United States 12 Month Natural Gas Fund (UNL) 10-K 21 Mar 18 2017 FY Annual report Financial data

Document And Entity Information

Document And Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2017	Mar. 19, 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 12 Month Natural Gas Fund, LP
Entity Central Index Key	1,405,513
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	Non-accelerated Filer
Entity Public Float			$ 9,481,000
Trading Symbol	UNL
Entity Common Stock, Shares Outstanding		800,000

Statements of Financial Conditi

Statements of Financial Condition - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Assets
Cash and cash equivalents (at cost $7,217,601 and $15,061,018, respectively) (Notes 2 and 5)	$ 7,217,601	$ 15,061,018
Equity in trading accounts:
Cash and cash equivalents (at cost $1,701,275 and $699,804, respectively)	1,701,275	699,804
Unrealized gain (loss) on open commodity futures contracts	(568,922)	2,796,004
Receivable from General Partner (Note 3)	61,713	102,092
Dividends receivable	2,319	1,488
Interest receivable	88	0
Directors' fees and insurance receivable	66	0
ETF transaction fees receivable	0	350
Total assets	8,414,140	18,660,756
Liabilities and Partners' Capital
Payable due to Broker	0	2,099,689
General Partner management fees payable (Note 3)	5,493	10,437
Professional fees payable	72,695	102,301
Brokerage commissions payable	1,181	1,801
Directors' fees and insurance payable	0	106
License fees payable	331	744
Total liabilities	79,700	2,215,078
Commitments and Contingencies (Notes 3, 4 and 5)
Partners' Capital
General Partner	0	0
Limited Partners	8,334,440	16,445,678
Total Partners' Capital	8,334,440	16,445,678
Total liabilities and partners' capital	$ 8,414,140	$ 18,660,756
Limited Partners' shares outstanding	900,000	1,400,000
Net asset value per share	$ 9.26	$ 11.75
Market value per share	$ 9.18	$ 11.69

