United States Natural Gas Fund (UNG) 10-Q 10 Nov 14 2014 Q3 Quarterly report Financial data

Document_And_Entity_Informatio

Document And Entity Information	9 Months Ended
	Sep. 30, 2014
Document Information [Line Items]	'
Document Type	'10-Q
Amendment Flag	'false
Document Period End Date	30-Sep-14
Document Fiscal Year Focus	'2014
Document Fiscal Period Focus	'Q3
Entity Registrant Name	'United States Natural Gas Fund, LP
Entity Central Index Key	'0001376227
Current Fiscal Year End Date	'--12-31
Entity Filer Category	'Large Accelerated Filer
Trading Symbol	'UNG
Entity Common Stock, Shares Outstanding	0

Condensed_Statements_of_Financ

Condensed Statements of Financial Condition (USD $)	Sep. 30, 2014	Dec. 31, 2013
Assets	'	'
Cash and cash equivalents (Notes 2 and 5)	$654,210,103	$792,445,608
Equity in trading accounts:	'	'
Cash and cash equivalents	64,810,509	24,147,579
Unrealized gain (loss) on open commodity futures contracts	19,351,110	-14,033,910
Unrealized loss on open swap contracts	0	-6,654,820
Receivable for shares sold	0	159,392,268
Dividends receivable	7,407	8,580
Directors' fees receivable	939	0
Other assets	764,517	19,044
Total assets	739,144,585	955,324,349
Liabilities and Partners' Capital	'	'
Payable for shares redeemed	31,064,894	14,887,362
Professional fees payable	1,154,378	1,454,406
General Partner management fees payable (Note 3)	354,115	473,547
Brokerage commissions payable	72,750	81,750
Other liabilities	27,284	45,120
Total liabilities	32,673,421	16,942,185
Commitments and Contingencies (Notes 3, 4 and 5)	'	'
Partners' Capital	'	'
General Partner	0	0
Limited Partners	706,471,164	938,382,164
Total Partners' Capital	706,471,164	938,382,164
Total liabilities and partners' capital	$739,144,585	$955,324,349
Limited Partners' shares outstanding	31,966,476	45,566,476
Net asset value per share	$22.10	$20.59
Market value per share	$22.11	$20.69

Condensed_Schedule_of_Investme

Condensed Schedule of Investments (USD $)	Sep. 30, 2014
Unrealized Gain on Open Commodity Futures Contracts	$19,351,110
Open Futures Contracts, Long [Member] | United States [Member] | ICE Natural Gas Futures LD1 H November 2014 contracts, expiring October 2014	'
Number of Contracts	31,872
Unrealized Gain on Open Commodity Futures Contracts	8,590,520
% of Partners' Capital	1.22%
Open Futures Contracts, Long [Member] | United States [Member] | NYMEX Natural Gas Futures NG November 2014 contracts, expiring October 2014	'
Number of Contracts	9,175
Unrealized Gain on Open Commodity Futures Contracts	10,760,590
% of Partners' Capital	1.52%
Total Open Futures Contracts [Member] | Open Futures Contracts, Long [Member] | United States [Member]	'
Number of Contracts	41,047	[1]
Unrealized Gain on Open Commodity Futures Contracts	19,351,110	[1]
% of Partners' Capital	2.74%	[1]
Cash Equivalents [Member] | United States [Member]	'
Market Value	570,484,681
% of Partners' Capital	80.75%
Cash Equivalents [Member] | United States [Member] | US Treasury Securities [Member]	'
Market Value	299,978,930
% of Partners' Capital	42.46%
Cash Equivalents [Member] | United States [Member] | US Treasury Securities [Member] | U.S. Treasury Bills, 0.04%, 10/30/2014 [Member]	'
Principal Amount	200,000,000
Market Value	199,993,555
% of Partners' Capital	28.30%
Cash Equivalents [Member] | United States [Member] | US Treasury Securities [Member] | U.S. Treasury Bills, 0.05%, 12/26/2014 [Member]	'
Principal Amount	50,000,000
Market Value	49,994,625
% of Partners' Capital	7.08%
Cash Equivalents [Member] | United States [Member] | US Treasury Securities [Member] | U.S. Treasury Bills,0.05%, 2/26/2015 [Member]	'
Principal Amount	50,000,000
Market Value	49,990,750
% of Partners' Capital	7.08%
Cash Equivalents [Member] | United States [Member] | Money Market Funds [Member]	'
Market Value	270,505,751
% of Partners' Capital	38.29%
Cash Equivalents [Member] | United States [Member] | Money Market Funds [Member] | Goldman Sachs Financial Square Funds - Government Fund - Class FS [Member]	'
Principal Amount	8,087
Market Value	8,087
% of Partners' Capital	0.00%	[2]
Cash Equivalents [Member] | United States [Member] | Money Market Funds [Member] | Morgan Stanley Institutional Liquidity Funds - Government Portfolio [Member]	'
Principal Amount	200,495,952
Market Value	200,495,952
% of Partners' Capital	28.38%
Cash Equivalents [Member] | United States [Member] | Money Market Funds [Member] | Wells Fargo Advantage Government Money Market Fund - Class I [Member]	'
Principal Amount	70,001,712
Market Value	$70,001,712
% of Partners' Capital	9.91%
[1]	Collateral amounted to $64,810,509 on open future contracts.
[2]	Represents less than 0.005%.

Condensed_Schedule_of_Investme1

Condensed Schedule of Investments (Parenthetical) (USD $)	9 Months Ended
	Sep. 30, 2014
Swap transaction as a percentage of total asset	0.01%
Collateral Amount On Open Futures Contracts	64,810,509
U.S. Treasury Bills, 0.04%, 10/30/2014 [Member] | US Treasury Securities [Member] | Cash Equivalents [Member]	'
Interest rate	0.04%
Expiration date	'10/30/2014
U.S. Treasury Bill, 0.05%, 12/26/2014 [Member] | US Treasury Securities [Member] | Cash Equivalents [Member]	'
Interest rate	0.05%
Expiration date	'12/26/2014
U.S. Treasury Bills,0.05%, 2/26/2015 [Member] | US Treasury Securities [Member] | Cash Equivalents [Member]	'
Interest rate	0.05%
Expiration date	'2/26/2015
United States [Member] | ICE Natural Gas Futures LD1 H November 2014 contracts, expiring October 2014 | Open Futures Contracts, Long [Member]	'
Expiration date	'October 2014
United States [Member] | NYMEX Natural Gas Futures NG November 2014 contracts, expiring October 2014 | Open Futures Contracts, Long [Member]	'
Expiration date	'October 2014

Condensed_Statements_of_Operat

Condensed Statements of Operations (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Gain (loss) on trading of commodity futures contracts:	'	'	'	'
Realized gain (loss) on closed futures contracts	($120,447,892)	($7,662,805)	$40,248,943	$69,898,707
Realized gain (loss) on closed swap contracts	0	-14,494,336	25,690,444	-6,290,828
Change in unrealized gain (loss) on open futures contracts	55,629,167	-2,591,930	33,385,020	-32,409,377
Change in unrealized gain on open swap contracts	0	11,245,517	6,654,820	3,864,997
Dividend income	21,981	28,790	66,823	100,407
Interest income	38,039	40,717	142,476	141,104
Other income	41,000	51,000	168,000	173,000
Total income (loss)	-64,717,705	-13,383,047	106,356,526	35,478,010
Expenses	'	'	'	'
General Partner management fees (Note 3)	1,040,973	1,392,568	3,273,416	4,317,497
Professional fees	399,377	415,870	1,230,020	1,313,124
Brokerage commissions	462,183	615,823	1,485,185	1,814,781
Other expenses	146,890	86,424	392,301	255,998
Total expenses	2,049,423	2,510,685	6,380,922	7,701,400
Net income (loss)	($66,767,128)	($15,893,732)	$99,975,604	$27,776,610
Net income (loss) per limited partnership share	($2.48)	($0.59)	$1.51	($0.57)
Net income (loss) per weighted average limited partnership share	($2.10)	($0.32)	$3.22	$0.57
Weighted average limited partnership shares outstanding	31,767,563	49,127,346	31,086,989	48,795,780

Condensed_Statement_of_Changes

Condensed Statement of Changes in Partners' Capital (USD $)	Total	General Partner [Member]	Limited Partners [Member]
Balances at Dec. 31, 2013	$938,382,164	$0	$938,382,164
Net asset value, beginning of period at Dec. 31, 2013	$20.59	'	'
Addition of 86,500,000 partnership shares	2,082,263,899	0	2,082,263,899
Redemption of 100,100,000 partnership shares	-2,414,150,503	0	-2,414,150,503
Net income	99,975,604	0	99,975,604
Balances at Sep. 30, 2014	$706,471,164	$0	$706,471,164
Net asset value, end of period at Sep. 30, 2014	$22.10	'	'

