Finance Receivables by Credit Quality Indicator and Portfolio Class (Detail) (Financial Services, USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Financing Receivable, Recorded Investment [Line Items]
Financing Receivables	$ 8,820.1	$ 8,316.3
Pass
Financing Receivable, Recorded Investment [Line Items]
Financing Receivables	8,713.0	8,146.4
Special Mention
Financing Receivable, Recorded Investment [Line Items]
Financing Receivables	56.5	98.8
Substandard
Financing Receivable, Recorded Investment [Line Items]
Financing Receivables	50.6	71.1
Dealer wholesale financing
Financing Receivable, Recorded Investment [Line Items]
Financing Receivables	1,616.5	1,541.0
Dealer wholesale financing | Pass
Financing Receivable, Recorded Investment [Line Items]
Financing Receivables	1,576.9	1,479.1
Dealer wholesale financing | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Financing Receivables	31.1	58.3
Dealer wholesale financing | Substandard
Financing Receivable, Recorded Investment [Line Items]
Financing Receivables	8.5	3.6
Retail | Dealer
Financing Receivable, Recorded Investment [Line Items]
Financing Receivables	1,525.6	1,429.7
Retail | Dealer | Pass
Financing Receivable, Recorded Investment [Line Items]
Financing Receivables	1,520.1	1,423.3
Retail | Dealer | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Financing Receivables	5.5	6.3
Retail | Dealer | Substandard
Financing Receivable, Recorded Investment [Line Items]
Financing Receivables		0.1
Retail | Fleet
Financing Receivable, Recorded Investment [Line Items]
Financing Receivables	4,442.5	3,956.6
Retail | Fleet | Pass
Financing Receivable, Recorded Investment [Line Items]
Financing Receivables	4,396.5	3,878.4
Retail | Fleet | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Financing Receivables	12.7	23.5
Retail | Fleet | Substandard
Financing Receivable, Recorded Investment [Line Items]
Financing Receivables	33.3	54.7
Retail | Owner/operator
Financing Receivable, Recorded Investment [Line Items]
Financing Receivables	1,235.5	1,389.0
Retail | Owner/operator | Pass
Financing Receivable, Recorded Investment [Line Items]
Financing Receivables	1,219.5	1,365.6
Retail | Owner/operator | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Financing Receivables	7.2	10.7
Retail | Owner/operator | Substandard
Financing Receivable, Recorded Investment [Line Items]
Financing Receivables	$ 8.8	$ 12.7