Balance Sheet Classifications of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Schedule Of Deferred Income Tax Assets And Liabilities [Line Items]
Deferred Tax Liabilities	$ (349.4)	$ (510.2)
Truck, Parts and Other | Other Noncurrent Assets
Schedule Of Deferred Income Tax Assets And Liabilities [Line Items]
Deferred Tax Assets Net	199.0	51.5
Truck, Parts and Other | Other liabilities
Schedule Of Deferred Income Tax Assets And Liabilities [Line Items]
Deferred Tax Liabilities	(75.5)	(91.5)
Financial Services | Other Assets
Schedule Of Deferred Income Tax Assets And Liabilities [Line Items]
Deferred Tax Assets Net	51.0	48.4
Financial Services | Deferred Taxes and Other Liabilities
Schedule Of Deferred Income Tax Assets And Liabilities [Line Items]
Deferred Tax Liabilities	$ (523.9)	$ (518.6)