CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Millions	12 Months Ended
	Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2018
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 214.5	$ (80.8)	$ (566.9)
Other comprehensive income (loss), net of reclassifications:
Net (loss) gain on derivative instruments (net of tax effect of ($1.1), ($1.1), and $3.2)	(6.6)
Net (loss) gain on derivative instruments (net of tax effect of ($1.1), ($1.1), and $3.2)		31.6	(31.2)
Change in net unrealized gain (loss) on available-for-sale securities (net of tax effect of ($0.4), $0.0, and $0.1)	1.4	2.0	(0.2)
Change in defined benefit pension items (net of tax effect of $1.6, ($2.0), and ($0.7))	(6.5)	13.0	4.5
Net change in cumulative foreign currency translation (loss) gain (net of tax effect of $0.1, $0.5, and ($4.8))	(13.6)	(57.8)	81.6
Total other comprehensive (loss) income	(25.3)	(11.2)	54.7
Total comprehensive income (loss)	$ 189.2	$ (92.0)	$ (512.2)