FAIR VALUE OF FINANCIAL INSTRUMENTS - The Effect of Derivative Instruments on the Statements of Operations (Details) - USD ($)	6 Months Ended
Jun. 30, 2026	Jun. 30, 2025
FAIR VALUE OF FINANCIAL INSTRUMENTS
Change in Unrealized Gain (Loss) on Derivatives Recognized in Income	$ 6,650,612	$ (100,571,249)
Commodity Contracts \| Futures Contracts \| Location, Statement of Income, Balance [Axis]: us-gaap:GainLossOnSaleOfCommodityContracts
FAIR VALUE OF FINANCIAL INSTRUMENTS
Realized Gain (Loss) on Derivatives Recognized in Income	118,609,712	186,693,689
Commodity Contracts \| Futures Contracts \| Location, Statement of Income, Balance [Axis]: us-gaap:UnrealizedGainLossOnCommodityContracts
FAIR VALUE OF FINANCIAL INSTRUMENTS
Change in Unrealized Gain (Loss) on Derivatives Recognized in Income	6,650,612	(100,571,249)
Commodity Contracts \| OTC Commodity Swap Contracts \| Location, Statement of Income, Balance [Axis]: ung:ChangeInUnrealizedGainLossOnOpenOtcCommoditySwapContracts
FAIR VALUE OF FINANCIAL INSTRUMENTS
Change in Unrealized Gain (Loss) on Derivatives Recognized in Income	29	1,024
Commodity Contracts \| OTC Commodity Swap Contracts \| Location, Statement of Income, Balance [Axis]: ung:RealizedGainLossOnClosedOtcCommoditySwapContracts
FAIR VALUE OF FINANCIAL INSTRUMENTS
Realized Gain (Loss) on Derivatives Recognized in Income	$ (5,164,131)	$ (5,978,323)

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- Definition

The net realized gain (loss) on investments sold during the period, not including gains (losses) on securities separately or otherwise categorized as trading, available-for-sale, or held-to-maturity, which, for cash flow reporting, is a component of proceeds from investing activities.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 45
-Paragraph 28
-Subparagraph (b)
-SubTopic 10
-Topic 230
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-28

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- Definition

The net change in the difference between the fair value and the carrying value, or in the comparative fair values, of open derivatives, commodity, or energy contracts, held at each balance sheet date, that was included in earnings for the period.

+ References

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