Document and Entity Information - shares	6 Months Ended
	Jul. 31, 2017	Aug. 24, 2017
Document and Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jul. 31, 2017
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	Q2
Trading Symbol	ADSK
Entity Registrant Name	AUTODESK INC
Entity Central Index Key	0000769397
Current Fiscal Year End Date	--01-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		219,192,248