Schedule of Investments

Schedule of Investments	Dec. 31, 2017USD ($)Contracts		Dec. 31, 2016USD ($)Contracts
United States [Member] | Money Market Funds [Member]
Market Value	$ 2,500,000		$ 5,000,000
% of Partners' Capital	30.00%		30.40%
United States [Member] | Fidelity Investments Money Market Funds - Government Portfolio [Member] | Money Market Funds [Member]
Principal Amount	$ 1,000,000		$ 2,000,000
Market Value	$ 1,000,000		$ 2,000,000
% of Partners' Capital	12.00%		12.16%
United States [Member] | Goldman Sachs Financial Square Funds - Government Fund - Class FS [Member] | Money Market Funds [Member]
Principal Amount	$ 1,000,000		$ 1,000,000
Market Value	$ 1,000,000		$ 1,000,000
% of Partners' Capital	12.00%		6.08%
United States [Member] | Morgan Stanley Institutional Liquidity Funds - Government Portfolio [Member] | Money Market Funds [Member]
Principal Amount	$ 500,000		$ 2,000,000
Market Value	$ 500,000		$ 2,000,000
% of Partners' Capital	6.00%		12.16%
Cash Equivalents [Member] | United States Treasury Obligations [Member]
Market Value	$ 5,183,698		$ 6,292,035
% of Partners' Capital	62.19%		38.26%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills: 1.12%, 1/04/2018 [Member]
Principal Amount	$ 200,000
Market Value	$ 199,981
% of Partners' Capital	2.40%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills: 1.11%, 1/11/2018 [Member]
Principal Amount	$ 300,000
Market Value	$ 299,908
% of Partners' Capital	3.60%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills: 1.10%, 1/18/2018 [Member]
Principal Amount	$ 300,000
Market Value	$ 299,846
% of Partners' Capital	3.60%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills: 1.12%, 1/25/2018 [Member]
Principal Amount	$ 300,000
Market Value	$ 299,777
% of Partners' Capital	3.60%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills: 1.12%, 2/01/2018 [Member]
Principal Amount	$ 200,000
Market Value	$ 199,808
% of Partners' Capital	2.40%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills: 1.13%, 2/08/2018 [Member]
Principal Amount	$ 200,000
Market Value	$ 199,763
% of Partners' Capital	2.40%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills: 1.12%, 2/15/2018 [Member]
Principal Amount	$ 200,000
Market Value	$ 199,723
% of Partners' Capital	2.40%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills: 1.10%, 2/22/2018 [Member]
Principal Amount	$ 200,000
Market Value	$ 199,685
% of Partners' Capital	2.40%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills: 1.09%, 3/01/2018 [Member]
Principal Amount	$ 100,000
Market Value	$ 99,822
% of Partners' Capital	1.20%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills: 1.14%, 3/08/2018 [Member]
Principal Amount	$ 200,000
Market Value	$ 199,585
% of Partners' Capital	2.39%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills: 1.14%, 3/15/2018 [Member]
Principal Amount	$ 200,000
Market Value	$ 199,542
% of Partners' Capital	2.39%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills: 1.16%, 3/22/2018 [Member]
Principal Amount	$ 200,000
Market Value	$ 199,489
% of Partners' Capital	2.39%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills: 1.17%, 3/29/2018 [Member]
Principal Amount	$ 200,000
Market Value	$ 199,439
% of Partners' Capital	2.39%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills: 1.19%, 4/05/2018 [Member]
Principal Amount	$ 200,000
Market Value	$ 199,381
% of Partners' Capital	2.39%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills: 1.22%, 4/12/2018 [Member]
Principal Amount	$ 100,000
Market Value	$ 99,659
% of Partners' Capital	1.19%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills: 1.23%, 4/19/2018 [Member]
Principal Amount	$ 200,000
Market Value	$ 199,270
% of Partners' Capital	2.39%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills: 1.25%, 4/26/2018 [Member]
Principal Amount	$ 200,000
Market Value	$ 199,208
% of Partners' Capital	2.39%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills: 1.27%, 5/03/2018 [Member]
Principal Amount	$ 100,000
Market Value	$ 99,573
% of Partners' Capital	1.19%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills: 1.32%, 5/10/2018 [Member]
Principal Amount	$ 200,000
Market Value	$ 199,061
% of Partners' Capital	2.39%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills: 1.37%, 5/17/2018 [Member]
Principal Amount	$ 200,000
Market Value	$ 198,974
% of Partners' Capital	2.39%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills: 1.43%, 5/24/2018 [Member]
Principal Amount	$ 200,000
Market Value	$ 198,876
% of Partners' Capital	2.39%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills: 1.43%, 5/31/2018 [Member]
Principal Amount	$ 100,000
Market Value	$ 99,408
% of Partners' Capital	1.19%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills: 1.45%, 6/07/2018 [Member]
Principal Amount	$ 300,000
Market Value	$ 298,116
% of Partners' Capital	3.58%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills: 1.46%, 6/14/2018 [Member]
Principal Amount	$ 200,000
Market Value	$ 198,683
% of Partners' Capital	2.38%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills: 1.49%, 6/21/2018 [Member]
Principal Amount	$ 200,000
Market Value	$ 198,594
% of Partners' Capital	2.38%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills: 1.50%, 6/28/2018 [Member]
Principal Amount	$ 200,000
Market Value	$ 198,527
% of Partners' Capital	2.38%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills: 0.34%, 1/05/2017 [Member]
Principal Amount			$ 400,000
Market Value			$ 399,985
% of Partners' Capital			2.43%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills :0.43%, 1/19/2017 [Member]
Principal Amount			$ 500,000
Market Value			$ 499,894
% of Partners' Capital			3.04%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills : 0.36%, 1/26/2017 [Member]
Principal Amount			$ 500,000
Market Value			$ 499,875
% of Partners' Capital			3.04%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills : 0.40%, 2/02/2017 [Member]
Principal Amount			$ 200,000
Market Value			$ 199,929
% of Partners' Capital			1.22%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills : 0.42%, 2/09/2017 [Member]
Principal Amount			$ 300,000
Market Value			$ 299,864
% of Partners' Capital			1.82%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills : 0.45%, 2/16/2017 [Member]
Principal Amount			$ 200,000
Market Value			$ 199,885
% of Partners' Capital			1.22%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills : 0.45%, 2/23/2017 [Member]
Principal Amount			$ 300,000
Market Value			$ 299,803
% of Partners' Capital			1.82%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills : 0.45%, 3/02/2017 [Member]
Principal Amount			$ 200,000
Market Value			$ 199,850
% of Partners' Capital			1.22%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills : 0.47%, 3/09/2017 [Member]
Principal Amount			$ 200,000
Market Value			$ 199,825
% of Partners' Capital			1.22%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills : 0.50%, 3/16/2017 [Member]
Principal Amount			$ 200,000
Market Value			$ 199,793
% of Partners' Capital			1.22%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills : 0.45%, 3/23/2017 [Member]
Principal Amount			$ 300,000
Market Value			$ 299,700
% of Partners' Capital			1.82%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills : 0.43%, 3/30/2017 [Member]
Principal Amount			$ 200,000
Market Value			$ 199,790
% of Partners' Capital			1.22%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills : 0.46%, 4/06/2017 [Member]
Principal Amount			$ 200,000
Market Value			$ 199,760
% of Partners' Capital			1.22%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills : 0.47%, 4/13/2017 [Member]
Principal Amount			$ 200,000
Market Value			$ 199,734
% of Partners' Capital			1.22%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills : 0.46%, 4/20/2017 [Member]
Principal Amount			$ 200,000
Market Value			$ 199,725
% of Partners' Capital			1.21%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills : 0.47%, 4/27/2017 [Member]
Principal Amount			$ 200,000
Market Value			$ 199,700
% of Partners' Capital			1.21%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills :0.49%, 5/04/2017 [Member]
Principal Amount			$ 200,000
Market Value			$ 199,663
% of Partners' Capital			1.21%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills : 0.55%, 5/11/2017 [Member]
Principal Amount			$ 200,000
Market Value			$ 199,606
% of Partners' Capital			1.21%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills : 0.60%, 5/18/2017 [Member]
Principal Amount			$ 200,000
Market Value			$ 199,547
% of Partners' Capital			1.21%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills : 0.61%, 5/25/2017 [Member]
Principal Amount			$ 200,000
Market Value			$ 199,514
