Document and Entity Information - USD ($)
$ in Billions
12 Months Ended
Jul. 01, 2016
Aug. 11, 2016
Dec. 31, 2015
Document Document And Entity Information [Abstract]      
Document Type 10-K    
Amendment Flag false    
Document Period End Date Jul. 01, 2016    
Document Fiscal Year Focus 2016    
Document Fiscal Period Focus FY    
Entity Registrant Name WESTERN DIGITAL CORP    
Entity Central Index Key 0000106040    
Current Fiscal Year End Date --07-01    
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   284,264,636  
Entity Public Float     $ 14