CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jul. 31, 2018	Jul. 31, 2017	Jul. 31, 2018	Jul. 31, 2017
Statement of Comprehensive Income [Abstract]
Net loss	$ (39.4)	$ (144.0)	$ (121.8)	$ (273.6)
Other comprehensive (loss) income, net of reclassifications:
Net gain (loss) on derivative instruments (net of tax effect of ($1.1), $0.9, ($1.8), and $1.4, respectively)	11.6	(11.6)	17.6	(13.0)
Change in net unrealized (loss) gain on available-for-sale debt securities (net of tax effect of $(0.1), $0.4, $0.0 and $0.1, respectively)	(1.3)	(0.5)	(0.7)	0.2
Change in defined benefit pension items (net of tax effect of ($0.1), $0.0, ($1.5) and $0.0, respectively)	2.3	0.3	10.0	(0.2)
Net change in cumulative foreign currency translation (loss) gain (net of tax effect of $0.2, ($0.6), $0.5 and ($0.9), respectively)	(29.7)	25.2	(54.0)	38.6
Total other comprehensive (loss) income	(17.1)	13.4	(27.1)	25.6
Total comprehensive loss	$ (56.5)	$ (130.6)	$ (148.9)	$ (248.0)