Accumulated Other Comprehensive Income (Loss) - Components of Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	$ 14,181.3
Total other comprehensive income, net of tax	51.4	$ 96.1
Ending balance	14,167.3
Cumulative Translation Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(318.8)
Other comprehensive (loss) income before reclassifications	64.1
Total other comprehensive income, net of tax	64.1
Ending balance	(254.7)
Pension and Postretirement Costs [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(385.5)
Other comprehensive (loss) income before reclassifications	(19.2)
Amounts reclassified to earnings	2.9
Total other comprehensive income, net of tax	(16.3)
Ending balance	(401.8)
Derivative Financial Instruments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(58.8)
Other comprehensive (loss) income before reclassifications	(8.8)
Amounts reclassified to earnings	12.4
Total other comprehensive income, net of tax	3.6
Ending balance	(55.2)
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(763.1)
Other comprehensive (loss) income before reclassifications	36.1
Amounts reclassified to earnings	15.3
Total other comprehensive income, net of tax	51.4
Ending balance	$ (711.7)