CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Oct. 31, 2017	Oct. 31, 2016	Oct. 31, 2017	Oct. 31, 2016
Statement of Comprehensive Income [Abstract]
Net loss	$ (119.8)	$ (142.8)	$ (393.4)	$ (408.7)
Other comprehensive (loss) income, net of reclassifications:
Net loss on derivative instruments (net of tax effect of $0.3, $0.2, $1.7 and ($0.6), respectively)	(2.4)	(0.7)	(15.4)	(11.7)
Change in net unrealized gain (loss) on available-for-sale securities (net of tax effect of ($0.4), $0.0, ($0.3), and ($0.6), respectively)	0.2	(1.6)	0.4	1.8
Change in defined benefit pension items (net of tax effect of $0.0, $0.0, $0.0, and ($0.2), respectively)	0.2	0.3	0.0	0.6
Net change in cumulative foreign currency translation (loss) gain (net of tax effect of $0.0, ($0.5), ($0.9) and ($0.5), respectively)	(0.6)	(55.7)	38.0	(57.1)
Total other comprehensive (loss) income	(2.6)	(57.7)	23.0	(66.4)
Total comprehensive loss	$ (122.4)	$ (200.5)	$ (370.4)	$ (475.1)