Stockholders' Equity - Additions to and Reclassifications out of Accumulated Other Comprehensive (Loss) Earnings (Detail) - USD ($) $ in Millions		3 Months Ended
		Apr. 30, 2016	Apr. 30, 2015
Equity [Abstract]
Foreign currency translation adjustments		$ 58.8	$ 3.8
Income tax expense		(7.1)	(0.2)
Foreign currency translation adjustments		51.7	3.6
Unrealized gain on marketable securities		1.8	1.5
Income tax expense		(0.6)	(0.4)
Unrealized gain on marketable securities		1.2	1.1
Unrealized gain (loss) on hedging instruments		8.0	(4.1)
Reclassification adjustment for gain included in net earnings	[1]	(0.4)	(2.8)
Income tax (expense) benefit		(3.3)	2.5
Unrealized gain (loss) on hedging instruments		4.3	(4.4)
Amortization of net loss included in net earnings	[2]	3.9	7.8
Amortization of prior service credit included in net earnings	[2]	(0.2)	(0.2)
Income tax expense		(1.4)	(2.9)
Net unrealized gain on benefit plans		2.3	4.7
Other comprehensive earnings, net of tax		$ 59.5	$ 5.0

[1] These gains are reclassified into Cost of sales and Interest and other expenses, net (see "Note 8. Hedging Instruments" for additional details).

[2] These accumulated other comprehensive income components are included in the computation of net periodic pension costs (see "Note 12. Employee Benefit Plans" for additional details).