Restructuring (Details) - USD ($) $ in Millions		3 Months Ended
		Apr. 30, 2016	Apr. 30, 2015	Apr. 30, 2016	Feb. 29, 2016	Jan. 31, 2016
Restructuring Reserve [Roll Forward]
Additions		$ 52.3	$ 0.0
Fiscal 2017 Plan
Restructuring Reserve [Roll Forward]
Beginning Balance		0.0
Additions		52.3
Payments		(39.4)
Adjustments	[1]	(1.9)
Ending Balance		11.0
Current portion	[2]			$ 10.7		$ 0.0
Non-current portion	[2]			0.3		0.0
Total Restructuring Reserve		0.0		11.0		0.0
Fiscal 2017 Plan | Employee termination costs
Restructuring Cost and Reserve [Line Items]
Expected cost					$ 76.0
Restructuring Reserve [Roll Forward]
Beginning Balance		0.0
Additions		47.6
Payments		(38.2)
Adjustments	[1]	0.0
Ending Balance		9.4
Total Restructuring Reserve		0.0		9.4		0.0
Fiscal 2017 Plan | Lease termination and asset costs
Restructuring Cost and Reserve [Line Items]
Expected cost					$ 12.0
Restructuring Reserve [Roll Forward]
Beginning Balance		0.0
Additions		4.7
Payments		(1.2)
Adjustments	[1]	(1.9)
Ending Balance		1.6
Total Restructuring Reserve		$ 0.0		$ 1.6		$ 0.0

[1] Adjustments include the impact of computer equipment, software, furniture, 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.