v3.26.3
Contractual Maturities on Marketable Debt Securities (Detail) - Truck, Parts and Other
$ in Millions
Sep. 30, 2026
USD ($)
Amortized Cost Maturities:  
Within one year $ 640.3
One to five years 2,638.1
Six to ten years 6.5
More than ten years 4.9
Marketable debt securities, Cost 3,289.8
Fair Value Maturities:  
Within one year 639.7
One to five years 2,591.7
Six to ten years 6.3
More than ten years 4.8
Fair Value $ 3,242.5