United States 12 Month Natural Gas Fund (UNL) 10-K26 Mar 192018 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, 2018	Mar. 22, 2019	Jun. 30, 2018
Document and Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2018
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	FY
Entity Registrant Name	United States 12 Month Natural Gas Fund, LP
Entity Central Index Key	0001405513
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			$ 6,214,000
Trading Symbol	UNL
Entity Common Stock, Shares Outstanding		450,000
Entity Shell Company	false
Entity Emerging Growth Company	false
Entity Small Business	false

Statements of Financial Conditi

Statements of Financial Condition - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Assets
Cash and cash equivalents (at cost $5,167,367 and $7,217,601, respectively) (Notes 2 and 5)	$ 5,167,367	$ 7,217,601
Equity in trading accounts:
Cash and cash equivalents (at cost $596,555 and $1,701,275, respectively)	596,555	1,701,275
Unrealized gain (loss) on open commodity futures contracts	(46,103)	(568,922)
Receivable from General Partner (Note 3)	59,956	61,713
Dividends receivable	2,579	2,319
Interest receivable	289	88
Directors' fees and insurance receivable	0	66
Other assets	216	0
Total assets	5,780,859	8,414,140
Liabilities and Partners' Capital
Payable due to Broker	81,581	0
General Partner management fees payable (Note 3)	3,709	5,493
Professional fees payable	51,486	72,695
Brokerage commissions payable	571	1,181
Directors' fees and insurance payable	641	0
License fees payable	0	331
Total liabilities	137,988	79,700
Commitments and Contingencies (Notes 3, 4 and 5)
Partners' Capital
General Partner	0	0
Limited Partners	5,642,871	8,334,440
Total Partners' Capital	5,642,871	8,334,440
Total liabilities and partners' capital	$ 5,780,859	$ 8,414,140
Limited Partners' shares outstanding	550,000	900,000
Net asset value per share	$ 10.26	$ 9.26
Market value per share	$ 10.33	$ 9.18

Schedule of Investments

Schedule of Investments	Dec. 31, 2018USD ($)Contracts		Dec. 31, 2017USD ($)Contracts
Open Futures Contracts - Long [Member] \| United States Contracts [Member]
Notional Amount	$ 5,685,063	[1]	$ 8,907,842	[2]
Number of Contracts \| Contracts	201	[1]	292	[2]
Value/ Unrealized Gain (Loss) on Open Commodity Contracts	$ (46,103)	[1]	$ (568,922)	[2]
% of Partners' Capital	(0.82%)	[1]	(6.83%)	[2]
Open Futures Contracts - Long [Member] \| United States Contracts [Member] \| NYMEX Natural Gas Futures NG February 2019 contracts, expiring January 2019
Notional Amount	$ 520,650
Number of Contracts \| Contracts	16
Value/ Unrealized Gain (Loss) on Open Commodity Contracts	$ (50,250)
% of Partners' Capital	(0.89%)
Open Futures Contracts - Long [Member] \| United States Contracts [Member] \| NYMEX Natural Gas Futures NG March 2019 contracts, expiring February 2019
Notional Amount	$ 520,524
Number of Contracts \| Contracts	17
Value/ Unrealized Gain (Loss) on Open Commodity Contracts	$ (35,854)
% of Partners' Capital	(0.63%)
Open Futures Contracts - Long [Member] \| United States Contracts [Member] \| NYMEX Natural Gas Futures NG April 2019 contracts, expiring March 2019
Notional Amount	$ 462,954
Number of Contracts \| Contracts	17
Value/ Unrealized Gain (Loss) on Open Commodity Contracts	$ (6,844)
% of Partners' Capital	(0.12%)
Open Futures Contracts - Long [Member] \| United States Contracts [Member] \| NYMEX Natural Gas Futures NG May 2019 contracts, expiring April 2019
Notional Amount	$ 450,609
Number of Contracts \| Contracts	17
Value/ Unrealized Gain (Loss) on Open Commodity Contracts	$ 3,631
% of Partners' Capital	0.07%
