Financing Receivables by Aging Category (Detail) - Financial Services - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables, current and up to 30 days past due	$ 11,249.6	$ 10,745.4
Financing Receivables	11,303.4	10,780.0
31 - 60 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables, past due	33.0	18.0
Greater than 60 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables, past due	20.8	16.6
Dealer \| Wholesale
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables, current and up to 30 days past due	2,727.6	2,342.1
Financing Receivables	2,728.5	2,342.3
Dealer \| Retail
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables, current and up to 30 days past due	1,453.4	1,464.6
Financing Receivables	1,453.4	1,464.6
Dealer \| 31 - 60 days past due \| Wholesale
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables, past due	0.9	0.1
Dealer \| Greater than 60 days past due \| Wholesale
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables, past due		0.1
Customer Retail \| Fleet
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables, current and up to 30 days past due	5,983.6	5,835.6
Financing Receivables	6,022.5	5,857.5
Customer Retail \| Owner/Operator
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables, current and up to 30 days past due	1,085.0	1,103.1
Financing Receivables	1,099.0	1,115.6
Customer Retail \| 31 - 60 days past due \| Fleet
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables, past due	25.0	11.2
Customer Retail \| 31 - 60 days past due \| Owner/Operator
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables, past due	7.1	6.7
Customer Retail \| Greater than 60 days past due \| Fleet
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables, past due	13.9	10.7
Customer Retail \| Greater than 60 days past due \| Owner/Operator
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables, past due	$ 6.9	$ 5.8

Financing receivables that are current.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 7A
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953401-111524

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Recorded Investment in financing receivables that are past due at the balance sheet date.

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Amount representing an agreement for an unconditional promise by the maker to pay the entity (holder) a definite sum of money at a future date. Such amount may include accrued interest receivable in accordance with the terms of the note. The note also may contain provisions and related items including a discount or premium, payable on demand, secured, or unsecured, interest bearing or noninterest bearing, among a myriad of other features and characteristics. Excludes amounts related to receivables held-for-sale.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.10(3))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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