Condensed_Statement_of_Changes1

Condensed Statement of Changes in Partners' Capital (Parenthetical)	9 Months Ended
	Sep. 30, 2014
Addition of partnership units	86,500,000
Redemption of partnership units	100,100,000

Condensed_Statement_of_Cash_Fl

Condensed Statement of Cash Flows (USD $)	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Cash Flows from Operating Activities:	'	'
Net income	$99,975,604	$27,776,610
Adjustments to reconcile net income to net cash provided by operating activities:	'	'
(Increase) decrease in commodity futures trading account - cash and cash equivalents	-40,662,930	14,621,459
Unrealized (gain) loss on open futures contracts	-33,385,020	32,409,377
Unrealized gain on open swap contracts	-6,654,820	-3,864,997
Decrease in dividends receivable	1,173	7,052
Increase in directors' fees receivable	-939	0
Increase in other assets	-745,473	-25,060
Decrease in professional fees payable	-300,028	-501,890
Decrease in General Partner management fees payable	-119,432	-122,681
Decrease in brokerage commissions payable	-9,000	-40,500
Decrease in other liabilities	-17,836	-11,971
Net cash provided by operating activities	18,081,299	70,247,399
Cash Flows from Financing Activities:	'	'
Addition of partnership shares	2,241,656,167	1,708,914,582
Redemption of partnership shares	-2,397,972,971	-2,032,426,291
Net cash used in financing activities	-156,316,804	-323,511,709
Net Decrease in Cash and Cash Equivalents	-138,235,505	-253,264,310
Cash and Cash Equivalents, beginning of period	792,445,608	1,100,510,722
Cash and Cash Equivalents, end of period	$654,210,103	$847,246,412

Organization_and_Business

Organization and Business	9 Months Ended
	Sep. 30, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Organization and Business	'
	NOTE 1 — ORGANIZATION AND BUSINESS
	The United States Natural Gas Fund, LP (“UNG”) was organized as a limited partnership under the laws of the state of Delaware on September 11, 2006. UNG is a commodity pool that issues limited partnership shares (“shares”) that may be purchased and sold on the NYSE Arca, Inc. (the “NYSE Arca”). Prior to November 25, 2008, UNG’s shares traded on the American Stock Exchange (the “AMEX”). UNG will continue in perpetuity, unless terminated sooner upon the occurrence of one or more events as described in its Fourth Amended and Restated Agreement of Limited Partnership dated as of March 1, 2013 (the “LP Agreement”). The investment objective of UNG is for the daily changes in percentage terms of its shares’ per share net asset value (“NAV”) to reflect the daily changes in percentage terms of the price of natural gas delivered at the Henry Hub, Louisiana as measured by the daily changes in the price of the futures contract on natural gas as traded on the New York Mercantile Exchange (the “NYMEX”), that is the near month contract to expire, except when the near month contract is within two weeks of expiration, in which case the futures contract will be the next month contract to expire (the “Benchmark Futures Contract”), less UNG’s expenses. It is not the intent of UNG to be operated in a fashion such that the per share NAV will equal, in dollar terms, the spot price of natural gas or any particular futures contract based on natural gas. It is not the intent of UNG to be operated in a fashion such that its per share NAV will reflect the percentage change of the price of any particular futures contract as measured over a time period greater than one day. United States Commodity Funds LLC (“USCF”), the general partner of UNG, believes that it is not practical to manage the portfolio to achieve such an investment goal when investing in Natural Gas Futures Contracts (as defined below) and Other Natural Gas-Related Investments (as defined below). The net assets of UNG consist primarily of investments in futures contracts for natural gas that are traded on the NYMEX, ICE Futures Exchange (“ICE Futures”) or other U.S. and foreign exchanges (collectively, “Natural Gas Futures Contracts”) and, to a lesser extent, in order to comply with regulatory requirements or in view of market conditions, other natural gas-related investments such as cash-settled options on Natural Gas Futures Contracts, forward contracts for natural gas, cleared swap contracts, and non-exchange traded (“over-the-counter”) transactions that are based on the price of natural gas, crude oil and other petroleum-based fuels, as well as futures contracts for crude oil, heating oil, gasoline and other petroleum-based fuels and indices based on the foregoing (collectively, “Other Natural Gas-Related Investments”). Market conditions that USCF currently anticipates could cause UNG to invest in Other Natural Gas-Related Investments including those allowing UNG to obtain greater liquidity or to execute transactions with more favorable pricing. For convenience and unless otherwise specified, Natural Gas Futures Contracts and Other Natural Gas-Related Investments collectively are referred to as “Natural Gas Interests” in this quarterly report on Form 10-Q. USCF is authorized by UNG in its sole judgment to employ, establish the terms of employment for and terminate commodity trading advisors of futures commission merchants. As of September 30, 2014, UNG held 9,175 NG Futures November 2014 Contracts traded on the NYMEX and 31,872 LD1 H Futures November 2014 Contracts traded on the ICE Futures US.
	UNG commenced investment operations on April 18, 2007 and has a fiscal year ending on December 31. USCF is responsible for the management of UNG. USCF is a member of the National Futures Association (the “NFA”) and became a commodity pool operator registered with the Commodity Futures Trading Commission (the “CFTC”) effective December 1, 2005 and a swaps firm on August 8, 2013. USCF is also the general partner of the United States Oil Fund, LP (“USO”), the United States 12 Month Oil Fund, LP (“USL”), the United States Gasoline Fund, LP (“UGA”) and the United States Diesel-Heating Oil Fund, LP (“UHN”), which listed their limited partnership shares on the AMEX under the ticker symbols “USO” on April 10, 2006, “USL” on December 6, 2007, “UGA” on February 26, 2008 and “UHN” on April 9, 2008, respectively. As a result of the acquisition of the AMEX by NYSE Euronext, each of USO’s, USL’s, UGA’s and UHN’s shares commenced trading on the NYSE Arca on November 25, 2008. USCF is also the general partner of the United States Short Oil Fund, LP (“DNO”), the United States 12 Month Natural Gas Fund, LP (“UNL”) and the United States Brent Oil Fund, LP (“BNO”), which listed their limited partnership shares on the NYSE Arca under the ticker symbols “DNO” on September 24, 2009, “UNL” on November 18, 2009 and “BNO” on June 2, 2010, respectively. USCF is also the sponsor of the United States Commodity Index Fund (“USCI”), the United States Copper Index Fund (“CPER”), the United States Agriculture Index Fund (“USAG”) and the United States Metals Index Fund (“USMI”), each a series of the United States Commodity Index Funds Trust. USCI, CPER, USAG and USMI listed their shares on the NYSE Arca under the ticker symbol “USCI” on August 10, 2010, “CPER” on November 15, 2011, “USAG” on April 13, 2012 and “USMI” on June 19, 2012, respectively. All funds listed previously are referred to collectively herein as the “Related Public Funds.”
	UNG issues shares to certain authorized purchasers (“Authorized Purchasers”) by offering baskets consisting of 100,000 shares (“Creation Baskets”) through ALPS Distributors, Inc., as the marketing agent (the “Marketing Agent”). The purchase price for a Creation Basket is based upon the NAV of a share calculated shortly after the close of the core trading session on the NYSE Arca on the day the order to create the basket is properly received.
	In addition, Authorized Purchasers pay UNG a $1,000 fee for each order placed to create one or more Creation Baskets or to redeem one or more baskets (“Redemption Baskets”), consisting of 100,000 shares. Shares may be purchased or sold on a nationally recognized securities exchange in smaller increments than a Creation Basket or Redemption Basket. Shares purchased or sold on a nationally recognized securities exchange are not purchased or sold at the per share NAV of UNG but rather at market prices quoted on such exchange.
	In April 2007, UNG initially registered 30,000,000 shares on Form S-1 with the U.S. Securities and Exchange Commission (the “SEC”). On April 18, 2007, UNG listed its shares on the AMEX under the ticker symbol “UNG”. On that day, UNG established its initial per share NAV by setting the price at $50.00 and issued 200,000 shares in exchange for $10,001,000. UNG also commenced investment operations on April 18, 2007, by purchasing Natural Gas Futures Contracts traded on the NYMEX based on natural gas. As a result of the acquisition of the AMEX by NYSE Euronext, UNG commenced trading on the NYSE Arca on November 25, 2008. As of September 30, 2014, UNG had registered a total of 1,680,000,000 shares.
	The accompanying unaudited condensed financial statements have been prepared in accordance with Rule 10-01 of Regulation S-X promulgated by the SEC and, therefore, do not include all information and footnote disclosure required under generally accepted accounting principles (“GAAP”) in the United States of America. The financial information included herein is unaudited; however, such financial information reflects all adjustments, consisting only of normal recurring adjustments, which are, in the opinion of USCF, necessary for the fair presentation of the condensed financial statements for the interim period.

