United States Natural Gas Fund (UNG) 10-K28 Feb 182017 FY Annual reportFinancial data

Company Profile

Document And Entity Information

Document And Entity Information - USD ($)	12 Months Ended
Document And Entity Information - USD ($)	Dec. 31, 2017	Feb. 26, 2018	Jun. 30, 2017
Document Information [Line Items]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	FY
Entity Registrant Name	United States Natural Gas Fund, LP
Entity Central Index Key	1,376,227
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$ 447,252,707
Trading Symbol	UNG
Entity Common Stock, Shares Outstanding		18,284,588

Statements of Financial Conditi

Statements of Financial Condition - USD ($)		Dec. 31, 2017	Dec. 31, 2016
Assets
Cash and cash equivalents (at cost $550,936,887 and $522,819,857, respectively) (Notes 2 and 5)		$ 550,936,887	$ 522,819,857
Equity in trading accounts:
Cash and cash equivalents (at cost $101,001,407 and $44,966,225, respectively)		101,001,407	44,966,225
Unrealized gain (loss) on open commodity futures contracts		55,721,680	37,435,507
Receivable for shares sold		0	4,646,990
Dividends receivable		17,044	14,954
Interest receivable		11,573	0
Prepaid registration fees		158,272	187,798
ETF transaction fees receivable		2,000	2,000
Total assets		707,848,863	610,073,331
Liabilities and Partners' Capital
Payable due to Broker		0	44,770,339
Payable for shares redeemed		54,457,966	26,641,069
General Partner management fees payable (Note 3)		312,466	303,354
Professional fees payable		892,759	437,218
Brokerage commissions payable		72,800	85,200
Directors' fees and insurance payable		8,345	5,417
License fees payable		12,794	19,932
Total liabilities		55,757,130	72,262,529
Commitments and Contingencies (Notes 3, 4 and 5)
Partners' Capital
General Partner		0	0
Limited Partners		652,091,733	537,810,802
Total Partners' Capital		652,091,733	537,810,802
Total liabilities and partners' capital		$ 707,848,863	$ 610,073,331
Limited Partners' shares outstanding	[1]	27,941,619	14,466,619
Net asset value per share	[1],[2],[3]	$ 23.34	$ 37.18
Market value per share	[1]	$ 23.32	$ 37.36

[1]	On January 4, 2018, there was a 1-for-4 reverse share split. Historical shares outstanding, net asset value per share and market value per share have been adjusted to reflect the 1-for-4 reverse share split on a retroactive basis.
[2]	On January 4, 2018, there was a 1-for-4 reverse share split. The Financial Highlights have been adjusted for the period shown to reflect the 1-for-4 reverse share split on a retroactive basis.
[3]	On January 4, 2018, there was a 1-for-4 reverse share split. The Statement of Changes in Partners’ Capital have been adjusted for the period shown to reflect the 1-for-4 reverse share split on a retroactive basis.

