v3.26.1
Loans and allowance for loan losses - Summary of loans in Accrual and Nonaccrual Status (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  
Residential Real Estate      
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]      
Total 1 2  
Consumer      
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]      
Total 88 $ 86  
Revolving Loans      
Financing Receivable, Credit Quality Indicator [Line Items]      
Revolving Loans 36,175   35,268
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]      
Revolving Loans 41    
Revolving Loans Converted to Term Loans      
Financing Receivable, Credit Quality Indicator [Line Items]      
Revolving Loans Converted to Term Loans 1,535   1,513
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]      
Revolving Loans Converted to Term Loans 1    
Residential | Residential Real Estate      
Financing Receivable, Credit Quality Indicator [Line Items]      
Year one 1,029   3,780
Year two 3,230   1,820
Year three 1,719   1,231
Year four 1,182   4,323
Year five 4,293   3,635
Prior 13,271   9,957
Total 24,857   24,874
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    
Total 1    
Residential | Revolving Loans | Residential Real Estate      
Financing Receivable, Credit Quality Indicator [Line Items]      
Revolving Loans 133   128
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]      
Revolving Loans 0    
Residential | Revolving Loans Converted to Term Loans | Residential Real Estate      
Financing Receivable, Credit Quality Indicator [Line Items]      
Revolving Loans Converted to Term Loans 0   0
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]      
Revolving Loans Converted to Term Loans 0    
Home equity lines and loans (e) | Consumer      
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   1
Prior 77   80
Total 4,796   4,807
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    
Total 1    
Home equity lines and loans (e) | Revolving Loans | Consumer      
Financing Receivable, Credit Quality Indicator [Line Items]      
Revolving Loans 3,341   3,363
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]      
Revolving Loans 0    
Home equity lines and loans (e) | Revolving Loans Converted to Term Loans | Consumer      
Financing Receivable, Credit Quality Indicator [Line Items]      
Revolving Loans Converted to Term Loans 1,378   1,363
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]      
Revolving Loans Converted to Term Loans 1    
Recreational finance | Consumer      
Financing Receivable, Credit Quality Indicator [Line Items]      
Year one 853   4,093
Year two 3,831   3,077
Year three 2,899   1,760
Year four 1,653   1,694
Year five 1,619   1,364
Prior 3,289   2,104
Total 14,144   14,092
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]      
Year one 0    
Year two 5    
Year three 9    
Year four 10    
Year five 7    
Prior 15    
Total 46    
Recreational finance | Revolving Loans | Consumer      
Financing Receivable, Credit Quality Indicator [Line Items]      
Revolving Loans 0   0
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]      
Revolving Loans 0    
Recreational finance | Revolving Loans Converted to Term Loans | Consumer      
Financing Receivable, Credit Quality Indicator [Line Items]      
Revolving Loans Converted to Term Loans 0   0
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]      
Revolving Loans Converted to Term Loans 0    
Automobile | Consumer      
Financing Receivable, Credit Quality Indicator [Line Items]      
Year one 385   1,943
Year two 1,810   1,710
Year three 1,542   575
Year four 509   485
Year five 418   345
Prior 352   109
Total 5,016   5,167
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]      
Year one 0    
Year two 3    
Year three 5    
Year four 2    
Year five 2    
Prior 1    
Total 13    
Automobile | Revolving Loans | Consumer      
Financing Receivable, Credit Quality Indicator [Line Items]      
Revolving Loans 0   0
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]      
Revolving Loans 0    
Automobile | Revolving Loans Converted to Term Loans | Consumer      
Financing Receivable, Credit Quality Indicator [Line Items]      
Revolving Loans Converted to Term Loans 0   0
