v3.26.1
Loans and allowance for loan losses - Summary of Loan grades applied various classes of Commercial and Real Estate Loans (Detail) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Dec. 31, 2025
Financing Receivable, Credit Quality Indicator [Line Items]      
Year one $ 6,527   $ 23,922
Year two 22,331   14,450
Year three 13,548   11,389
Year four 10,528   14,171
Year five 13,371   9,181
Prior 35,899   28,808
Total [1] 139,914   138,702
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]      
Year one 0    
Year two 18    
Year three 23    
Year four 19    
Year five 15    
Prior 36    
Total 153 $ 160  
Commercial and industrial      
Financing Receivable, Credit Quality Indicator [Line Items]      
Year one 3,070   9,686
Year two 9,408   7,026
Year three 6,587   4,626
Year four 4,190   4,541
Year five 4,134   2,344
Prior 7,276   5,562
Revolving Loans 30,571   29,615
Revolving Loans Converted to Term Loans 155   148
Total 65,391   63,548
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]      
Year one 0    
Year two 4    
Year three 6    
Year four 5    
Year five 4    
Prior 4    
Revolving Loans 23    
Revolving Loans Converted to Term Loans 0    
Total 46    
Commercial and industrial | Pass      
Financing Receivable, Credit Quality Indicator [Line Items]      
Year one 3,057   9,462
Year two 9,161   6,640
Year three 6,171   4,075
Year four 3,664   4,086
Year five 3,746   2,203
Prior 6,752   5,059
Revolving Loans 29,241   28,124
Revolving Loans Converted to Term Loans 101   95
Total 61,893   59,744
Commercial and industrial | Criticized accrual      
Financing Receivable, Credit Quality Indicator [Line Items]      
Year one 12   216
Year two 231   337
Year three 353   479
Year four 452   390
Year five 310   116
Prior 349   348
Revolving Loans 1,219   1,355
Revolving Loans Converted to Term Loans 37   36
Total 2,963   3,277
Commercial and industrial | Criticized nonaccrual      
Financing Receivable, Credit Quality Indicator [Line Items]      
Year one 1   8
Year two 16   49
Year three 63   72
Year four 74   65
Year five 78   25
Prior 175   155
Revolving Loans 111   136
Revolving Loans Converted to Term Loans 17   17
Total 535   527
Commercial Real Estate      
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]      
Total 18 $ 22  
Commercial Real Estate | Commercial      
Financing Receivable, Credit Quality Indicator [Line Items]      
Year one 999   3,781
Year two 3,350   429
Year three 425   1,822
Year four 1,832   1,950
Year five 1,877   1,250
Prior 11,210   10,592
Revolving Loans 337   368
Revolving Loans Converted to Term Loans 0   0
Total 20,030   20,192
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]      
Year one 0    
Year two 0    
Year three 0    
Year four 1    
Year five 2    
Prior 14    
Revolving Loans 0    
Revolving Loans Converted to Term Loans 0    
Total 17    
Commercial Real Estate | Commercial | Pass      
Financing Receivable, Credit Quality Indicator [Line Items]      
Year one 999   3,757
Year two 3,317   400
Year three 423   1,535
Year four 1,556   1,681
Year five 1,579   1,121
Prior 9,598   8,970
Revolving Loans 337   367
Revolving Loans Converted to Term Loans 0   0
Total 17,809   17,831
Commercial Real Estate | Commercial | Criticized accrual      
Financing Receivable, Credit Quality Indicator [Line Items]      
Year one 0   0
Year two 9   29
Year three 2   283
Year four 275   244
Year five 275   80
Prior 1,366   1,404
Revolving Loans 0   1
Revolving Loans Converted to Term Loans 0   0
Total 1,927   2,041
Commercial Real Estate | Commercial | Criticized nonaccrual      
Financing Receivable, Credit Quality Indicator [Line Items]      
Year one 0   24
Year two 24   0
Year three 0   4
Year four 1   25
Year five 23   49
Prior 246   218
Revolving Loans 0   0
Revolving Loans Converted to Term Loans 0   0
Total 294   320
Commercial Real Estate | Residential builder and developer      
Financing Receivable, Credit Quality Indicator [Line Items]      
Year one 41   9
Year two 14   1
Year three 1   2
Year four 1   14
Year five 14   0
Prior 5   5
Revolving Loans 34   38
Revolving Loans Converted to Term Loans 0   0
Total 110   69
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]      
Year one 0    
Year two 0    
Year three 0    
Year four 0    
Year five 0    
Prior 0    
Revolving Loans 0    
Revolving Loans Converted to Term Loans 0    
Total 0    
Commercial Real Estate | Residential builder and developer | Pass      
Financing Receivable, Credit Quality Indicator [Line Items]      
Year one 41   9
Year two 14   1
Year three 1   2
Year four 1   2
Year five 1   0
Prior 5   5
Revolving Loans 34   38
Revolving Loans Converted to Term Loans 0   0
Total 97   57
Commercial Real Estate | Residential builder and developer | Criticized accrual      
Financing Receivable, Credit Quality Indicator [Line Items]      
Year one 0   0
Year two 0   0
Year three 0   0
Year four 0   12
Year five 13   0
Prior 0   0
Revolving Loans 0   0
Revolving Loans Converted to Term Loans 0   0
Total 13   12
Commercial Real Estate | Residential builder and developer | Criticized nonaccrual      
Financing Receivable, Credit Quality Indicator [Line Items]      
Year one 0   0
Year two 0   0
Year three 0   0
Year four 0   0
Year five 0   0
Prior 0   0
Revolving Loans 0   0
Revolving Loans Converted to Term Loans 0   0
Total 0   0
Commercial Real Estate | Other commercial construction      
Financing Receivable, Credit Quality Indicator [Line Items]      
Year one 59   313
Year two 419   229
Year three 238   1,282
Year four 1,084   1,107
Year five 967   200
Prior 374   376
Revolving Loans 64   51
Revolving Loans Converted to Term Loans 0   0
Total 3,205   3,558
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]      
Year one 0    
Year two 0    
Year three 0    
Year four 0    
Year five 0    
Prior 1    
Revolving Loans 0    
Revolving Loans Converted to Term Loans 0    
Total 1    
Commercial Real Estate | Other commercial construction | Pass      
Financing Receivable, Credit Quality Indicator [Line Items]      
Year one 59   313
Year two 419   221
Year three 229   1,031
Year four 932   606
Year five 521   63
Prior 162   198
Revolving Loans 63   45
Revolving Loans Converted to Term Loans 0   0
Total 2,385   2,477
Commercial Real Estate | Other commercial construction | Criticized accrual      
Financing Receivable, Credit Quality Indicator [Line Items]      
Year one 0   0
Year two 0   8
Year three 9   251
Year four 152   493
Year five 438   136
Prior 210   174
Revolving Loans 1   6
Revolving Loans Converted to Term Loans 0   0
Total 810   1,068
Commercial Real Estate | Other commercial construction | Criticized nonaccrual      
Financing Receivable, Credit Quality Indicator [Line Items]      
Year one 0   0
Year two 0   0
Year three 0   0
Year four 0   8
Year five 8   1
Prior 2   4
Revolving Loans 0   0
Revolving Loans Converted to Term Loans 0   0
Total $ 10   $ 13
[1] Loans of $2.4 billion and $2.1 billion at March 31, 2026 and December 31, 2025, respectively, were held in special purpose trusts to settle the respective obligations of asset-backed notes issued by those trusts. The outstanding balances of those asset-backed notes issued to third party investors were included in Long-term borrowings and were $2.0 billion at March 31, 2026 and $1.7 billion at December 31, 2025.