Open Futures Contracts - Long [Member] \| United States Contracts [Member] \| NYMEX Natural Gas Futures NG June 2019 contracts, expiring May 2019
Notional Amount	$ 413,663
Number of Contracts \| Contracts	16
Value/ Unrealized Gain (Loss) on Open Commodity Contracts	$ 21,057
% of Partners' Capital	0.37%
Open Futures Contracts - Long [Member] \| United States Contracts [Member] \| NYMEX Natural Gas Futures NG July 2019 contracts, expiring June 2019
Notional Amount	$ 458,258
Number of Contracts \| Contracts	17
Value/ Unrealized Gain (Loss) on Open Commodity Contracts	$ 10,942
% of Partners' Capital	0.19%
Open Futures Contracts - Long [Member] \| United States Contracts [Member] \| NYMEX Natural Gas Futures NG August 2019 contracts, expiring July 2019
Notional Amount	$ 451,616
Number of Contracts \| Contracts	17
Value/ Unrealized Gain (Loss) on Open Commodity Contracts	$ 17,074
% of Partners' Capital	0.30%
Open Futures Contracts - Long [Member] \| United States Contracts [Member] \| NYMEX Natural Gas Futures NG September 2019 contracts, expiring August 2019
Notional Amount	$ 462,462
Number of Contracts \| Contracts	17
Value/ Unrealized Gain (Loss) on Open Commodity Contracts	$ 788
% of Partners' Capital	0.01%
Open Futures Contracts - Long [Member] \| United States Contracts [Member] \| NYMEX Natural Gas Futures NG October 2019 contracts, expiring September 2019
Notional Amount	$ 427,220
Number of Contracts \| Contracts	16
Value/ Unrealized Gain (Loss) on Open Commodity Contracts	$ 13,100
% of Partners' Capital	0.23%
Open Futures Contracts - Long [Member] \| United States Contracts [Member] \| NYMEX Natural Gas Futures NG November 2019 contracts, expiring October 2019
Notional Amount	$ 480,253
Number of Contracts \| Contracts	17
Value/ Unrealized Gain (Loss) on Open Commodity Contracts	$ (4,423)
% of Partners' Capital	(0.08%)
Open Futures Contracts - Long [Member] \| United States Contracts [Member] \| NYMEX Natural Gas Futures NG December 2019 contracts, expiring November 2019
Notional Amount	$ 501,461
Number of Contracts \| Contracts	17
Value/ Unrealized Gain (Loss) on Open Commodity Contracts	$ (641)
% of Partners' Capital	(0.01%)
Open Futures Contracts - Long [Member] \| United States Contracts [Member] \| NYMEX Natural Gas Futures NG January 2020 contracts, expiring December 2019
Notional Amount	$ 535,393
Number of Contracts \| Contracts	17
Value/ Unrealized Gain (Loss) on Open Commodity Contracts	$ (14,683)
% of Partners' Capital	(0.26%)
Open Futures Contracts - Long [Member] \| United States Contracts [Member] \| NYMEX Natural Gas Futures NG February 2018 contracts, expiring January 2018
Notional Amount			$ 872,763
Number of Contracts \| Contracts			24
Value/ Unrealized Gain (Loss) on Open Commodity Contracts			$ (164,043)
% of Partners' Capital			(1.97%)
Open Futures Contracts - Long [Member] \| United States Contracts [Member] \| NYMEX Natural Gas Futures NG March 2018 contracts, expiring February 2018
Notional Amount			$ 832,869
Number of Contracts \| Contracts			24
Value/ Unrealized Gain (Loss) on Open Commodity Contracts			$ (135,429)
% of Partners' Capital			(1.63%)
Open Futures Contracts - Long [Member] \| United States Contracts [Member] \| NYMEX Natural Gas Futures NG April 2018 contracts, expiring March 2018
Notional Amount			$ 715,113
Number of Contracts \| Contracts			25
Value/ Unrealized Gain (Loss) on Open Commodity Contracts			$ (27,863)
% of Partners' Capital			(0.33%)
Open Futures Contracts - Long [Member] \| United States Contracts [Member] \| NYMEX Natural Gas Futures NG May 2018 contracts, expiring April 2018
Notional Amount			$ 685,247
Number of Contracts \| Contracts			24