Schedule of Investments

Schedule of Investments	Dec. 31, 2017USD ($)Contracts		Dec. 31, 2016USD ($)Contracts
Value/ Unrealized Gain (Loss) on Open Commodity Contracts	$ 55,721,680		$ 37,435,507
Open Futures Contracts, Long [Member] \| United States [Member] \| NYMEX Natural Gas Futures NG February 2018 contracts, expiring January 2018 [Member]
Notional Amount	$ 461,049,780
Number of Contracts \| Contracts	17,082
Value/ Unrealized Gain (Loss) on Open Commodity Contracts	$ 43,381,680
% of Partners' Capital	6.66%
Open Futures Contracts, Long [Member] \| United States [Member] \| ICE Natural Gas Futures LD1 H February 2018 contracts, expiring February 2018 [Member]
Notional Amount	$ 135,310,000
Number of Contracts \| Contracts	20,000
Value/ Unrealized Gain (Loss) on Open Commodity Contracts	$ 12,340,000
% of Partners' Capital	1.89%
Open Futures Contracts, Long [Member] \| United States [Member] \| NYMEX Natural Gas Futures NG February 2017 contracts, expiring January 2017
Notional Amount			$ 326,459,573
Number of Contracts \| Contracts			9,442
Value/ Unrealized Gain (Loss) on Open Commodity Contracts			$ 25,160,507
% of Partners' Capital			4.68%
Open Futures Contracts, Long [Member] \| United States [Member] \| ICE Natural Gas Futures LD1 H February 2017 contracts, expiring February 2017
Notional Amount			$ 173,925,000
Number of Contracts \| Contracts			20,000
Value/ Unrealized Gain (Loss) on Open Commodity Contracts			$ 12,275,000
% of Partners' Capital			2.28%
Total Open Futures Contracts [Member] \| Open Futures Contracts, Long [Member] \| United States [Member]
Notional Amount	$ 596,359,780	[1]	$ 500,384,573	[2]
Number of Contracts \| Contracts	37,082	[1]	29,442	[2]
Value/ Unrealized Gain (Loss) on Open Commodity Contracts	$ 55,721,680	[1]	$ 37,435,507	[2]
% of Partners' Capital	8.55%	[1]	6.96%	[2]
Cash Equivalents [Member] \| United States [Member]
Market Value	$ 483,194,474		$ 484,298,065
% of Partners' Capital	74.10%		90.05%
Cash Equivalents [Member] \| United States [Member] \| US Treasury Securities [Member]
Market Value	$ 463,194,474		$ 434,298,065
% of Partners' Capital	71.04%		80.75%
Cash Equivalents [Member] \| United States [Member] \| US Treasury Securities [Member] \| U.S. Treasury Bills 1.12%, 1/04/2018 [Member]
Principal Amount	$ 10,000,000
Market Value	$ 9,999,071
% of Partners' Capital	1.53%
Cash Equivalents [Member] \| United States [Member] \| US Treasury Securities [Member] \| U.S. Treasury Bills 1.11%, 1/11/2018 [Member]
Principal Amount	$ 15,000,000
Market Value	$ 14,995,396
% of Partners' Capital	2.30%
Cash Equivalents [Member] \| United States [Member] \| US Treasury Securities [Member] \| U.S. Treasury Bills 1.10%, 1/18/2018 [Member]
Principal Amount	$ 15,000,000
Market Value	$ 14,992,279
% of Partners' Capital	2.30%
Cash Equivalents [Member] \| United States [Member] \| US Treasury Securities [Member] \| U.S. Treasury Bills 1.12%, 1/25/2018 [Member]
Principal Amount	$ 10,000,000
Market Value	$ 9,992,567
% of Partners' Capital	1.53%
Cash Equivalents [Member] \| United States [Member] \| US Treasury Securities [Member] \| U.S. Treasury Bills 1.12%, 2/01/2018 [Member]
Principal Amount	$ 10,000,000
Market Value	$ 9,990,399
% of Partners' Capital	1.53%
Cash Equivalents [Member] \| United States [Member] \| US Treasury Securities [Member] \| U.S. Treasury Bills 1.13%, 2/08/2018 [Member]
Principal Amount	$ 10,000,000
Market Value	$ 9,988,125
% of Partners' Capital	1.53%
Cash Equivalents [Member] \| United States [Member] \| US Treasury Securities [Member] \| U.S. Treasury Bills 1.12%, 2/15/2018 [Member]
Principal Amount	$ 10,000,000
Market Value	$ 9,986,125
% of Partners' Capital	1.53%
Cash Equivalents [Member] \| United States [Member] \| US Treasury Securities [Member] \| U.S. Treasury Bills 1.10%, 2/22/2018 [Member]
Principal Amount	$ 15,000,000
Market Value	$ 14,976,383
% of Partners' Capital	2.30%
Cash Equivalents [Member] \| United States [Member] \| US Treasury Securities [Member] \| U.S. Treasury Bills 1.09%, 3/01/2018 [Member]
Principal Amount	$ 20,000,000
Market Value	$ 19,964,436
% of Partners' Capital	3.06%
Cash Equivalents [Member] \| United States [Member] \| US Treasury Securities [Member] \| U.S. Treasury Bills 1.14%, 3/08/2018 [Member]
Principal Amount	$ 10,000,000
Market Value	$ 9,979,237
% of Partners' Capital	1.53%
Cash Equivalents [Member] \| United States [Member] \| US Treasury Securities [Member] \| U.S. Treasury Bills 1.14%, 3/15/2018 [Member]
Principal Amount	$ 10,000,000
Market Value	$ 9,977,086
% of Partners' Capital	1.53%
Cash Equivalents [Member] \| United States [Member] \| US Treasury Securities [Member] \| U.S. Treasury Bills 1.16%, 3/22/2018 [Member]
Principal Amount	$ 15,000,000
Market Value	$ 14,961,667
% of Partners' Capital	2.30%
Cash Equivalents [Member] \| United States [Member] \| US Treasury Securities [Member] \| U.S. Treasury Bills 1.17%, 3/29/2018 [Member]
Principal Amount	$ 15,000,000
Market Value	$ 14,957,950
% of Partners' Capital	2.29%
Cash Equivalents [Member] \| United States [Member] \| US Treasury Securities [Member] \| U.S. Treasury Bills 1.19%, 4/05/2018 [Member]
Principal Amount	$ 25,000,000
Market Value	$ 24,922,646
% of Partners' Capital	3.82%
Cash Equivalents [Member] \| United States [Member] \| US Treasury Securities [Member] \| U.S. Treasury Bills 1.22%, 4/12/2018 [Member]
Principal Amount	$ 25,000,000
Market Value	$ 24,914,781
% of Partners' Capital	3.82%
Cash Equivalents [Member] \| United States [Member] \| US Treasury Securities [Member] \| U.S. Treasury Bills 1.23%, 4/19/2018 [Member]
Principal Amount	$ 25,000,000
Market Value	$ 24,908,687
% of Partners' Capital	3.82%
Cash Equivalents [Member] \| United States [Member] \| US Treasury Securities [Member] \| U.S. Treasury Bills 1.25%, 4/26/2018 [Member]
Principal Amount	$ 25,000,000
Market Value	$ 24,900,972
% of Partners' Capital	3.82%
Cash Equivalents [Member] \| United States [Member] \| US Treasury Securities [Member] \| U.S. Treasury Bills 1.27%, 5/03/2018 [Member]
Principal Amount	$ 15,000,000
Market Value	$ 14,935,950
% of Partners' Capital	2.29%
Cash Equivalents [Member] \| United States [Member] \| US Treasury Securities [Member] \| U.S. Treasury Bills 1.32%, 5/10/2018 [Member]
Principal Amount	$ 20,000,000
Market Value	$ 19,906,117
% of Partners' Capital	3.05%
Cash Equivalents [Member] \| United States [Member] \| US Treasury Securities [Member] \| U.S. Treasury Bills 1.37%, 5/17/2018 [Member]
Principal Amount	$ 20,000,000
Market Value	$ 19,897,433
% of Partners' Capital	3.05%
Cash Equivalents [Member] \| United States [Member] \| US Treasury Securities [Member] \| U.S. Treasury Bills 1.43%, 5/24/2018 [Member]
Principal Amount	$ 20,000,000
Market Value	$ 19,887,586
% of Partners' Capital	3.05%
Cash Equivalents [Member] \| United States [Member] \| US Treasury Securities [Member] \| U.S. Treasury Bills 1.43%, 5/31/2018 [Member]
Principal Amount	$ 20,000,000
Market Value	$ 19,881,667
% of Partners' Capital	3.05%
Cash Equivalents [Member] \| United States [Member] \| US Treasury Securities [Member] \| U.S. Treasury Bills 1.45%, 6/07/2018 [Member]
Principal Amount	$ 20,000,000
Market Value	$ 19,874,400
% of Partners' Capital	3.05%
Cash Equivalents [Member] \| United States [Member] \| US Treasury Securities [Member] \| U.S. Treasury Bills 1.46%, 6/14/2018 [Member]
Principal Amount	$ 25,000,000
Market Value	$ 24,835,431
% of Partners' Capital	3.82%
Cash Equivalents [Member] \| United States [Member] \| US Treasury Securities [Member] \| Us Treasury Bills 1.49%, 6/21/2018 [Member]
Principal Amount	$ 30,000,000
Market Value	$ 29,789,100
% of Partners' Capital	4.57%
Cash Equivalents [Member] \| United States [Member] \| US Treasury Securities [Member] \| U.S. Treasury Bills 1.50%, 6/28/2018 [Member]
Principal Amount	$ 30,000,000
Market Value	$ 29,778,983
% of Partners' Capital	4.57%
Cash Equivalents [Member] \| United States [Member] \| US Treasury Securities [Member] \| U.S. Treasury Bills 0.34%, 1/05/2017 [Member]
Principal Amount			$ 15,000,000
Market Value			$ 14,999,433
% of Partners' Capital			2.79%
Cash Equivalents [Member] \| United States [Member] \| US Treasury Securities [Member] \| Us Treasury Bills 0.36%, 1/26/2017 [Member]
Principal Amount			$ 10,000,000
Market Value			$ 9,997,500
% of Partners' Capital			1.86%
Cash Equivalents [Member] \| United States [Member] \| US Treasury Securities [Member] \| Us Treasury Bills 0.40%, 2/02/2017 [Member]
Principal Amount			$ 10,000,000
Market Value			$ 9,996,444
% of Partners' Capital			1.86%
Cash Equivalents [Member] \| United States [Member] \| US Treasury Securities [Member] \| Us Treasury Bills 0.42%, 2/09/2017 [Member]
Principal Amount			$ 10,000,000
Market Value			$ 9,995,450
% of Partners' Capital			1.86%
Cash Equivalents [Member] \| United States [Member] \| US Treasury Securities [Member] \| Us Treasury Bills 0.45%, 2/16/2017 [Member]
Principal Amount			$ 10,000,000
Market Value			$ 9,994,250
% of Partners' Capital			1.86%
Cash Equivalents [Member] \| United States [Member] \| US Treasury Securities [Member] \| U.S Treasury Bills 0.45%, 2/23/2017 [Member]
Principal Amount			$ 10,000,000
Market Value			$ 9,993,449
% of Partners' Capital			1.86%
Cash Equivalents [Member] \| United States [Member] \| US Treasury Securities [Member] \| U.S Treasury Bills 0.45%, 3/02/2017 [Member]
Principal Amount			$ 15,000,000
Market Value			$ 14,988,750
% of Partners' Capital			2.79%
Cash Equivalents [Member] \| United States [Member] \| US Treasury Securities [Member] \| U.S Treasury Bills 0.47%, 3/09/2017 [Member]
Principal Amount			$ 15,000,000
Market Value			$ 14,986,879
% of Partners' Capital			2.79%
Cash Equivalents [Member] \| United States [Member] \| US Treasury Securities [Member] \| U.S Treasury Bills 0.50%, 3/16/2017 [Member]
Principal Amount			$ 15,000,000
Market Value			$ 14,984,506
% of Partners' Capital			2.79%
Cash Equivalents [Member] \| United States [Member] \| US Treasury Securities [Member] \| U.S Treasury Bills 0.45%, 3/23/2017 [Member]
Principal Amount			$ 20,000,000
Market Value			$ 19,979,975
% of Partners' Capital			3.71%
Cash Equivalents [Member] \| United States [Member] \| US Treasury Securities [Member] \| U.S Treasury Bills 0.43%, 3/30/2017 [Member]
Principal Amount			$ 25,000,000
Market Value			$ 24,973,722
% of Partners' Capital			4.64%
Cash Equivalents [Member] \| United States [Member] \| US Treasury Securities [Member] \| U.S Treasury Bills 0.46%, 4/06/2017 [Member]
Principal Amount			$ 20,000,000
Market Value			$ 19,975,986
% of Partners' Capital			3.71%
Cash Equivalents [Member] \| United States [Member] \| US Treasury Securities [Member] \| U.S Treasury Bills 0.47%, 4/13/2017 [Member]
Principal Amount			$ 25,000,000
Market Value			$ 24,966,708
% of Partners' Capital			4.64%
Cash Equivalents [Member] \| United States [Member] \| US Treasury Securities [Member] \| U.S Treasury Bills 0.46%, 4/20/2017 [Member]
Principal Amount			$ 25,000,000
Market Value			$ 24,965,559
% of Partners' Capital			4.64%
Cash Equivalents [Member] \| United States [Member] \| US Treasury Securities [Member] \| U.S Treasury Bills 0.47%, 4/27/2017 [Member]
Principal Amount			$ 25,000,000
Market Value			$ 24,962,542
% of Partners' Capital			4.64%
Cash Equivalents [Member] \| United States [Member] \| US Treasury Securities [Member] \| Us Treasury Bills 0.49%, 5/04/2017 [Member]
Principal Amount			$ 20,000,000
Market Value			$ 19,966,346
% of Partners' Capital			3.71%
Cash Equivalents [Member] \| United States [Member] \| US Treasury Securities [Member] \| Us Treasury Bills 0.55%, 5/11/2017 [Member]
Principal Amount			$ 20,000,000
Market Value			$ 19,960,639
% of Partners' Capital			3.71%
Cash Equivalents [Member] \| United States [Member] \| US Treasury Securities [Member] \| Us Treasury Bills 0.60%, 5/18/2017 [Member]
Principal Amount			$ 20,000,000
Market Value			$ 19,954,714
% of Partners' Capital			3.71%
Cash Equivalents [Member] \| United States [Member] \| US Treasury Securities [Member] \| Us Treasury Bills 0.61%, 5/25/2017 [Member]
Principal Amount			$ 20,000,000
Market Value			$ 19,951,400
% of Partners' Capital			3.71%
Cash Equivalents [Member] \| United States [Member] \| US Treasury Securities [Member] \| Us Treasury Bills 0.60%, 6/01/2017 [Member]
Principal Amount			$ 25,000,000
Market Value			$ 24,937,608
% of Partners' Capital			4.64%
Cash Equivalents [Member] \| United States [Member] \| US Treasury Securities [Member] \| Us Treasury Bills 0.62%, 6/08/2017 [Member]
Principal Amount			$ 20,000,000
Market Value			$ 19,946,017
% of Partners' Capital			3.71%
Cash Equivalents [Member] \| United States [Member] \| US Treasury Securities [Member] \| Us Treasury Bills 0.65%, 6/15/2017 [Member]
Principal Amount			$ 25,000,000
Market Value			$ 24,926,094
% of Partners' Capital			4.63%
Cash Equivalents [Member] \| United States [Member] \| US Treasury Securities [Member] \| Us Treasury Bills 0.64%, 6/22/2017 [Member]
Principal Amount			$ 20,000,000
Market Value			$ 19,938,844
% of Partners' Capital			3.71%
Cash Equivalents [Member] \| United States [Member] \| US Treasury Securities [Member] \| Us Treasury Bills 0.60%, 6/29/2017 [Member]
Principal Amount			$ 15,000,000
Market Value			$ 14,955,250
% of Partners' Capital			2.78%
Cash Equivalents [Member] \| United States [Member] \| Money Market Funds [Member]
Market Value	$ 20,000,000		$ 50,000,000
% of Partners' Capital	3.06%		9.30%
Cash Equivalents [Member] \| United States [Member] \| Money Market Funds [Member] \| Fidelity Investments Money Market Funds - Government Portfolio [Member]
Principal Amount	$ 10,000,000		$ 20,000,000
Market Value	$ 10,000,000		$ 20,000,000
% of Partners' Capital	1.53%		3.72%
Cash Equivalents [Member] \| United States [Member] \| Money Market Funds [Member] \| Goldman Sachs Financial Square Funds - Government Fund - Class FS [Member]
Principal Amount	$ 10,000,000		$ 20,000,000
Market Value	$ 10,000,000		$ 20,000,000
% of Partners' Capital	1.53%		3.72%
Cash Equivalents [Member] \| United States [Member] \| Money Market Funds [Member] \| Morgan Stanley Institutional Liquidity Funds - Government Portfolio [Member]
Principal Amount			$ 10,000,000
Market Value			$ 10,000,000
% of Partners' Capital			1.86%

