| Label | Element | Value |
|---|---|---|
| Prospectus: | rr_ProspectusTable | |
| Document Type | dei_DocumentType | 485BPOS |
| Document Period End Date | dei_DocumentPeriodEndDate | May 31, 2022 |
| Registrant Name | dei_EntityRegistrantName | JOHN HANCOCK MUNICIPAL SECURITIES TRUST |
| Central Index Key | dei_EntityCentralIndexKey | 0000857769 |
| Entity Inv Company Type | dei_EntityInvCompanyType | N-1A |
| Amendment Flag | dei_AmendmentFlag | false |
| Document Creation Date | dei_DocumentCreationDate | Jun. 07, 2022 |
| Document Effective Date | dei_DocumentEffectiveDate | Jun. 07, 2022 |
| Prospectus Date | rr_ProspectusDate | Jun. 07, 2022 |