Value/ Unrealized Gain (Loss) on Open Commodity Contracts			$ (27,407)
% of Partners' Capital			(0.33%)
Open Futures Contracts - Long [Member] \| United States Contracts [Member] \| NYMEX Natural Gas Futures NG June 2018 contracts, expiring May 2018
Notional Amount			$ 731,645
Number of Contracts \| Contracts			25
Value/ Unrealized Gain (Loss) on Open Commodity Contracts			$ (38,395)
% of Partners' Capital			(0.46%)
Open Futures Contracts - Long [Member] \| United States Contracts [Member] \| NYMEX Natural Gas Futures NG July 2018 contracts, expiring June 2018
Notional Amount			$ 692,833
Number of Contracts \| Contracts			24
Value/ Unrealized Gain (Loss) on Open Commodity Contracts			$ (19,873)
% of Partners' Capital			(0.24%)
Open Futures Contracts - Long [Member] \| United States Contracts [Member] \| NYMEX Natural Gas Futures NG August 2018 contracts, expiring July 2018
Notional Amount			$ 722,063
Number of Contracts \| Contracts			25
Value/ Unrealized Gain (Loss) on Open Commodity Contracts			$ (20,313)
% of Partners' Capital			(0.24%)
Open Futures Contracts - Long [Member] \| United States Contracts [Member] \| NYMEX Natural Gas Futures NG September 2018 contracts, expiring August 2018
Notional Amount			$ 693,242
Number of Contracts \| Contracts			24
Value/ Unrealized Gain (Loss) on Open Commodity Contracts			$ (23,882)
% of Partners' Capital			(0.29%)
Open Futures Contracts - Long [Member] \| United States Contracts [Member] \| NYMEX Natural Gas Futures NG October 2018 contracts, expiring September 2018
Notional Amount			$ 712,475
Number of Contracts \| Contracts			24
Value/ Unrealized Gain (Loss) on Open Commodity Contracts			$ (37,595)
% of Partners' Capital			(0.45%)
Open Futures Contracts - Long [Member] \| United States Contracts [Member] \| NYMEX Natural Gas Futures NG November 2018 contracts, expiring November 2018
Notional Amount			$ 762,732
Number of Contracts \| Contracts			25
Value/ Unrealized Gain (Loss) on Open Commodity Contracts			$ (45,982)
% of Partners' Capital			(0.55%)
Open Futures Contracts - Long [Member] \| United States Contracts [Member] \| NYMEX Natural Gas Futures NG December 2018 contracts, expiring November 2018
Notional Amount			$ 762,850
Number of Contracts \| Contracts			24
Value/ Unrealized Gain (Loss) on Open Commodity Contracts			$ (43,570)
% of Partners' Capital			(0.52%)
Open Futures Contracts - Long [Member] \| United States Contracts [Member] \| NYMEX Natural Gas Futures NG January 2019 contracts, expiring December 2018
Notional Amount			$ 724,010
Number of Contracts \| Contracts			24
Value/ Unrealized Gain (Loss) on Open Commodity Contracts			$ 15,430
% of Partners' Capital			0.18%
Cash Equivalents [Member]
Market Value	$ 5,577,527		$ 7,683,698
% of Partners' Capital	98.84%		92.19%
Cash Equivalents [Member] \| United States Treasury Obligations [Member]
Market Value	$ 3,977,527		$ 5,183,698
% of Partners' Capital	70.49%		62.19%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 2.10%, 1/03/2019 [Member]
Principal Amount	$ 200,000
Market Value	$ 199,977
% of Partners' Capital	3.54%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 2.10%, 1/10/2019 [Member]
Principal Amount	$ 200,000
Market Value	$ 199,896
% of Partners' Capital	3.54%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 2.13%, 1/17/2019 [Member]
Principal Amount	$ 200,000
Market Value	$ 199,812
% of Partners' Capital	3.54%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 2.15%, 1/24/2019 [Member]
Principal Amount	$ 200,000
Market Value	$ 199,729
% of Partners' Capital	3.54%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 2.18%, 1/31/2019 [Member]
Principal Amount	$ 200,000
