Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Contingency [Line Items]
Undistributed earnings of foreign subsidiaries	$ 0.0
Valuation allowance	12.8	$ 3.2	$ 4.3	$ 6.9
Unrecognized Tax Benefits	389.1	199.8	$ 203.4	$ 220.3
Uncertain tax positions if recognized would impact the effective tax rate	353.0
Interest accrued on UTPs	$ 54.7	$ 34.1
Change to tax rate due to change in accounting principle	2.20%
Estimated Repriation Tax Liability Resulting from Tax Reform Legislation	$ 247.3
Estimated Repatriation Tax Liability Resulting from The Tax Act, Pay Period	8 years
U.S. statutory tax rate	35.00%	35.00%	35.00%
Tax Asset Resulting from Change in Non US Tax Rate under Tax Act	$ 57.9
Decrease in Net Deferred Tax Liabilities Under Tax Reform Legislation	56.2
Excess tax benefit effect of adoption adjustment on provision for income taxes	39.5
Bureau van Dijk (BvD) [Member]
Income Tax Contingency [Line Items]
Interest accrued on UTPs	5.6
Retained Earnings [Member]
Income Tax Contingency [Line Items]
Effect of Adoption Adjustments to retained earnings	4.6
UTPs
Income Tax Contingency [Line Items]
Net interest expense	$ 15.3	$ 7.8
Tax Reform [Member]
Income Tax Contingency [Line Items]
U.S. statutory tax rate	21.00%