Annual report pursuant to Section 13 and 15(d)

Document and Entity Information

Document and Entity Information (USD $)
12 Months Ended
Jun. 30, 2011
Jul. 21, 2011
Dec. 31, 2010
Document Information [Line Items]      
Document Type 10-K    
Amendment Flag false    
Document Period End Date Jun. 30, 2011
Document Fiscal Year Focus 2011    
Document Fiscal Period Focus Q4    
Entity Registrant Name KLA TENCOR CORP    
Entity Central Index Key 0000319201    
Entity Filer Category Large Accelerated Filer    
Current Fiscal Year End Date --06-30    
Entity Current Reporting Status Yes    
Entity Voluntary Filers No    
Entity Well-known Seasoned Issuer Yes    
Trading Symbol klac    
Entity Common Stock, Shares Outstanding   167,000,217  
Entity Public Float     $ 6,400,000,000