[1]	Collateral amounted to $101,001,407 on open futures contracts.
[2]	Collateral amounted to $44,966,225 on open futures contracts.

Schedule of Investments (Parent

Schedule of Investments (Parenthetical) - USD ($)	12 Months Ended
Schedule of Investments (Parenthetical) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Collateral Amount On Open Futures Contracts	$ 101,001,407	$ 44,966,225
United States [Member] \| US Treasury Bill Securities 1.12%, 1/04/2018 [Member] \| US Treasury Securities [Member] \| Cash Equivalents [Member]
Interest rate	1.12%
Expiration date	1/04/2018
United States [Member] \| US Treasury Bill Securities 1.11%, 1/11/2018 [Member] \| US Treasury Securities [Member] \| Cash Equivalents [Member]
Interest rate	1.11%
Expiration date	1/11/2018
United States [Member] \| US Treasury Bill Securities 1.10%, 1/18/2018 [Member] \| US Treasury Securities [Member] \| Cash Equivalents [Member]
Interest rate	1.10%
Expiration date	1/18/2018
United States [Member] \| US Treasury Bill Securities 1.12%, 1/25/2018 [Member] \| US Treasury Securities [Member] \| Cash Equivalents [Member]
Interest rate	1.12%
Expiration date	1/25/2018
United States [Member] \| US Treasury Bill Securities 1.12%, 2/01/2018 [Member] \| US Treasury Securities [Member] \| Cash Equivalents [Member]
Interest rate	1.12%
Expiration date	2/01/2018
United States [Member] \| US Treasury Bill Securities 1.13%, 2/08/2018 [Member] \| US Treasury Securities [Member] \| Cash Equivalents [Member]
Interest rate	1.13%
Expiration date	2/08/2018
United States [Member] \| US Treasury Bill Securities 1.12%, 2/15/2018 [Member] \| US Treasury Securities [Member] \| Cash Equivalents [Member]
Interest rate	1.12%
Expiration date	2/15/2018
United States [Member] \| US Treasury Bill Securities 1.10%, 2/22/2018 [Member] \| US Treasury Securities [Member] \| Cash Equivalents [Member]
Interest rate	1.10%
Expiration date	2/22/2018
United States [Member] \| US Treasury Bill Securities 1.09%, 3/01/2018 [Member] \| US Treasury Securities [Member] \| Cash Equivalents [Member]
Interest rate	1.09%
Expiration date	3/01/2018
United States [Member] \| US Treasury Bill Securities 1.14%, 3/08/2018 [Member] \| US Treasury Securities [Member] \| Cash Equivalents [Member]
Interest rate	1.14%
Expiration date	3/08/2018
United States [Member] \| US Treasury Bill Securities 1.14%, 3/15/2018 [Member] \| US Treasury Securities [Member] \| Cash Equivalents [Member]
Interest rate	1.14%
Expiration date	3/15/2018
United States [Member] \| US Treasury Bill Securities 1.16%, 3/22/2018 [Member] \| US Treasury Securities [Member] \| Cash Equivalents [Member]
Interest rate	1.16%
Expiration date	3/22/2018
United States [Member] \| US Treasury Bill Securities 1.17%, 3/29/2018 [Member] \| US Treasury Securities [Member] \| Cash Equivalents [Member]
Interest rate	1.17%
Expiration date	3/29/2018
United States [Member] \| US Treasury Bill Securities 1.19%, 4/05/2018 [Member] \| US Treasury Securities [Member] \| Cash Equivalents [Member]
Interest rate	1.19%
Expiration date	4/05/2018
United States [Member] \| US Treasury Bill Securities 1.22%, 4/12/2018 [Member] \| US Treasury Securities [Member] \| Cash Equivalents [Member]
Interest rate	1.22%
Expiration date	4/12/2018
United States [Member] \| US Treasury Bill Securities 1.23%, 4/19/2018 [Member] \| US Treasury Securities [Member] \| Cash Equivalents [Member]
Interest rate	1.23%
Expiration date	4/19/2018
United States [Member] \| US Treasury Bill Securities 1.25%, 4/26/2018 [Member] \| US Treasury Securities [Member] \| Cash Equivalents [Member]
Interest rate	1.25%
Expiration date	4/26/2018
United States [Member] \| US Treasury Bill Securities 1.27%, 5/03/2018 [Member] \| US Treasury Securities [Member] \| Cash Equivalents [Member]
Interest rate	1.27%
Expiration date	5/03/2018
United States [Member] \| US Treasury Bill Securities 1.32%, 5/10/2018 [Member] \| US Treasury Securities [Member] \| Cash Equivalents [Member]
Interest rate	1.32%
Expiration date	5/10/2018
United States [Member] \| US Treasury Bill Securities 1.37%, 5/17/2018 [Member] \| US Treasury Securities [Member] \| Cash Equivalents [Member]
Interest rate	1.37%
Expiration date	5/17/2018
United States [Member] \| US Treasury Bill Securities 1.43%, 5/24/2018 [Member] \| US Treasury Securities [Member] \| Cash Equivalents [Member]
Interest rate	1.43%
Expiration date	5/24/2018
United States [Member] \| US Treasury Bill Securities 1.43%, 5/31/2018 [Member] \| US Treasury Securities [Member] \| Cash Equivalents [Member]
Interest rate	1.43%
Expiration date	5/31/2018
United States [Member] \| US Treasury Bill Securities 1.45%, 6/07/2018 [Member] \| US Treasury Securities [Member] \| Cash Equivalents [Member]
Interest rate	1.45%
Expiration date	6/07/2018
United States [Member] \| US Treasury Bill Securities 1.46%, 6/14/2018 [Member] \| US Treasury Securities [Member] \| Cash Equivalents [Member]
Interest rate	1.46%
Expiration date	6/14/2018
United States [Member] \| US Treasury Bill Securities 1.49%, 6/21/2018 [Member] \| US Treasury Securities [Member] \| Cash Equivalents [Member]
Interest rate	1.49%
Expiration date	6/21/2018
United States [Member] \| US Treasury Bill Securities 1.50%, 6/28/2018 [Member] \| US Treasury Securities [Member] \| Cash Equivalents [Member]
Interest rate	1.50%
Expiration date	6/28/2018
United States [Member] \| U.S. Treasury Bills Securities 0.34%, 1/05/2017 [Member] \| US Treasury Securities [Member] \| Cash Equivalents [Member]
Interest rate		0.34%
Expiration date		1/05/2017
United States [Member] \| U.S. Treasury Bills Securities 0.36%, 1/26/2017 [Member] \| US Treasury Securities [Member] \| Cash Equivalents [Member]
Interest rate		0.36%
Expiration date		1/26/2017
United States [Member] \| Us Treasury Bills Securities 0.40%, 2/02/2017 [Member] \| US Treasury Securities [Member] \| Cash Equivalents [Member]
Interest rate		0.40%
Expiration date		2/02/2017
United States [Member] \| Us Treasury Bills Securities 0.42%, 2/09/2017 [Member] \| US Treasury Securities [Member] \| Cash Equivalents [Member]
Interest rate		0.42%
Expiration date		2/09/2017
United States [Member] \| Us Treasury Bills Securities 0.45%, 2/16/2017 [Member] \| US Treasury Securities [Member] \| Cash Equivalents [Member]
Interest rate		0.45%
Expiration date		2/16/2017
United States [Member] \| Us Treasury Bills Securities 0.45%, 2/23/2017 [Member] \| US Treasury Securities [Member] \| Cash Equivalents [Member]
Interest rate		0.45%
Expiration date		2/23/2017
United States [Member] \| Us Treasury Bills Securities 0.45%, 3/02/2017 [Member] \| US Treasury Securities [Member] \| Cash Equivalents [Member]
Interest rate		0.45%
Expiration date		3/02/2017
United States [Member] \| Us Treasury Bills Securities 0.47%, 3/09/2017 [Member] \| US Treasury Securities [Member] \| Cash Equivalents [Member]
Interest rate		0.47%
Expiration date		3/09/2017
United States [Member] \| Us Treasury Bills Securities 0.50%, 3/16/2017 [Member] \| US Treasury Securities [Member] \| Cash Equivalents [Member]
Interest rate		0.50%
Expiration date		3/16/2017
United States [Member] \| Us Treasury Bills Securities 0.45%, 3/23/2017 [Member] \| US Treasury Securities [Member] \| Cash Equivalents [Member]
Interest rate		0.45%
Expiration date		3/23/2017
United States [Member] \| Us Treasury Bills Securities 0.43%, 3/30/2017 [Member] \| US Treasury Securities [Member] \| Cash Equivalents [Member]
Interest rate		0.43%
Expiration date		3/30/2017
United States [Member] \| Us Treasury Bills Securities 0.46%, 4/06/2017 [Member] \| US Treasury Securities [Member] \| Cash Equivalents [Member]
Interest rate		0.46%
Expiration date		4/06/2017
United States [Member] \| Us Treasury Bills Securities 0.47%, 4/13/2017 [Member] \| US Treasury Securities [Member] \| Cash Equivalents [Member]
Interest rate		0.47%
Expiration date		4/13/2017
United States [Member] \| Us Treasury Bills Securities 0.46%, 4/20/2017 [Member] \| US Treasury Securities [Member] \| Cash Equivalents [Member]
Interest rate		0.46%
Expiration date		4/20/2017
United States [Member] \| Us Treasury Bills Securities 0.47%, 4/27/2017 [Member] \| US Treasury Securities [Member] \| Cash Equivalents [Member]
Interest rate		0.47%
Expiration date		4/27/2017
United States [Member] \| Us Treasury Bills Securities 0.49%, 5/04/2017 [Member] \| US Treasury Securities [Member] \| Cash Equivalents [Member]
Interest rate		0.49%
Expiration date		5/04/2017
United States [Member] \| Us Treasury Bills Securities 0.55%, 5/11/2017 [Member] \| US Treasury Securities [Member] \| Cash Equivalents [Member]
Interest rate		0.55%
Expiration date		5/11/2017
United States [Member] \| Us Treasury Bills Securities 0.60%, 5/18/2017 [Member] \| US Treasury Securities [Member] \| Cash Equivalents [Member]
Interest rate		0.60%
Expiration date		5/18/2017
United States [Member] \| Us Treasury Bills Securities 0.61%, 5/25/2017 [Member] \| US Treasury Securities [Member] \| Cash Equivalents [Member]
Interest rate		0.61%
Expiration date		5/25/2017
United States [Member] \| Us Treasury Bills Securities 0.60%, 6/01/2017 [Member] \| US Treasury Securities [Member] \| Cash Equivalents [Member]
Interest rate		0.60%
Expiration date		6/01/2017
United States [Member] \| Us Treasury Bills Securities 0.62%, 6/08/2017 [Member] \| US Treasury Securities [Member] \| Cash Equivalents [Member]
Interest rate		0.62%
Expiration date		6/08/2017
United States [Member] \| Us Treasury Bills Securities 0.65%, 6/15/2017 [Member] \| US Treasury Securities [Member] \| Cash Equivalents [Member]
Interest rate		0.65%
Expiration date		6/15/2017
United States [Member] \| Us Treasury Bills Securities 0.64%, 6/22/2017 [Member] \| US Treasury Securities [Member] \| Cash Equivalents [Member]
Interest rate		0.64%
Expiration date		6/22/2017
United States [Member] \| Us Treasury Bills Securities 0.60%, 6/29/2017 [Member] \| US Treasury Securities [Member] \| Cash Equivalents [Member]
Interest rate		0.60%
Expiration date		6/29/2017

Statements of Operations

Statements of Operations - USD ($)		12 Months Ended
Statements of Operations - USD ($)		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Gain (loss) on trading of commodity futures contracts:
Realized gain (loss) on closed futures contracts		$ (209,701,928)	$ 166,847,846	$ (507,207,439)
Change in unrealized gain (loss) on open futures contracts		18,286,173	(63,973,835)	269,221,125
Realized gain (loss) on short-term investments		(1,172)	0	0
Dividend income		148,745	117,246	64,640
Interest income	[1]	3,982,312	1,707,539	340,320
ETF transaction fees		277,000	133,000	156,000
Total income (loss)		(187,008,870)	104,831,796	(237,425,354)
Expenses
General Partner management fees (Note 3)		2,972,340	3,263,777	3,645,561
Professional fees		1,390,036	254,042	1,109,436
Brokerage commissions		1,728,440	2,000,888	2,371,433
Directors' fees and insurance		64,982	94,521	118,994
License fees		74,309	81,594	91,139
Registration fees		204,998	404,792	379,106
Total expenses		6,435,105	6,099,614	7,715,669
Net income (loss)		$ (193,443,975)	$ 98,732,182	$ (245,141,023)
Net income (loss) per limited partnership share	[2]	$ (13.84)	$ 2.42	$ (23.75)
Net income (loss) per weighted average limited partnership share	[2]	$ (10.54)	$ 5.6	$ (19.93)
Weighted average limited partnership shares outstanding	[2]	18,356,071	17,619,898	12,299,290

[1]	Interest income does not exceed paid in kind of 5%.
[2]	On January 4, 2018, there was a 1-for-4 reverse share split. The Statement of Operations have been adjusted for the period shown to reflect the 1-for-4 reverse share split on a retroactive basis.

Statements of Changes in Partne

Statements of Changes in Partners' Capital - USD ($)		Total	General Partner [Member]	Limited Partners [Member]
Balances at Dec. 31, 2014		$ 650,353,579	$ 0	$ 650,353,579
Addition of partnership shares		1,622,768,501	0	1,622,768,501
Redemption of partnership shares		(1,513,008,177)	0	(1,513,008,177)
Net income (loss)		(245,141,023)	0	(245,141,023)
Balances at Dec. 31, 2015		$ 514,972,880	0	514,972,880
Net asset value, beginning of year at Dec. 31, 2014	[1],[2]	$ 58.50
Net asset value, end of year at Dec. 31, 2015	[1],[2]	$ 34.76
Addition of partnership shares		$ 731,029,440	0	731,029,440
Redemption of partnership shares		(806,923,700)	0	(806,923,700)
Net income (loss)		98,732,182	0	98,732,182
Balances at Dec. 31, 2016		$ 537,810,802	0	537,810,802
Net asset value, end of year at Dec. 31, 2016	[1],[2],[3]	$ 37.18
Addition of partnership shares		$ 1,781,669,130	0	1,781,669,130
Redemption of partnership shares		(1,473,944,224)	0	(1,473,944,224)
Net income (loss)		(193,443,975)	0	(193,443,975)
Balances at Dec. 31, 2017		$ 652,091,733	$ 0	$ 652,091,733
Net asset value, end of year at Dec. 31, 2017	[1],[2],[3]	$ 23.34

[1]	On January 4, 2018, there was a 1-for-4 reverse share split. The Financial Highlights have been adjusted for the period shown to reflect the 1-for-4 reverse share split on a retroactive basis.
[2]	On January 4, 2018, there was a 1-for-4 reverse share split. The Statement of Changes in Partners’ Capital have been adjusted for the period shown to reflect the 1-for-4 reverse share split on a retroactive basis.
[3]	On January 4, 2018, there was a 1-for-4 reverse share split. Historical shares outstanding, net asset value per share and market value per share have been adjusted to reflect the 1-for-4 reverse share split on a retroactive basis.

