Document and Entity Information - shares	9 Months Ended
	Mar. 30, 2018	May 01, 2018
Document And Entity Information [Abstract]
Entity Registrant Name	WESTERN DIGITAL CORP
Entity Central Index Key	0000106040
Current Fiscal Year End Date	--06-29
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	Mar. 30, 2018
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	Q3
Amendment Flag	false
Entity Common Stock, Shares Outstanding (in shares)		299,242,061
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes