Document and Entity Information - shares
3 Months Ended
Sep. 24, 2017
Oct. 19, 2017
Document And Entity Information [Abstract]    
Document Type 10-Q  
Amendment Flag false  
Document Period End Date Sep. 24, 2017  
Document Fiscal Year Focus 2018  
Document Fiscal Period Focus Q1  
Trading Symbol LRCX  
Entity Registrant Name LAM RESEARCH CORP  
Entity Central Index Key 0000707549  
Current Fiscal Year End Date --06-24  
Entity Filer Category Large Accelerated Filer  
Entity Common Stock, Shares Outstanding   161,946,248