XML 39 R24.htm IDEA: XBRL DOCUMENT
v3.7.0.1

CONTRACTS AND AGREEMENTS (Brokerage Commission) (Details) - USD ($) | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2017 | Jun. 30, 2016 | Jun. 30, 2017 | Jun. 30, 2016
Floor Brokerage Exchange and Clearance Fees | $ 380,958 | $ 522,847 | $ 800,656 | $ 1,085,522
Percentage Of Average Daily Net Assets | 0.34% | 0.42% | 0.34% | 0.42%
Rebalancing Investments Transaction [Member] |  |  |  |
Floor Brokerage Exchange and Clearance Fees |  |  | $ 647,003 | $ 1,030,262
Percentage Of Average Daily Net Assets | 80.81% | 94.91% | 80.81% | 94.91%
Creation And Redemption Activity [Member] |  |  |  |
Floor Brokerage Exchange and Clearance Fees |  |  | $ 153,653 | $ 55,260
Percentage Of Average Daily Net Assets | 19.19% | 5.09% | 19.19% | 5.09%

X
- Definition Percentage of Average Daily Net Assets + References No definition available. + Details
Name: | ung_PercentageOfAverageDailyNetAssets
Namespace Prefix: | ung_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition The amount of expense during the period for floor brokerage fees paid to other broker-dealers to execute trades on their behalf, stock exchange fees, order flow fees, and clearance fees. + References No definition available. + Details
Name: | us-gaap_FloorBrokerageExchangeAndClearanceFees
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_StatementClassOfStockAxis=ung_RebalancingInvestmentsTransactionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementClassOfStockAxis=ung_TradesNecessitatedByCreationAndRedemptionActivityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |