Computer Equipment, Software, Furniture and Leasehold Improvements, Net (Details) (USD $) In Millions, unless otherwise specified	Jul. 31, 2014	Jan. 31, 2014
Property, Plant and Equipment [Line Items]
Computer software, hardware, leasehold improvements, furniture and equipment, gross	$ 498.8	$ 459.3
Less: Accumulated depreciation	(351.9)	(329.0)
Computer software, hardware, leasehold improvements, furniture and equipment, net	146.9	130.3
Computer software, at cost
Property, Plant and Equipment [Line Items]
Computer software, hardware, leasehold improvements, furniture and equipment, gross	86.4	80.9
Computer hardware, at cost
Property, Plant and Equipment [Line Items]
Computer software, hardware, leasehold improvements, furniture and equipment, gross	180.4	163.0
Leasehold improvements, land and buildings, at cost
Property, Plant and Equipment [Line Items]
Computer software, hardware, leasehold improvements, furniture and equipment, gross	174.8	163.7
Furniture and equipment, at cost
Property, Plant and Equipment [Line Items]
Computer software, hardware, leasehold improvements, furniture and equipment, gross	$ 57.2	$ 51.7