XML 19 R4.htm IDEA: XBRL DOCUMENT
v3.21.1

Condensed Schedule of Investments (Parenthetical) | 3 Months Ended
--- | ---
Mar. 31, 2021 USD ($)
Expiration date | March 31, 2021
Collateral Amount On Open Commodity Futures Contracts | $ 18,801,522
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills, 0.04%, 5/06/2021 [Member] |
Interest rate | 0.04%
Expiration date | 5/06/2021
Cash Equivalents [Member] | Money Market Funds [Member] | Goldman Sachs Financial Square Government Fund Institutional Shares [Member] |
Investment Interest Rate | 0.04%
Cash Equivalents [Member] | Money Market Funds [Member] | Morgan Stanley Institutional Liquidity Funds Government Portfolio Institutional Shares [Member] |
Investment Interest Rate | 0.03%
Cash Equivalents [Member] | Money Market Funds [Member] | RBC U.S. Government Money Market Fund Institutional Shares [Member] |
Investment Interest Rate | 0.03%

X
- Definition The collateral amount on open future contracts. + References No definition available. + Details
Name: | ung_CollateralAmountOnOpenFuturesContracts
Namespace Prefix: | ung_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Contractual interest rate for funds borrowed, under the debt agreement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(1)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Rate of interest on investment. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=121645371&loc=d3e27232-111563 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=121645371&loc=d3e27161-111563 + Details
Name: | us-gaap_InvestmentInterestRate
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition The list of dates or date range within which the options may be exercised of the investment subject to option. + References Reference 1: 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(Footnote 8(d))) -URI http://asc.fasb.org/extlink&oid=120401592&loc=SL120429264-123010 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 946 -SubTopic 320 -Section S99 -Paragraph 6 -Subparagraph (SX 210.12-14.4(b)) -URI http://asc.fasb.org/extlink&oid=120401592&loc=d3e611322-123010 + Details
Name: | us-gaap_InvestmentOwnedSubjectToOptionExerciseDates
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_InvestmentTypeAxis=us-gaap_CashEquivalentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CashAndCashEquivalentsAxis=us-gaap_USTreasurySecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=ung_UsTreasuryBillsOneMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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: |