Document and Entity Information - shares	6 Months Ended
	Dec. 30, 2016	Feb. 03, 2017
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Dec. 30, 2016
Document Fiscal Year Focus	2017
Document Fiscal Period Focus	Q2
Entity Registrant Name	WESTERN DIGITAL CORP
Entity Central Index Key	0000106040
Current Fiscal Year End Date	--06-30
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		288,070,433