v3.25.2
Cover - shares
 6 Months Ended
Jun. 30, 2025
Aug. 13, 2025
Document Information [Line Items]    
Document Type 10-Q  
Document Quarterly Report true  
Document Transition Report false  
Entity Interactive Data Current Yes  
Amendment Flag false  
Document Period End Date Jun. 30, 2025  
Document Fiscal Year Focus 2025  
Document Fiscal Period Focus Q2  
Entity Information [Line Items]    
Entity Registrant Name Energy Resources 12, L.P.  
Entity Central Index Key 0001696088  
Entity File Number 000-55916  
Entity Tax Identification Number 81-4805237  
Entity Incorporation, State or Country Code DE  
Current Fiscal Year End Date --12-31  
Entity Current Reporting Status Yes  
Entity Shell Company false  
Entity Filer Category Non-accelerated Filer  
Entity Small Business true  
Entity Emerging Growth Company false  
Entity Contact Personnel [Line Items]    
Entity Address, Address Line One 120 W 3rd Street, Suite 220  
Entity Address, City or Town Fort Worth  
Entity Address, State or Province TX  
Entity Address, Postal Zip Code 76102  
Entity Phone Fax Numbers [Line Items]    
City Area Code 817  
Local Phone Number 882-9192  
Entity Listings [Line Items]    
Title of 12(b) Security None  
Entity Common Stock, Shares Outstanding   11,031,579