Accumulated Other Comprehensive Income - Changes in Components of Accumulated Other Comprehensive Income, Net of Tax (Detail) $ in Millions	6 Months Ended
	Jun. 30, 2018 USD ($)
Other Comprehensive Income Loss [Line Items]
Stockholders Equity, Beginning Balance	$ 11,735.8
AOCI before reclassifications	(61.6)
Reclassifications to retained earnings (Note 2)	(42.9)
Reclassifications to statement of earnings	24.7
Stockholders Equity, Ending Balance	12,043.1
Foreign Currency Translation [Member]
Other Comprehensive Income Loss [Line Items]
Stockholders Equity, Beginning Balance	121.5
AOCI before reclassifications	(83.0)
Reclassifications to retained earnings (Note 2)	(17.4)
Stockholders Equity, Ending Balance	21.1
Defined Benefit Plan Items [Member]
Other Comprehensive Income Loss [Line Items]
Stockholders Equity, Beginning Balance	(138.2)
AOCI before reclassifications	(3.8)
Reclassifications to retained earnings (Note 2)	(21.1)
Reclassifications to statement of earnings	5.8
Stockholders Equity, Ending Balance	(157.3)
Total AOCI [Member]
Other Comprehensive Income Loss [Line Items]
Stockholders Equity, Beginning Balance	(83.2)
Stockholders Equity, Ending Balance	(163.0)
Cash Flow Hedges [Member]
Other Comprehensive Income Loss [Line Items]
Stockholders Equity, Beginning Balance	(66.5)
AOCI before reclassifications	25.2
Reclassifications to retained earnings (Note 2)	(4.4)
Reclassifications to statement of earnings	18.9
Stockholders Equity, Ending Balance	$ (26.8)