Statements of Changes in Partn7

Statements of Changes in Partners' Capital (Parenthetical) - shares		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Addition of partnership units	[1]	66,825,000	23,900,000	32,500,000
Redemption of partnership units	[1]	53,350,000	24,250,000	28,800,000

[1]	On January 4, 2018, there was a 1-for-4 reverse share split. The Statement of Changes in Partners’ Capital have been adjusted for the period shown to reflect the 1-for-4 reverse share split on a retroactive basis.

Statements of Cash Flows

Statements of Cash Flows - USD ($)	12 Months Ended
Statements of Cash Flows - USD ($)	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash Flows from Operating Activities:
Net income (loss)	$ (193,443,975)	$ 98,732,182	$ (245,141,023)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
(Increase) decrease in commodity futures trading account - cash and cash equivalents	(56,035,182)	(20,024,673)	201,219,414
Unrealized (gain) loss on open futures contracts	(18,286,173)	63,973,835	(269,221,125)
(Increase) decrease in dividends receivable	(2,090)	(14,212)	6,665
(Increase) decrease in interest receivable	(11,573)	0	0
(Increase) decrease in directors' fees and insurance receivable	0	26,732	(9,371)
(Increase) decrease in prepaid registration fees	29,526	404,792	58,107
(Increase) decrease in ETF transaction fees receivable	0	0	(2,000)
Increase (decrease) in payable due to Broker	(44,770,339)	3,906,389	40,863,950
Increase (decrease) in General Partner management fees payable	9,112	53,400	(114,291)
Increase (decrease) in professional fees payable	455,541	(713,180)	(162,250)
Increase (decrease) in brokerage commissions payable	(12,400)	1,450	11,000
Increase (decrease) in directors' fees and insurance payable	2,928	5,417	0
Increase (decrease) in license fees payable	(7,138)	(1,954)	(6,027)
Net cash provided by (used in) operating activities	(312,071,763)	146,350,178	(272,496,951)
Cash Flows from Financing Activities:
Addition of partnership shares	1,786,316,120	726,382,450	1,626,007,655
Redemption of partnership shares	(1,446,127,327)	(803,743,255)	(1,489,547,553)
Net cash provided by (used in) financing activities	340,188,793	(77,360,805)	136,460,102
Net Increase (Decrease) in Cash and Cash Equivalents	28,117,030	68,989,373	(136,036,849)
Cash and Cash Equivalents, beginning of year	522,819,857	453,830,484	589,867,333
Cash and Cash Equivalents, end of year	$ 550,936,887	$ 522,819,857	$ 453,830,484

ORGANIZATION AND BUSINESS

ORGANIZATION AND BUSINESS	12 Months Ended
ORGANIZATION AND BUSINESS	Dec. 31, 2017
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 Fifth Amended and Restated Agreement of Limited Partnership dated as of December 15, 2017 (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 it will be measured by the futures contract that is the next month contract to expire (the “Benchmark Futures Contract”), less UNG’s expenses. UNG’s investment objective is not nor 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 (“OTC”) 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, diesel-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 annual report on Form 10-K. As of December 31, 2017, UNG held 17,082 20,000 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 registered as a commodity pool operator 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 USCF Canadian Crude Oil Index Fund (“UCCO”), each a series of the United States Commodity Index Funds Trust. USCI, CPER and USAG listed their shares on the NYSE Arca under the ticker symbols “USCI” on August 10, 2010, “CPER” on November 15, 2011 and “USAG” on April 13, 2012, respectively. UCCO is currently in registration and has not commenced operations. In addition, USCF is the sponsor of the USCF Funds Trust, a Delaware statutory trust, and each of its series, the REX S&P MLP Fund (“RMLP”) and the REX S&P MLP Inverse Fund (“MLPD”), which are currently in registration and have not commenced operations (together, the “REX Funds”), and the United States 3x Oil Fund (“USOU”) and the United States 3x Short Oil Fund (“USOD”) which commenced operations on July 20, 2017. All funds listed previously, other than UCCO and the REX Funds, are referred to collectively herein as the “Related Public Funds.” UNG issues shares to certain authorized purchasers (“Authorized Participants”) by offering baskets consisting of 100,000 In addition, Authorized Participants pay UNG a $ 1,000 100,000 In April 2007, UNG initially registered 30,000,000 50.00 200,000 10,001,000 April 18, 2007 2,080,000,000 On February 21, 2012, after the close of trading on the NYSE Arca, UNG effected a 1-for-4 reverse share split and post-split shares of UNG began trading on February 22, 2012. As a result of the reverse share split, every four pre-split shares of UNG were automatically exchanged for one post-split share. Immediately prior to the reverse share split, there were 174,297,828 5.51 43,574,457 22.04 On January 4, 2018, after the close of trading on the NYSE Arca, UNG effected a 1-for-4 reverse share split and post-split shares of UNG began trading on January 5, 2018. As a result of the reverse share split, every four pre-split shares of UNG were automatically exchanged for one post-split share. Immediately prior to the reverse split, there were 97,466,476 5.69 24,366,619 22.76

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	12 Months Ended
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	Dec. 31, 2017
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	NOTE 2 SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES The financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America ("U.S. 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. 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 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 financial statements. Changes in the unrealized gains or losses between periods are reflected in the statements of operations. UNG earns income on funds held at the custodian or futures commission merchant (“FCM”) at prevailing market rates earned on such investments. Investments in OTC 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 OTC 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 statements of operations. Brokerage commissions on all open commodity futures contracts are accrued on a full-turn basis. 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 U.S. 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 2014. 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 year ended December 31, 2017. Authorized Participants may purchase Creation Baskets or redeem Redemption Baskets only in blocks of 100,000 UNG receives or pays the proceeds from shares sold or redeemed within two business days after the trade date of the purchase or redemption. The amounts due from Authorized Participants are reflected in UNG’s statements of financial condition as receivable for shares sold, and amounts payable to Authorized Participants upon redemption are reflected as payable for shares redeemed. Authorized Participants pay UNG a transaction fee of $ 1,000 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. 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 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 December 31, 2017. 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 include money market funds and overnight deposits or time deposits with original maturity dates of six months or less. Certain amounts in the accompanying financial statements were reclassified to conform to the current presentation. The preparation of financial statements in conformity with U.S. 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 financial statements, and the reported amounts of the revenue and expenses during the reporting period. Actual results may differ from those estimates and assumptions. On February 21, 2012, after the close of the NYSE Arca, UNG effected a 1-for-4 reverse share split and post-split shares of UNG began trading on February 22, 2012. The audited financial statements in this annual report on Form 10-K are presented in accordance with Accounting Standards Codification 260 for purposes of presenting the 1-for-4 reverse split on a historical basis for all periods reported.

FEES PAID BY THE FUND AND RELAT

FEES PAID BY THE FUND AND RELATED PARTY TRANSACTIONS	12 Months Ended
FEES PAID BY THE FUND AND RELATED PARTY TRANSACTIONS	Dec. 31, 2017
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, equal to 0.60% per annum of average daily total net assets of $ 1,000,000,000 0.50 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 years ended December 31, 2017, 2016 and 2015, UNG incurred $ 204,998 404,792 379,106 Independent Directors’ and Officers’ 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. 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 ended December 31, 2017 were $536,375 for UNG and the Related Public Funds. UNG's portion of such fees and expenses for the year ended December 31, 2017 was $ 64,982 94,521 569,303 118,994 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 through October 19, 2011, UNG and the Related Public Funds, other than BNO, USCI, CPER and USAG, paid a licensing fee that was equal to 0.04 0.02 0.015 74,309 81,594 91,139 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 were approximately $ 1,000,000 Other Expenses and Fees In addition to the fees described above, UNG pays all brokerage fees, transaction costs for OTC swaps, if any, taxes and other expenses in connection with the operation of UNG, excluding costs and expenses paid by USCF as outlined in Note 4 Contracts and Agreements

