Accumulated Other Comprehensive Income - Changes in Components of Accumulated Other Comprehensive Income, Net of Tax (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2019 USD ($)
Other Comprehensive Income Loss [Line Items]
Stockholders Equity, Beginning Balance	$ 11,271.3
AOCI before reclassifications	(24.4)
Reclassifications to statements of earnings	(30.1)
Stockholders Equity, Ending Balance	12,388.1
Foreign Currency Translation [Member]
Other Comprehensive Income Loss [Line Items]
Stockholders Equity, Beginning Balance	(31.3)
AOCI before reclassifications	(1.5)
Stockholders Equity, Ending Balance	(32.8)
Defined Benefit Plan Items [Member]
Other Comprehensive Income Loss [Line Items]
Stockholders Equity, Beginning Balance	(177.0)
AOCI before reclassifications	(53.5)
Reclassifications to statements of earnings	5.0
Stockholders Equity, Ending Balance	(225.5)
Total AOCI [Member]
Other Comprehensive Income Loss [Line Items]
Stockholders Equity, Beginning Balance	(187.4)
Stockholders Equity, Ending Balance	(241.9)
Cash Flow Hedges [Member]
Other Comprehensive Income Loss [Line Items]
Stockholders Equity, Beginning Balance	20.9
AOCI before reclassifications	30.6
Reclassifications to statements of earnings	(35.1)
Stockholders Equity, Ending Balance	$ 16.4