v3.26.1
FAIR VALUE OF FINANCIAL INSTRUMENTS - Valuation of UNG's securities using the fair value hierarchy (Details) - USD ($)
Jun. 30, 2026
Dec. 31, 2025
Short-Term Investments    
FAIR VALUE OF FINANCIAL INSTRUMENTS    
Fair value of securities $ 240,250,000 $ 270,950,000
United States Contracts    
FAIR VALUE OF FINANCIAL INSTRUMENTS    
Fair value of securities 7,579,576 928,964
OTC Commodity Swap Contracts    
FAIR VALUE OF FINANCIAL INSTRUMENTS    
Fair value of securities (878) (907)
Level 1 | Short-Term Investments    
FAIR VALUE OF FINANCIAL INSTRUMENTS    
Fair value of securities 240,250,000 270,950,000
Level 1 | United States Contracts    
FAIR VALUE OF FINANCIAL INSTRUMENTS    
Fair value of securities 7,579,576 928,964
Level 2 | OTC Commodity Swap Contracts    
FAIR VALUE OF FINANCIAL INSTRUMENTS    
Fair value of securities $ (878) $ (907)