CONTRACTS AND AGREEMENTS

CONTRACTS AND AGREEMENTS	12 Months Ended
CONTRACTS AND AGREEMENTS	Dec. 31, 2017
Contractors [Abstract]
Contracts and Agreements	NOTE 4 CONTRACTS AND AGREEMENTS Marketing Agent Agreement 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 3 0.04 3 10 The above fee does not include website construction and development, which are also borne by USCF. Brown Brothers Harriman & Co. Agreements 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 20,000 0.06 500 0.0465 500 1 0.035 1 7 15 Brokerage and Futures Commission Merchant Agreements On October 8, 2013, UNG entered into a brokerage agreement with RBC Capital Markets, LLC (“RBC Capital” or “RBC”) to serve as UNG’s FCM effective October 10, 2013. The agreement with RBC requires it 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 for UNG’s account. In accordance with the agreement, RBC Capital charges UNG commissions of approximately $ 7 8 For the Year Ended For the Year Ended For the Year Ended Total commissions accrued to brokers $ 1,728,440 $ 2,000,888 $ 2,371,433 Total commissions as annualized percentage of average total net assets 0.35 % 0.37 % 0.39 % Commissions accrued as a result of rebalancing $ 1,420,519 $ 1,872,019 $ 2,089,974 Percentage of commissions accrued as a result of rebalancing 82.19 % 93.56 % 88.13 % Commissions accrued as a result of creation and redemption activity $ 307,921 $ 128,869 $ 281,459 Percentage of commissions accrued as a result of creation and redemption activity 17.81 % 6.44 % 11.87 % The decrease in total commissions accrued to brokers for the year ended December 31, 2017, compared to the year ended December 31, 2016, was due primarily to a lower number of natural gas Futures Contracts being held and traded. The decrease in total commissions accrued to brokers for the year ended December 31, 2016, compared to the year ended December 31, 2015, was due primarily to lower number of Futures Contracts being held and traded. However, there can be no assurance that commission costs and portfolio turnover will not cause commission expenses to rise in future quarters. NYMEX Licensing Agreement 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, USOU and USOD, 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, OFF-BALA

FINANCIAL INSTRUMENTS, OFF-BALANCE SHEET RISKS AND CONTINGENCIES	12 Months Ended
	Dec. 31, 2017
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 may engage in the trading of futures contracts, options on futures contracts, cleared swaps and OTC 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 and cleared 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 agreements that are eligible to be cleared by a clearinghouse, e.g., ICE Clear Europe, and 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 an FCM. Additional deposits may be necessary for any loss on contract value. The Commodity Exchange Act requires an FCM to segregate all customer transactions and assets from the FCM’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 the futures contracts held by UNG through December 31, 2017 were exchange-traded. The risks associated with exchange-traded contracts are generally perceived to be less than those associated with OTC swaps since, in OTC swaps, a party must rely solely on the credit of its respective individual counterparties. As of December 31, 2015, UNG maintained no OTC swap transactions. The OTC swap transaction with JPMorgan Chase Bank, NA was terminated effective April 23, 2014. 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. UNG’s cash and other property, such as Treasuries, deposited with an FCM are considered commingled with all other customer funds, subject to the FCM’s segregation requirements. In the event of an FCM’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 an FCM could result in the complete loss of UNG’s assets posted with that FCM; however, the majority of UNG’s assets are held in investments in Treasuries, cash and/or cash equivalents with UNG’s custodian and would not be impacted by the insolvency of an FCM. 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 December 31, 2017 and December 31, 2016, UNG held investments in money market funds in the amounts of $ 20,000,000 50,000,000 631,938,294 517,786,082 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 broker or counterparty with which it conducts business. The financial instruments held by UNG are reported in its 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	12 Months Ended
FINANCIAL HIGHLIGHTS	Dec. 31, 2017
Financial Highlights [Abstract]
Financial Highlights	NOTE 6 FINANCIAL HIGHLIGHTS Year ended December Year ended December Year ended December Per Share Operating Performance: Net asset value, beginning of year $ 37.18 * $ 34.76 * $ 58.50 * Total income (loss) (13.49) * 2.77 * (23.12) * Total expenses (0.35) * (0.35) * (0.62) * Net increase (decrease) in net asset value (13.84) * 2.42 * (23.74) * Net asset value, end of year $ 23.34 * $ 37.18 * $ 34.76 * Total Return (37.22) % 6.90 % (40.60) % Ratios to Average Net Assets Total income (loss) (37.75) % 19.27 % (39.08) % Management fees 0.60 % 0.60 % 0.60 % Expenses excluding management fees 0.70 % 0.52 % 0.67 % Net income (loss) (39.05) % 18.15 % (40.35) % * On January 4, 2018, there was a 1-for-4 reverse share split. The Financial Highlights have been adjusted for the period shown to reflect the 1-for-4 reverse share split on a retroactive basis. 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.

QUARTERLY FINANCIAL DATA (Unaud

QUARTERLY FINANCIAL DATA (Unaudited)	12 Months Ended
QUARTERLY FINANCIAL DATA (Unaudited)	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Data (Unaudited)	NOTE 7 - QUARTERLY FINANCIAL DATA (Unaudited) First Second Third Fourth Total Income (Loss) $ (93,242,321) $ (43,745,913) $ (10,667,801) $ (39,352,835) Total Expenses 1,636,118 1,473,807 1,365,327 1,959,853 Net Income (Loss) $ (94,878,439) $ (45,219,720) $ (12,033,128) $ (41,312,688) Net Income (Loss) per Share $ (6.90) * $ (3.15) * $ (0.96) * $ (2.83) * First Second Third Fourth Total Income (Loss) $ (113,577,426) $ 153,225,194 $ (18,658,356) $ 83,842,384 Total Expenses 1,479,702 1,571,572 1,449,083 1,599,257 Net Income (Loss) $ (115,057,128) $ 151,653,622 $ (20,107,439) $ 82,243,127 Net Income (Loss) per Share $ (8.15) * $ 8.00 * $ (1.31) * $ 3.88 * * Adjusted to give effect to the reverse share split of 1-for-4 executed on January 4, 2018.

FAIR VALUE OF FINANCIAL INSTRUM

FAIR VALUE OF FINANCIAL INSTRUMENTS	12 Months Ended
FAIR VALUE OF FINANCIAL INSTRUMENTS	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	NOTE 8 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 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 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. At December 31, 2017 Total Level I Level II Level III Short-Term Investments $ 483,194,474 $ 483,194,474 $ $ Exchange-Traded Futures Contracts United States Contracts 55,721,680 55,721,680 During the year ended December 31, 2017, there were no transfers between Level I and Level II. The following table summarizes the valuation of UNG’s securities at December 31, 2016 using the fair value hierarchy: At December 31, 2016 Total Level I Level II Level III Short-Term Investments $ 484,298,065 $ 484,298,065 $ $ Exchange-Traded Futures Contracts United States Contracts 37,435,507 37,435,507 During the year ended December 31, 2016, there were no transfers between Level I and Level II. 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. Derivatives not Statements of Financial Fair Value Fair Value Futures - Commodity Contracts Assets $ 55,721,680 $ 37,435,507 For the year ended For the year ended For the year ended Derivatives Location of Realized Change in Realized Change in Realized Change in Futures - Commodity Contracts Realized gain (loss) on closed positions $ (209,701,928) $ 166,847,846 $ (507,207,439) Change in unrealized gain (loss) on open positions $ 18,286,173 $ (63,973,835) $ 269,221,125

RECENT ACCOUNTING PRONOUNCEMENT

RECENT ACCOUNTING PRONOUNCEMENTS	12 Months Ended
RECENT ACCOUNTING PRONOUNCEMENTS	Dec. 31, 2017
Accounting Changes and Error Corrections [Abstract]
Recent Accounting Pronouncements	NOTE 9 - RECENT ACCOUNTING PRONOUNCEMENTS In August 2015, the Financial Accounting Standards Board (“FASB”) issued Accounting Standard Update (“ASU”) 2015-14, Revenue from Contracts with Customers, modifying ASU 2014-09. The core principle of the guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. ASU 2015-14 is effective for fiscal years beginning on or after December 15, 2016, and interim periods within those annual periods. Early application is permitted. At this time, management does not believe there will be any impact to the Fund’s financial statements.

SUBSEQUENT EVENTS

SUBSEQUENT EVENTS	12 Months Ended
SUBSEQUENT EVENTS	Dec. 31, 2017
Subsequent Events [Abstract]
Subsequent Events	NOTE 10 SUBSEQUENT EVENTS UNG has performed an evaluation of subsequent events through the date the financial statements were issued. This evaluation did not result in any subsequent events that necessitated disclosures and/or adjustments.

SUMMARY OF SIGNIFICANT ACCOUN19

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	12 Months Ended
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	Dec. 31, 2017
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America ("U.S. 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 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 financial statements. Changes in the unrealized gains or losses between periods are reflected in the statements of operations. UNG earns income on funds held at the custodian or futures commission merchant (“FCM”) at prevailing market rates earned on such investments. Investments in OTC 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 OTC 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 statements of operations.
Brokerage Commissions	Brokerage Commissions Brokerage commissions on all open commodity futures contracts are accrued on a full-turn basis.
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 U.S. 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 2014. 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 year ended December 31, 2017.
Creations and Redemptions	Creations and Redemptions Authorized Participants may purchase Creation Baskets or redeem Redemption Baskets only in blocks of 100,000 UNG receives or pays the proceeds from shares sold or redeemed within two business days after the trade date of the purchase or redemption. The amounts due from Authorized Participants are reflected in UNG’s statements of financial condition as receivable for shares sold, and amounts payable to Authorized Participants upon redemption are reflected as payable for shares redeemed. Authorized Participants pay UNG a transaction fee of $ 1,000
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 Share NAV	Calculation of Per Share NAV 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 December 31, 2017.
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 financial statements were reclassified to conform to the current presentation.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with U.S. 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 financial statements, and the reported amounts of the revenue and expenses during the reporting period. Actual results may differ from those estimates and assumptions.
Other	Other On February 21, 2012, after the close of the NYSE Arca, UNG effected a 1-for-4 reverse share split and post-split shares of UNG began trading on February 22, 2012. The audited financial statements in this annual report on Form 10-K are presented in accordance with Accounting Standards Codification 260 for purposes of presenting the 1-for-4 reverse split on a historical basis for all periods reported.