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]      
Revolving Loans Converted to Term Loans 0    
Other | Consumer      
Financing Receivable, Credit Quality Indicator [Line Items]      
Year one 91   317
Year two 269   158
Year three 137   91
Year four 77   57
Year five 49   42
Prior 45   23
Total 2,365   2,395
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]      
Year one 0    
Year two 6    
Year three 3    
Year four 1    
Year five 0    
Prior 0    
Total 28    
Other | Revolving Loans | Consumer      
Financing Receivable, Credit Quality Indicator [Line Items]      
Revolving Loans 1,695   1,705
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]      
Revolving Loans 18    
Other | Revolving Loans Converted to Term Loans | Consumer      
Financing Receivable, Credit Quality Indicator [Line Items]      
Revolving Loans Converted to Term Loans 2   2
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]      
Revolving Loans Converted to Term Loans 0    
Current | Residential | Residential Real Estate      
Financing Receivable, Credit Quality Indicator [Line Items]      
Year one 1,029   3,769
Year two 3,214   1,797
Year three 1,696   1,188
Year four 1,128   4,040
Year five 4,001   3,433
Prior 12,197   9,056
Total 23,398   23,410
Current | Residential | Revolving Loans | Residential Real Estate      
Financing Receivable, Credit Quality Indicator [Line Items]      
Revolving Loans 133   127
Current | Residential | Revolving Loans Converted to Term Loans | Residential Real Estate      
Financing Receivable, Credit Quality Indicator [Line Items]      
Revolving Loans Converted to Term Loans 0   0
Current | Home equity lines and loans (e) | Consumer      
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   1
Prior 72   76
Total 4,681   4,690
Current | Home equity lines and loans (e) | Revolving Loans | Consumer      
Financing Receivable, Credit Quality Indicator [Line Items]      
Revolving Loans 3,340   3,362
Current | Home equity lines and loans (e) | Revolving Loans Converted to Term Loans | Consumer      
Financing Receivable, Credit Quality Indicator [Line Items]      
Revolving Loans Converted to Term Loans 1,269   1,251
Current | Recreational finance | Consumer      
Financing Receivable, Credit Quality Indicator [Line Items]      
Year one 853   4,081
Year two 3,817   3,052
Year three 2,876   1,729
Year four 1,626   1,673
Year five 1,598   1,345
Prior 3,233   2,066
Total 14,003   13,946
Current | Recreational finance | Revolving Loans | Consumer      
Financing Receivable, Credit Quality Indicator [Line Items]      
Revolving Loans 0   0
Current | Recreational finance | Revolving Loans Converted to Term Loans | Consumer      
Financing Receivable, Credit Quality Indicator [Line Items]      
Revolving Loans Converted to Term Loans 0   0
Current | Automobile | Consumer      
Financing Receivable, Credit Quality Indicator [Line Items]      
Year one 385   1,933
Year two 1,796   1,690
Year three 1,523   561
Year four 495   473
Year five 407   336
Prior 341   104
Total 4,947   5,097
Current | Automobile | Revolving Loans | Consumer      
Financing Receivable, Credit Quality Indicator [Line Items]      
Revolving Loans 0   0
Current | Automobile | Revolving Loans Converted to Term Loans | Consumer      
Financing Receivable, Credit Quality Indicator [Line Items]      
Revolving Loans Converted to Term Loans 0   0
Current | Other | Consumer      
Financing Receivable, Credit Quality Indicator [Line Items]      
Year one 88   312
Year two 266   155
Year three 134   89
Year four 76   56
Year five 48   42
Prior 43   22
Total 2,314   2,357
Current | Other | Revolving Loans | Consumer      
Financing Receivable, Credit Quality Indicator [Line Items]      
Revolving Loans 1,658   1,680
Current | Other | Revolving Loans Converted to Term Loans | Consumer      
Financing Receivable, Credit Quality Indicator [Line Items]      
Revolving Loans Converted to Term Loans 1   1
30-89 days past due | Residential | Residential Real Estate      
Financing Receivable, Credit Quality Indicator [Line Items]      
Year one 0   10
Year two 13   11
Year three 8   19
Year four 23   117
Year five 91   93
Prior 418   407
Total 553   657