% of Partners' Capital			1.21%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills : 0.60%, 6/01/2017 [Member]
Principal Amount			$ 200,000
Market Value			$ 199,501
% of Partners' Capital			1.21%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills : 0.62%, 6/08/2017 [Member]
Principal Amount			$ 300,000
Market Value			$ 299,190
% of Partners' Capital			1.82%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills : 0.65%, 6/15/2017 [Member]
Principal Amount			$ 200,000
Market Value			$ 199,409
% of Partners' Capital			1.21%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills : 0.64%, 6/22/2017 [Member]
Principal Amount			$ 200,000
Market Value			$ 199,388
% of Partners' Capital			1.21%
Cash Equivalents [Member] | United States Treasury Obligations [Member] | U.S. Treasury Bills : 0.60%, 6/29/2017 [Member]
Principal Amount			$ 300,000
Market Value			$ 299,105
% of Partners' Capital			1.82%
Cash Equivalents [Member] | United States [Member]
Market Value	$ 7,683,698		$ 11,292,035
% of Partners' Capital	92.19%		68.66%
Open Futures Contracts, Long [Member] | United States [Member]
Notional Amount	$ 8,907,842	[1]	$ 13,642,496	[2]
Number of Contracts | Contracts	292	[1]	454	[2]
Unrealized Gain (Loss) on Open Commodity Contracts	$ (568,922)	[1]	$ 2,796,004	[2]
% of Partners' Capital	(6.83%)	[1]	17.00%	[2]
Open Futures Contracts, Long [Member] | United States [Member] | NYMEX Natural Gas Futures NG February 2018 contracts, expiring January 2018 [Member]
Notional Amount	$ 872,763
Number of Contracts | Contracts	24
Unrealized Gain (Loss) on Open Commodity Contracts	$ (164,043)
% of Partners' Capital	(1.97%)
Open Futures Contracts, Long [Member] | United States [Member] | NYMEX Natural Gas Futures NG March 2018 contracts, expiring February 2018 [Member]
Notional Amount	$ 832,869
Number of Contracts | Contracts	24
Unrealized Gain (Loss) on Open Commodity Contracts	$ (135,429)
% of Partners' Capital	(1.63%)
Open Futures Contracts, Long [Member] | United States [Member] | NYMEX Natural Gas Futures NG April 2018 contracts, expiring March 2018 [Member]
Notional Amount	$ 715,113
Number of Contracts | Contracts	25
Unrealized Gain (Loss) on Open Commodity Contracts	$ (27,863)
% of Partners' Capital	(0.33%)
Open Futures Contracts, Long [Member] | United States [Member] | NYMEX Natural Gas Futures NG May 2018 contracts, expiring April 2018 [Member]
Notional Amount	$ 685,247
Number of Contracts | Contracts	24
Unrealized Gain (Loss) on Open Commodity Contracts	$ (27,407)
% of Partners' Capital	(0.33%)
Open Futures Contracts, Long [Member] | United States [Member] | NYMEX Natural Gas Futures NG June 2018 contracts, expiring May 2018 [Member]
Notional Amount	$ 731,645
Number of Contracts | Contracts	25
Unrealized Gain (Loss) on Open Commodity Contracts	$ (38,395)
% of Partners' Capital	(0.46%)
Open Futures Contracts, Long [Member] | United States [Member] | NYMEX Natural Gas Futures NG July 2018 contracts, expiring June 2018 [Member]
Notional Amount	$ 692,833
Number of Contracts | Contracts	24
Unrealized Gain (Loss) on Open Commodity Contracts	$ (19,873)
% of Partners' Capital	(0.24%)
Open Futures Contracts, Long [Member] | United States [Member] | NYMEX Natural Gas Futures NG August 2018 contracts, expiring July 2018 [Member]
Notional Amount	$ 722,063
Number of Contracts | Contracts	25
Unrealized Gain (Loss) on Open Commodity Contracts	$ (20,313)
% of Partners' Capital	(0.24%)
Open Futures Contracts, Long [Member] | United States [Member] | NYMEX Natural Gas Futures NG September 2018 contracts, expiring August 2018 [Member]
Notional Amount	$ 693,242
Number of Contracts | Contracts	24
Unrealized Gain (Loss) on Open Commodity Contracts	$ (23,882)
% of Partners' Capital	(0.29%)
Open Futures Contracts, Long [Member] | United States [Member] | NYMEX Natural Gas Futures NG October 2018 contracts, expiring September 2018 [Member]
Notional Amount	$ 712,475
Number of Contracts | Contracts	24
Unrealized Gain (Loss) on Open Commodity Contracts	$ (37,595)
% of Partners' Capital	(0.45%)
Open Futures Contracts, Long [Member] | United States [Member] | NYMEX Natural Gas Futures NG November 2018 contracts, expiring October 2018 [Member]
Notional Amount	$ 762,732
Number of Contracts | Contracts	25
Unrealized Gain (Loss) on Open Commodity Contracts	$ (45,982)
% of Partners' Capital	(0.55%)
Open Futures Contracts, Long [Member] | United States [Member] | NYMEX Natural Gas Futures NG December 2018 contracts, expiring November 2018 [Member]
Notional Amount	$ 762,850
Number of Contracts | Contracts	24
Unrealized Gain (Loss) on Open Commodity Contracts	$ (43,570)
% of Partners' Capital	(0.52%)
Open Futures Contracts, Long [Member] | United States [Member] | NYMEX Natural Gas Futures NG January 2019 contracts, expiring December 2018 [Member]
Notional Amount	$ 724,010
Number of Contracts | Contracts	24
Unrealized Gain (Loss) on Open Commodity Contracts	$ 15,430
% of Partners' Capital	0.18%
Open Futures Contracts, Long [Member] | United States [Member] | NYMEX Natural Gas Futures NG February 2017 contracts, expiring January 2017 [Member]
Notional Amount			$ 1,090,833
Number of Contracts | Contracts			38
Unrealized Gain (Loss) on Open Commodity Contracts			$ 324,287
% of Partners' Capital			1.97%
Open Futures Contracts, Long [Member] | United States [Member] | NYMEX Natural Gas Futures NG March 2017 contracts, expiring February 2017 [Member]
Notional Amount			$ 1,027,264
Number of Contracts | Contracts			38
Unrealized Gain (Loss) on Open Commodity Contracts			$ 372,656
% of Partners' Capital			2.27%
Open Futures Contracts, Long [Member] | United States [Member] | NYMEX Natural Gas Futures NG April 2017 contracts, expiring March 2017 [Member]
Notional Amount			$ 959,850
Number of Contracts | Contracts			37
Unrealized Gain (Loss) on Open Commodity Contracts			$ 359,570
% of Partners' Capital			2.19%
Open Futures Contracts, Long [Member] | United States [Member] | NYMEX Natural Gas Futures NG May 2017 contracts, expiring April 2017 [Member]
Notional Amount			$ 1,026,488
Number of Contracts | Contracts			38
Unrealized Gain (Loss) on Open Commodity Contracts			$ 319,852
% of Partners' Capital			1.94%
Open Futures Contracts, Long [Member] | United States [Member] | NYMEX Natural Gas Futures NG June 2017 contracts, expiring May 2017 [Member]
Notional Amount			$ 1,083,055
Number of Contracts | Contracts			38
Unrealized Gain (Loss) on Open Commodity Contracts			$ 269,745
% of Partners' Capital			1.64%
Open Futures Contracts, Long [Member] | United States [Member] | NYMEX Natural Gas Futures NG July 2017 contracts, expiring June 2017 [Member]
Notional Amount			$ 1,138,072
Number of Contracts | Contracts			38
Unrealized Gain (Loss) on Open Commodity Contracts			$ 224,608
% of Partners' Capital			1.37%
Open Futures Contracts, Long [Member] | United States [Member] | NYMEX Natural Gas Futures NG August 2017 contracts, expiring July 2017 [Member]
Notional Amount			$ 1,178,151
Number of Contracts | Contracts			38
Unrealized Gain (Loss) on Open Commodity Contracts			$ 180,349
% of Partners' Capital			1.10%
Open Futures Contracts, Long [Member] | United States [Member] | NYMEX Natural Gas Futures NG September 2017 contracts, expiring August 2017 [Member]
Notional Amount			$ 1,125,511
Number of Contracts | Contracts			38
Unrealized Gain (Loss) on Open Commodity Contracts			$ 224,249
% of Partners' Capital			1.36%
Open Futures Contracts, Long [Member] | United States [Member] | NYMEX Natural Gas Futures NG October 2017 contracts, expiring September 2017 [Member]
Notional Amount			$ 1,134,848
Number of Contracts | Contracts			37
Unrealized Gain (Loss) on Open Commodity Contracts			$ 186,052
% of Partners' Capital			1.13%
Open Futures Contracts, Long [Member] | United States [Member] | NYMEX Natural Gas Futures NG November 2017 contracts, expiring October 2017 [Member]
Notional Amount			$ 1,271,197
Number of Contracts | Contracts			38
Unrealized Gain (Loss) on Open Commodity Contracts			$ 98,323
% of Partners' Capital			0.60%
Open Futures Contracts, Long [Member] | United States [Member] | NYMEX Natural Gas Futures NG December 2017 contracts, expiring November 2017 [Member]
Notional Amount			$ 1,218,727
Number of Contracts | Contracts			38
Unrealized Gain (Loss) on Open Commodity Contracts			$ 188,413
% of Partners' Capital			1.14%
Open Futures Contracts, Long [Member] | United States [Member] | NYMEX Natural Gas Futures NG January 2018 contracts, expiring December 2017 [Member]
Notional Amount			$ 1,388,500
Number of Contracts | Contracts			38
Unrealized Gain (Loss) on Open Commodity Contracts			$ 47,900
% of Partners' Capital			0.29%
[1]	Collateral amounted to $1,701,275 on open futures contracts.
[2]	Collateral amounted to $699,804 on open futures contracts.