Summary_of_Significant_Account

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2014
Accounting Policies [Abstract]	'
Summary of Significant Accounting Policies	'
	NOTE 2 — SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
	Basis of Presentation
	The financial statements have been prepared in conformity with GAAP as detailed in the Financial Accounting Standards Board’s (“FASB”) Accounting Standards Codification.  UNG is an investment company and follows the accounting and reporting guidance in FASB Topic 946.
	Revenue Recognition
	Commodity futures contracts, forward contracts, physical commodities and related options are recorded on the trade date. All such transactions are recorded on the identified cost basis and marked to market daily. Unrealized gains or losses on open contracts are reflected in the condensed statements of financial condition and represent the difference between the original contract amount and the market value (as determined by exchange settlement prices for futures contracts and related options and cash dealer prices at a predetermined time for forward contracts, physical commodities, and their related options) as of the last business day of the year or as of the last date of the condensed financial statements. Changes in the unrealized gains or losses between periods are reflected in the condensed statements of operations. UNG earns interest on its assets denominated in U.S. dollars on deposit with the futures commission merchant at the overnight Federal Funds Rate less 32 basis points. In addition, UNG earns income on funds held at the custodian or futures commission merchant at prevailing market rates earned on such investments.
	Investments in over-the-counter total return swap contracts (see Note 5) are arrangements to exchange a periodic payment for a market-linked return, each based on a notional amount. To the extent that the total return of the commodity future, security or index underlying the transaction exceeds or falls short of the offsetting periodic payment obligation, UNG receives a payment from, or makes a payment to, the swap counterparty. The over-the-counter swap contracts are valued daily based upon the appreciation or depreciation of the underlying securities subsequent to the effective date of the contract. Changes in the value of the swaps are reported as unrealized gains and losses and periodic payments are recorded as realized gains or losses in the accompanying condensed statements of operations.
	Brokerage Commissions
	Brokerage commissions on all open commodity futures contracts are accrued on a full-turn basis.
	Swap Premiums
	Upfront fees paid by UNG for over-the-counter swap contracts are reflected on the condensed statements of financial condition and represent payments made upon entering into a swap agreement to compensate for differences between the stated terms of the agreement and prevailing market conditions. The fees are amortized daily over the term of the swap agreement.
	Income Taxes
	UNG is not subject to federal income taxes; each partner reports his/her allocable share of income, gain, loss deductions or credits on his/her own income tax return.
	In accordance with GAAP, UNG is required to determine whether a tax position is more likely than not to be sustained upon examination by the applicable taxing authority, including resolution of any tax related appeals or litigation processes, based on the technical merits of the position. UNG files an income tax return in the U.S. federal jurisdiction, and may file income tax returns in various U.S. states. UNG is not subject to income tax return examinations by major taxing authorities for years before 2010. The tax benefit recognized is measured as the largest amount of benefit that has a greater than fifty percent likelihood of being realized upon ultimate settlement. De-recognition of a tax benefit previously recognized results in UNG recording a tax liability that reduces net assets. However, UNG’s conclusions regarding this policy may be subject to review and adjustment at a later date based on factors including, but not limited to, on-going analysis of and changes to tax laws, regulations and interpretations thereof. UNG recognizes interest accrued related to unrecognized tax benefits and penalties related to unrecognized tax benefits in income tax fees payable, if assessed. No interest expense or penalties have been recognized as of and for the period ended September 30, 2014.
	Creations and Redemptions
	Authorized Purchasers may purchase Creation Baskets or redeem Redemption Baskets only in blocks of 100,000 shares at a price equal to the NAV of the shares calculated shortly after the close of the core trading session on the NYSE Arca on the day the order is placed.
	UNG receives or pays the proceeds from shares sold or redeemed within three business days after the trade date of the purchase or redemption. The amounts due from Authorized Purchasers are reflected in UNG’s condensed statements of financial condition as receivable for shares sold, and amounts payable to Authorized Purchasers upon redemption are reflected as payable for shares redeemed.
	Authorized Purchasers pay UNG a fee of $1,000 for each order placed to create one or more Creation Baskets or to redeem one or more Redemption Baskets.
	Partnership Capital and Allocation of Partnership Income and Losses
	Profit or loss shall be allocated among the partners of UNG in proportion to the number of shares each partner holds as of the close of each month. USCF may revise, alter or otherwise modify this method of allocation as described in the LP Agreement.
	Calculation of Per Share Net Asset Value
	UNG’s per share NAV is calculated on each NYSE Arca trading day by taking the current market value of its total assets, subtracting any liabilities and dividing that amount by the total number of shares outstanding. UNG uses the closing price for the contracts on the relevant exchange on that day to determine the value of contracts held on such exchange.
	Net Income (Loss) Per Share
	Net income (loss) per share is the difference between the per share NAV at the beginning of each period and at the end of each period. The weighted average number of shares outstanding was computed for purposes of disclosing net income (loss) per weighted average share. The weighted average shares are equal to the number of shares outstanding at the end of the period, adjusted proportionately for shares added and redeemed based on the amount of time the shares were outstanding during such period. There were no shares held by USCF at September 30, 2014.
	Offering Costs
	Offering costs incurred in connection with the registration of additional shares after the initial registration of shares are borne by UNG. These costs include registration fees paid to regulatory agencies and all legal, accounting, printing and other expenses associated with such offerings. These costs are accounted for as a deferred charge and thereafter amortized to expense over twelve months on a straight-line basis or a shorter period if warranted.
	Cash Equivalents
	Cash equivalents include money market funds and overnight deposits or time deposits with original maturity dates of six months or less.
	Reclassification
	Certain amounts in the accompanying condensed financial statements were reclassified to conform to the current presentation.
	Use of Estimates
	The preparation of condensed financial statements in conformity with GAAP requires USCF to make estimates and assumptions that affect the reported amount of assets and liabilities and disclosure of contingent assets and liabilities at the date of the condensed financial statements, and the reported amounts of the revenue and expenses during the reporting period. Actual results may differ from those estimates and assumptions.

Fees_Paid_by_the_Fund_and_Rela

Fees Paid by the Fund and Related Party Transactions	9 Months Ended
	Sep. 30, 2014
Fees Paid By Fund and Related Party Transactions [Abstract]	'
Fees Paid by the Fund and Related Party Transactions	'
	NOTE 3 — FEES PAID BY THE FUND AND RELATED PARTY TRANSACTIONS
	USCF Management Fee
	Under the LP Agreement, USCF is responsible for investing the assets of UNG in accordance with the objectives and policies of UNG. In addition, USCF has arranged for one or more third parties to provide administrative, custody, accounting, transfer agency and other necessary services to UNG. For these services, UNG is contractually obligated to pay USCF a fee, which is paid monthly, that is equal to 0.60% per annum of average daily total net assets of $1,000,000,000 or less and 0.50% per annum of average daily total net assets that are greater than $1,000,000,000.
	Ongoing Registration Fees and Other Offering Expenses
	UNG pays all costs and expenses associated with the ongoing registration of its shares subsequent to the initial offering. These costs include registration or other fees paid to regulatory agencies in connection with the offer and sale of shares, and all legal, accounting, printing and other expenses associated with such offer and sale. For the nine months ended September 30, 2014, UNG incurred $163,036 in registration fees and other offering expenses. For the nine months ended September 30, 2013, UNG did not incur registration fees and other offering expenses.
	Directors’ Fees and Expenses
	UNG is responsible for paying its portion of the directors’ and officers’ liability insurance for UNG and the Related Public Funds and the fees and expenses of the independent directors who also serve as audit committee members of UNG and the Related Public Funds organized as limited partnerships and, as of July 8, 2011, the Related Public Funds organized as a series of a Delaware statutory trust. UNG shares the fees and expenses on a pro rata basis with each Related Public Fund, as described above, based on the relative assets of each Related Public Fund computed on a daily basis. These fees and expenses for the year ending December 31, 2014 are estimated to be a total of $560,625 for UNG and the Related Public Funds.
	Licensing Fees
	As discussed in Note 4 below, UNG entered into a licensing agreement with the NYMEX on April 10, 2006, as amended on October 20, 2011. Pursuant to the agreement, UNG and the Related Public Funds, other than BNO, USCI, CPER, USAG and USMI, pay a licensing fee that is equal to 0.015% on all net assets. During the nine months ended September 30, 2014 and 2013, UNG incurred $81,836 and $108,358, respectively, under this arrangement.
	Investor Tax Reporting Cost
	The fees and expenses associated with UNG’s audit expenses and tax accounting and reporting requirements are paid by UNG. These costs are estimated to be $1,400,000 for the year ending December 31, 2014.
	Other Expenses and Fees
	In addition to the fees described above, UNG pays all brokerage fees, transaction costs for over-the-counter swaps and other expenses in connection with the operation of UNG, but excluding costs and expenses paid by USCF as outlined in Note 4 below.

