Document and Entity Information - USD ($)	12 Months Ended
	Mar. 31, 2018	May 09, 2018	Sep. 30, 2017
Document And Entity Information [Abstract]
Entity Registrant Name	MICROCHIP TECHNOLOGY INC
Entity Central Index Key	0000827054
Current Fiscal Year End Date	--03-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-K
Document Period End Date	Mar. 31, 2018
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Common Stock, Shares Outstanding		235,036,703
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 20,543,563,116