XML 45 R30.htm IDEA: XBRL DOCUMENT v3.21.2

FAIR VALUE OF FINANCIAL INSTRUMENTS - Valuation of Securities Using Fair Value Hierarchy (Details) - USD ($)	Sep. 30, 2021	Dec. 31, 2020
Short-Term Investments [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Securities, fair value	$ 174,943,000	$ 21,143,000
Exchange-Traded Futures Contracts [Member] | United States Contracts [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Securities, fair value	30,233,070	(14,454,899)
Fair Value, Inputs, Level 1 [Member] | Short-Term Investments [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Securities, fair value	174,943,000	21,143,000
Fair Value, Inputs, Level 1 [Member] | Exchange-Traded Futures Contracts [Member] | United States Contracts [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Securities, fair value	30,233,070	(14,454,899)
Fair Value, Inputs, Level 2 [Member] | Short-Term Investments [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Securities, fair value	0	0
Fair Value, Inputs, Level 2 [Member] | Exchange-Traded Futures Contracts [Member] | United States Contracts [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Securities, fair value	0	0
Fair Value, Inputs, Level 3 [Member] | Short-Term Investments [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Securities, fair value	0	0
Fair Value, Inputs, Level 3 [Member] | Exchange-Traded Futures Contracts [Member] | United States Contracts [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Securities, fair value	$ 0	$ 0

X

- 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 http://asc.fasb.org/extlink&oid=123874694&loc=d3e19207-110258

+ Details

Name:	us-gaap_InvestmentsFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_ScheduleOfTradingSecuritiesAndOtherTradingAssetsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_ShortTermInvestmentsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_ForeignExchangeFutureMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	srt_StatementGeographicalAxis=ung_UnitedStatesContractsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: