Finance Receivables by Credit Quality Indicator and Portfolio Class (Detail) - Financial Services - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Financing Receivable, Recorded Investment [Line Items]
Financing Receivables	$ 8,797.7	$ 9,286.5
Performing
Financing Receivable, Recorded Investment [Line Items]
Financing Receivables	8,710.8	9,160.9
Watch
Financing Receivable, Recorded Investment [Line Items]
Financing Receivables	29.5	56.6
At-risk
Financing Receivable, Recorded Investment [Line Items]
Financing Receivables	57.4	69.0
Dealer | Wholesale
Financing Receivable, Recorded Investment [Line Items]
Financing Receivables	1,528.5	1,950.1
Dealer | Wholesale | Performing
Financing Receivable, Recorded Investment [Line Items]
Financing Receivables	1,519.3	1,922.4
Dealer | Wholesale | Watch
Financing Receivable, Recorded Investment [Line Items]
Financing Receivables	9.1	22.7
Dealer | Wholesale | At-risk
Financing Receivable, Recorded Investment [Line Items]
Financing Receivables	0.1	5.0
Dealer | Retail
Financing Receivable, Recorded Investment [Line Items]
Financing Receivables	1,406.0	1,561.3
Dealer | Retail | Performing
Financing Receivable, Recorded Investment [Line Items]
Financing Receivables	1,406.0	1,561.3
Dealer | Retail | Watch
Financing Receivable, Recorded Investment [Line Items]
Financing Receivables	0.0	0.0
Dealer | Retail | At-risk
Financing Receivable, Recorded Investment [Line Items]
Financing Receivables	0.0	0.0
Customer Retail | Fleet
Financing Receivable, Recorded Investment [Line Items]
Financing Receivables	4,928.7	4,761.4
Customer Retail | Fleet | Performing
Financing Receivable, Recorded Investment [Line Items]
Financing Receivables	4,863.4	4,680.6
Customer Retail | Fleet | Watch
Financing Receivable, Recorded Investment [Line Items]
Financing Receivables	14.9	27.0
Customer Retail | Fleet | At-risk
Financing Receivable, Recorded Investment [Line Items]
Financing Receivables	50.4	53.8
Customer Retail | Owner/Operator
Financing Receivable, Recorded Investment [Line Items]
Financing Receivables	934.5	1,013.7
Customer Retail | Owner/Operator | Performing
Financing Receivable, Recorded Investment [Line Items]
Financing Receivables	922.1	996.6
Customer Retail | Owner/Operator | Watch
Financing Receivable, Recorded Investment [Line Items]
Financing Receivables	5.5	6.9
Customer Retail | Owner/Operator | At-risk
Financing Receivable, Recorded Investment [Line Items]
Financing Receivables	$ 6.9	$ 10.2