Schedule of Investments (Parent

Schedule of Investments (Parenthetical) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Debt Instrument, Collateral Amount	$ 1,701,275	$ 699,804
Cash Equivalents [Member] | Us Treasury Securities [Member] | U.S. Treasury Bills: 1.12%, 1/04/2018 [Member]
Expiration date	1/04/2018
Interest Rate	1.12%
Cash Equivalents [Member] | Us Treasury Securities [Member] | U.S. Treasury Bills: 1.11%, 1/11/2018 [Member]
Expiration date	1/11/2018
Interest Rate	1.11%
Cash Equivalents [Member] | Us Treasury Securities [Member] | U.S. Treasury Bills: 1.10%, 1/18/2018 [Member]
Expiration date	1/18/2018
Interest Rate	1.10%
Cash Equivalents [Member] | Us Treasury Securities [Member] | U.S. Treasury Bills: 1.12%, 01/25/2018 [Member]
Expiration date	1/25/2018
Interest Rate	1.12%
Cash Equivalents [Member] | Us Treasury Securities [Member] | U.S. Treasury Bills: 1.12%, 2/01/2018 [Member]
Expiration date	2/01/2018
Interest Rate	1.12%
Cash Equivalents [Member] | Us Treasury Securities [Member] | U.S. Treasury Bills: 1.13%, 2/08/2018 [Member]
Expiration date	2/08/2018
Interest Rate	1.13%
Cash Equivalents [Member] | Us Treasury Securities [Member] | U.S. Treasury Bills: 1.12%, 2/15/2018 [Member]
Expiration date	2/15/2018
Interest Rate	1.12%
Cash Equivalents [Member] | Us Treasury Securities [Member] | U.S. Treasury Bills: 1.10%, 2/22/2018 [Member]
Expiration date	2/22/2018
Interest Rate	1.10%
Cash Equivalents [Member] | Us Treasury Securities [Member] | U.S. Treasury Bills:1.09%, 3/01/2018[Member]
Expiration date	3/01/2018
Interest Rate	1.09%
Cash Equivalents [Member] | Us Treasury Securities [Member] | U.S. Treasury Bills:1.14%, 3/08/2018 [Member]
Expiration date	3/08/2018
Interest Rate	1.14%
Cash Equivalents [Member] | Us Treasury Securities [Member] | U.S. Treasury Bills: 1.14%, 3/15/2018 [Member]
Expiration date	3/15/2018
Interest Rate	1.14%
Cash Equivalents [Member] | Us Treasury Securities [Member] | U.S. Treasury Bills:1.16%,3/22/2018 [Member]
Expiration date	3/22/2018
Interest Rate	1.16%
Cash Equivalents [Member] | Us Treasury Securities [Member] | U.S. Treasury Bills: 1.17%, 3/29/2018 [Member]
Expiration date	3/29/2018
Interest Rate	1.17%
Cash Equivalents [Member] | Us Treasury Securities [Member] | U.S. Treasury Bills:1.19%, 4/05/2018 [Member]
Expiration date	4/05/2018
Interest Rate	1.19%
Cash Equivalents [Member] | Us Treasury Securities [Member] | U.S. Treasury Bills: 1.22%, 4/12/2018 [Member]
Expiration date	4/12/2018
Interest Rate	1.22%
Cash Equivalents [Member] | Us Treasury Securities [Member] | U.S. Treasury Bills: 1.23%,4/19/2018 [Member]
Expiration date	4/19/2018
Interest Rate	1.23%
Cash Equivalents [Member] | Us Treasury Securities [Member] | U.S. Treasury Bills:1.25%, 4/26/2018[Member]
Expiration date	4/26/2018
Interest Rate	1.25%
Cash Equivalents [Member] | Us Treasury Securities [Member] | U.S. Treasury Bills: 1.27%, 5/03/2018 [Member]
Expiration date	5/03/2018
Interest Rate	1.27%
Cash Equivalents [Member] | Us Treasury Securities [Member] | U.S. Treasury Bills:1.32%, 5/10/2018 [Member]
Expiration date	5/10/2018
Interest Rate	1.32%
Cash Equivalents [Member] | Us Treasury Securities [Member] | U.S. Treasury Bills:1.37%, 5/17/2018 [Member]
Expiration date	5/17/2018
Interest Rate	1.37%
Cash Equivalents [Member] | Us Treasury Securities [Member] | U.S. Treasury Bills:1.43%, 5/24/2018 [Member]
Expiration date	5/24/2018
Interest Rate	1.43%
Cash Equivalents [Member] | Us Treasury Securities [Member] | U.S. Treasury Bills:1.43%, 5/31/2018 [Member]
Expiration date	5/31/2018
Interest Rate	1.43%
Cash Equivalents [Member] | Us Treasury Securities [Member] | U.S. Treasury Bills:1.45%, 6/07/2018[Member]
Expiration date	6/07/2018
Interest Rate	1.45%
Cash Equivalents [Member] | Us Treasury Securities [Member] | U.S. Treasury Bills:1.46%, 6/14/2018 [Member]
Expiration date	6/14/2018
Interest Rate	1.46%
Cash Equivalents [Member] | Us Treasury Securities [Member] | U.S. Treasury Bills:1.49%, 6/21/2018 [Member]
Expiration date	6/21/2018
Interest Rate	1.49%
Cash Equivalents [Member] | Us Treasury Securities [Member] | U.S. Treasury Bills:1.50%,6/28/2018 [Member]
Expiration date	6/28/2018
Interest Rate	1.50%
Cash Equivalents [Member] | Us Treasury Securities [Member] | U.S. Treasury Bills: 0.34%, 1/05/2017 [Member]
Expiration date		1/05/2017
Interest Rate		0.34%
Cash Equivalents [Member] | Us Treasury Securities [Member] | U.S. Treasury Bills: 0.43%, 1/19/2017 [Member]
Expiration date		1/19/2017
Interest Rate		0.43%
Cash Equivalents [Member] | Us Treasury Securities [Member] | U.S. Treasury Bills: 0.36%, 1/26/2017 [Member]
Expiration date		1/26/2017
Interest Rate		0.36%
Cash Equivalents [Member] | Us Treasury Securities [Member] | U.S. Treasury Bills : 0.40%, 2/02/2017 [Member]
Expiration date		2/02/2017
Interest Rate		0.40%
Cash Equivalents [Member] | Us Treasury Securities [Member] | U.S. Treasury Bills : 0.42%, 2/09/2017 [Member]
Expiration date		2/09/2017
Interest Rate		0.42%
Cash Equivalents [Member] | Us Treasury Securities [Member] | U.S. Treasury Bills : 0.45%, 2/16/2017 [Member]
Expiration date		2/16/2017
Interest Rate		0.45%
Cash Equivalents [Member] | Us Treasury Securities [Member] | U.S. Treasury Bills : 0.45%, 2/23/2017 [Member]
Expiration date		2/23/2017
Interest Rate		0.45%
Cash Equivalents [Member] | Us Treasury Securities [Member] | U.S. Treasury Bills : 0.45%, 3/02/2017 [Member]
Expiration date		3/02/2017
Interest Rate		0.45%
Cash Equivalents [Member] | Us Treasury Securities [Member] | U.S. Treasury Bills : 0.47%, 3/09/2017 [Member]
Expiration date		3/09/2017
Interest Rate		0.47%
Cash Equivalents [Member] | Us Treasury Securities [Member] | U.S. Treasury Bills : 0.50%, 3/16/2017 [Member]
Expiration date		3/16/2017
Interest Rate		0.50%
Cash Equivalents [Member] | Us Treasury Securities [Member] | U.S. Treasury Bills : 0.45%, 3/23/2017 [Member]
Expiration date		3/23/2017
Interest Rate		0.45%
Cash Equivalents [Member] | Us Treasury Securities [Member] | U.S. Treasury Bills : 0.43%, 3/30/2017 [Member]
Expiration date		3/30/2017
Interest Rate		0.43%
Cash Equivalents [Member] | Us Treasury Securities [Member] | U.S. Treasury Bills : 0.46%, 4/06/2017 [Member]
Expiration date		4/06/2017
Interest Rate		0.46%
Cash Equivalents [Member] | Us Treasury Securities [Member] | U.S. Treasury Bills : 0.47%, 4/13/2017 [Member]
Expiration date		4/13/2017
Interest Rate		0.47%
Cash Equivalents [Member] | Us Treasury Securities [Member] | U.S. Treasury Bills : 0.46%, 4/20/2017 [Member]
Expiration date		4/20/2017
Interest Rate		0.46%
Cash Equivalents [Member] | Us Treasury Securities [Member] | U.S. Treasury Bills : 0.47%, 4/27/2017 [Member]
Expiration date		4/27/2017
Interest Rate		0.47%
Cash Equivalents [Member] | Us Treasury Securities [Member] | U.S. Treasury Bills : 0.49%, 5/04/2017 [Member]
Expiration date		5/04/2017
Interest Rate		0.49%
Cash Equivalents [Member] | Us Treasury Securities [Member] | U.S. Treasury Bills : 0.55%, 5/11/2017 [Member]
Expiration date		5/11/2017
Interest Rate		0.55%
Cash Equivalents [Member] | Us Treasury Securities [Member] | U.S. Treasury Bills : 0.60%, 5/18/2017 [Member]
Expiration date		5/18/2017
Interest Rate		0.60%
Cash Equivalents [Member] | Us Treasury Securities [Member] | U.S. Treasury Bills : 0.61%, 5/25/2017 [Member]
Expiration date		5/25/2017
Interest Rate		0.61%
Cash Equivalents [Member] | Us Treasury Securities [Member] | U.S. Treasury Bills : 0.60%, 6/01/2017 [Member]
Expiration date		6/01/2017
Interest Rate		0.60%
Cash Equivalents [Member] | Us Treasury Securities [Member] | U.S. Treasury Bills : 0.62%, 6/08/2017 [Member]
Expiration date		6/08/2017
Interest Rate		0.62%
Cash Equivalents [Member] | Us Treasury Securities [Member] | U.S. Treasury Bills : 0.65%, 6/15/2017 [Member]
Expiration date		6/15/2017
Interest Rate		0.65%
Cash Equivalents [Member] | Us Treasury Securities [Member] | U.S. Treasury Bills : 0.64%, 6/22/2017 [Member]
Expiration date		6/22/2017
Interest Rate		0.64%
Cash Equivalents [Member] | Us Treasury Securities [Member] | U.S. Treasury Bills : 0.60%, 6/29/2017 [Member]
Expiration date		6/29/2017
Interest Rate		0.60%

Statements of Operations

Statements of Operations - USD ($)		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Gain (loss) on trading of commodity futures contracts:
Realized gain (loss) on closed futures contracts		$ 229,715	$ (2,271,270)	$ (6,916,714)
Change in unrealized gain (loss) on open futures contracts		(3,364,926)	5,217,980	2,497,914
Dividend income		27,445	10,786	2,766
Interest income	[1]	53,398	32,944	3,669
ETF transaction fees		2,450	1,750	6,650
Total income (loss)		(3,051,918)	2,992,190	(4,405,715)
Expenses
General Partner management fees (Note 3)		78,805	102,306	118,848
Professional fees		71,759	114,167	101,338
Brokerage commissions		2,209	3,451	6,117
Directors' fees and insurance		1,929	2,888	3,140
License fees		1,576	2,046	2,377
Total expenses		156,278	224,858	231,820
Expense waiver (Note 3)		(61,713)	(102,092)	(89,122)
Net expenses		94,565	122,766	142,698
Net income (loss)		$ (3,146,483)	$ 2,869,424	$ (4,548,413)
Net income (loss) per limited partnership share		$ (2.49)	$ 2.03	$ (3.97)
Net income (loss) per weighted average limited partnership share		$ (3.06)	$ 2.07	$ (3.48)
Weighted average limited partnership shares outstanding		1,027,534	1,387,568	1,305,753
[1]	Interest income does not exceed paid in kind of 5%.

