Computer Equipment, Software, Furniture and Leasehold Improvements, Net (Details) (USD $) In Millions, unless otherwise specified	Oct. 31, 2014	Jan. 31, 2014
Property, Plant and Equipment [Line Items]
Computer software, hardware, leasehold improvements, furniture and equipment, gross	$ 499.9	$ 459.3
Less: Accumulated depreciation	(339.5)	(329.0)
Computer software, hardware, leasehold improvements, furniture and equipment, net	160.4	130.3
Computer software, at cost
Property, Plant and Equipment [Line Items]
Computer software, hardware, leasehold improvements, furniture and equipment, gross	84.6	80.9
Computer hardware, at cost
Property, Plant and Equipment [Line Items]
Computer software, hardware, leasehold improvements, furniture and equipment, gross	185.7	163.0
Leasehold improvements, land and buildings, at cost
Property, Plant and Equipment [Line Items]
Computer software, hardware, leasehold improvements, furniture and equipment, gross	180.0	163.7
Furniture and equipment, at cost
Property, Plant and Equipment [Line Items]
Computer software, hardware, leasehold improvements, furniture and equipment, gross	$ 49.6	$ 51.7