v3.26.3
LOANS, LEASES, AND ALLOWANCE FOR CREDIT LOSSES (Summary Aging Analysis, Modified) (Details) - USD ($)
$ in Millions
Sep. 30, 2026
Sep. 30, 2025
Financing Receivable, Allowance for Credit Losses [Line Items]    
Total $ 582 $ 559
Current    
Financing Receivable, Allowance for Credit Losses [Line Items]    
Total 577 525
Total past due    
Financing Receivable, Allowance for Credit Losses [Line Items]    
Total 5 34
30-89 days past due    
Financing Receivable, Allowance for Credit Losses [Line Items]    
Total 2 22
90+ days past due    
Financing Receivable, Allowance for Credit Losses [Line Items]    
Total 3 12
Commercial:    
Financing Receivable, Allowance for Credit Losses [Line Items]    
Total 152 139
Commercial: | Current    
Financing Receivable, Allowance for Credit Losses [Line Items]    
Total 147 136
Commercial: | Total past due    
Financing Receivable, Allowance for Credit Losses [Line Items]    
Total 5 3
Commercial: | 30-89 days past due    
Financing Receivable, Allowance for Credit Losses [Line Items]    
Total 2 2
Commercial: | 90+ days past due    
Financing Receivable, Allowance for Credit Losses [Line Items]    
Total 3 1
Commercial: | Commercial and industrial    
Financing Receivable, Allowance for Credit Losses [Line Items]    
Total 111 106
Commercial: | Commercial and industrial | Current    
Financing Receivable, Allowance for Credit Losses [Line Items]    
Total 109 104
Commercial: | Commercial and industrial | Total past due    
Financing Receivable, Allowance for Credit Losses [Line Items]    
Total 2 2
Commercial: | Commercial and industrial | 30-89 days past due    
Financing Receivable, Allowance for Credit Losses [Line Items]    
Total 2 2
Commercial: | Commercial and industrial | 90+ days past due    
Financing Receivable, Allowance for Credit Losses [Line Items]    
Total 0 0
Commercial: | Owner-occupied    
Financing Receivable, Allowance for Credit Losses [Line Items]    
Total 41 33
Commercial: | Owner-occupied | Current    
Financing Receivable, Allowance for Credit Losses [Line Items]    
Total 38 32
Commercial: | Owner-occupied | Total past due    
Financing Receivable, Allowance for Credit Losses [Line Items]    
Total 3 1
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 3 1
Commercial real estate:    
Financing Receivable, Allowance for Credit Losses [Line Items]    
Total 427 406
Commercial real estate: | Current    
Financing Receivable, Allowance for Credit Losses [Line Items]    
Total 427 378
Commercial real estate: | Total past due    
Financing Receivable, Allowance for Credit Losses [Line Items]    
Total 0 28
Commercial real estate: | 30-89 days past due    
Financing Receivable, Allowance for Credit Losses [Line Items]    
Total 0 18
Commercial real estate: | 90+ days past due    
Financing Receivable, Allowance for Credit Losses [Line Items]    
Total 0 10
Commercial real estate: | Term    
Financing Receivable, Allowance for Credit Losses [Line Items]    
Total 395 380
Commercial real estate: | Term | Current    
Financing Receivable, Allowance for Credit Losses [Line Items]    
Total 395 352
Commercial real estate: | Term | Total past due    
Financing Receivable, Allowance for Credit Losses [Line Items]    
Total 0 28
Commercial real estate: | Term | 30-89 days past due    
Financing Receivable, Allowance for Credit Losses [Line Items]    
Total 0 18
Commercial real estate: | Term | 90+ days past due    
Financing Receivable, Allowance for Credit Losses [Line Items]    
Total 0 10
Commercial real estate: | Construction and land development    
Financing Receivable, Allowance for Credit Losses [Line Items]    
Total 32 26
Commercial real estate: | Construction and land development | Current    
Financing Receivable, Allowance for Credit Losses [Line Items]    
Total 32 26
Commercial real estate: | Construction and land development | Total past due    
Financing Receivable, Allowance for Credit Losses [Line Items]    
Total 0 0
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 0
Consumer:    
Financing Receivable, Allowance for Credit Losses [Line Items]    
Total 3 14
Consumer: | Current    
Financing Receivable, Allowance for Credit Losses [Line Items]    
Total 3 11
Consumer: | Total past due    
Financing Receivable, Allowance for Credit Losses [Line Items]    
Total 0 3
Consumer: | 30-89 days past due    
Financing Receivable, Allowance for Credit Losses [Line Items]    
Total 0 2
Consumer: | 90+ days past due    
Financing Receivable, Allowance for Credit Losses [Line Items]    
Total 0 1
Consumer: | 1-4 family residential    
Financing Receivable, Allowance for Credit Losses [Line Items]    
Total 2 12
Consumer: | 1-4 family residential | Current    
Financing Receivable, Allowance for Credit Losses [Line Items]    
Total 2 10
Consumer: | 1-4 family residential | Total past due    
Financing Receivable, Allowance for Credit Losses [Line Items]    
Total 0 2
Consumer: | 1-4 family residential | 30-89 days past due    
Financing Receivable, Allowance for Credit Losses [Line Items]    
Total 0 1
Consumer: | 1-4 family residential | 90+ days past due    
Financing Receivable, Allowance for Credit Losses [Line Items]    
Total 0 1
Consumer: | Home equity credit line    
Financing Receivable, Allowance for Credit Losses [Line Items]    
Total 1 2
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 0 1
Consumer: | Home equity credit line | 30-89 days past due    
Financing Receivable, Allowance for Credit Losses [Line Items]    
Total 0 1
Consumer: | Home equity credit line | 90+ days past due    
Financing Receivable, Allowance for Credit Losses [Line Items]    
Total $ 0 $ 0