Computer Equipment, Software, Furniture and Leasehold Improvements, Net (Details) - USD ($) $ in Millions	Oct. 31, 2015	Jan. 31, 2015
Property, Plant and Equipment [Line Items]
Computer software, hardware, leasehold improvements, furniture and equipment, gross	$ 523.4	$ 508.2
Less: Accumulated depreciation	(368.1)	(349.0)
Computer software, hardware, leasehold improvements, furniture and equipment, net	155.3	159.2
Computer hardware, at cost
Property, Plant and Equipment [Line Items]
Computer software, hardware, leasehold improvements, furniture and equipment, gross	198.9	194.0
Computer software, at cost
Property, Plant and Equipment [Line Items]
Computer software, hardware, leasehold improvements, furniture and equipment, gross	79.8	84.9
Leasehold improvements, land and buildings, at cost
Property, Plant and Equipment [Line Items]
Computer software, hardware, leasehold improvements, furniture and equipment, gross	187.5	176.3
Furniture and equipment, at cost
Property, Plant and Equipment [Line Items]
Computer software, hardware, leasehold improvements, furniture and equipment, gross	$ 57.2	$ 53.0