XML 40 R25.htm IDEA: XBRL DOCUMENT
v3.7.0.1

CONTRACTS AND AGREEMENTS (Additional Information) (Details) | 3 Months Ended
--- | ---
Mar. 31, 2017 USD ($) $ / Unit
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items] |
Annual Fee for custody, fund accounting and fund administration services | $ 20,000
Maximum [Member] |
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items] |
Transaction fees per transaction | $ / Unit | 15
Commissions per round-turn trade, including applicable exchange and NFA fees for Futures Contracts and options on Futures Contracts | $ / Unit | 8
Minimum [Member] |
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items] |
Annual Fee for custody, fund accounting and fund administration services | $ 75,000
Transaction fees per transaction | $ / Unit | 7
Commissions per round-turn trade, including applicable exchange and NFA fees for Futures Contracts and options on Futures Contracts | $ / Unit | 7
First $500 million of USNG's, USOF's, US12OF's, UGA's, USDHO's, USSO's, US12NG's, USBO's, USCI's, CPER's, USAG's and USMI's combined net assets [Member] |
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items] |
Fee percentage | 0.06%
First $500 million of USNG's, USOF's, US12OF's, UGA's, USDHO's, USSO's, US12NG's, USBO's, USCI's, CPER's, USAG's and USMI's combined net assets [Member] | Maximum [Member] |
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items] |
Base amount for determining fee percentage | $ 500,000,000
USNG's, USOF's, US12OF's, UGA's, USDHO's, USSO's, US12NG's, USBO's, USCI's, CPER's, USAG's and USMI's combined net assets greater than $500 million but less than $1 billion [Member] |
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items] |
Fee percentage | 0.0465%
Base amount for determining fee percentage | $ 1,000,000,000
USNG's, USOF's, US12OF's, UGA's, USDHO's, USSO's, US12NG's, USBO's, USCI's, CPER's, USAG's and USMI's combined net assets greater than $500 million but less than $1 billion [Member] | Maximum [Member] |
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items] |
Base amount for determining fee percentage | $ 500,000,000
USNG's, USOF's, US12OF's, UGA's, USDHO's, USSO's, US12NG's, USBO's, USCI's, CPER's, USAG's and USMI's combined net assets exceed $1 billion [Member] |
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items] |
Fee percentage | 0.035%
USNG's, USOF's, US12OF's, UGA's, USDHO's, USSO's, US12NG's, USBO's, USCI's, CPER's, USAG's and USMI's combined net assets exceed $1 billion [Member] | Maximum [Member] |
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items] |
Base amount for determining fee percentage | $ 1,000,000,000
Marketing Agreement [Member] |
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items] |
Fee percentage | 0.04%
Marketing Agreement [Member] | USNG's assets up to $3 billion [Member] |
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items] |
Fee percentage | 0.06%
Base amount for determining fee percentage | $ 3,000,000,000
Marketing Agreement [Member] | USNG's assets in excess of $3 billion [Member] |
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items] |
Ratio of expense to Average Net Assets | 10.00%
Marketing Agreement [Member] | USNG's assets in excess of $3 billion [Member] | Minimum [Member] |
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items] |
Base amount for determining fee percentage | $ 3,000,000,000

X
- Definition Base Fee Percentage + References No definition available. + Details
Name: | ung_BaseFeePercentage
Namespace Prefix: | ung_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Basis Amount for Fee Percentage + References No definition available. + Details
Name: | ung_BasisAmountForFeePercentage
Namespace Prefix: | ung_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Commissions Paid + References No definition available. + Details
Name: | ung_CommissionsPaid
Namespace Prefix: | ung_
Data Type: | us-types:perUnitItemType
Balance Type: | na
Period Type: | duration

X
- Definition Ratio Of Expenses To Average Net Assets + References No definition available. + Details
Name: | ung_RatioOfExpensesToAverageNetAssets
Namespace Prefix: | ung_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Transaction Fees Paid + References No definition available. + Details
Name: | ung_TransactionFeesPaid
Namespace Prefix: | ung_
Data Type: | us-types:perUnitItemType
Balance Type: | na
Period Type: | duration

X
- Definition Those fees charged for services related to holding, advising, and managing customer investment assets. These account fees usually charged annually or semi-annually, on a per security basis, for the costs of services. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.3) -URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688 + Details
Name: | us-gaap_CustodyFees
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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_LongDurationContractsAssumptionsByProductAndGuaranteeLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | invest_InvestmentIdentifierSchemeAxis=ung_GroupFiveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | invest_InvestmentIdentifierSchemeAxis=ung_GroupSixMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | invest_InvestmentIdentifierSchemeAxis=ung_GroupSevenMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_TypeOfArrangementAxis=ung_MarketingAgreementMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | invest_InvestmentIdentifierSchemeAxis=ung_GroupThreeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | invest_InvestmentIdentifierSchemeAxis=ung_GroupFourMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |