Derivative Financial Instruments - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative assets	$ 115.4		$ 115.4		$ 137.3
Designated under hedge accounting
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative assets	110.3		$ 110.3		136.1
Cash Flow Hedging
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Maximum length of future cash flow hedges			4 years 10 months 24 days
Recognized gain (loss) on the ineffective portion	0.0	$ 0.0	$ 0.0	$ 0.0
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			0.2
Gains (losses) reclassified out of AOCI into net income based on the probability that the original forecasted transaction would not occur	0.3	0.0	(0.3)	0.0
Interest-Rate Contracts
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional amount of outstanding contracts	3,345.7		3,345.7
Notional maturities for interest-rate contracts 2016	500.8		500.8
Notional maturities for interest-rate contracts 2017	743.2		743.2
Notional maturities for interest-rate contracts 2018	1,058.1		1,058.1
Notional maturities for interest-rate contracts 2019	714.6		714.6
Notional maturities for interest-rate contracts 2020	139.4		139.4
Notional maturities for interest-rate contracts thereafter	189.6		189.6
(Income) Expense recognized in earnings	0.0	0.0	0.0	0.0
Interest-Rate Contracts | Financial Services | Designated under hedge accounting | Other Assets
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative assets	100.7		100.7		$ 132.2
Foreign-exchange contracts
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative notional amount outstanding	416.2		$ 416.2
Foreign-exchange contracts maturity period			Within one year
(Income) Expense recognized in earnings	$ (9.1)	$ (4.5)	$ (7.9)	$ (18.8)