| Cover | Jun. 28, 2024 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Jun. 28, 2024 |
| Entity File Number | 811-08476 |
| Entity Registrant Name | THE GABELLI MULTIMEDIA TRUST INC. |
| Entity Central Index Key | 0000921671 |
| Entity Tax Identification Number | 13-3767317 |
| Entity Incorporation, State or Country Code | MD |
| Entity Address, Address Line One | One Corporate Center |
| Entity Address, City or Town | Rye |
| Entity Address, State or Province | NY |
| Entity Address, Postal Zip Code | 10580 |
| City Area Code | 800 |
| Local Phone Number | 422-3554 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Shares of Beneficial Interest |
| Trading Symbol | GGT |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
