Document and Entity Information (USD $)	12 Months Ended
	Jun. 30, 2011	Jul. 20, 2011	Dec. 31, 2010
Document Type	10-K
Amendment Flag	false
Document Period End Date	Jun. 30, 2011
Document Fiscal Year Focus	2011
Document Fiscal Period Focus	FY
Trading Symbol	MSFT
Entity Registrant Name	MICROSOFT CORP
Entity Central Index Key	0000789019
Current Fiscal Year End Date	--06-30
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Par Value Per Share	$ 0.00000625
Entity Common Stock, Shares Outstanding		8,378,265,782
Latest Practicable Date		Jul. 20, 2011
Entity Public Float			$ 208,370,414,170