LOANS, LEASES, AND ALLOWANCE FOR CREDIT LOSSES (Collateral-Dependent Loans) (Details) - USD ($) $ in Millions	Sep. 30, 2026	Dec. 31, 2025
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized cost	$ 49	$ 70
Commercial and industrial \| Commercial: \| Single family residential
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized cost		$ 3
Weighted average LTV		71.00%
Owner-occupied \| Commercial: \| Agriculture production and office buildings
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized cost	$ 18
Weighted average LTV	46.00%
Owner-occupied \| Commercial: \| Agriculture production and industrial buildings
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized cost		$ 23
Weighted average LTV		67.00%
Municipal \| Commercial: \| Multifamily apartments
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized cost		$ 2
Weighted average LTV		93.00%
Term \| Commercial real estate: \| Office and industrial buildings
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized cost	$ 28
Weighted average LTV	51.00%
Term \| Commercial real estate: \| Office building
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized cost		$ 37
Weighted average LTV		98.00%
1-4 family residential \| Consumer: \| Single family residential
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized cost	$ 3	$ 5
Weighted average LTV	80.00%	62.00%