Statements of Operations (Paren

Statements of Operations (Parenthetical)	Dec. 31, 2017
ReceivedIn Kind Interest Percentage	5.00%

Statements of Changes in Partne

Statements of Changes in Partners' Capital - USD ($)	Total	General Partner [Member]	Limited Partners [Member]
Balances at Dec. 31, 2014	$ 16,426,468	$ 0	$ 16,426,468
Addition of partnership share	11,129,688	0	11,129,688
Redemption of partnership shares	(9,882,640)	0	(9,882,640)
Net income (loss)	(4,548,413)	0	(4,548,413)
Balances at Dec. 31, 2015	$ 13,125,103	0	13,125,103
Net asset value, beginning of year at Dec. 31, 2014	$ 13.69
Net asset value, end of year at Dec. 31, 2015	$ 9.72
Addition of partnership share	$ 1,418,858	0	1,418,858
Redemption of partnership shares	(967,707)	0	(967,707)
Net income (loss)	2,869,424	0	2,869,424
Balances at Dec. 31, 2016	$ 16,445,678	0	16,445,678
Net asset value, end of year at Dec. 31, 2016	$ 11.75
Addition of partnership share	$ 1,021,619	0	1,021,619
Redemption of partnership shares	(5,986,374)	0	(5,986,374)
Net income (loss)	(3,146,483)	0	(3,146,483)
Balances at Dec. 31, 2017	$ 8,334,440	$ 0	$ 8,334,440
Net asset value, end of year at Dec. 31, 2017	$ 9.26

Statements of Changes in Partn8

Statements of Changes in Partners' Capital (Parenthetical) - shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Addition of partnership share	100,000	150,000	900,000
Redemption of partnership shares	600,000	100,000	750,000

Statements of Cash Flows

Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash Flows from Operating Activities:
Net income (loss)	$ (3,146,483)	$ 2,869,424	$ (4,548,413)
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	(1,001,471)	3,622,568	1,202,800
Unrealized (gain) loss on open futures contracts	3,364,926	(5,217,980)	(2,497,914)
(Increase) decrease in receivable from General Partner	40,379	(12,970)	(22,856)
(Increase) decrease in dividends receivable	(831)	(1,337)	96
(Increase) decrease in interest receivable	(88)	0	0
(Increase) decrease in directors' fees and insurance receivable	(66)	1,197	(85)
(Increase) decrease in ETF transaction fees receivable	350	(350)	350
Increase (decrease) in payable due to Broker	(2,099,689)	2,099,689	0
Increase (decrease) in General Partner management fees payable	(4,944)	2,510	(3,142)
Increase (decrease) in professional fees payable	(29,606)	27,360	(5,108)
Increase (decrease) in brokerage commissions payable	(620)	0	220
Increase (decrease) in directors' fees and insurance payable	(106)	106	0
Increase (decrease) in license fees payable	(413)	(84)	(170)
Net cash provided by (used in) operating activities	(2,878,662)	3,390,133	(5,874,222)
Cash Flows from Financing Activities:
Addition of partnership shares	1,021,619	1,418,858	11,863,149
Redemption of partnership shares	(5,986,374)	(967,707)	(9,882,640)
Net cash provided by (used in) financing activities	(4,964,755)	451,151	1,980,509
Net Increase (Decrease) in Cash and Cash Equivalents	(7,843,417)	3,841,284	(3,893,713)
Cash and Cash Equivalents, beginning of year	15,061,018	11,219,734	15,113,447
Cash and Cash Equivalents, end of year	$ 7,217,601	$ 15,061,018	$ 11,219,734

ORGANIZATION AND BUSINESS

ORGANIZATION AND BUSINESS	12 Months Ended
	Dec. 31, 2017
Organization and Business [Abstract]
Organization and Business	NOTE 1 — ORGANIZATION AND BUSINESS The United States 12 Month Natural Gas Fund, LP (“UNL”) was organized as a limited partnership under the laws of the state of Delaware on June 27, 2007. UNL is a commodity pool that issues limited partnership shares (“shares”) that may be purchased and sold on the NYSE Arca, Inc. (the “NYSE Arca”). UNL will continue in perpetuity, unless terminated sooner upon the occurrence of one or more events as described in its Third Amended and Restated Agreement of Limited Partnership dated as of December 15, 2017 (the “LP Agreement”). The investment objective of UNL 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 spot price of natural gas delivered at the Henry Hub, Louisiana, as measured by the daily changes in the average of the prices of 12 futures contracts for natural gas traded on the New York Mercantile Exchange (the “NYMEX”), consisting of the near month contract to expire and the contracts for the following 11 months for a total of 12 consecutive months’ contracts, except when the near month contract is within two weeks of expiration, in which case it will be measured by the futures contracts that is the next month contract to expire and the contracts for the following 11 consecutive months (the “Benchmark Futures Contracts”), less UNL’s expenses. UNL’s investment objective is not nor greater than one day United States Commodity Funds LLC (“USCF”), the general partner of UNL, believes that it is not practical to manage the portfolio to achieve such an investment goal when investing in Futures Contracts (as defined below) and Other Natural Gas-Related Investments (as defined below). UNL accomplishes its objective through investments in futures contracts for natural gas, crude oil, diesel-heating oil, gasoline and other petroleum-based fuels that are traded on the NYMEX, ICE Futures or other U.S. and foreign exchanges (collectively, “Futures Contracts”) and other natural gas-related investments such as cash-settled options on Futures Contracts, forward contracts for natural gas, cleared swap contracts and over-the-counter (“OTC”) transactions that are based on the price of natural gas, crude oil and other petroleum-based fuels, Futures Contracts and indices based on the foregoing (collectively, “Other Natural Gas-Related Investments”). As of December 31, 2017, UNL held 292 Futures Contracts for natural gas traded on the NYMEX and did not hold any Futures Contracts traded on ICE Futures US. UNL commenced investment operations on November 18, 2009 and has a fiscal year ending on December 31. USCF is responsible for the management of UNL. 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 Natural Gas Fund, LP (“UNG”), 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 American Stock Exchange (the “AMEX”) under the ticker symbols “USO” on April 10, 2006, “UNG” on April 18, 2007, “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, UNG’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”) 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 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.” UNL issues shares to certain authorized purchasers (“Authorized Participants”) by offering baskets consisting of 50,000 In addition, Authorized Participants pay UNL a $ 350 50,000 In November 2009, UNL initially registered 30,000,000 November 18, 2009 50.00 200,000 10,000,000 30,000,000

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	12 Months Ended
	Dec. 31, 2017
Summary Of Significant 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. UNL 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. UNL earns income on funds held at the custodian or futures commission merchant (“FCM”) at prevailing market rates earned on such investments. Brokerage commissions on all open commodity futures contracts are accrued on a full-turn basis. UNL 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, UNL 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. UNL files an income tax return in the U.S. federal jurisdiction, and may file income tax returns in various U.S. states. UNL 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 UNL recording a tax liability that reduces net assets. However, UNL’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. UNL 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 50,000 UNL 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 UNL’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 UNL a transaction fee of $ 350 Profit or loss shall be allocated among the partners of UNL 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. UNL’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. UNL 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 UNL. 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.

