CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jul. 31, 2015	Jul. 31, 2014	Jul. 31, 2015	Jul. 31, 2014
Statement of Comprehensive Income [Abstract]
Net (loss) income		$ (235.5)	$ 31.3	$ (216.4)	$ 59.6
Other comprehensive (loss) income, net of reclassifications:
Net (loss) gain on derivative instruments (net of tax effect of $0.8, ($0.4), ($0.7) and ($1.1), respectively)		(4.7)	1.8	(10.1)	(1.5)
Change in net unrealized loss on available-for-sale securities (net of tax effect of $0.3, $0.4, $0.2 and $0.0, respectively)		(1.4)	(1.0)	(1.2)	(1.6)
Change in defined benefit pension items	[1]	0.3	0.0	1.0	0.0
Net change in cumulative foreign currency translation (loss) gain (net of tax effect of $0.7, $0.9, $4.5, and ($0.4), respectively)		(8.5)	(4.1)	(6.7)	6.0
Total other comprehensive (loss) income		(14.3)	(3.3)	(17.0)	2.9
Total comprehensive (loss) income		$ (249.8)	$ 28.0	$ (233.4)	$ 62.5

[1] Tax effects related to defined benefit pension items were immaterial for each of the periods presented.