Contracts_and_Agreements

Contracts and Agreements	9 Months Ended
	Sep. 30, 2014
Contractors [Abstract]	'
Contracts and Agreements	'
	NOTE 4 — CONTRACTS AND AGREEMENTS
	UNG is party to a marketing agent agreement, dated as of April 17, 2007, as amended from time to time, with the Marketing Agent and USCF, whereby the Marketing Agent provides certain marketing services for UNG as outlined in the agreement. The fee of the Marketing Agent, which is borne by USCF, is equal to 0.06% on UNG’s assets up to $3 billion and 0.04% on UNG’s assets in excess of $3 billion.
	The above fee does not include website construction and development, which are also borne by USCF.
	UNG is also party to a custodian agreement, dated March 5, 2007, as amended from time to time, with Brown Brothers Harriman & Co. (“BBH&Co.”) and USCF, whereby BBH&Co. holds investments on behalf of UNG. USCF pays the fees of the custodian, which are determined by the parties from time to time. In addition, UNG is party to an administrative agency agreement, dated March 5, 2007, as amended from time to time, with USCF and BBH&Co., whereby BBH&Co. acts as the administrative agent, transfer agent and registrar for UNG. USCF also pays the fees of BBH&Co. for its services under such agreement and such fees are determined by the parties from time to time.
	Currently, USCF pays BBH&Co. for its services, in the foregoing capacities, a minimum amount of $75,000 annually for its custody, fund accounting and fund administration services rendered to UNG and each of the Related Public Funds, as well as a $20,000 annual fee for its transfer agency services. In addition, USCF pays BBH&Co. an asset-based charge of (a)  0.06% for the first $500 million of the Related Public Funds’ combined net assets, (b)  0.0465% for the Related Public Funds’ combined net assets greater than $500 million but less than $1 billion, and (c)  0.035% once Related Public Funds’ combined net assets exceed $1 billion. The annual minimum amount will not apply if the asset-based charge for all accounts in the aggregate exceeds $75,000. USCF also pays transaction fees ranging from $7 to $15 per transaction.
	On October 8, 2013, UNG entered into a brokerage agreement with RBC Capital Markets, LLC (“RBC Capital” or “RBC”) to serve as UNG’s futures commission merchant (“FCM”), effective October 10, 2013. Prior to October 10, 2013, the FCM was UBS Securities LLC (“UBS Securities”). The agreements require RBC Capital and UBS Securities to provide services to UNG in connection with the purchase and sale of Natural Gas Futures Contracts and Other Natural Gas-Related Investments that may be purchased and sold by or through RBC Capital and/or UBS Securities for UNG’s account. In accordance with each agreement, RBC Capital and UBS Securities charge UNG commissions of approximately $7 to $15 per round-turn trade, including applicable exchange and NFA fees for Natural Gas Futures Contracts and options on Natural Gas Futures Contracts. Such fees include those incurred when purchasing Natural Gas Futures Contracts and options on Natural Gas Futures Contracts when UNG issues shares as a result of a Creation Basket, as well as fees incurred when selling Natural Gas Futures Contracts and options on Natural Gas Futures Contracts when UNG redeems shares as a result of a Redemption Basket. Such fees are also incurred when Natural Gas Futures Contracts and options on Natural Gas Futures Contracts are purchased or redeemed for the purpose of rebalancing the portfolio. UNG also incurs commissions to brokers for the purchase and sales of Natural Gas Futures Contracts, Other Natural Gas-Related Investments or short-term obligations of the United States of two years or less (“Treasuries”).
		For the nine months ended			For the nine months ended
		September 30, 2014			September 30, 2013
	Total commissions accrued to brokers	$	1,485,185		$	1,814,781
	Commissions accrued as a result of rebalancing	$	1,199,662		$	1,540,235
	Percentage of commissions accrued as a result of rebalancing		80.78	%		84.87	%
	Commissions accrued as a result of creation and redemption activity	$	285,523		$	274,546
	Percentage of commissions accrued as a result of creation and redemption activity		19.22	%		15.13	%
	The decrease in the total commissions accrued to brokers for the nine months ended September 30, 2014, compared to the nine months ended September 30, 2013, was a result of decreased brokerage fees due to a lower number of futures contracts being held and traded as a result of UNG’s reduced net assets during the nine months ended September 30, 2014. As an annualized percentage of average daily total net assets, the figure for the nine months ended September 30, 2014, represents approximately 0.27% of average daily total net assets. By comparison, the figure for the nine months ended September 30, 2013, represented approximately 0.25% of average daily total net assets. However, there can be no assurance that commission costs and portfolio turnover will not cause commission expenses to rise in future quarters.
	UNG and the NYMEX entered into a licensing agreement on April 10, 2006, as amended on October 20, 2011, whereby UNG was granted a non-exclusive license to use certain of the NYMEX’s settlement prices and service marks. Under the licensing agreement, UNG and the Related Public Funds, other than BNO, USCI, CPER, USAG and USMI, pay the NYMEX an asset-based fee for the license, the terms of which are described in Note 3. UNG expressly disclaims any association with the NYMEX or endorsement of UNG by the NYMEX and acknowledges that “NYMEX” and “New York Mercantile Exchange” are registered trademarks of the NYMEX.

