CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Millions	12 Months Ended
	Jan. 31, 2019	Jan. 31, 2018	Jan. 31, 2017
Statement of Comprehensive Income [Abstract]
Net loss	$ (80.8)	$ (566.9)	$ (582.1)
Other comprehensive (loss) income, net of reclassifications:
Net gain (loss) on derivative instruments (net of tax effect of ($1.1), $3.2, and ($1.1))	31.6	(31.2)	(1.1)
Change in net unrealized gain (loss) on available-for-sale securities (net of tax effect of $0.0, $0.1, and ($0.5))	2.0	(0.2)	1.3
Change in defined benefit pension items (net of tax effect of ($2.0), ($0.7), and ($0.9))	13.0	4.5	(5.5)
Net change in cumulative foreign currency translation (loss) gain (net of tax effect of $0.5, ($4.8), and $0.2))	(57.8)	81.6	(52.1)
Total other comprehensive (loss) income	(11.2)	54.7	(57.4)
Total comprehensive loss	$ (92.0)	$ (512.2)	$ (639.5)