Segments - Concerning the Operations Of Reportable Segments (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Jan. 31, 2015	Oct. 31, 2014	Jul. 31, 2014	Apr. 30, 2014	Jan. 31, 2014	Oct. 31, 2013	Jul. 31, 2013	Apr. 30, 2013	Jan. 31, 2015		Jan. 31, 2014		Jan. 31, 2013
Segment Reporting Information [Line Items]
Net revenue	$ 664.6	$ 618.0	$ 637.1	$ 592.5	$ 586.6	$ 555.2	$ 561.7	$ 570.4	$ 2,512.2		$ 2,273.9		$ 2,312.2
Gross profit	575.1	532.0	549.2	513.8	514.7	488.1	493.9	502.9	2,170.1		1,999.6		2,073.7
Depreciation and Amortization									145.9		128.9		127.8
Architecture, Engineering, and Construction
Segment Reporting Information [Line Items]
Net revenue									872.6	[1]	730.6	[1]	701.1	[1]
Gross profit									785.8	[1]	663.8	[1]	642.0	[1]
Depreciation and Amortization									1.3		0.2		0.2
Platform Solutions and Emerging Business
Segment Reporting Information [Line Items]
Net revenue									796.7	[1]	789.2	[1]	843.0	[1]
Gross profit									712.3	[1]	716.8	[1]	788.8	[1]
Depreciation and Amortization									6.8		5.5		1.8
Manufacturing
Segment Reporting Information [Line Items]
Net revenue									675.6		579.4		573.8
Gross profit									604.0		531.5		531.3
Depreciation and Amortization									3.0		0.9		0.5
Media and Entertainment
Segment Reporting Information [Line Items]
Net revenue									167.3	[1]	174.7	[1]	194.3	[1]
Gross profit									127.3		137.8		156.5
Depreciation and Amortization									0.3		0.2		0.4
Unallocated
Segment Reporting Information [Line Items]
Gross profit									(59.3)	[2]	(50.3)	[2]	(44.9)	[2]
Depreciation and Amortization									$ 134.5		$ 122.1		$ 124.9

[1] Prior period segment revenue amounts have been updated to conform to the current period's presentation.

[2] Unallocated amounts primarily relate to corporate expenses and other costs and expenses that are managed outside the reportable segments, including stock-based compensation expense.