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LOANS, LEASES, AND ALLOWANCE FOR CREDIT LOSSES (Summary Aging Analysis, Modified) (Details) - USD ($) $ in Millions | Sep. 30, 2025 | Sep. 30, 2024
--- | --- | ---
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total | $ 559 | $ 307
Current |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total | 525 | 285
Total past due |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total | 34 | 22
30-89 days past due |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total | 22 | 12
90+ days past due |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total | 12 | 10
Commercial: |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total | 139 | 100
Commercial: | Current |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total | 136 | 85
Commercial: | Total past due |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total | 3 | 15
Commercial: | 30-89 days past due |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total | 2 | 12
Commercial: | 90+ days past due |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total | 1 | 3
Commercial: | Commercial and industrial |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total | 106 | 83
Commercial: | Commercial and industrial | Current |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total | 104 | 76
Commercial: | Commercial and industrial | Total past due |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total | 2 | 7
Commercial: | Commercial and industrial | 30-89 days past due |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total | 2 | 4
Commercial: | Commercial and industrial | 90+ days past due |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total | 0 | 3
Commercial: | Owner-occupied |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total | 33 | 6
Commercial: | Owner-occupied | Current |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total | 32 | 6
Commercial: | Owner-occupied | Total past due |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total | 1 | 0
Commercial: | Owner-occupied | 30-89 days past due |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total | 0 | 0
Commercial: | Owner-occupied | 90+ days past due |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total | 1 | 0
Commercial: | Municipal |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total |  | 11
Commercial: | Municipal | Current |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total |  | 3
Commercial: | Municipal | Total past due |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total |  | 8
Commercial: | Municipal | 30-89 days past due |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total |  | 8
Commercial: | Municipal | 90+ days past due |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total |  | 0
Commercial real estate: |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total | 406 | 201
Commercial real estate: | Current |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total | 378 | 194
Commercial real estate: | Total past due |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total | 28 | 7
Commercial real estate: | 30-89 days past due |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total | 18 | 0
Commercial real estate: | 90+ days past due |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total | 10 | 7
Commercial real estate: | Term |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total | 380 | 175
Commercial real estate: | Term | Current |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total | 352 | 170
Commercial real estate: | Term | Total past due |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total | 28 | 5
Commercial real estate: | Term | 30-89 days past due |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total | 18 | 0
Commercial real estate: | Term | 90+ days past due |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total | 10 | 5
Commercial real estate: | Construction and land development |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total | 26 | 26
Commercial real estate: | Construction and land development | Current |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total | 26 | 24
Commercial real estate: | Construction and land development | Total past due |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total | 0 | 2
Commercial real estate: | Construction and land development | 30-89 days past due |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total | 0 | 0
Commercial real estate: | Construction and land development | 90+ days past due |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total | 0 | 2
Consumer: |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total | 14 | 6
Consumer: | Current |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total | 11 | 6
Consumer: | Total past due |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total | 3 | 0
Consumer: | 30-89 days past due |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total | 2 | 0
Consumer: | 90+ days past due |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total | 1 | 0
Consumer: | 1-4 family residential |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total | 12 | 4
Consumer: | 1-4 family residential | Current |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total | 10 | 4
Consumer: | 1-4 family residential | Total past due |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total | 2 | 0
Consumer: | 1-4 family residential | 30-89 days past due |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total | 1 | 0
Consumer: | 1-4 family residential | 90+ days past due |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total | 1 | 0
Consumer: | Home equity credit line |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total | 2 | 1
Consumer: | Home equity credit line | Current |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total | 1 | 1
Consumer: | Home equity credit line | Total past due |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total | 1 | 0
Consumer: | Home equity credit line | 30-89 days past due |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total | 1 | 0
Consumer: | Home equity credit line | 90+ days past due |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total | $ 0 | 0
Consumer: | Other |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total |  | 1
Consumer: | Other | Current |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total |  | 1
Consumer: | Other | Total past due |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total |  | 0
Consumer: | Other | 30-89 days past due |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total |  | 0
Consumer: | Other | 90+ days past due |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Total |  | $ 0

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