Document and Entity Information (USD $)
In Billions, except Share data, unless otherwise specified
3 Months Ended
Sep. 30, 2011
Oct. 20, 2011
Dec. 31, 2010
Document and Entity Information [Abstract]      
Entity Registrant Name WESTERN DIGITAL CORP    
Entity Central Index Key 0000106040    
Document Type 10-Q    
Document Period End Date Sep. 30, 2011    
Amendment Flag false    
Document Fiscal Year Focus 2012    
Document Fiscal Period Focus Q1    
Current Fiscal Year End Date --06-29    
Entity Well-known Seasoned Issuer Yes    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Filer Category Large Accelerated Filer    
Entity Public Float     $ 7.9
Entity Common Stock, Shares Outstanding (actual number)   233,790,441