Financial_Instruments_OffBalan

Financial Instruments, Off-Balance Sheet Risks and Contingencies	9 Months Ended
	Sep. 30, 2014
Financial Instruments Off Balance Sheet Risks and Contingencies [Abstract]	'
Financial Instruments, Off-Balance Sheet Risks and Contingencies	'
	NOTE 5 — FINANCIAL INSTRUMENTS, OFF-BALANCE SHEET RISKS AND CONTINGENCIES
	UNG engages in the trading of futures contracts, options on futures contracts, cleared swaps and over-the-counter swaps (collectively, “derivatives”). UNG is exposed to both market risk, which is the risk arising from changes in the market value of the contracts, and credit risk, which is the risk of failure by another party to perform according to the terms of a contract.
	UNG may enter into futures contracts, options on futures contracts, cleared swaps and over-the-counter swaps to gain exposure to changes in the value of an underlying commodity. A futures contract obligates the seller to deliver (and the purchaser to accept) the future delivery of a specified quantity and type of a commodity at a specified time and place. Some futures contracts may call for physical delivery of the asset, while others are settled in cash. The contractual obligations of a buyer or seller may generally be satisfied by taking or making physical delivery of the underlying commodity or by making an offsetting sale or purchase of an identical futures contract on the same or linked exchange before the designated date of delivery. Cleared swaps are over-the-counter agreements that are eligible to be cleared by a clearinghouse, e.g., ICE Clear Europe, but which are not traded on an exchange. A cleared swap is created when the parties to an off-exchange over-the-counter swap transaction agree to extinguish their over-the-counter contract and replace it with a cleared swap. Cleared swaps are intended to provide the efficiencies and benefits that centralized clearing on an exchange offers to traders of futures contracts, including credit risk intermediation and the ability to offset positions initiated with different counterparties.
	The purchase and sale of futures contracts, options on futures contracts and cleared swaps require margin deposits with a futures commission merchant. Additional deposits may be necessary for any loss on contract value. The Commodity Exchange Act requires a futures commission merchant to segregate all customer transactions and assets from the futures commission merchant’s proprietary activities.
	Futures contracts, options on futures contracts and cleared swaps involve, to varying degrees, elements of market risk (specifically commodity price risk) and exposure to loss in excess of the amount of variation margin. The face or contract amounts reflect the extent of the total exposure UNG has in the particular classes of instruments. Additional risks associated with the use of futures contracts are an imperfect correlation between movements in the price of the futures contracts and the market value of the underlying securities and the possibility of an illiquid market for a futures contract. Buying and selling options on futures contracts exposes investors to the risks of purchasing or selling futures contracts.
	All of UNG’s investment contracts were exchange-traded futures contracts or fully-collateralized over-the-counter swaps through September 30, 2014. UNG held no over-the-counter swaps effective April 23, 2014. The risks associated with exchange-traded contracts are generally perceived to be less than those associated with over-the-counter transactions, since, in over-the-counter transactions, a party must rely solely on the credit of its respective individual counterparties. However, in the future, if UNG were to enter into non-exchange traded contracts, it would be subject to the credit risk associated with counterparty non-performance. The credit risk from counterparty non-performance associated with such instruments is the net unrealized gain, if any, on the transaction. UNG has credit risk under its futures contracts since the sole counterparty to all domestic and foreign futures contracts is the clearinghouse for the exchange on which the relevant contracts are traded. In addition, UNG bears the risk of financial failure by the clearing broker.
	At September 30, 2014, UNG did not hold any over-the-counter swap agreements, as compared to September 30, 2013 when UNG held one over-the-counter swap agreement whereby UNG’s counterparty posted $0 in cash and $ 1,214,685 in securities.
	UNG’s cash and other property, such as Treasuries, deposited with a futures commission merchant are considered commingled with all other customer funds, subject to the futures commission merchant’s segregation requirements. In the event of a futures commission merchant’s insolvency, recovery may be limited to a pro rata share of segregated funds available. It is possible that the recovered amount could be less than the total of cash and other property deposited. The insolvency of a futures commission merchant could result in the complete loss of UNG’s assets posted with that futures commission merchant; however, the majority of UNG’s assets are held in Treasuries, cash and/or cash equivalents with UNG’s custodian and would not be impacted by the insolvency of a futures commission merchant. The failure or insolvency of UNG’s custodian, however, could result in a substantial loss of UNG’s assets.
	USCF invests a portion of UNG’s cash in money market funds that seek to maintain a stable per share NAV. UNG is exposed to any risk of loss associated with an investment in such money market funds. As of September 30, 2014 and December 31, 2013, UNG held investments in money market funds in the amounts of $270,505,751 and $392,614,029, respectively. UNG also holds cash deposits with its custodian. Pursuant to a written agreement with BBH&Co., uninvested overnight cash balances are swept to offshore branches of U.S. regulated and domiciled banks located in Toronto, Canada; London, United Kingdom; Grand Cayman, Cayman Islands; and Nassau, Bahamas; which are subject to U.S. regulation and regulatory oversight. As of September 30, 2014 and December 31, 2013, UNG held cash deposits and investments in Treasuries in the amounts of $448,514,861 and $423,979,158, respectively, with the custodian and futures commission merchant. Some or all of these amounts may be subject to loss should UNG’s custodian and/or futures commission merchant cease operations.
	For derivatives, risks arise from changes in the market value of the contracts. Theoretically, UNG is exposed to market risk equal to the value of futures contracts purchased and unlimited liability on such contracts sold short. As both a buyer and a seller of options, UNG pays or receives a premium at the outset and then bears the risk of unfavorable changes in the price of the contract underlying the option.
	UNG’s policy is to continuously monitor its exposure to market and counterparty risk through the use of a variety of financial, position and credit exposure reporting controls and procedures. In addition, UNG has a policy of requiring review of the credit standing of each counterparty with which it conducts business.
	The financial instruments held by UNG are reported in its condensed statements of financial condition at market or fair value, or at carrying amounts that approximate fair value, because of their highly liquid nature and short-term maturity.

Financial_Highlights

Financial Highlights	9 Months Ended
	Sep. 30, 2014
Financial Highlights [Abstract]	'
Financial Highlights	'
	NOTE 6 — FINANCIAL HIGHLIGHTS
	The following table presents per share performance data and other supplemental financial data for the nine months ended September 30, 2014 and 2013 for the shareholders. This information has been derived from information presented in the condensed financial statements.
			For the nine months			For the nine months
			ended September 30, 2014			ended September 30, 2013
			(Unaudited)			(Unaudited)
	Per Share Operating Performance:
	Net asset value, beginning of period		$	20.59		$	18.87
	Total income (loss)			1.72			-0.41
	Total expenses			-0.21			-0.16
	Net increase (decrease) in net asset value			1.51			-0.57
	Net asset value, end of period		$	22.1		$	18.3
	Total Return			7.33	%		-3.02	%
	Ratios to Average Net Assets
	Total income			14.58	%		3.67	%
	Expenses excluding management fees*			0.57	%		0.47	%
	Management fees*			0.6	%		0.6	%
	Net income			13.71	%		2.88	%
	*	Annualized.
	Total returns are calculated based on the change in value during the period. An individual shareholder’s total return and ratio may vary from the above total returns and ratios based on the timing of contributions to and withdrawals from UNG.

Fair_Value_Of_Financial_Instru

Fair Value Of Financial Instruments

9 Months Ended

Sep. 30, 2014

Fair Value Disclosures [Abstract]

'

Fair Value Of Financial Instruments

'

NOTE 7 — FAIR VALUE OF FINANCIAL INSTRUMENTS

UNG values its investments in accordance with Accounting Standards Codification 820 – Fair Value Measurements and Disclosures (“ASC 820”). ASC 820 defines fair value, establishes a framework for measuring fair value in generally accepted accounting principles, and expands disclosures about fair value measurement. The changes to past practice resulting from the application of ASC 820 relate to the definition of fair value, the methods used to measure fair value, and the expanded disclosures about fair value measurement. ASC 820 establishes a fair value hierarchy that distinguishes between: (1) market participant assumptions developed based on market data obtained from sources independent of UNG (observable inputs) and (2) UNG’s own assumptions about market participant assumptions developed based on the best information available under the circumstances (unobservable inputs). The three levels defined by the ASC 820 hierarchy are as follows:

Level I – Quoted prices (unadjusted) in active markets for identical assets or liabilities that the reporting entity has the ability to access at the measurement date.

Level II – Inputs other than quoted prices included within Level I that are observable for the asset or liability, either directly or indirectly. Level II assets include the following: quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the asset or liability, and inputs that are derived principally from or corroborated by observable market data by correlation or other means (market-corroborated inputs).

Level III – Unobservable pricing input at the measurement date for the asset or liability. Unobservable inputs shall be used to measure fair value to the extent that observable inputs are not available.

In some instances, the inputs used to measure fair value might fall within different levels of the fair value hierarchy. The level in the fair value hierarchy within which the fair value measurement in its entirety falls shall be determined based on the lowest input level that is significant to the fair value measurement in its entirety.

The following table summarizes the valuation of UNG’s securities at September 30, 2014 using the fair value hierarchy:

At September 30, 2014

Total

Level I

Level II

Level III

Short-Term Investments

$

570,484,681

$

570,484,681

$

—

$

—

Exchange-Traded Futures Contracts

United States Contracts

19,351,110

19,351,110

—

—

During the nine months ended September 30, 2014, there were no transfers between Level I and Level II.

Following is a reconciliation of assets in which significant unobservable inputs (Level III) were used in determining fair value as of September 30, 2014:

Total Return Swap Contracts

Beginning balance as of 12/31/13

$

-6,654,820

Realized gain (loss)*

—

Change in unrealized gain

6,654,820

Ending balance as of 09/30/14

$

—

*

The realized gain (loss) incurred during the nine months ended September 30, 2014 for total return swaps was $25,690,444.

The following table summarizes the valuation of UNG’s securities at December 31, 2013 using the fair value hierarchy:

At December 31, 2013

Total

Level I

Level II

Level III

Short-Term Investments

$

742,544,890

$

742,544,890

$

—

$

—

Exchange-Traded Futures Contracts

United States Contracts

-14,033,910

-14,033,910

—

—

Over-the-Counter Total Return Swap Contracts

-6,654,820

—

—

-6,654,820

During the year ended December 31, 2013, there were no transfers between Level I and Level II.

Following is a reconciliation of assets in which significant unobservable inputs (Level III) were used in determining fair value as of December 31, 2013:

Total Return Swap Contracts

Beginning balance as of 12/31/12

$

-3,470,939

Realized gain (loss)*

—

Change in unrealized loss

-3,183,881

Ending balance as of 12/31/13

$

-6,654,820

*

The realized gain (loss) incurred during the fiscal year ended December 31, 2013 for total return swaps was $13,643,971.

