Document and Entity Information	6 Months Ended
	Dec. 28, 2014	Jan. 28, 2015
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Dec. 28, 2014
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q2
Trading Symbol	LRCX
Entity Registrant Name	LAM RESEARCH CORP
Entity Central Index Key	0000707549
Current Fiscal Year End Date	--06-28
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		159,316,108