Changes in Accumulated Other Comprehensive Income (Loss) by Component (Detail) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	[1]	$ 8,592.9
Reclassified out of AOCI		14.8	$ 15.2
Net other comprehensive (loss) income		3.0	75.3
Ending balance		9,105.5	8,567.3
Derivative Contracts
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance		2.0	1.2
Recorded into AOCI		(22.7)	(11.8)
Reclassified out of AOCI		11.1	9.3
Net other comprehensive (loss) income		(11.6)	(2.5)
Ending balance		(9.6)	(1.3)
Marketable Debt Securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance		(2.3)	(1.8)
Recorded into AOCI		4.6	(1.7)
Reclassified out of AOCI			(0.3)
Net other comprehensive (loss) income		4.6	(2.0)
Ending balance		2.3	(3.8)
Pension Plans
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance		(477.8)	(375.6)
Recorded into AOCI		(3.1)	(4.2)
Reclassified out of AOCI		3.7	6.2
Net other comprehensive (loss) income		0.6	2.0
Ending balance		(477.2)	(373.6)
Foreign Currency Translation
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance		(620.4)	(417.4)
Recorded into AOCI		9.4	77.8
Net other comprehensive (loss) income		9.4	77.8
Ending balance		(611.0)	(339.6)
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance		(1,098.5)	(793.6)
Recorded into AOCI		(11.8)	60.1
Reclassified out of AOCI		14.8	15.2
Net other comprehensive (loss) income		3.0	75.3
Ending balance		$ (1,095.5)	$ (718.3)

[1] The December 31, 2018 consolidated balance sheet has been derived from audited financial statements.