Interest And Other Income, net (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Jan. 31, 2015	Jan. 31, 2014	Jan. 31, 2013
Interest and Other Income, net [Abstract]
Interest and investment (expense) income, net	$ (13.2)	$ (9.8)	$ 4.9
(Loss) gain on foreign currency	(3.9)	4.0	1.2
Loss on strategic investments	(23.3)	(1.8)	(4.0)
Other income	2.7	2.7	2.0
Interest and other (expense) income, net	$ (37.7)	$ (4.9)	$ 4.1