Document and Entity Information (USD $)
In Billions, except Share data, unless otherwise specified
6 Months Ended
Dec. 31, 2010
Jan. 19, 2011
Dec. 31, 2009
Document and Entity Information [Abstract]      
Entity Registrant Name WESTERN DIGITAL CORP    
Entity Central Index Key 0000106040    
Document Type 10-Q    
Document Period End Date Dec. 31, 2010    
Amendment Flag false    
Document Fiscal Year Focus 2011    
Document Fiscal Period Focus Q2    
Current Fiscal Year End Date --07-01    
Entity Well-known Seasoned Issuer Yes    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Filer Category Large Accelerated Filer    
Entity Public Float     $ 10.1
Entity Common Stock, Shares Outstanding (actual number)   231,667,319