FEES PAID BY THE FUND AND RELAT

FEES PAID BY THE FUND AND RELATED PARTY TRANSACTIONS	12 Months Ended
	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 UNL in accordance with the objectives and policies of UNL. In addition, USCF has arranged for one or more third parties to provide administrative, custody, accounting, transfer agency and other necessary services to UNL. For these services, UNL is contractually obligated to pay USCF a fee, which is paid monthly, equal to 0.75% per annum of average daily total net assets. Ongoing Registration Fees and Other Offering Expenses UNL 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, UNL did not incur registration fees and other offering expenses. Independent Directors’ and Officers’ Expenses UNL is responsible for paying its portion of the directors’ and officers’ liability insurance for UNL and the Related Public Funds and the fees and expenses of the independent directors who also serve as audit committee members of UNL and the Related Public Funds. UNL 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 1,929 582,050 2,888 Licensing Fees As discussed in Note 4 below, UNL entered into a licensing agreement with the NYMEX on December 4, 2007, as amended on October 20, 2011. Pursuant to the agreement, UNL and the Related Public Funds, other than BNO, USCI, CPER, USAG, USOU and USOD, pay a licensing fee that is equal to 0.015 1,576 2,046 2,377 Investor Tax Reporting Cost The fees and expenses associated with UNL’s audit expenses and tax accounting and reporting requirements are paid by UNL. These costs were approximately $ 72,000 76,000 86,000 Other Expenses and Fees and Expense Waivers In addition to the fees described above, UNL pays all brokerage fees and other expenses in connection with the operation of UNL, excluding costs and expenses paid by USCF as outlined in Note 4 – Contracts and Agreements 0.15 61,713 Note 4 – Contracts and Agreements

CONTRACTS AND AGREEMENTS

CONTRACTS AND AGREEMENTS	12 Months Ended
	Dec. 31, 2017
Contracts and Agreements [Abstract]
Contracts and Agreements	NOTE 4 — CONTRACTS AND AGREEMENTS Marketing Agent Agreement UNL is party to a marketing agent agreement, dated as of October 30, 2009, as amended from time to time, with the Marketing Agent and USCF, whereby the Marketing Agent provides certain marketing services for UNL 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 UNL is also party to a custodian agreement, dated November 3, 2009, as amended from time to time, with Brown Brothers Harriman & Co. (“BBH&Co.”) and USCF, whereby BBH&Co. holds investments on behalf of UNL. USCF pays the fees of the custodian, which are determined by the parties from time to time. In addition, UNL is party to an administrative agency agreement, dated November 3, 2009, as amended from time to time, with USCF and BBH&Co., whereby BBH&Co. acts as the administrative agent, transfer agent and registrar for UNL. 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 75,000 15 Brokerage and Futures Commission Merchant Agreements On October 8, 2013, UNL entered into a brokerage agreement with RBC Capital Markets, LLC (“RBC Capital” or “RBC”) to serve as UNL’s FCM effective October 10, 2013. The agreement with RBC requires it to provide services to UNL 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 UNL’s account. In accordance with the agreement, RBC Capital charges UNL commissions of approximately $ 7 8 For the Year Ended For the Year Ended For the Year Ended Total commissions accrued to brokers $ 2,209 $ 3,451 $ 6,117 Total commissions as annualized percentage of average total net assets 0.02 % 0.03 % 0.04 % Commissions accrued as a result of rebalancing $ 1,605 $ 3,305 $ 4,698 Percentage of commissions accrued as a result of rebalancing 72.66 % 95.77 % 76.80 % Commissions accrued as a result of creation and redemption activity $ 604 $ 146 $ 1,419 Percentage of commissions accrued as a result of creation and redemption activity 27.34 % 4.23 % 23.20 % 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 UNL and the NYMEX entered into a licensing agreement on December 4, 2007, as amended on October 20, 2011, whereby UNL was granted a non-exclusive license to use certain of the NYMEX’s settlement prices and service marks. Under the licensing agreement, UNL 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. UNL expressly disclaims any association with the NYMEX or endorsement of UNL 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 UNL may engage in the trading of futures contracts, options on futures contracts, cleared swaps and OTC swaps (collectively, “derivatives”). UNL 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. UNL 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 UNL 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 UNL 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. However, in the future, if UNL 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. UNL 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, UNL bears the risk of financial failure by the clearing broker. UNL’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 UNL’s assets posted with that FCM; however, the majority of UNL’s assets are held in investments in Treasuries, cash and/or cash equivalents with UNL’s custodian and would not be impacted by the insolvency of an FCM. The failure or insolvency of UNL’s custodian, however, could result in a substantial loss of UNL’s assets. USCF invests a portion of UNL’s cash in money market funds that seek to maintain a stable per share NAV. UNL 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, UNL held investments in money market funds in the amounts of $ 2,500,000 5,000,000 6,418,876 10,760,822 For derivatives, risks arise from changes in the market value of the contracts. Theoretically, UNL 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, UNL 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. UNL’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, UNL 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 UNL 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
	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 $ 11.75 $ 9.72 $ 13.69 Total income (loss) (2.40) 2.12 (3.86) Net expenses (0.09) (0.09) (0.11) Net increase (decrease) in net asset value (2.49) 2.03 (3.97) Net asset value, end of year $ 9.26 $ 11.75 $ 9.72 Total Return (21.19) % 20.88 % (29.00) % Ratios to Average Net Assets Total income (loss) (29.05) % 21.94 % (27.80) % Management fees 0.75 % 0.75 % 0.75 % Total expenses excluding management fees 0.74 % 0.90 % 0.71 % Expenses waived (0.59) % (0.75) % (0.56) % Net expenses excluding management fees 0.15 % 0.15 % 0.15 % Net income (loss) (29.95) % 21.04 % (28.70) % 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 UNL.

QUARTERLY FINANCIAL DATA (Unaud

QUARTERLY FINANCIAL DATA (Unaudited)	12 Months Ended
	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Data (Unaudited)	NOTE 7 - QUARTERLY FINANCIAL DATA (Unaudited) The following summarized (unaudited) quarterly financial information presents the results of operations and other data for the three-month periods ended March 31, June 30, September 30 and December 31, 2017 and 2016. First Second Third Fourth Total Income (Loss) $ (1,880,112) $ (536,427) $ 9,809 $ (645,188) Total Expenses 45,520 33,306 40,970 36,482 Expense Waivers (15,053) (9,907) (19,588) (17,165) Net Expenses 30,467 23,399 21,382 19,317 Net Income (Loss) $ (1,910,579) $ (559,826) $ (11,573) $ (664,505) Net Income (Loss) per Share $ (1.10) $ (0.63) $ (0.01) $ (0.75) First Second Third Fourth Total Income (Loss) $ (1,337,347) $ 2,659,703 $ (673,185) $ 2,343,019 Total Expenses 50,619 53,295 61,441 59,503 Expense Waivers (23,616) (24,115) (28,986) (25,375) Net Expenses 27,003 29,180 32,455 34,128 Net Income (Loss) $ (1,364,350) $ 2,630,523 $ (705,640) $ 2,308,891 Net Income (Loss) per Share $ (0.98) $ 1.90 $ (0.50) $ 1.61

FAIR VALUE OF FINANCIAL INSTRUM

FAIR VALUE OF FINANCIAL INSTRUMENTS	12 Months Ended
	Dec. 31, 2017
Fair Value Of Financial Instruments [Abstract]
Fair Value of Financial Instruments	NOTE 8 — FAIR VALUE OF FINANCIAL INSTRUMENTS UNL 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 UNL (observable inputs) and (2) UNL’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 $ 7,683,698 $ 7,683,698 $ — $ — Exchange-Traded Futures Contracts United States Contracts (568,922) (568,922) — — During the year ended December 31, 2017, there were no transfers between Level I and Level II. The following table summarizes the valuation of UNL’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 $ 11,292,035 $ 11,292,035 $ — $ — Exchange-Traded Futures Contracts United States Contracts 2,796,004 2,796,004 — — During the year ended December 31, 2016, there were no transfers between Level I and Level II. Effective January 1, 2009, UNL 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 $ (568,922) $ 2,796,004 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 $ 229,715 $ (2,271,270) $ (6,916,714) Change in unrealized $ (3,364,926) $ 5,217,980 $ 2,497,914