30-89 days past due | Residential | Revolving Loans | Residential Real Estate      
Financing Receivable, Credit Quality Indicator [Line Items]      
Revolving Loans 0   0
30-89 days past due | Residential | Revolving Loans Converted to Term Loans | Residential Real Estate      
Financing Receivable, Credit Quality Indicator [Line Items]      
Revolving Loans Converted to Term Loans 0   0
30-89 days past due | Home equity lines and loans (e) | Consumer      
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 1   2
Total 31   35
30-89 days past due | Home equity lines and loans (e) | Revolving Loans | Consumer      
Financing Receivable, Credit Quality Indicator [Line Items]      
Revolving Loans 0   0
30-89 days past due | Home equity lines and loans (e) | Revolving Loans Converted to Term Loans | Consumer      
Financing Receivable, Credit Quality Indicator [Line Items]      
Revolving Loans Converted to Term Loans 30   33
30-89 days past due | Recreational finance | Consumer      
Financing Receivable, Credit Quality Indicator [Line Items]      
Year one 0   10
Year two 11   20
Year three 19   25
Year four 17   17
Year five 17   15
Prior 45   29
Total 109   116
30-89 days past due | Recreational finance | Revolving Loans | Consumer      
Financing Receivable, Credit Quality Indicator [Line Items]      
Revolving Loans 0   0
30-89 days past due | Recreational finance | Revolving Loans Converted to Term Loans | Consumer      
Financing Receivable, Credit Quality Indicator [Line Items]      
Revolving Loans Converted to Term Loans 0   0
30-89 days past due | Automobile | Consumer      
Financing Receivable, Credit Quality Indicator [Line Items]      
Year one 0   8
Year two 11   17
Year three 17   13
Year four 13   10
Year five 10   7
Prior 9   4
Total 60   59
30-89 days past due | Automobile | Revolving Loans | Consumer      
Financing Receivable, Credit Quality Indicator [Line Items]      
Revolving Loans 0   0
30-89 days past due | Automobile | Revolving Loans Converted to Term Loans | Consumer      
Financing Receivable, Credit Quality Indicator [Line Items]      
Revolving Loans Converted to Term Loans 0   0
30-89 days past due | Other | Consumer      
Financing Receivable, Credit Quality Indicator [Line Items]      
Year one 2   3
Year two 2   2
Year three 2   1
Year four 1   1
Year five 1   0
Prior 1   0
Total 37   23
30-89 days past due | Other | Revolving Loans | Consumer      
Financing Receivable, Credit Quality Indicator [Line Items]      
Revolving Loans 27   15
30-89 days past due | Other | Revolving Loans Converted to Term Loans | Consumer      
Financing Receivable, Credit Quality Indicator [Line Items]      
Revolving Loans Converted to Term Loans 1   1
Accruing Loans Past Due 90 Days or More | Residential | Residential Real Estate      
Financing Receivable, Credit Quality Indicator [Line Items]      
Year one 0   1
Year two 2   8
Year three 10   21
Year four 27   126
Year five 158   90
Prior 437   297
Total 634   543
Accruing Loans Past Due 90 Days or More | Residential | Revolving Loans | Residential Real Estate      
Financing Receivable, Credit Quality Indicator [Line Items]      
Revolving Loans 0   0
Accruing Loans Past Due 90 Days or More | Residential | Revolving Loans Converted to Term Loans | Residential Real Estate      
Financing Receivable, Credit Quality Indicator [Line Items]      
Revolving Loans Converted to Term Loans 0   0
Accruing Loans Past Due 90 Days or More | Home equity lines and loans (e) | Consumer      
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
Total 0   0
Accruing Loans Past Due 90 Days or More | Home equity lines and loans (e) | Revolving Loans | Consumer      
Financing Receivable, Credit Quality Indicator [Line Items]      
Revolving Loans 0   0
Accruing Loans Past Due 90 Days or More | Home equity lines and loans (e) | Revolving Loans Converted to Term Loans | Consumer      
Financing Receivable, Credit Quality Indicator [Line Items]      
Revolving Loans Converted to Term Loans 0   0
Accruing Loans Past Due 90 Days or More | Recreational finance | Consumer      
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
Total 0   0
Accruing Loans Past Due 90 Days or More | Recreational finance | Revolving Loans | Consumer      
