Derivative Financial Instruments - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative assets	$ 97.7		$ 97.7		$ 137.3
Designated under hedge accounting
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative assets	92.7		$ 92.7		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 gain 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			6.2
losses reclassified out of AOCI into net income based on the probability that the original forecasted transaction would not occur	0.0	$ 0.0	0.3	$ 0.0
Interest-Rate Contracts
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional amount of outstanding contracts	3,394.9		3,394.9
Notional maturities for interest-rate contracts 2016	296.8		296.8
Notional maturities for interest-rate contracts 2017	740.2		740.2
Notional maturities for interest-rate contracts 2018	1,057.4		1,057.4
Notional maturities for interest-rate contracts 2019	962.3		962.3
Notional maturities for interest-rate contracts 2020	139.0		139.0
Notional maturities for interest-rate contracts thereafter	199.2		199.2
Interest-Rate Contracts | Financial Services | Designated under hedge accounting | Other Assets
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative assets	82.7		82.7		$ 132.2
Foreign-exchange contracts
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative notional amount outstanding	$ 593.5		$ 593.5
Foreign-exchange contracts maturity period			Within one year