RECENT ACCOUNTING PRONOUNCEMENT

RECENT ACCOUNTING PRONOUNCEMENTS	12 Months Ended
	Dec. 31, 2017
New Accounting Pronouncements and Changes in Accounting Principles [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
	Dec. 31, 2017
Subsequent Events [Abstract]
Subsequent Events	NOTE 10 — SUBSEQUENT EVENTS UNL 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 ACCOUN20

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	12 Months Ended
	Dec. 31, 2017
Summary Of Significant 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. UNL 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. UNL earns income on funds held at the custodian or futures commission merchant (“FCM”) at prevailing market rates earned on such investments.
Brokerage Commissions	Brokerage Commissions Brokerage commissions on all open commodity futures contracts are accrued on a full-turn basis.
Income Taxes	Income Taxes UNL 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, UNL 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. UNL files an income tax return in the U.S. federal jurisdiction, and may file income tax returns in various U.S. states. UNL 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 UNL recording a tax liability that reduces net assets. However, UNL’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. UNL 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 50,000 UNL 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 UNL’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 UNL a transaction fee of $ 350
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 UNL in proportion to the number of shares each partner holds as of the close of each month. USCF may revise, alter or otherwise modify this method of allocation as described in the LP Agreement.
Calculation of Per Share Net Asset Value (“NAV”)	Calculation of Per Share NAV UNL’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. UNL 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 UNL. 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.

CONTRACTS AND AGREEMENTS (Table

CONTRACTS AND AGREEMENTS (Tables)	12 Months Ended
	Dec. 31, 2017
Contracts and Agreements [Abstract]
Brokerage Commissions	UNL also incurs commissions to brokers for the purchase and sale of natural gas Futures Contracts, Other Natural Gas-Related Investments or short-term obligations of the United States of two years or less (“Treasuries”). For the Year Ended For the Year Ended For the Year Ended Total commissions accrued to brokers $ 2,209 $ 3,451 $ 6,117 Total commissions as annualized percentage of average total net assets 0.02 % 0.03 % 0.04 % Commissions accrued as a result of rebalancing $ 1,605 $ 3,305 $ 4,698 Percentage of commissions accrued as a result of rebalancing 72.66 % 95.77 % 76.80 % Commissions accrued as a result of creation and redemption activity $ 604 $ 146 $ 1,419 Percentage of commissions accrued as a result of creation and redemption activity 27.34 % 4.23 % 23.20 %

FINANCIAL HIGHLIGHTS (Tables)

FINANCIAL HIGHLIGHTS (Tables)	12 Months Ended
	Dec. 31, 2017
Financial Highlights [Abstract]
Per Unit Performance Data and Other Supplemental Financial Data	The following table presents per share performance data and other supplemental financial data for the years ended December 31, 2017, 2016 and 2015 for the shareholders. This information has been derived from information presented in the financial statements. Year ended December Year ended December Year ended December Per Share Operating Performance: Net asset value, beginning of year $ 11.75 $ 9.72 $ 13.69 Total income (loss) (2.40) 2.12 (3.86) Net expenses (0.09) (0.09) (0.11) Net increase (decrease) in net asset value (2.49) 2.03 (3.97) Net asset value, end of year $ 9.26 $ 11.75 $ 9.72 Total Return (21.19) % 20.88 % (29.00) % Ratios to Average Net Assets Total income (loss) (29.05) % 21.94 % (27.80) % Management fees 0.75 % 0.75 % 0.75 % Total expenses excluding management fees 0.74 % 0.90 % 0.71 % Expenses waived (0.59) % (0.75) % (0.56) % Net expenses excluding management fees 0.15 % 0.15 % 0.15 % Net income (loss) (29.95) % 21.04 % (28.70) %

QUARTERLY FINANCIAL DATA (Una23

QUARTERLY FINANCIAL DATA (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Schedule of Quarterly Financial Information	The following summarized (unaudited) quarterly financial information presents the results of operations and other data for the three-month periods ended March 31, June 30, September 30 and December 31, 2017 and 2016. First Second Third Fourth Total Income (Loss) $ (1,880,112) $ (536,427) $ 9,809 $ (645,188) Total Expenses 45,520 33,306 40,970 36,482 Expense Waivers (15,053) (9,907) (19,588) (17,165) Net Expenses 30,467 23,399 21,382 19,317 Net Income (Loss) $ (1,910,579) $ (559,826) $ (11,573) $ (664,505) Net Income (Loss) per Share $ (1.10) $ (0.63) $ (0.01) $ (0.75) First Second Third Fourth Total Income (Loss) $ (1,337,347) $ 2,659,703 $ (673,185) $ 2,343,019 Total Expenses 50,619 53,295 61,441 59,503 Expense Waivers (23,616) (24,115) (28,986) (25,375) Net Expenses 27,003 29,180 32,455 34,128 Net Income (Loss) $ (1,364,350) $ 2,630,523 $ (705,640) $ 2,308,891 Net Income (Loss) per Share $ (0.98) $ 1.90 $ (0.50) $ 1.61

FAIR VALUE OF FINANCIAL INSTR24

FAIR VALUE OF FINANCIAL INSTRUMENTS (Tables)	12 Months Ended
	Dec. 31, 2017
Fair Value Of Financial Instruments [Abstract]
Valuation of Securities Using the Fair Value Hierarchy	The following table summarizes the valuation of UNL’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 $ 7,683,698 $ 7,683,698 $ — $ — Exchange-Traded Futures Contracts United States Contracts (568,922) (568,922) — — During the year ended December 31, 2017, there were no transfers between Level I and Level II. The following table summarizes the valuation of UNL’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 $ 11,292,035 $ 11,292,035 $ — $ — Exchange-Traded Futures Contracts United States Contracts 2,796,004 2,796,004 — —
Fair Value of Derivative Instruments	Fair Value of Derivative Instruments Derivatives not Statements of Financial Fair Value Fair Value Futures - Commodity Contracts Assets $ (568,922) $ 2,796,004
Effect of Derivative Instruments on the Condensed 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 $ 229,715 $ (2,271,270) $ (6,916,714) Change in unrealized $ (3,364,926) $ 5,217,980 $ 2,497,914

ORGANIZATION AND BUSINESS (Addi

ORGANIZATION AND BUSINESS (Additional Information) (Details)	1 Months Ended
	Nov. 30, 2009	Nov. 18, 2009USD ($)$ / sharesshares	Dec. 31, 2017$ / shares$ / Baskets$ / Units	Dec. 31, 2016$ / shares	Dec. 31, 2015$ / shares	Dec. 31, 2014$ / shares	Dec. 31, 2013$ / shares
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 | $ / Units			350
Number of initially registered units on Form S-1 with the U.S. Securities and Exchange Commission	30,000,000
Net asset value per share | $ / shares		$ 50	$ 9.26	$ 11.75	$ 9.72	$ 13.69	$ 13.69
Number of units issued | shares		200,000
Value of unit issued | $		$ 10,000,000
Commenced investment operations date	Nov. 18, 2009
Number of registered units			30,000,000
Creation Baskets [Member]
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Number of units per basket			50,000
Redemption Baskets [Member]
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Number of units per basket			50,000

SUMMARY OF SIGNIFICANT ACCOUN26

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Additional Information) (Details)	Dec. 31, 2017$ / Baskets$ / Units
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 | $ / Units	350
Redemption Baskets [Member]
Significant Accounting Policies [Line Items]
Number of units per basket | $ / Baskets	50,000

