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Derivative Financial Instruments - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative assets	$ 65.8		$ 59.7
Truck, Parts and Other \| Derivative Contracts
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Pre-tax gain (loss) recognized in OCI	35.9
Fair Value Hedging
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Remaining cumulative basis adjustments on discontinued hedge relationship	$ 0.6		$ 0.1
Cash Flow Hedging
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Maximum length of future cash flow hedges	6 years 3 months 18 days
Accumulated net loss on derivative contracts included in accumulated other comprehensive loss expected to be recognized in the Consolidated Statements of Comprehensive Income in the following 12 months, net of tax	$ 2.3
Reclassification from AOCI	0.1	$ (0.1)
Net Investment Hedging
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative notional amount outstanding	347.0
Pre-tax gain (loss) recognized in OCI	18.2
Cost of sales and revenues
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Loss from commodity contracts	4.9
Interest-Rate Contracts
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional amount of outstanding contracts	2,968.8
Notional maturities for interest-rate contracts, remainder of 2022	791.4
Notional maturities for interest-rate contracts 2023	714.3
Notional maturities for interest-rate contracts 2024	552.1
Notional maturities for interest-rate contracts 2025	577.5
Notional maturities for interest-rate contracts 2026	217.4
Notional maturities for interest-rate contracts 2027	61.1
Notional maturities for interest-rate contracts thereafter	55.0
Interest-Rate Contracts \| Derivative Contracts
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Pre-tax gain (loss) recognized in OCI	19.9	33.7
Foreign-exchange contracts
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative notional amount outstanding	$ 2,223.0
Foreign-exchange contracts maturity period	within two years
Foreign-exchange contracts \| Derivative Contracts
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Pre-tax gain (loss) recognized in OCI	$ (28.9)	0.3
Foreign-exchange contracts \| Truck, Parts and Other \| Derivative Contracts
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Pre-tax gain (loss) recognized in OCI	(28.4)	$ 2.1
Commodity Contract
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative notional amount outstanding	$ 116.9
Foreign-exchange contracts maturity period	within one year