Document And Entity Information (USD $)	9 Months Ended
	Nov. 30, 2011	Aug. 31, 2010
Entity Registrant Name	STANDARD MICROSYSTEMS CORP
Entity Central Index Key	0000093384
Current Fiscal Year End Date	--02-28
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Accelerated Filer
Entity Public Float		$ 407,441,790
Entity Common Stock, Shares Outstanding	22,231,699
Document Fiscal Year Focus	2012
Document Fiscal Period Focus	Q3
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Nov. 30, 2011