v3.26.1
Finance Receivables within Credit Quality Indicator and Portfolio Class (Detail) - USD ($)
$ in Millions
 6 Months Ended 12 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Dec. 31, 2025
Financing Receivable Recorded Investment [Line Items]      
Revolving Loans $ 2,536.8   $ 2,669.3
2026 1,275.2   3,044.4
2025 2,761.6   2,393.2
2024 2,086.0   1,624.4
2023 1,355.0   859.5
2022 638.6   315.3
Prior 281.1   152.0
Total 10,934.3   11,058.1
Total 26.8 $ 27.8  
Dealer      
Financing Receivable Recorded Investment [Line Items]      
Revolving Loans 2,536.8   2,669.3
2026 183.4   517.9
2025 472.7   497.2
2024 440.7   444.0
2023 384.6   285.8
2022 247.0   127.5
Prior 170.1   106.7
Total 4,435.3   4,648.4
Dealer | Wholesale      
Financing Receivable Recorded Investment [Line Items]      
Revolving Loans 2,308.0   2,440.8
Total 2,308.0   2,440.8
Dealer | Wholesale | Performing      
Financing Receivable Recorded Investment [Line Items]      
Revolving Loans 2,308.0   2,437.6
Total 2,308.0   2,437.6
Dealer | Wholesale | Watch      
Financing Receivable Recorded Investment [Line Items]      
Revolving Loans     3.2
Total     3.2
Dealer | Retail      
Financing Receivable Recorded Investment [Line Items]      
Revolving Loans 228.8   228.5
2026 183.4   517.9
2025 472.7   497.2
2024 440.7   444.0
2023 384.6   285.8
2022 247.0   127.5
Prior 170.1   106.7
Total 2,127.3   2,207.6
Dealer | Retail | Performing      
Financing Receivable Recorded Investment [Line Items]      
Revolving Loans 228.8   228.5
2026 183.4   517.9
2025 472.7   497.2
2024 440.7   444.0
2023 384.6   285.8
2022 247.0   127.5
Prior 170.1   106.7
Total 2,127.3   2,207.6
Customer Retail      
Financing Receivable Recorded Investment [Line Items]      
2026 1,091.8   2,526.5
2025 2,288.9   1,896.0
2024 1,645.3   1,180.4
2023 970.4   573.7
2022 391.6   187.8
Prior 111.0   45.3
Total 6,499.0   6,409.7
Total 26.5 $ 27.8  
Customer Retail | Gross Charge-Offs      
Financing Receivable Recorded Investment [Line Items]      
Current Fiscal Year     0.2
Fiscal Year before Current Fiscal Year 3.6   7.4
Two Years before Current Fiscal Year 3.7   22.7
Three Years before Current Fiscal Year 9.4   11.2
Four Years before Current Fiscal Year 6.8   2.6
Prior 3.0   0.4
Total 26.5   44.5
Customer Retail | Fleet      
Financing Receivable Recorded Investment [Line Items]      
2026 955.6   2,247.3
2025 2,047.2   1,723.9
2024 1,502.2   1,109.5
2023 916.9   524.9
2022 360.6   162.8
Prior 98.1   39.9
Total 5,880.6   5,808.3
Customer Retail | Fleet | Performing      
Financing Receivable Recorded Investment [Line Items]      
2026 938.0   2,188.6
2025 1,965.5   1,693.1
2024 1,441.6   973.7
2023 769.6   463.2
2022 308.3   145.8
Prior 83.8   38.7
Total 5,506.8   5,503.1
Customer Retail | Fleet | Watch      
Financing Receivable Recorded Investment [Line Items]      
2026 15.8   48.3
2025 53.8   16.0
2024 17.6   51.6
2023 29.8   40.7
2022 25.9   14.8
Prior 10.8   0.6
Total 153.7   172.0
Customer Retail | Fleet | At-risk      
Financing Receivable Recorded Investment [Line Items]      
2026 1.8   10.4
2025 27.9   14.8
2024 43.0   84.2
2023 117.5   21.0
2022 26.4   2.2
Prior 3.5   0.6
Total 220.1   133.2
Customer Retail | Fleet | Gross Charge-Offs      
Financing Receivable Recorded Investment [Line Items]      
Fiscal Year before Current Fiscal Year 2.7   6.2
Two Years before Current Fiscal Year 3.1   21.2
Three Years before Current Fiscal Year 9.0   9.9
Four Years before Current Fiscal Year 6.0   2.4
Prior 2.9   0.2
Total 23.7   39.9
Customer Retail | Owner/Operator      
Financing Receivable Recorded Investment [Line Items]      
2026 136.2   279.2
2025 241.7   172.1
2024 143.1   70.9
2023 53.5   48.8
2022 31.0   25.0
Prior 12.9   5.4
Total 618.4   601.4
Customer Retail | Owner/Operator | Performing      
Financing Receivable Recorded Investment [Line Items]      
2026 135.8   275.6
2025 239.7   168.3
2024 140.8   68.3
2023 52.3   44.4
2022 29.9   23.7
Prior 12.2   5.0
Total 610.7   585.3
Customer Retail | Owner/Operator | Watch      
Financing Receivable Recorded Investment [Line Items]      
2026 0.4   2.4
2025 1.3   2.2
2024 0.9   1.8
2023 0.6   2.4
2022 0.5   0.9
Prior 0.2   0.2
Total 3.9   9.9
Customer Retail | Owner/Operator | At-risk      
Financing Receivable Recorded Investment [Line Items]      
2026     1.2
2025 0.7   1.6
2024 1.4   0.8
2023 0.6   2.0
2022 0.6   0.4
Prior 0.5   0.2
Total 3.8   6.2
Customer Retail | Owner/Operator | Gross Charge-Offs      
Financing Receivable Recorded Investment [Line Items]      
Current Fiscal Year     0.2
Fiscal Year before Current Fiscal Year 0.9   1.2
Two Years before Current Fiscal Year 0.6   1.5
Three Years before Current Fiscal Year 0.4   1.3
Four Years before Current Fiscal Year 0.8   0.2
Prior 0.1   0.2
Total $ 2.8   $ 4.6