Changes in Accumulated Other Comprehensive Income (Loss) by Component (Detail) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	[1]			$ 9,706.1
Reclassified out of AOCI		$ 41.2	$ (25.8)	18.7	$ 1.5
Net other comprehensive income (loss)		100.9	(127.8)	(88.9)	(91.5)
Ending balance		10,184.4	9,962.7	10,184.4	9,962.7
Derivative Contracts
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance		1.1	(10.0)	(15.3)	2.0
Recorded into AOCI		(46.9)	20.0	14.5	(10.9)
Reclassified out of AOCI		32.4	(29.8)	(12.6)	(10.9)
Net other comprehensive income (loss)		(14.5)	(9.8)	1.9	(21.8)
Ending balance		(13.4)	(19.8)	(13.4)	(19.8)
Marketable Debt Securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance		15.5	6.3	6.1	(2.3)
Recorded into AOCI		0.4	0.3	10.6	9.0
Reclassified out of AOCI		(0.4)	(0.1)	(1.2)	(0.2)
Net other comprehensive income (loss)			0.2	9.4	8.8
Ending balance		15.5	6.5	15.5	6.5
Pension Plans
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance		(485.6)	(470.0)	(517.7)	(477.8)
Recorded into AOCI		(6.4)	4.2	2.4	3.5
Reclassified out of AOCI		9.2	4.1	32.5	12.6
Net other comprehensive income (loss)		2.8	8.3	34.9	16.1
Ending balance		(482.8)	(461.7)	(482.8)	(461.7)
Foreign Currency Translation
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance		(820.9)	(588.5)	(573.2)	(620.4)
Recorded into AOCI		112.6	(126.5)	(135.1)	(94.6)
Net other comprehensive income (loss)		112.6	(126.5)	(135.1)	(94.6)
Ending balance		(708.3)	(715.0)	(708.3)	(715.0)
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance		(1,289.9)	(1,062.2)	(1,100.1)	(1,098.5)
Recorded into AOCI		59.7	(102.0)	(107.6)	(93.0)
Reclassified out of AOCI		41.2	(25.8)	18.7	1.5
Net other comprehensive income (loss)		100.9	(127.8)	(88.9)	(91.5)
Ending balance		$ (1,189.0)	$ (1,190.0)	$ (1,189.0)	$ (1,190.0)

[1] The December 31, 2019 consolidated balance sheet has been derived from audited financial statements.