Summary of Net Gain (Loss) on Foreign Exchange Forwards Not Designated as Hedging Instruments and on Interest Rate Swaps Designated as Fair Value Hedges (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Derivatives Designated as Accounting Hedges [Member] | Interest Rate Swap [Member] | Interest Income (Expense), Net [Member]
Derivative Instruments Gain Loss [Line Items]
Amount of gain (loss) recognized in income	$ 6.7	$ 11.2	$ 15.2
Derivatives Not Designated as Accounting Hedges [Member] | Foreign Exchange Forwards [Member] | Other Nonoperating Income (Expense) [Member]
Derivative Instruments Gain Loss [Line Items]
Amount of gain (loss) recognized in income	21.5	$ (7.2)	$ (2.8)
Bureau van Dijk (BvD) [Member] | Derivatives Not Designated as Accounting Hedges [Member] | Foreign Exchange Forwards [Member] | Purchase Price Hedge [Member]
Derivative Instruments Gain Loss [Line Items]
Amount of gain (loss) recognized in income	10.3
Bureau van Dijk (BvD) [Member] | Derivatives Not Designated as Accounting Hedges [Member] | Foreign Exchange Collar [Member] | Purchase Price Hedge [Member]
Derivative Instruments Gain Loss [Line Items]
Amount of gain (loss) recognized in income	$ 100.8