v3.26.1
Reclassifications Out of Accumulated Other Comprehensive Income (Detail) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Accumulated Other Comprehensive Income (Loss) [Line Items]        
Cost of sales and revenues $ 5,989.0 $ 5,995.4 $ 11,405.5 $ 11,886.4
Interest and other (income) expenses, net (16.3) (9.5) (37.6) 316.3
Interest and other borrowing expenses 179.9 200.3 362.7 390.9
Income before income taxes 981.5 931.9 1,757.8 1,575.0
Investment income 86.0 83.9 166.4 167.7
Tax (benefit) expense 229.5 208.1 400.5 346.1
Net Income 752.0 723.8 1,357.3 1,228.9
Reclassified out of AOCI 20.7 111.4 79.2 165.9
Derivative Contracts        
Accumulated Other Comprehensive Income (Loss) [Line Items]        
Reclassified out of AOCI 19.6 111.0 76.2 164.8
Derivative Contracts | Reclassification out of Accumulated Other Comprehensive Income        
Accumulated Other Comprehensive Income (Loss) [Line Items]        
Income before income taxes 26.1 142.7 103.3 210.9
Tax (benefit) expense (6.5) (31.7) (27.1) (46.1)
Net Income 19.6 111.0 76.2 164.8
Marketable Debt Securities        
Accumulated Other Comprehensive Income (Loss) [Line Items]        
Reclassified out of AOCI 0.2 0.1 0.8  
Marketable Debt Securities | Reclassification out of Accumulated Other Comprehensive Income        
Accumulated Other Comprehensive Income (Loss) [Line Items]        
Investment income 0.3 0.2 1.1  
Tax (benefit) expense (0.1) (0.1) (0.3)  
Net Income 0.2 0.1 0.8  
Truck, Parts and Other        
Accumulated Other Comprehensive Income (Loss) [Line Items]        
Net sales and revenues (6,997.0) (6,962.8) (13,231.3) (13,876.5)
Truck, Parts and Other | Derivative Contracts | Foreign-exchange contracts | Reclassification out of Accumulated Other Comprehensive Income        
Accumulated Other Comprehensive Income (Loss) [Line Items]        
Net sales and revenues 1.4 6.8 5.8 4.0
Cost of sales and revenues 0.2 (1.3) 1.9 (10.8)
Interest and other (income) expenses, net (4.9) 17.8 11.8 30.2
Truck, Parts and Other | Derivative Contracts | Commodity contracts | Reclassification out of Accumulated Other Comprehensive Income        
Accumulated Other Comprehensive Income (Loss) [Line Items]        
Cost of sales and revenues (0.6) (0.7) (0.5) (0.8)
Truck, Parts and Other | Actuarial loss | Reclassification out of Accumulated Other Comprehensive Income        
Accumulated Other Comprehensive Income (Loss) [Line Items]        
Interest and other (income) expenses, net 0.9 0.1 2.0 0.8
Truck, Parts and Other | Prior service costs | Reclassification out of Accumulated Other Comprehensive Income        
Accumulated Other Comprehensive Income (Loss) [Line Items]        
Interest and other (income) expenses, net 0.4 0.4 0.8 0.7
Truck, Parts and Other | Settlement loss | Reclassification out of Accumulated Other Comprehensive Income        
Accumulated Other Comprehensive Income (Loss) [Line Items]        
Income before income taxes 1.3 0.5 2.8 1.5
Tax (benefit) expense (0.4) (0.2) (0.6) (0.4)
Net Income 0.9 0.3 2.2 1.1
Financial Services | Derivative Contracts | Foreign-exchange contracts | Reclassification out of Accumulated Other Comprehensive Income        
Accumulated Other Comprehensive Income (Loss) [Line Items]        
Interest and other borrowing expenses 3.1 7.0 10.8 12.8
Financial Services | Derivative Contracts | Interest-Rate Contracts | Reclassification out of Accumulated Other Comprehensive Income        
Accumulated Other Comprehensive Income (Loss) [Line Items]        
Interest and other borrowing expenses $ 26.9 $ 113.1 $ 73.5 $ 175.5