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FAIR VALUE OF FINANCIAL INSTRUMENTS - Valuation of UNG's securities using the fair value hierarchy (Details) - USD ($) | Mar. 31, 2025 | Dec. 31, 2024
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Short-Term Investments |  |
FAIR VALUE OF FINANCIAL INSTRUMENTS |  |
Fair value of securities | $ 145,950,000 | $ 532,370,156
United States Contracts |  |
FAIR VALUE OF FINANCIAL INSTRUMENTS |  |
Fair value of securities | 1,475,440 | 80,696,279
OTC Commodity Swap Contracts |  |
FAIR VALUE OF FINANCIAL INSTRUMENTS |  |
Fair value of securities | (1,631) | (2,205)
Level 1 | Short-Term Investments |  |
FAIR VALUE OF FINANCIAL INSTRUMENTS |  |
Fair value of securities | 145,950,000 | 532,370,156
Level 1 | United States Contracts |  |
FAIR VALUE OF FINANCIAL INSTRUMENTS |  |
Fair value of securities | 1,475,440 | 80,696,279
Level 2 | OTC Commodity Swap Contracts |  |
FAIR VALUE OF FINANCIAL INSTRUMENTS |  |
Fair value of securities | $ (1,631) | $ (2,205)

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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/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2E -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2E Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 + Details
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