| Document And Entity Information | May 26, 2022 |
| Document Information Line Items | |
| Entity Registrant Name | ENERGY RESOURCES 12, L.P |
| Document Type | 8-K |
| Amendment Flag | false |
| Entity Central Index Key | 0001696088 |
| Document Period End Date | May 26, 2022 |
| Entity Emerging Growth Company | true |
| Entity Ex Transition Period | true |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 000-55916 |
| Entity Tax Identification Number | 81-4805237 |
| Entity Address, Address Line One | 120 W 3rd Street, |
| Entity Address, Address Line Two | Suite 220 |
| Entity Address, City or Town | Fort Worth |
| Entity Address, State or Province | TX |
| Entity Address, Postal Zip Code | 76102 |
| City Area Code | (817) |
| Local Phone Number | 882-9192 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | None |
