v3.10.0.1
Document and Entity Information - USD ($)
$ in Billions
12 Months Ended
Jun. 29, 2018
Aug. 15, 2018
Dec. 29, 2017
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-K    
Document Period End Date Jun. 29, 2018    
Document Fiscal Year Focus 2018    
Document Fiscal Period Focus FY    
Amendment Flag false    
Entity Common Stock, Shares Outstanding (in shares)   291,356,809  
Entity Well-known Seasoned Issuer Yes    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Public Float     $ 18.9