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FAIR VALUE OF FINANCIAL INSTRUMENTS - Valuation of UNG's securities using the fair value hierarchy (Details) - USD ($) | Sep. 30, 2022 | Dec. 31, 2021
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Short-Term Investments |  |
Schedule of Trading Securities and Other Trading Assets |  |
Fair value of securities | $ 275,850,000 | $ 243,443,000
Exchange-Traded Futures Contracts | United States Contracts |  |
Schedule of Trading Securities and Other Trading Assets |  |
Fair value of securities | (101,887,101) | 1,362,413
Level 1 | Short-Term Investments |  |
Schedule of Trading Securities and Other Trading Assets |  |
Fair value of securities | 275,850,000 | 243,443,000
Level 1 | Exchange-Traded Futures Contracts | United States Contracts |  |
Schedule of Trading Securities and Other Trading Assets |  |
Fair value of securities | $ (101,887,101) | $ 1,362,413

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- Definition Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a) -URI https://asc.fasb.org/extlink&oid=126976982&loc=d3e19207-110258 + Details
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