Financing Receivable, Credit Quality Indicator [Line Items]      
Revolving Loans 0   0
Accruing Loans Past Due 90 Days or More | Recreational finance | Revolving Loans Converted to Term Loans | Consumer      
Financing Receivable, Credit Quality Indicator [Line Items]      
Revolving Loans Converted to Term Loans 0   0
Accruing Loans Past Due 90 Days or More | Automobile | Consumer      
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
Total 0   0
Accruing Loans Past Due 90 Days or More | Automobile | Revolving Loans | Consumer      
Financing Receivable, Credit Quality Indicator [Line Items]      
Revolving Loans 0   0
Accruing Loans Past Due 90 Days or More | Automobile | Revolving Loans Converted to Term Loans | Consumer      
Financing Receivable, Credit Quality Indicator [Line Items]      
Revolving Loans Converted to Term Loans 0   0
Accruing Loans Past Due 90 Days or More | Other | Consumer      
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
Total 10   10
Accruing Loans Past Due 90 Days or More | Other | Revolving Loans | Consumer      
Financing Receivable, Credit Quality Indicator [Line Items]      
Revolving Loans 10   10
Accruing Loans Past Due 90 Days or More | Other | Revolving Loans Converted to Term Loans | Consumer      
Financing Receivable, Credit Quality Indicator [Line Items]      
Revolving Loans Converted to Term Loans 0   0
Nonaccrual | Residential | Residential Real Estate      
Financing Receivable, Credit Quality Indicator [Line Items]      
Year one 0   0
Year two 1   4
Year three 5   3
Year four 4   40
Year five 43   19
Prior 219   197
Total 272   264
Nonaccrual | Residential | Revolving Loans | Residential Real Estate      
Financing Receivable, Credit Quality Indicator [Line Items]      
Revolving Loans 0   1
Nonaccrual | Residential | Revolving Loans Converted to Term Loans | Residential Real Estate      
Financing Receivable, Credit Quality Indicator [Line Items]      
Revolving Loans Converted to Term Loans 0   0
Nonaccrual | Home equity lines and loans (e) | Consumer      
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 4   2
Total 84   82
Nonaccrual | Home equity lines and loans (e) | Revolving Loans | Consumer      
Financing Receivable, Credit Quality Indicator [Line Items]      
Revolving Loans 1   1
Nonaccrual | Home equity lines and loans (e) | Revolving Loans Converted to Term Loans | Consumer      
Financing Receivable, Credit Quality Indicator [Line Items]      
Revolving Loans Converted to Term Loans 79   79
Nonaccrual | Recreational finance | Consumer      
Financing Receivable, Credit Quality Indicator [Line Items]      
Year one 0   2
Year two 3   5
Year three 4   6
Year four 10   4
Year five 4   4
Prior 11   9
Total 32   30
Nonaccrual | Recreational finance | Revolving Loans | Consumer      
Financing Receivable, Credit Quality Indicator [Line Items]      
Revolving Loans 0   0
Nonaccrual | Recreational finance | Revolving Loans Converted to Term Loans | Consumer      
Financing Receivable, Credit Quality Indicator [Line Items]      
Revolving Loans Converted to Term Loans 0   0
Nonaccrual | Automobile | Consumer      
Financing Receivable, Credit Quality Indicator [Line Items]      
Year one 0   2
Year two 3   3
Year three 2   1
Year four 1   2
Year five 1   2
Prior 2   1
Total 9   11
Nonaccrual | Automobile | Revolving Loans | Consumer      
Financing Receivable, Credit Quality Indicator [Line Items]      
Revolving Loans 0   0
Nonaccrual | Automobile | Revolving Loans Converted to Term Loans | Consumer      
Financing Receivable, Credit Quality Indicator [Line Items]      
Revolving Loans Converted to Term Loans 0   0
Nonaccrual | Other | Consumer      
Financing Receivable, Credit Quality Indicator [Line Items]      
Year one 1   2
Year two 1   1
Year three 1   1
Year four 0   0
Year five 0   0
Prior 1   1
Total 4   5
Nonaccrual | Other | Revolving Loans | Consumer      
Financing Receivable, Credit Quality Indicator [Line Items]      
Revolving Loans 0   0
Nonaccrual | Other | Revolving Loans Converted to Term Loans | Consumer      
Financing Receivable, Credit Quality Indicator [Line Items]      
Revolving Loans Converted to Term Loans $ 0   $ 0
[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.