Effective January 1, 2009, UNG adopted the provisions of Accounting Standards Codification 815 — Derivatives and Hedging, which require presentation of qualitative disclosures about objectives and strategies for using derivatives, quantitative disclosures about fair value amounts and gains and losses on derivatives.

Fair Value of Derivative Instruments

Condensed

Fair Value

Fair Value

Derivatives not Accounted for

Statements of Financial

At September 30,

At December 31,

as Hedging Instruments

Condition Location

2014

2013

Futures - Commodity Contracts

Assets

$

19,351,110

$

-14,033,910

Swaps - Commodity Contracts

Assets

—

-6,654,820

The Effect of Derivative Instruments on the Condensed Statements of Operations

For the nine months ended

For the nine months ended

September 30, 2014

September 30, 2013

Change in

Change in

Location of

Realized

Unrealized

Realized

Unrealized

Derivatives not

Gain or (Loss)

Gain

Gain

Gain or (Loss)

Gain or (Loss)

Accounted for

on Derivatives

on Derivatives

on Derivatives

on Derivatives

on Derivatives

as Hedging

Recognized in

Recognized in

Recognized in

Recognized in

Recognized in

Instruments

Income

Income

Income

Income

Income

Futures - Commodity Contracts

Realized gain on closed futures positions

$

40,248,943

$

69,898,707

Change in unrealized gain or (loss) on open futures positions

$

33,385,020

$

-32,409,377

Swaps - Commodity Contracts

Realized gain or (loss) on closed swap contracts

25,690,444

-6,290,828

Change in unrealized gain on open swap contracts

6,654,820

3,864,997

Subsequent_Events

Subsequent Events	9 Months Ended
	Sep. 30, 2014
Subsequent Events [Abstract]	'
Subsequent Events	'
	NOTE 8 — SUBSEQUENT EVENTS
	UNG has performed an evaluation of subsequent events through the date the condensed financial statements were issued. This evaluation did not result in any subsequent events that necessitated disclosures and/or adjustments.

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2014
Accounting Policies [Abstract]	'
Basis of Presentation	'
	Basis of Presentation
	The financial statements have been prepared in conformity with GAAP as detailed in the Financial Accounting Standards Board’s (“FASB”) Accounting Standards Codification.  UNG is an investment company and follows the accounting and reporting guidance in FASB Topic 946.
Revenue Recognition	'
	Revenue Recognition
	Commodity futures contracts, forward contracts, physical commodities and related options are recorded on the trade date. All such transactions are recorded on the identified cost basis and marked to market daily. Unrealized gains or losses on open contracts are reflected in the condensed statements of financial condition and represent the difference between the original contract amount and the market value (as determined by exchange settlement prices for futures contracts and related options and cash dealer prices at a predetermined time for forward contracts, physical commodities, and their related options) as of the last business day of the year or as of the last date of the condensed financial statements. Changes in the unrealized gains or losses between periods are reflected in the condensed statements of operations. UNG earns interest on its assets denominated in U.S. dollars on deposit with the futures commission merchant at the overnight Federal Funds Rate less 32 basis points. In addition, UNG earns income on funds held at the custodian or futures commission merchant at prevailing market rates earned on such investments.
	Investments in over-the-counter total return swap contracts (see Note 5) are arrangements to exchange a periodic payment for a market-linked return, each based on a notional amount. To the extent that the total return of the commodity future, security or index underlying the transaction exceeds or falls short of the offsetting periodic payment obligation, UNG receives a payment from, or makes a payment to, the swap counterparty. The over-the-counter swap contracts are valued daily based upon the appreciation or depreciation of the underlying securities subsequent to the effective date of the contract. Changes in the value of the swaps are reported as unrealized gains and losses and periodic payments are recorded as realized gains or losses in the accompanying condensed statements of operations.
Brokerage Commissions	'
	Brokerage Commissions
	Brokerage commissions on all open commodity futures contracts are accrued on a full-turn basis.
Swap Premiums	'
	Swap Premiums
	Upfront fees paid by UNG for over-the-counter swap contracts are reflected on the condensed statements of financial condition and represent payments made upon entering into a swap agreement to compensate for differences between the stated terms of the agreement and prevailing market conditions. The fees are amortized daily over the term of the swap agreement.
Income Taxes	'
	Income Taxes
	UNG is not subject to federal income taxes; each partner reports his/her allocable share of income, gain, loss deductions or credits on his/her own income tax return.
	In accordance with GAAP, UNG is required to determine whether a tax position is more likely than not to be sustained upon examination by the applicable taxing authority, including resolution of any tax related appeals or litigation processes, based on the technical merits of the position. UNG files an income tax return in the U.S. federal jurisdiction, and may file income tax returns in various U.S. states. UNG is not subject to income tax return examinations by major taxing authorities for years before 2010. The tax benefit recognized is measured as the largest amount of benefit that has a greater than fifty percent likelihood of being realized upon ultimate settlement. De-recognition of a tax benefit previously recognized results in UNG recording a tax liability that reduces net assets. However, UNG’s conclusions regarding this policy may be subject to review and adjustment at a later date based on factors including, but not limited to, on-going analysis of and changes to tax laws, regulations and interpretations thereof. UNG recognizes interest accrued related to unrecognized tax benefits and penalties related to unrecognized tax benefits in income tax fees payable, if assessed. No interest expense or penalties have been recognized as of and for the period ended September 30, 2014.
Creations and Redemptions	'
	Creations and Redemptions
	Authorized Purchasers may purchase Creation Baskets or redeem Redemption Baskets only in blocks of 100,000 shares at a price equal to the NAV of the shares calculated shortly after the close of the core trading session on the NYSE Arca on the day the order is placed.
	UNG receives or pays the proceeds from shares sold or redeemed within three business days after the trade date of the purchase or redemption. The amounts due from Authorized Purchasers are reflected in UNG’s condensed statements of financial condition as receivable for shares sold, and amounts payable to Authorized Purchasers upon redemption are reflected as payable for shares redeemed.
	Authorized Purchasers pay UNG a fee of $1,000 for each order placed to create one or more Creation Baskets or to redeem one or more Redemption Baskets.
Partnership Capital and Allocation of Partnership Income and Losses	'
	Partnership Capital and Allocation of Partnership Income and Losses
	Profit or loss shall be allocated among the partners of UNG in proportion to the number of shares each partner holds as of the close of each month. USCF may revise, alter or otherwise modify this method of allocation as described in the LP Agreement.
Calculation of Per Unit Net Asset Value	'
	Calculation of Per Share Net Asset Value
	UNG’s per share NAV is calculated on each NYSE Arca trading day by taking the current market value of its total assets, subtracting any liabilities and dividing that amount by the total number of shares outstanding. UNG uses the closing price for the contracts on the relevant exchange on that day to determine the value of contracts held on such exchange.
Net Income (Loss) Per Share	'
	Net Income (Loss) Per Share
	Net income (loss) per share is the difference between the per share NAV at the beginning of each period and at the end of each period. The weighted average number of shares outstanding was computed for purposes of disclosing net income (loss) per weighted average share. The weighted average shares are equal to the number of shares outstanding at the end of the period, adjusted proportionately for shares added and redeemed based on the amount of time the shares were outstanding during such period. There were no shares held by USCF at September 30, 2014.
Offering Costs	'
	Offering Costs
	Offering costs incurred in connection with the registration of additional shares after the initial registration of shares are borne by UNG. These costs include registration fees paid to regulatory agencies and all legal, accounting, printing and other expenses associated with such offerings. These costs are accounted for as a deferred charge and thereafter amortized to expense over twelve months on a straight-line basis or a shorter period if warranted.
Cash Equivalents	'
	Cash Equivalents
	Cash equivalents include money market funds and overnight deposits or time deposits with original maturity dates of six months or less.
Reclassification	'
	Reclassification
	Certain amounts in the accompanying condensed financial statements were reclassified to conform to the current presentation.
Use of Estimates	'
	Use of Estimates
	The preparation of condensed financial statements in conformity with GAAP requires USCF to make estimates and assumptions that affect the reported amount of assets and liabilities and disclosure of contingent assets and liabilities at the date of the condensed financial statements, and the reported amounts of the revenue and expenses during the reporting period. Actual results may differ from those estimates and assumptions.

