Interest and Other Expense, net (Details) - USD ($) $ in Millions	12 Months Ended
	Jan. 31, 2018	Jan. 31, 2017	Jan. 31, 2016
Interest and Other Income, net [Abstract]
Interest and investment expense, net	$ (34.5)	$ (29.7)	$ (33.9)
Loss on foreign currency	(3.3)	(3.3)	0.0
(Loss) gain on strategic investments	(16.4)	0.3	3.8
Other income	6.0	8.5	8.5
Interest and other expense, net	$ (48.2)	$ (24.2)	$ (21.6)