Segments Information Regarding Operations by Geographic Area and Product Family (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Oct. 31, 2016	Oct. 31, 2015	Oct. 31, 2016	Oct. 31, 2015
Segment Reporting Information [Line Items]
Net revenue	$ 489.6	$ 599.8	$ 1,552.2	$ 1,855.8
Operating Segments
Segment Reporting Information [Line Items]
Net revenue	489.6	599.8	1,552.2	1,855.8
Architecture, Engineering and Construction | Operating Segments
Segment Reporting Information [Line Items]
Net revenue	212.3	224.9	684.4	695.0
Manufacturing | Operating Segments
Segment Reporting Information [Line Items]
Net revenue	146.6	174.9	481.5	530.7
AutoCAD and AutoCAD LT Family | Operating Segments
Segment Reporting Information [Line Items]
Net revenue	80.1	143.6	239.1	451.7
Media and Entertainment | Operating Segments
Segment Reporting Information [Line Items]
Net revenue	34.2	39.1	103.6	119.8
Other | Operating Segments
Segment Reporting Information [Line Items]
Net revenue	16.4	17.3	43.6	58.6
Americas
Segment Reporting Information [Line Items]
Net revenue	213.3	235.8	661.1	715.5
Americas | U.S.
Segment Reporting Information [Line Items]
Net revenue	182.2	195.6	562.1	589.7
Americas | Other Americas
Segment Reporting Information [Line Items]
Net revenue	31.1	40.2	99.0	125.8
Europe, Middle East and Africa
Segment Reporting Information [Line Items]
Net revenue	191.0	225.1	614.1	696.2
Asia Pacific
Segment Reporting Information [Line Items]
Net revenue	85.3	138.9	277.0	444.1
Asia Pacific | Japan
Segment Reporting Information [Line Items]
Net revenue	28.7	49.0	102.8	164.8
Asia Pacific | Other Asia Pacific
Segment Reporting Information [Line Items]
Net revenue	$ 56.6	$ 89.9	$ 174.2	$ 279.3