Contracts_and_Agreements_Table

Contracts and Agreements (Tables)	9 Months Ended
	Sep. 30, 2014
Contractors [Abstract]	'
Brokerage Commissions	'
		For the nine months ended			For the nine months ended
		September 30, 2014			September 30, 2013
	Total commissions accrued to brokers	$	1,485,185		$	1,814,781
	Commissions accrued as a result of rebalancing	$	1,199,662		$	1,540,235
	Percentage of commissions accrued as a result of rebalancing		80.78	%		84.87	%
	Commissions accrued as a result of creation and redemption activity	$	285,523		$	274,546
	Percentage of commissions accrued as a result of creation and redemption activity		19.22	%		15.13	%

Financial_Highlights_Tables

Financial Highlights (Tables)	9 Months Ended
	Sep. 30, 2014
Financial Highlights [Abstract]	'
Per Unit Performance Data and Other Supplemental Financial Data	'
	The following table presents per share performance data and other supplemental financial data for the nine months ended September 30, 2014 and 2013 for the shareholders. This information has been derived from information presented in the condensed financial statements.
			For the nine months			For the nine months
			ended September 30, 2014			ended September 30, 2013
			(Unaudited)			(Unaudited)
	Per Share Operating Performance:
	Net asset value, beginning of period		$	20.59		$	18.87
	Total income (loss)			1.72			-0.41
	Total expenses			-0.21			-0.16
	Net increase (decrease) in net asset value			1.51			-0.57
	Net asset value, end of period		$	22.1		$	18.3
	Total Return			7.33	%		-3.02	%
	Ratios to Average Net Assets
	Total income			14.58	%		3.67	%
	Expenses excluding management fees*			0.57	%		0.47	%
	Management fees*			0.6	%		0.6	%
	Net income			13.71	%		2.88	%
	*	Annualized.

Fair_Value_Of_Financial_Instru1

Fair Value Of Financial Instruments (Tables)

9 Months Ended

Sep. 30, 2014

Fair Value Disclosures [Abstract]

'

Valuation of USNG's Securities Using the Fair Value Hierarchy

'

The following table summarizes the valuation of UNG’s securities at September 30, 2014 using the fair value hierarchy:

At September 30, 2014

Total

Level I

Level II

Level III

Short-Term Investments

$

570,484,681

$

570,484,681

$

—

$

—

Exchange-Traded Futures Contracts

United States Contracts

19,351,110

19,351,110

—

—

The following table summarizes the valuation of UNG’s securities at December 31, 2013 using the fair value hierarchy:

At December 31, 2013

Total

Level I

Level II

Level III

Short-Term Investments

$

742,544,890

$

742,544,890

$

—

$

—

Exchange-Traded Futures Contracts

United States Contracts

-14,033,910

-14,033,910

—

—

Over-the-Counter Total Return Swap Contracts

-6,654,820

—

—

-6,654,820

Reconciliation of Assets in which Significant Observable Inputs (Level III) were Used in Determining Fair Value

'

Following is a reconciliation of assets in which significant unobservable inputs (Level III) were used in determining fair value as of September 30, 2014:

Total Return Swap Contracts

Beginning balance as of 12/31/13

$

-6,654,820

Realized gain (loss)*

—

Change in unrealized gain

6,654,820

Ending balance as of 09/30/14

$

—

*

The realized gain (loss) incurred during the nine months ended September 30, 2014 for total return swaps was $25,690,444.

Following is a reconciliation of assets in which significant unobservable inputs (Level III) were used in determining fair value as of December 31, 2013:

Total Return Swap Contracts

Beginning balance as of 12/31/12

$

-3,470,939

Realized gain (loss)*

—

Change in unrealized loss

-3,183,881

Ending balance as of 12/31/13

$

-6,654,820

*

The realized gain (loss) incurred during the fiscal year ended December 31, 2013 for total return swaps was $13,643,971.

Fair Value of Derrivative Instruments

'

Fair Value of Derivative Instruments

Condensed

Fair Value

Fair Value

Derivatives not Accounted for

Statements of Financial

At September 30,

At December 31,

as Hedging Instruments

Condition Location

2014

2013

Futures - Commodity Contracts

Assets

$

19,351,110

$

-14,033,910

Swaps - Commodity Contracts

Assets

—

-6,654,820

Effect of Derivative Instruments on the Statements of Operations

'

The Effect of Derivative Instruments on the Condensed Statements of Operations

For the nine months ended

For the nine months ended

September 30, 2014

September 30, 2013

Change in

Change in

Location of

Realized

Unrealized

Realized

Unrealized

Derivatives not

Gain or (Loss)

Gain

Gain

Gain or (Loss)

Gain or (Loss)

Accounted for

on Derivatives

on Derivatives

on Derivatives

on Derivatives

on Derivatives

as Hedging

Recognized in

Recognized in

Recognized in

Recognized in

Recognized in

Instruments

Income

Income

Income

Income

Income

Futures - Commodity Contracts

Realized gain on closed futures positions

$

40,248,943

$

69,898,707

Change in unrealized gain or (loss) on open futures positions

$

33,385,020

$

-32,409,377

Swaps - Commodity Contracts

Realized gain or (loss) on closed swap contracts

25,690,444

-6,290,828

Change in unrealized gain on open swap contracts

6,654,820

3,864,997

Organization_and_Business_Addi

Organization and Business (Additional Information) (Details) (USD $)	0 Months Ended
	Apr. 30, 2007	Apr. 18, 2007	Sep. 30, 2014		Dec. 31, 2013	Sep. 30, 2013	Dec. 31, 2012
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]	'	'	'		'	'	'
Fee paid by Authorized Purchasers for each order placed to create one or more Creation Baskets or to redeem one or more baskets	'	'	1,000		'	'	'
Number of initially registered units on Form S-1 with the U.S. Securities and Exchange Commission	30,000,000	'	'		'	'	'
Net Asset Value Per Unit	'	$50	$22.10		$20.59	$18.30	$18.87
Number of units issued	'	200,000	'		'	'	'
Value of unit issued	'	$10,001,000	'		'	'	'
Number of registered units	'	'	1,680,000,000		'	'	'
Open Futures Contracts, Long [Member] | United States [Member] | NYMEX Natural Gas Futures NG November 2014 contracts, expiring October 2014	'	'	'		'	'	'
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]	'	'	'		'	'	'
Number of Contracts	'	'	9,175		'	'	'
Open Futures Contracts, Long [Member] | United States [Member] | ICE Natural Gas Futures LD1 H August 2013 contracts, expiring August 2013 [Member]	'	'	'		'	'	'
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]	'	'	'		'	'	'
Number of Contracts	'	'	31,872		'	'	'
Total Open Futures Contracts [Member] | Open Futures Contracts, Long [Member] | United States [Member]	'	'	'		'	'	'
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]	'	'	'		'	'	'
Number of Contracts	'	'	41,047	[1]	'	'	'
Creation Baskets [Member]	'	'	'		'	'	'
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]	'	'	'		'	'	'
Number of units per basket	'	'	100,000		'	'	'
Redemption Baskets [Member]	'	'	'		'	'	'
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]	'	'	'		'	'	'
Number of units per basket	'	'	100,000		'	'	'
[1]	Collateral amounted to $64,810,509 on open future contracts.

Summary_of_Significant_Account2

Summary of Significant Accounting Policies (Additional Information) (Details)	9 Months Ended
	Sep. 30, 2014
Significant Accounting Policies [Line Items]	'
Basis points subtracted from overnight Federal Funds Rate	32.00%
Fee paid by Authorized Purchasers for each order placed to create one or more Creation Baskets or to redeem one or more baskets	1,000
Maximum [Member]	'
Significant Accounting Policies [Line Items]	'
Cash equivalents maturity period	'6 months
Redemption Baskets [Member]	'
Significant Accounting Policies [Line Items]	'
Number of units per basket	100,000

Fees_Paid_by_Fund_and_Related_

Fees Paid by Fund and Related Party Transactions (Additional Information) (Details) (USD $)	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Fees Paid and Related Party Transactions [Line Items]	'	'
USCF Management Fee	'UNG is contractually obligated to pay USCF a fee, which is paid monthly, that is equal to 0.60% per annum of average daily total net assets of $1,000,000,000 or less and 0.50% per annum of average daily total net assets that are greater than $1,000,000,000.	'
Fee percentage	0.02%	'
Ongoing Registration Fees and Other Offering Expenses	$163,036	$0
Licensing fee incurred	81,836	108,358
Estimated investor tax reporting cost	1,400,000	'
USNG and the Related Public Funds [Member]	'	'
Fees Paid and Related Party Transactions [Line Items]	'	'
Estimated directors fees and expenses	$560,625	'

