Restructuring Reserve (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Jan. 31, 2013	Oct. 31, 2012	Jul. 31, 2012	Apr. 30, 2012	Jan. 31, 2012	Oct. 31, 2011	Jul. 31, 2011	Apr. 30, 2011	Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2011
Restructuring Cost and Reserve
Restructuring program, reduced the number of employees		500
Leased facilities that were consolidated		8
Restructuring (benefits) charges	$ 7.2	$ 36.7	$ 0	$ 0	$ 0	$ 0	$ (1.3)	$ 0	$ 43.9	$ (1.3)	$ 10.8
Other Restructuring [Member]
Restructuring Cost and Reserve
Restructuring (benefits) charges									43.9
One-time Termination Benefits [Member]
Restructuring Cost and Reserve
Restructuring (benefits) charges									40.6
Facility Closing [Member]
Restructuring Cost and Reserve
Restructuring (benefits) charges									3.3
Maximum | World Wide [Member]
Restructuring Cost and Reserve
Restructuring (benefits) charges		$ 52.0