FEES PAID BY THE FUND AND REL27

FEES PAID BY THE FUND AND RELATED PARTY TRANSACTIONS - (Additional 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
Fees Paid and Related Party Transactions [Line Items]
USCF Management Fee									UNL is contractually obligated to pay USCF a fee, which is paid monthly, equal to 0.75% per annum of average daily total net assets
Estimated directors fees and expenses									$ 1,929	$ 2,888	$ 3,140
Assets basis for determining fee percentage									on all net assets
Licensing fee incurred									$ 1,576	2,046	2,377
Expense waiver (Note 3)	$ (17,165)	$ (19,588)	$ (9,907)	$ (15,053)	$ (25,375)	$ (28,986)	$ (24,115)	$ (23,616)	$ 61,713	102,092	89,122
Licensing Agreements [Member]
Fees Paid and Related Party Transactions [Line Items]
Fee percentage									0.015%
Future Period - for the year ending December 31, 2016 [Member]
Fees Paid and Related Party Transactions [Line Items]
Estimated investor tax reporting cost									$ 72,000	76,000	86,000
Future Period - for the year ending December 31, 2016 [Member] | Maximum [Member]
Fees Paid and Related Party Transactions [Line Items]
Costs and expenses annual limit for reimbursement									0.15%
UNL [Member] | Related Public Funds [Member]
Fees Paid and Related Party Transactions [Line Items]
Estimated directors fees and expenses									$ 536,375	$ 582,050	$ 569,303

CONTRACTS AND AGREEMENTS (Broke

CONTRACTS AND AGREEMENTS (Brokerage Commissions) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Total commissions accrued to brokers	$ 2,209	$ 3,451	$ 6,117
Total commissions as annualized percentage of average total net assets	0.02%	0.03%	0.04%
Rebalancing Investments Transaction [Member]
Total commissions accrued to brokers	$ 1,605	$ 3,305	$ 4,698
Total commissions as annualized percentage of average total net assets	72.66%	95.77%	76.80%
Creation And Redemption Activity [Member]
Total commissions accrued to brokers	$ 604	$ 146	$ 1,419
Total commissions as annualized percentage of average total net assets	27.34%	4.23%	23.20%

CONTRACTS AND AGREEMENTS (Addit

CONTRACTS AND AGREEMENTS (Additional Information) (Details)	12 Months Ended
	Dec. 31, 2017USD ($)$ / Units
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]
Annual Fee for transfer agency services	$ 20,000
Maximum [Member]
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]
Transaction fees per transaction	$ 15
Commissions per round-turn trade, including applicable exchange and NFA fees for Natural Gas-Related Futures Contracts and options on Futures Contracts | $ / Units	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	$ 7
Commissions per round-turn trade, including applicable exchange and NFA fees for Natural Gas-Related Futures Contracts and options on Futures Contracts | $ / Units	7
first $500 million of the Related Public Funds' combined net assets [Member]
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]
Fee percentage	0.06%
first $500 million of the Related Public Funds' 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
Related Public Funds' 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%
Related Public Funds' combined net assets greater than $500 million but less than $1 billion [Member] | Maximum [Member]
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]
Base amount for determining fee percentage	$ 1,000,000,000
Related Public Funds' combined net assets greater than $500 million but less than $1 billion [Member] | Minimum [Member]
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]
Base amount for determining fee percentage	$ 500,000,000
Related Public Funds' combined net assets exceed $1 billion [Member]
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]
Fee percentage	0.035%
Related Public Funds' combined net assets exceed $1 billion [Member] | Minimum [Member]
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]
Base amount for determining fee percentage	$ 1,000,000,000
Marketing Agent And Affliate Of Uscf [Member]
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]
Maximum Aggregate Compensation Paid For Distribution Related Services	10.00%
Marketing Agreement [Member] | UNL'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] | UNL's assets in excess of $3 billion [Member]
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]
Fee percentage	0.04%
Base amount for determining fee percentage	$ 3,000,000,000

FINANCIAL INSTRUMENTS, OFF-BA30

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	$ 2,500,000	$ 5,000,000
Deposits in domestic and foreign financial institutions	$ 6,418,876	$ 10,760,822

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	$ 11.75	$ 9.72	$ 13.69
Total income (loss)	(2.4)	2.12	(3.86)
Net expenses	(0.09)	(0.09)	(0.11)
Net increase (decrease) in net asset value	(2.49)	2.03	(3.97)
Net asset value, end of year	$ 9.26	$ 11.75	$ 9.72
Total Return	(21.19%)	20.88%	(29.00%)
Ratios to Average Net Assets
Total income (loss)	(29.05%)	21.94%	(27.80%)
Management fees	0.75%	0.75%	0.75%
Total expenses excluding management fees	0.74%	0.90%	0.71%
Expenses waived	(0.59%)	(0.75%)	(0.56%)
Net expenses excluding management fees	0.15%	0.15%	0.15%
Net income (loss)	(29.95%)	21.04%	(28.70%)

QUARTERLY FINANCIAL DATA (Una32

QUARTERLY FINANCIAL DATA (Unaudited) (Quarterly Financial Information Presents The Results Of Operations) (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 Data [Line Items]
Total income (loss)	$ (645,188)	$ 9,809	$ (536,427)	$ (1,880,112)	$ 2,343,019	$ (673,185)	$ 2,659,703	$ (1,337,347)	$ (3,051,918)	$ 2,992,190	$ (4,405,715)
Total expenses	36,482	40,970	33,306	45,520	59,503	61,441	53,295	50,619	156,278	224,858	231,820
Expense waivers	(17,165)	(19,588)	(9,907)	(15,053)	(25,375)	(28,986)	(24,115)	(23,616)	61,713	102,092	89,122
Net expenses	19,317	21,382	23,399	30,467	34,128	32,455	29,180	27,003	94,565	122,766	142,698
Net income (loss)	$ (664,505)	$ (11,573)	$ (559,826)	$ (1,910,579)	$ 2,308,891	$ (705,640)	$ 2,630,523	$ (1,364,350)	$ (3,146,483)	$ 2,869,424	$ (4,548,413)
Net income (loss) per share	$ (0.75)	$ (0.01)	$ (0.63)	$ (1.1)	$ 1.61	$ (0.5)	$ 1.9	$ (0.98)	$ (2.49)	$ 2.03	$ (3.97)

FAIR VALUE OF FINANCIAL INSTR33

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	$ 7,683,698	$ 11,292,035
Fair Value, Inputs, Level 1 [Member] | Short-Term Investments [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Securities, fair value	7,683,698	11,292,035
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 3 [Member] | Short-Term Investments [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Securities, fair value	0	0
United States Contracts [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Securities, fair value	(568,922)	2,796,004
United States Contracts [Member] | Fair Value, Inputs, Level 1 [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Securities, fair value	(568,922)	2,796,004
United States Contracts [Member] | Fair Value, Inputs, Level 2 [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Securities, fair value	0	0
United States Contracts [Member] | Fair Value, Inputs, Level 3 [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Securities, fair value	$ 0	$ 0

FAIR VALUE OF FINANCIAL INSTR34

FAIR VALUE OF FINANCIAL INSTRUMENTS (Fair Value of Derivative Instruments) (Details) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Commodity Contracts [Member] | Futures [Member] | Assets [Member]
Derivatives, Fair Value [Line Items]
Derivatives not Accounted for as Hedging Instruments	$ (568,922)	$ 2,796,004

FAIR VALUE OF FINANCIAL INSTR35

FAIR VALUE OF FINANCIAL INSTRUMENTS (Effect of Derivative Instruments on Condensed Statements of Operations) (Details) - 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	$ 229,715	$ (2,271,270)	$ (6,916,714)
Change in Unrealized Gain on (Loss) on Derivatives Recognized in Income	(3,364,926)	5,217,980	2,497,914
Commodity Contracts [Member] | Futures [Member] | Realized gain on closed positions
Derivative Instruments, Gain (Loss) [Line Items]
Realized Gain (Loss) on Derivatives Recognized in Income	229,715	(2,271,270)	(6,916,714)
Commodity Contracts [Member] | Futures [Member] | Change in unrealized gain on open positions
Derivative Instruments, Gain (Loss) [Line Items]
Change in Unrealized Gain on (Loss) on Derivatives Recognized in Income	$ (3,364,926)	$ 5,217,980	$ 2,497,914