CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Oct. 31, 2014	Oct. 31, 2013	Oct. 31, 2014	Oct. 31, 2013
Statement of Comprehensive Income [Abstract]
Net income	$ 10.7	$ 57.6	$ 70.3	$ 174.9
Other comprehensive income, net of reclassifications:
Net gain (loss) on derivative instruments (net of tax effect of $0.5, $0.3, ($0.6) and $0.5)	21.1	(6.5)	19.6	(1.6)
Change in net unrealized (loss) gain on available-for-sale securities (net of tax effect of $0.7, ($0.2), $0.7 and ($0.2))	(0.5)	0.6	(2.1)	(0.3)
Net change in cumulative foreign currency translation (loss) gain (net of tax effect of $3.4, ($1.0), $2.9 and $1.0)	(24.2)	9.3	(18.2)	3.5
Total other comprehensive (loss) gain	(3.6)	3.4	(0.7)	1.6
Total comprehensive income	$ 7.1	$ 61.0	$ 69.6	$ 176.5