Other Intangible Assets and Related Accumulated Amortization (Detail) (USD $) In Millions, unless otherwise specified	Apr. 30, 2013		Jan. 31, 2013
Finite-Lived Intangible Assets, Net [Abstract]
Purchased technologies at cost	$ 435.0		$ 431.0
Customer relationships and trade names, at cost	260.5	[1]	259.5	[1]
Finite-Lived Intangible Assets, Gross, Total	695.5		690.5
Less: Accumulated amortization	(566.8)		(546.3)
Other intangible assets, net	$ 128.7		$ 144.2

[1] Included in “Other assets” in the accompanying Condensed Consolidated Balance Sheets. Customer relationships and trade names include the effects of foreign currency translation.