Accumulated Other Comprehensive Loss - Components of Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Beginning balance	$ 5,004.6	$ 13,991.2	$ 5,253.2	$ 14,181.3
Total other comprehensive loss, net of tax:	(116.8)	(46.9)	(125.3)	(211.4)
Ending balance	4,168.5	6,026.2	4,168.5	6,026.2
Cumulative Translation Adjustment
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Beginning balance			(492.6)
Other comprehensive income (loss) before reclassifications			(94.7)
Amounts reclassified to earnings			5.4
Total other comprehensive loss, net of tax:			(89.3)
Ending balance	(581.9)		(581.9)
Pension and Postretirement Costs
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Beginning balance			(398.1)
Other comprehensive income (loss) before reclassifications			(37.2)
Amounts reclassified to earnings			4.6
Total other comprehensive loss, net of tax:			(32.6)
Ending balance	(430.7)		(430.7)
Derivative Financial Instruments
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Beginning balance			(22.1)
Other comprehensive income (loss) before reclassifications			0.6
Amounts reclassified to earnings			(4.0)
Total other comprehensive loss, net of tax:			(3.4)
Ending balance	(25.5)		(25.5)
AOCL
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Beginning balance	(921.3)	(990.2)	(912.8)	(763.1)
Other comprehensive income (loss) before reclassifications			(131.3)
Amounts reclassified to earnings			6.0
Total other comprehensive loss, net of tax:			(125.3)
Ending balance	$ (1,038.1)	$ (1,037.1)	$ (1,038.1)	$ (1,037.1)