Computer Equipment, Software, Furniture and Leasehold Improvements, Net (Details) (USD $) In Millions, unless otherwise specified	Jul. 31, 2013	Jan. 31, 2013
Property, Plant and Equipment [Abstract]
Computer software, at cost	$ 98.1	$ 95.1
Computer hardware, at cost	159.1	152.3
Leasehold improvements, land and buildings, at cost	176.2	152.4
Furniture and equipment, at cost	51.6	46.0
Property, Plant and Equipment, Gross, Total	485.0	445.8
Less: Accumulated depreciation	(351.6)	(330.9)
Computer software, hardware, leasehold improvements, furniture and equipment, net	$ 133.4	$ 114.9