collateral-Dependent Loans) (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized cost	$ 83	$ 57
Commercial
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized cost	21
Commercial real estate
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized cost	59	50
Commercial and industrial | Commercial | Accounts Receivable
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized cost	$ 12
Weighted average LTV	61.00%
Owner-occupied | Commercial | Hospital
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized cost		$ 7
Weighted average LTV		17.00%
Owner-occupied | Commercial | Retail Facility
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized cost	$ 4
Weighted average LTV	82.00%
Municipal | Commercial | Multifamily Apartments
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized cost	$ 5
Weighted average LTV	177.00%
Construction and land development | Commercial real estate | Lots / Homes
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized cost	$ 2
Weighted average LTV	122.00%
Construction and land development | Commercial real estate | Office Building
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized cost		$ 22
Weighted average LTV		92.00%
Term | Commercial real estate | Office Building
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized cost	$ 57	$ 28
Weighted average LTV	92.00%	87.00%
Home equity credit line | Consumer | Single Family Residential
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized cost	$ 3
Weighted average LTV	38.00%