Basis of Presentation Reclassification (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jul. 31, 2014	Jul. 31, 2013	Jul. 31, 2014	Jul. 31, 2013
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
(Decrease) to general and administrative	$ 71.5	$ 52.3	$ 134.0	$ 103.0
Increase to amortization of purchased intangibles	10.1	9.3	21.0	20.1
Reclassification of Amortization Of Intangible Assets
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
(Decrease) to general and administrative		(9.3)	(10.9)	(20.1)
Increase to amortization of purchased intangibles		$ 9.3	$ 10.9	$ 20.1