v3.26.3
Reclassifications Out of Accumulated Other Comprehensive Income (Detail) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Accumulated Other Comprehensive Income (Loss) [Line Items]        
Cost of sales and revenues $ 6,311.0 $ 5,345.4 $ 17,716.5 $ 17,231.8
Interest and other (income) expenses, net (26.5) (16.8) (64.1) 299.5
Interest and other borrowing expenses 181.5 201.0 544.2 591.9
Investment income 84.0 90.8 250.4 258.5
Income before income taxes 1,081.0 743.6 2,838.8 2,318.6
Tax (benefit) expense 233.5 153.6 634.0 499.7
Net Income 847.5 590.0 2,204.8 1,818.9
Reclassified out of AOCI (3.3) 3.7 75.9 169.6
Derivative Contracts        
Accumulated Other Comprehensive Income (Loss) [Line Items]        
Reclassified out of AOCI (4.3) 2.6 71.9 167.4
Derivative Contracts | Reclassification out of Accumulated Other Comprehensive Income        
Accumulated Other Comprehensive Income (Loss) [Line Items]        
Income before income taxes (7.0) 2.7 96.3 213.6
Tax (benefit) expense 2.7 (0.1) (24.4) (46.2)
Net Income (4.3) 2.6 71.9 167.4
Marketable Debt Securities        
Accumulated Other Comprehensive Income (Loss) [Line Items]        
Reclassified out of AOCI   0.4 0.8 0.4
Marketable Debt Securities | Reclassification out of Accumulated Other Comprehensive Income        
Accumulated Other Comprehensive Income (Loss) [Line Items]        
Investment income (0.1) 0.6 1.0 0.6
Tax (benefit) expense 0.1 (0.2) (0.2) (0.2)
Net Income   0.4 0.8 0.4
Truck, Parts and Other        
Accumulated Other Comprehensive Income (Loss) [Line Items]        
Net sales and revenues (7,377.6) (6,106.5) (20,608.9) (19,983.0)
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 2.3 1.1 8.1 5.1
Cost of sales and revenues 0.3 (12.2) 2.2 (23.0)
Interest and other (income) expenses, net (11.8) 10.8   41.0
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 (1.2) (0.6) (1.7) (1.4)
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 1.0 0.6 3.0 1.4
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 0.3 1.2 1.0
Truck, Parts and Other | Settlement loss | Reclassification out of Accumulated Other Comprehensive Income        
Accumulated Other Comprehensive Income (Loss) [Line Items]        
Income before income taxes 1.4 0.9 4.2 2.4
Tax (benefit) expense (0.4) (0.2) (1.0) (0.6)
Net Income 1.0 0.7 3.2 1.8
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 (3.4) 3.1 7.4 15.9
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 $ 6.8 $ 0.5 $ 80.3 $ 176.0