CONTRACTS AND AGREEMENTS (Table

CONTRACTS AND AGREEMENTS (Tables)	12 Months Ended
CONTRACTS AND AGREEMENTS (Tables)	Dec. 31, 2017
Contractors [Abstract]
Brokerage Commissions	For the Year Ended For the Year Ended For the Year Ended Total commissions accrued to brokers $ 1,728,440 $ 2,000,888 $ 2,371,433 Total commissions as annualized percentage of average total net assets 0.35 % 0.37 % 0.39 % Commissions accrued as a result of rebalancing $ 1,420,519 $ 1,872,019 $ 2,089,974 Percentage of commissions accrued as a result of rebalancing 82.19 % 93.56 % 88.13 % Commissions accrued as a result of creation and redemption activity $ 307,921 $ 128,869 $ 281,459 Percentage of commissions accrued as a result of creation and redemption activity 17.81 % 6.44 % 11.87 %

FINANCIAL HIGHLIGHTS (Tables)

FINANCIAL HIGHLIGHTS (Tables)	12 Months Ended
FINANCIAL HIGHLIGHTS (Tables)	Dec. 31, 2017
Financial Highlights [Abstract]
Per Unit Performance Data and Other Supplemental Financial Data	Year ended December Year ended December Year ended December Per Share Operating Performance: Net asset value, beginning of year $ 37.18 * $ 34.76 * $ 58.50 * Total income (loss) (13.49) * 2.77 * (23.12) * Total expenses (0.35) * (0.35) * (0.62) * Net increase (decrease) in net asset value (13.84) * 2.42 * (23.74) * Net asset value, end of year $ 23.34 * $ 37.18 * $ 34.76 * Total Return (37.22) % 6.90 % (40.60) % Ratios to Average Net Assets Total income (loss) (37.75) % 19.27 % (39.08) % Management fees 0.60 % 0.60 % 0.60 % Expenses excluding management fees 0.70 % 0.52 % 0.67 % Net income (loss) (39.05) % 18.15 % (40.35) % * On January 4, 2018, there was a 1-for-4 reverse share split. The Financial Highlights have been adjusted for the period shown to reflect the 1-for-4 reverse share split on a retroactive basis.

QUARTERLY FINANCIAL DATA (Una22

QUARTERLY FINANCIAL DATA (Unaudited) (Tables)	12 Months Ended
QUARTERLY FINANCIAL DATA (Unaudited) (Tables)	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Data	First Second Third Fourth Total Income (Loss) $ (93,242,321) $ (43,745,913) $ (10,667,801) $ (39,352,835) Total Expenses 1,636,118 1,473,807 1,365,327 1,959,853 Net Income (Loss) $ (94,878,439) $ (45,219,720) $ (12,033,128) $ (41,312,688) Net Income (Loss) per Share $ (6.90) * $ (3.15) * $ (0.96) * $ (2.83) * First Second Third Fourth Total Income (Loss) $ (113,577,426) $ 153,225,194 $ (18,658,356) $ 83,842,384 Total Expenses 1,479,702 1,571,572 1,449,083 1,599,257 Net Income (Loss) $ (115,057,128) $ 151,653,622 $ (20,107,439) $ 82,243,127 Net Income (Loss) per Share $ (8.15) * $ 8.00 * $ (1.31) * $ 3.88 * * Adjusted to give effect to the reverse share split of 1-for-4 executed on January 4, 2018.

FAIR VALUE OF FINANCIAL INSTR23

FAIR VALUE OF FINANCIAL INSTRUMENTS (Tables)	12 Months Ended
FAIR VALUE OF FINANCIAL INSTRUMENTS (Tables)	Dec. 31, 2017
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 December 31, 2017 using the fair value hierarchy: At December 31, 2017 Total Level I Level II Level III Short-Term Investments $ 483,194,474 $ 483,194,474 $ $ Exchange-Traded Futures Contracts United States Contracts 55,721,680 55,721,680 During the year ended December 31, 2017, there were no transfers between Level I and Level II. The following table summarizes the valuation of UNG’s securities at December 31, 2016 using the fair value hierarchy: At December 31, 2016 Total Level I Level II Level III Short-Term Investments $ 484,298,065 $ 484,298,065 $ $ Exchange-Traded Futures Contracts United States Contracts 37,435,507 37,435,507
Fair Value of Derrivative Instruments	Fair Value of Derivative Instruments Derivatives not Statements of Financial Fair Value Fair Value Futures - Commodity Contracts Assets $ 55,721,680 $ 37,435,507
Effect of Derivative Instruments on the Statements of Operations	The Effect of Derivative Instruments on the Statements of Operations For the year ended For the year ended For the year ended Derivatives Location of Realized Change in Realized Change in Realized Change in Futures - Commodity Contracts Realized gain (loss) on closed positions $ (209,701,928) $ 166,847,846 $ (507,207,439) Change in unrealized gain (loss) on open positions $ 18,286,173 $ (63,973,835) $ 269,221,125

ORGANIZATION AND BUSINESS (Addi

ORGANIZATION AND BUSINESS (Additional Information) (Details)

Jan. 04, 2018$ / sharesshares

Feb. 21, 2012$ / sharesshares

Apr. 30, 2007

Apr. 18, 2007USD ($)$ / sharesshares

Dec. 31, 2017Contracts$ / shares$ / Unit

Dec. 31, 2016$ / shares

[1],[2],[3]

Dec. 31, 2015$ / shares

[2],[3]

Dec. 31, 2014$ / shares

[2],[3]

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 | $ / Unit

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 | $ / shares

$ 50

$ 23.34

[1],[2],[3]

$ 37.18

$ 34.76

$ 58.50

Number of units issued | shares

200,000

Value of unit issued | $

$ 10,001,000

Number of registered units

2,080,000,000

Committee For Uniform Securities Identification Procedure Cusip

CUSIP number of UNGs shares changed to 912318201

Operations Commenced Date

Apr. 18,
2007

Reverse unit split ratio

Pre-split units of USNG automatically exchanged for one post-split unit

Subsequent Event [Member]

Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]

Committee For Uniform Securities Identification Procedure Cusip

CUSIP number of UNG’s shares changed to 912318201

Reverse unit split ratio

Pre-split units of USNG automatically exchanged for one post-split unit

Open Futures Contracts, Long [Member] | United States [Member] | NYMEX Natural Gas Futures Contracts [Member]

Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]

Number of Contracts | Contracts

17,082

Open Futures Contracts, Long [Member] | United States [Member] | ICE Natural Gas Futures LD1 H Contracts [Member]

Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]

Number of Contracts | Contracts

20,000

Prior to Reverse Split [Member]

Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]

Net Asset Value Per Unit | $ / shares

$ 5.51

Issued units | shares

174,297,828

Stockholders' Equity, Reverse Stock Split

1-for-4 reverse share split

Prior to Reverse Split [Member] | Subsequent Event [Member]

Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]

Net Asset Value Per Unit | $ / shares

$ 5.69

Issued units | shares

97,466,476

Stockholders' Equity, Reverse Stock Split

1-for-4 reverse share split

Following Reverse Split [Member]

Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]

Net Asset Value Per Unit | $ / shares

$ 22.04

Capital Units, Outstanding | shares

43,574,457

Following Reverse Split [Member] | Subsequent Event [Member]

Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]

Net Asset Value Per Unit | $ / shares

$ 22.76

Capital Units, Outstanding | shares

24,366,619

Creation Baskets [Member]

Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]

Number of units per basket | $ / Unit

100,000

Redemption Baskets [Member]

Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]

Number of units per basket | $ / Unit

100,000

[1]

On January 4, 2018, there was a 1-for-4 reverse share split. Historical shares outstanding, net asset value per share and market value per share have been adjusted to reflect the 1-for-4 reverse share split on a retroactive basis.

[2]

On January 4, 2018, there was a 1-for-4 reverse share split. The Financial Highlights have been adjusted for the period shown to reflect the 1-for-4 reverse share split on a retroactive basis.

[3]

On January 4, 2018, there was a 1-for-4 reverse share split. The Statement of Changes in Partners’ Capital have been adjusted for the period shown to reflect the 1-for-4 reverse share split on a retroactive basis.

