Restructuring (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jul. 31, 2016	Jul. 31, 2015	Jul. 31, 2016	Jul. 31, 2015	Jul. 31, 2016	Feb. 29, 2016	Jan. 31, 2016
Restructuring Cost and Reserve [Line Items]
Restructuring costs expected completion date				2017
Restructuring Reserve [Roll Forward]
Beginning Balance				$ 0.0
Additions		$ 16.0	$ 0.0	68.3	$ 0.0
Payments				(50.7)
Adjustments	[1]			(5.4)
Ending Balance		12.2		12.2
Current portion	[2]					$ 10.3		$ 0.0
Non-current portion	[2]					1.9		0.0
Total Restructuring Reserve		12.2		0.0		12.2		0.0
Lease termination and other exit costs
Restructuring Reserve [Roll Forward]
Beginning Balance				0.0
Additions				7.4
Payments				(0.2)
Adjustments	[1]			(3.5)
Ending Balance		3.7		3.7
Total Restructuring Reserve		3.7		0.0		3.7		0.0
Fiscal 2017 Plan | Employee termination costs
Restructuring Cost and Reserve [Line Items]
Expected cost							$ 69.0
Restructuring Reserve [Roll Forward]
Beginning Balance				0.0
Additions		8.0		55.7
Payments				(48.4)
Adjustments	[1]			0.0
Ending Balance		7.3		7.3
Total Restructuring Reserve		7.3		0.0		7.3		0.0
Fiscal 2017 Plan | Lease termination and other exit costs
Restructuring Cost and Reserve [Line Items]
Expected cost							$ 10.0
Restructuring Reserve [Roll Forward]
Beginning Balance				0.0
Additions		0.6		5.2
Payments				(2.1)
Adjustments	[1]			(1.9)
Ending Balance		1.2		1.2
Total Restructuring Reserve		$ 1.2		$ 0.0		$ 1.2		$ 0.0

[1] Adjustments include the impact of computer equipment, software, furniture, straight-line rent and leasehold improvement write-offs, and foreign currency translation.

[2] The current and non-current portions of the reserve are recorded in the Condensed Consolidated Balance Sheets under “Other accrued liabilities” and “Other liabilities,” respectively.