Product Support Liabilities (Detail) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Product Liability Contingency [Line Items]
Warranty Reserves	$ 767.0	$ 437.7
Deferred Revenues	1,229.1	904.9
Truck, Parts and Other
Product Liability Contingency [Line Items]
Warranty Reserves	767.0	437.7	$ 344.3	$ 389.7
Truck, Parts and Other | Accounts payable, accrued expenses and other
Product Liability Contingency [Line Items]
Warranty Reserves	513.6	279.2
Deferred Revenues	354.2	263.7
Truck, Parts and Other | Other liabilities
Product Liability Contingency [Line Items]
Warranty Reserves	253.4	158.5
Deferred Revenues	861.4	628.8
Financial Services | Accounts payable, accrued expenses and other
Product Liability Contingency [Line Items]
Deferred Revenues	5.3	4.9
Financial Services | Deferred Taxes and Other Liabilities
Product Liability Contingency [Line Items]
Deferred Revenues	$ 8.2	$ 7.5