XML 18 R3.htm IDEA: XBRL DOCUMENT v3.21.2

Condensed Schedule of Investments	Jun. 30, 2021 USD ($)
Fair Value/ Unrealized Gain (Loss) on Open Commodity Contracts	$ 27,568,962
Money Market Funds [Member]
Market Value	$ 177,943,000
% of Partners' Capital	64.05%
Money Market Funds [Member] | Goldman Sachs Financial Square Government Fund Institutional Shares [Member]
Shares/Principal Amount	$ 1,103,000
Market Value	$ 1,103,000
% of Partners' Capital	0.40%
Money Market Funds [Member] | Morgan Stanley Institutional Liquidity Funds Government Portfolio Institutional Shares [Member]
Shares/Principal Amount	$ 166,300,000
Market Value	$ 166,300,000
% of Partners' Capital	59.86%
Money Market Funds [Member] | RBC U.S. Government Money Market Fund Institutional Shares [Member]
Shares/Principal Amount	$ 10,540,000
Market Value	$ 10,540,000
% of Partners' Capital	3.79%
Open Commodity Futures Contracts, Long [Member] | United States Contracts | NYMEX Natural Gas Futures NG May 2021 contracts, expiring April 2021
Notional Amount	$ 250,269,038	[1]
Number of Contracts	7,612	[1]
Fair Value/ Unrealized Gain (Loss) on Open Commodity Contracts	$ 27,568,962	[1]
% of Partners' Capital	9.92%	[1]
[1] Collateral amounted to $50,000,000 on open commodity futures contracts.

X

- Definition

Percentage of Partners Capital

+ References

No definition available.

+ Details

Name:	ung_PercentageOfPartnersCapital
Namespace Prefix:	ung_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Unrealized gain (loss) on open commodity futures and cleared swap contracts.

+ References

No definition available.

+ Details

Name:	ung_UnrealizedGainLossOnOpenCommodityFuturesAndClearedSwapContracts
Namespace Prefix:	ung_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Value of the investment at close of period. For schedules of investments that are categorized, the value would be aggregated by category. For investment in and advances to affiliates, if operations of any controlled companies are different in character from those of the company, group such affiliates within divisions and by type of activities.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 210
-Section 50
-Paragraph 6
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=99383244&loc=d3e12121-115841

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 320
-Section S99
-Paragraph 5D
-Subparagraph (SX 210.12-13D(Column C))
-URI http://asc.fasb.org/extlink&oid=120401592&loc=SL120429264-123010

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 320
-Section S99
-Paragraph 3
-Subparagraph (SX 210.12-12B(Column C))
-URI http://asc.fasb.org/extlink&oid=120401592&loc=d3e611197-123010

+ Details

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

X

- Definition

Balance held at close of period in number of contracts.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 320
-Section S99
-Paragraph 6
-Subparagraph (SX 210.12-14.Column B)
-URI http://asc.fasb.org/extlink&oid=120401592&loc=d3e611322-123010

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 320
-Section S99
-Paragraph 3
-Subparagraph (SX 210.12-12B(Column B))
-URI http://asc.fasb.org/extlink&oid=120401592&loc=d3e611197-123010

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 320
-Section S99
-Paragraph 1
-Subparagraph (SX 210.12-12.Column B)
-URI http://asc.fasb.org/extlink&oid=120401592&loc=d3e611133-123010

+ Details

Name:	us-gaap_InvestmentOwnedBalanceContracts
Namespace Prefix:	us-gaap_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant

X

- Definition

For investments which are quantified by principal amount, the principle balance held at close of period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 210
-Section 50
-Paragraph 6
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=99383244&loc=d3e12121-115841

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 320
-Section S99
-Paragraph 3
-Subparagraph (SX 210.12-12B(Column B))
-URI http://asc.fasb.org/extlink&oid=120401592&loc=d3e611197-123010

+ Details

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

X

- Definition

Nominal or face amount on the investment owned.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 20
-Section 10
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6438156&loc=d3e57880-113973

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 10
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6431724&loc=d3e32938-113948

+ Details

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

X

- Details

Name:	us-gaap_CashAndCashEquivalentsAxis=us-gaap_MoneyMarketFundsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=ung_GoldmanSachsFinancialSquareGovernmentFundInstitutionalSharesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=ung_MorganStanleyInstitutionalLiquidityFundsGovernmentPortfolioInstitutionalSharesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=ung_RbcU.s.GovernmentMoneyMarketFundInstitutionalSharesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_InvestmentTypeAxis=ung_OpenCommodityFuturesContractsLongMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

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

X

- Details

Name:	srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=ung_NymexNaturalGasFuturesNgMay2021ContractsExpiringApril2021Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: