CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Millions	12 Months Ended
	Jan. 31, 2021	Jan. 31, 2020	Jan. 31, 2019
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 1,208.2	$ 214.5	$ (80.8)
Other comprehensive income (loss), net of reclassifications:
Net (loss) gain on derivative instruments (net of tax effect of $5.0, ($1.1), and ($1.1))	(32.5)	(6.6)	31.6
Change in net unrealized gain on available-for-sale securities (net of tax effect of $0.1, ($0.4), and $0.0)	1.7	1.4	2.0
Change in defined benefit pension items (net of tax effect of ($0.3), $1.6, and ($2.0))	1.5	(6.5)	13.0
Net change in cumulative foreign currency translation gain (loss) (net of tax effect of ($0.6), $0.1, and $0.5)	63.7	(13.6)	(57.8)
Total other comprehensive income (loss)	34.4	(25.3)	(11.2)
Total comprehensive income (loss)	$ 1,242.6	$ 189.2	$ (92.0)