| N-2 | Aug. 24, 2022 |
| Cover [Abstract] | |
| Entity Central Index Key | 0001282957 |
| Amendment Flag | false |
| Document Type | POS EX |
| Entity Registrant Name | GABELLI GLOBAL UTILITY & INCOME TRUST |
| 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 | 10580-1422 |
| City Area Code | 800 |
| Local Phone Number | 422-3554 |
| No Substantive Changes, 462(c) | false |
| Exhibits Only, 462(d) | true |
| Entity Well-known Seasoned Issuer | No |
| Entity Emerging Growth Company | false |
| Business Contact [Member] | |
| Cover [Abstract] | |
| 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 | 10580-1422 |
| Contact Personnel Name | John C. Ball |