SUMMARY OF SIGNIFICANT ACCOUN25

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Additional Information) (Details)	Dec. 31, 2017$ / Unit
Significant Accounting Policies [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
Redemption Baskets [Member]
Significant Accounting Policies [Line Items]
Number of units per basket	100,000

FEES PAID BY THE FUND AND REL26

FEES PAID BY THE FUND AND RELATED PARTY TRANSACTIONS (Additional Information) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Fees Paid and Related Party Transactions [Line Items]
USCF Management Fee	UNG. For these services, UNG is contractually obligated to pay USCF a fee, which is paid monthly, 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.
Licensing fee incurred	$ 74,309	$ 81,594	$ 91,139
Estimated investor tax reporting cost	1,000,000	400,000	800,000
Estimated directors fees and expenses	64,982	94,521	118,994
USNG and the Related Public Funds [Member]
Fees Paid and Related Party Transactions [Line Items]
Estimated directors fees and expenses	536,375	582,050	569,303
UNITED STATES GAS FUND LP [Member]
Fees Paid and Related Party Transactions [Line Items]
Licensing fee incurred	74,309	81,594
Estimated directors fees and expenses	$ 64,982
First $1,000,000,000 of combined net assets of the funds [Member]
Fees Paid and Related Party Transactions [Line Items]
Fee percentage	0.04%
Basis Amount For Fee Percentage	1,000,000,000
Combined net assets above $1,000,000,000 [Member]
Fees Paid and Related Party Transactions [Line Items]
Fee percentage	0.02%
Basis Amount For Fee Percentage	1,000,000,000
Licensing Agreements [Member]
Fees Paid and Related Party Transactions [Line Items]
Fee percentage	0.015%
United States Oil Fund LP [Member]
Fees Paid and Related Party Transactions [Line Items]
Ongoing Registration Fees and Other Offering Expenses	$ 204,998	404,792	379,106
Estimated directors fees and expenses		$ 94,521	$ 118,994

CONTRACTS AND AGREEMENTS (Broke

CONTRACTS AND AGREEMENTS (Brokerage Commission) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Commissions accrued to brokers	$ 1,728,440	$ 2,000,888	$ 2,371,433
Percentage of commissions accrued	0.35%	0.37%	0.39%
Rebalancing Investments Transaction [Member]
Commissions accrued to brokers	$ 1,420,519	$ 1,872,019	$ 2,089,974
Percentage of commissions accrued	82.19%	93.56%	88.13%
Creation And Redemption Activity [Member]
Commissions accrued to brokers	$ 307,921	$ 128,869	$ 281,459
Percentage of commissions accrued	17.81%	6.44%	11.87%

CONTRACTS AND AGREEMENTS (Addit

CONTRACTS AND AGREEMENTS (Additional Information) (Details)	12 Months Ended
CONTRACTS AND AGREEMENTS (Additional Information) (Details)	Dec. 31, 2017USD ($)$ / 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

FINANCIAL INSTRUMENTS, OFF-BA29

FINANCIAL INSTRUMENTS, OFF-BALANCE SHEET RISKS AND CONTINGENCIES (Additional Information) (Details) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Carrying Amounts and Fair Values of Financial Instruments or Liabilities [Line Items]
Cash investments in money market funds	$ 20,000,000	$ 50,000,000
Deposits in domestic and foreign financial institutions	$ 631,938,294	$ 517,786,082

FINANCIAL HIGHLIGHTS (Per Unit

FINANCIAL HIGHLIGHTS (Per Unit Performance Data and Other Supplemental Financial Data) (Details) - $ / shares		12 Months Ended
		Dec. 31, 2017		Dec. 31, 2016		Dec. 31, 2015
Per Share Operating Performance:
Net asset value, beginning of year	[2],[3]	$ 37.18	[1]	$ 34.76		$ 58.50
Total income (loss)		(13.49)		2.77	[2]	(23.12)	[2]
Total expenses		(0.35)		(0.35)		(0.62)	[2]
Net increase (decrease) in net asset value		(13.84)		2.42	[2]	(23.74)	[2]
Net asset value, end of year	[2],[3]	$ 23.34	[1]	$ 37.18	[1]	$ 34.76
Total Return		(37.22%)		6.90%		(40.60%)
Ratios to Average Net Assets
Total income (loss)		(37.75%)		19.27%		(39.08%)
Management fees		0.60%		0.60%		0.60%
Expenses excluding management fees		0.70%		0.52%		0.67%
Net income (loss)		(39.05%)		18.15%		(40.35%)

[1]	On January 4, 2018, there was a 1-for-4 reverse share split. Historical shares outstanding, net asset value per share and market value per share have been adjusted to reflect the 1-for-4 reverse share split on a retroactive basis.
[2]	On January 4, 2018, there was a 1-for-4 reverse share split. The Financial Highlights have been adjusted for the period shown to reflect the 1-for-4 reverse share split on a retroactive basis.
[3]	On January 4, 2018, there was a 1-for-4 reverse share split. The Statement of Changes in Partners’ Capital have been adjusted for the period shown to reflect the 1-for-4 reverse share split on a retroactive basis.

QUARTERLY FINANCIAL DATA (Una31

QUARTERLY FINANCIAL DATA (Unaudited) (Summarized Quarterly Financial Information) (Details) - USD ($)	3 Months Ended																12 Months Ended
	Dec. 31, 2017		Sep. 30, 2017		Jun. 30, 2017		Mar. 31, 2017		Dec. 31, 2016		Sep. 30, 2016		Jun. 30, 2016		Mar. 31, 2016		Dec. 31, 2017		Dec. 31, 2016		Dec. 31, 2015
Quarterly Financial Information [Line Items]
Total Income (Loss)	$ (39,352,835)		$ (10,667,801)		$ (43,745,913)		$ (93,242,321)		$ 83,842,384		$ (18,658,356)		$ 153,225,194		$ (113,577,426)		$ (187,008,870)		$ 104,831,796		$ (237,425,354)
Total Expenses	1,959,853		1,365,327		1,473,807		1,636,118		1,599,257		1,449,083		1,571,572		1,479,702		6,435,105		6,099,614		7,715,669
Net Income (Loss)	$ (41,312,688)		$ (12,033,128)		$ (45,219,720)		$ (94,878,439)		$ 82,243,127		$ (20,107,439)		$ 151,653,622		$ (115,057,128)		$ (193,443,975)		$ 98,732,182		$ (245,141,023)
Net Income (Loss) per Share	$ (2.83)	[1]	$ (0.96)	[1]	$ (3.15)	[1]	$ (6.90)	[1]	$ 3.88	[1]	$ (1.31)	[1]	$ 8	[1]	$ (8.15)	[1]	$ (13.84)	[2]	$ 2.42	[2]	$ (23.75)	[2]

[1]	Adjusted to give effect to the reverse share split of 1-for-4 executed on January 4, 2018.
[2]	On January 4, 2018, there was a 1-for-4 reverse share split. The Statement of Operations have been adjusted for the period shown to reflect the 1-for-4 reverse share split on a retroactive basis.

FAIR VALUE OF FINANCIAL INSTR32

FAIR VALUE OF FINANCIAL INSTRUMENTS (Valuation of Securities Using Fair Value Hierarchy) (Details) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Short-Term Investments [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Securities, fair value	$ 483,194,474	$ 484,298,065
Exchange-Traded Futures Contracts [Member] \| United States Contracts [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Securities, fair value	55,721,680	37,435,507
Fair Value, Inputs, Level 1 [Member] \| Short-Term Investments [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Securities, fair value	483,194,474	484,298,065
Fair Value, Inputs, Level 1 [Member] \| Exchange-Traded Futures Contracts [Member] \| United States Contracts [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Securities, fair value	55,721,680	37,435,507
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 Contracts [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Securities, fair value	0	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 Contracts [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Securities, fair value	$ 0	$ 0

FAIR VALUE OF FINANCIAL INSTR33

FAIR VALUE OF FINANCIAL INSTRUMENTS (Fair Value of Derivative Instruments) (Details) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Commodity Contracts [Member] \| Futures - Commodity Contracts [Member] \| Assets [Member]
Fair Value of Financial Instruments [Line Items]
Derivatives not Accounted for as Hedging Instruments	$ 55,721,680	$ 37,435,507

FAIR VALUE OF FINANCIAL INSTR34

FAIR VALUE OF FINANCIAL INSTRUMENTS (Effect of Derivative Instruments on Condensed Statements of Operations) (Details) - Commodity Contracts [Member] - Futures - Commodity Contracts [Member] - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Derivative Instruments, Gain (Loss) [Line Items]
Realized Gain (Loss) on Derivatives Recognized in Income	$ (209,701,928)	$ 166,847,846	$ (507,207,439)
Change in Unrealized Gain (Loss) on Derivatives Recognized in Income	$ 18,286,173	$ (63,973,835)	$ 269,221,125