Contracts_and_Agreements_Broke

Contracts and Agreements (Brokerage Commission) (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Floor Brokerage Exchange and Clearance Fees	$462,183	$615,823	$1,485,185	$1,814,781
Rebalancing Investments Transaction [Member]	'	'	'	'
Floor Brokerage Exchange and Clearance Fees	'	'	1,199,662	1,540,235
Percentage Of Average Daily Net Assets	80.78%	84.87%	80.78%	84.87%
Creation And Redemption Activity [Member]	'	'	'	'
Floor Brokerage Exchange and Clearance Fees	'	'	$285,523	$274,546
Percentage Of Average Daily Net Assets	19.22%	15.13%	19.22%	15.13%

Contracts_and_Agreements_Addit

Contracts and Agreements (Additional Information) (Details) (USD $)	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]	'	'
Fee percentage	0.02%	'
Annual Fee for custody, fund accounting and fund administration services	$20,000	'
Ratio of expense to Average Net Assets	0.27%	0.25%
Maximum [Member]	'	'
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]	'	'
Transaction fees per transaction	15	'
Commissions per round-turn trade, including applicable exchange and NFA fees for Futures Contracts and options on Futures Contracts	15	'
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	7	'
Commissions per round-turn trade, including applicable exchange and NFA fees for Futures Contracts and options on Futures Contracts	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	'
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] | Minimum [Member]	'	'
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]	'	'
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]	'	'
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]	'	'
Fee percentage	0.05%	'
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	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] | Minimum [Member]	'	'
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]	'	'
Base amount for determining fee percentage	500,000,000	'
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%	'
Marketing Agreement [Member] | USNG's assets up to $3 billion [Member] | Maximum [Member]	'	'
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]	'	'
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]	'	'
Fee percentage	0.04%	'
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	'

Financial_Instruments_OffBalan1

Financial Instruments, Off-Balance Sheet Risks and Contingencies (Additional Information) (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2013
Carrying Amounts and Fair Values of Financial Instruments or Liabilities [Line Items]	'	'	'
Cash collateral from counterparties	'	'	$0
Securities collateral from counterparties	'	'	1,214,685
Cash investments in money market funds	270,505,751	392,614,029	'
Deposits in domestic and foreign financial institutions	$448,514,861	$423,979,158	'

Financial_Highlights_Per_Unit_

Financial Highlights (Per Unit Performance Data and Other Supplemental Financial Data) (Details) (USD $)	9 Months Ended
	Sep. 30, 2014		Sep. 30, 2013		Apr. 18, 2007
Per Unit Operating Performance:	'		'		'
Net asset value, beginning of period	$20.59		$18.87		$50
Total income (loss)	$1.72		($0.41)		'
Total expenses	($0.21)		($0.16)		'
Net increase (decrease) in net asset value	$1.51		($0.57)		'
Net asset value, end of period	$22.10		$18.30		$50
Total Return	7.33%		-3.02%		'
Ratios to Average Net Assets	'		'		'
Total income	14.58%		3.67%		'
Expenses excluding management fees	0.57%	[1]	0.47%	[1]	'
Management fees	0.60%	[1]	0.60%	[1]	'
Net income	13.71%		2.88%		'
[1]	Annualized.

Fair_Value_Of_Financial_Instru2

Fair Value Of Financial Instruments (Valuation of Securities Using Fair Value Hierarchy) (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
Short-Term Investments [Member]	'	'
Schedule of Trading Securities and Other Trading Assets [Line Items]	'	'
Securities, fair value	$570,484,681	$742,544,890
Exchange-Traded Futures Contracts [Member] | United States [Member]	'	'
Schedule of Trading Securities and Other Trading Assets [Line Items]	'	'
Securities, fair value	19,351,110	-14,033,910
Open Over-the-Counter Total Return Swap Contracts [Member]	'	'
Schedule of Trading Securities and Other Trading Assets [Line Items]	'	'
Securities, fair value	'	-6,654,820
Fair Value, Inputs, Level 1 [Member] | Short-Term Investments [Member]	'	'
Schedule of Trading Securities and Other Trading Assets [Line Items]	'	'
Securities, fair value	570,484,681	742,544,890
Fair Value, Inputs, Level 1 [Member] | Exchange-Traded Futures Contracts [Member] | United States [Member]	'	'
Schedule of Trading Securities and Other Trading Assets [Line Items]	'	'
Securities, fair value	19,351,110	-14,033,910
Fair Value, Inputs, Level 1 [Member] | Open Over-the-Counter Total Return Swap Contracts [Member]	'	'
Schedule of Trading Securities and Other Trading Assets [Line Items]	'	'
Securities, fair value	'	0
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 [Member]	'	'
Schedule of Trading Securities and Other Trading Assets [Line Items]	'	'
Securities, fair value	0	0
Fair Value, Inputs, Level 2 [Member] | Open Over-the-Counter Total Return Swap Contracts [Member]	'	'
Schedule of Trading Securities and Other Trading Assets [Line Items]	'	'
Securities, fair value	'	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 [Member]	'	'
Schedule of Trading Securities and Other Trading Assets [Line Items]	'	'
Securities, fair value	0	0
Fair Value, Inputs, Level 3 [Member] | Open Over-the-Counter Total Return Swap Contracts [Member]	'	'
Schedule of Trading Securities and Other Trading Assets [Line Items]	'	'
Securities, fair value	'	($6,654,820)

Fair_Value_Of_Financial_Instru3

Fair Value Of Financial Instruments (Reconciliation of Assets in which Significant Observable Inputs (Level III) were used in Determining Fair Value) (Details) (USD $)	3 Months Ended		9 Months Ended				12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014		Dec. 31, 2013
					Total Return Swap Contracts [Member]		Total Return Swap Contracts [Member]
Total Return Swap Contracts	'	'	'	'	'		'
Beginning balance	'	'	'	'	($6,654,820)		($3,470,939)
Realized gain (loss)	0	-14,494,336	25,690,444	-6,290,828	0	[1]	0	[2]
Change in unrealized gain (loss)	0	11,245,517	6,654,820	3,864,997	6,654,820		-3,183,881
Ending balance	'	'	'	'	$0		($6,654,820)
[1]	The realized gain (loss) incurred during the nine months ended September 30, 2014 for total return swaps was $25,690,444.
[2]	The realized gain (loss) incurred during the fiscal year ended December 31, 2013 for total return swaps was $13,643,971.

Fair_Value_Of_Financial_Instru4

Fair Value Of Financial Instruments (Reconciliation of Assets in which Significant Observable Inputs (Level III) were used in Determining Fair Value) (Parenthetical) (Details) (USD $)	3 Months Ended		9 Months Ended			12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Dec. 31, 2013
					Total Return Swap [Member]	Total Return Swap [Member]
Total Return Swap Contracts	'	'	'	'	'	'
Realized gain (loss)	$0	($14,494,336)	$25,690,444	($6,290,828)	$25,690,444	$13,643,971

Fair_Value_Of_Financial_Instru5

Fair Value Of Financial Instruments (Fair Value of Derivative Instruments) (Details) (Commodity Contracts [Member], Assets [Member], USD $)	Sep. 30, 2014	Dec. 31, 2013
Futures - Commodity Contracts [Member]	'	'
Fair Value of Financial Instruments [Line Items]	'	'
Derivatives not Accounted for as Hedging Instruments	$19,351,110	($14,033,910)
Swaps - Commodity Contracts [Member]	'	'
Fair Value of Financial Instruments [Line Items]	'	'
Derivatives not Accounted for as Hedging Instruments	$0	($6,654,820)

Fair_Value_Of_Financial_Instru6

Fair Value Of Financial Instruments (Effect of Derivative Instruments on Condensed Statements of Operations) (Details) (Commodity Contracts [Member], USD $)	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Futures - Commodity Contracts [Member] | Realized gain on closed futures positions [Member]	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'
Realized Gain on Derivatives or (Loss) Recognized in Income	$40,248,943	$69,898,707
Futures - Commodity Contracts [Member] | Change in unrealized gain or (loss) on open futures positions [Member]	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'
Change in Unrealized Gain or (Loss) on Derivatives Recognized in Income	33,385,020	-32,409,377
Swaps - Commodity Contracts [Member] | Realized gain or (loss) on closed swap contracts [Member]	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'
Realized Gain on Derivatives or (Loss) Recognized in Income	25,690,444	-6,290,828
Swaps - Commodity Contracts [Member] | Change in unrealized gain on open swap contracts [Member]	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'
Change in Unrealized Gain or (Loss) on Derivatives Recognized in Income	$6,654,820	$3,864,997