Amount before tax and reclassification adjustments of other comprehensive income (loss).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 220
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-Section 45
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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-URI https://asc.fasb.org/1943274/2147481694/830-30-45-20

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-Topic 944
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Reference 7: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 220
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-URI https://asc.fasb.org/1943274/2147482765/220-10-50-4

Name:	us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsBeforeTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Pre-Tax Effects of Gain (Loss) on Cash Flow Hedges Recognized in OCI (Detail) - Derivative Contracts - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Interest-Rate Contracts
Derivative [Line Items]
Gain (loss) recognized in OCI	$ 56.9	$ (35.6)	$ 81.6	$ (77.9)
Foreign-exchange contracts
Derivative [Line Items]
Gain (loss) recognized in OCI	35.9	(44.5)	52.1	(65.6)
Commodity contracts
Derivative [Line Items]
Gain (loss) recognized in OCI	(8.4)	(2.0)	(13.0)	1.9
Truck, Parts and Other \| Foreign-exchange contracts
Derivative [Line Items]
Gain (loss) recognized in OCI	33.5	(47.1)	47.0	(67.2)
Truck, Parts and Other \| Commodity contracts
Derivative [Line Items]
Gain (loss) recognized in OCI	(8.4)	(2.0)	(13.0)	1.9
Financial Services \| Interest-Rate Contracts
Derivative [Line Items]
Gain (loss) recognized in OCI	56.9	(35.6)	81.6	(77.9)
Financial Services \| Foreign-exchange contracts
Derivative [Line Items]
Gain (loss) recognized in OCI	$ 2.4	$ 2.6	$ 5.1	$ 1.6