Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Document Type	dei_DocumentType	Other
Document Period End Date	dei_DocumentPeriodEndDate	Dec. 31, 2014
Registrant Name	dei_EntityRegistrantName	FIDELITY MUNICIPAL TRUST
Central Index Key	dei_EntityCentralIndexKey	0000035373
Amendment Flag	dei_AmendmentFlag	false
Document Creation Date	dei_DocumentCreationDate	Nov. 12, 2015
Document Effective Date	dei_DocumentEffectiveDate	Nov. 12, 2015
Prospectus Date	rr_ProspectusDate	Feb. 28, 2015