Market Value	$ 199,641
% of Partners' Capital	3.54%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 2.20%, 2/07/2019 [Member]
Principal Amount	$ 200,000
Market Value	$ 199,553
% of Partners' Capital	3.54%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 2.19%, 2/14/2019 [Member]
Principal Amount	$ 200,000
Market Value	$ 199,470
% of Partners' Capital	3.54%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 2.20%, 2/21/2019 [Member]
Principal Amount	$ 200,000
Market Value	$ 199,382
% of Partners' Capital	3.53%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 2.24%, 2/28/2019 [Member]
Principal Amount	$ 100,000
Market Value	$ 99,643
% of Partners' Capital	1.77%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 2.38%, 3/07/2019 [Member]
Principal Amount	$ 100,000
Market Value	$ 99,575
% of Partners' Capital	1.77%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 2.28%, 3/14/2019 [Member]
Principal Amount	$ 100,000
Market Value	$ 99,549
% of Partners' Capital	1.76%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 2.33%, 3/21/2019 [Member]
Principal Amount	$ 100,000
Market Value	$ 99,495
% of Partners' Capital	1.76%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 2.34%, 3/28/2019 [Member]
Principal Amount	$ 200,000
Market Value	$ 198,896
% of Partners' Capital	3.53%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 2.37%, 4/04/2019 [Member]
Principal Amount	$ 100,000
Market Value	$ 99,394
% of Partners' Capital	1.76%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 2.41%, 4/11/2019 [Member]
Principal Amount	$ 100,000
Market Value	$ 99,338
% of Partners' Capital	1.76%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 2.42%, 4/18/2019 [Member]
Principal Amount	$ 100,000
Market Value	$ 99,288
% of Partners' Capital	1.76%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 2.43%, 4/25/2019 [Member]
Principal Amount	$ 100,000
Market Value	$ 99,240
% of Partners' Capital	1.76%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 2.46%, 5/02/2019 [Member]
Principal Amount	$ 100,000
Market Value	$ 99,185
% of Partners' Capital	1.76%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 2.47%, 5/09/2019 [Member]
Principal Amount	$ 200,000
Market Value	$ 198,268
% of Partners' Capital	3.51%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 2.48%, 5/16/2019 [Member]
Principal Amount	$ 100,000
Market Value	$ 99,081
% of Partners' Capital	1.76%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 2.50%, 5/23/2019 [Member]
Principal Amount	$ 200,000
Market Value	$ 198,055
% of Partners' Capital	3.51%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 2.49%, 5/30/2019 [Member]
Principal Amount	$ 100,000
Market Value	$ 98,983
% of Partners' Capital	1.75%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 2.51%, 6/06/2019 [Member]
Principal Amount	$ 200,000
Market Value	$ 197,855
% of Partners' Capital	3.51%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 2.51%, 6/13/2019 [Member]
Principal Amount	$ 200,000
Market Value	$ 197,754
% of Partners' Capital	3.50%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 2.49%, 6/20/2019 [Member]
Principal Amount	$ 200,000
Market Value	$ 197,677
% of Partners' Capital	3.50%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 2.49%, 6/27/2019 [Member]
Principal Amount	$ 100,000
Market Value	$ 98,791
% of Partners' Capital	1.75%
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 - Money Market Funds [Member]
Market Value	$ 1,600,000		$ 2,500,000
% of Partners' Capital	28.35%		30.00%
Cash Equivalents [Member] \| United States - Money Market Funds [Member] \| Fidelity Investments Money Market Funds - Government Portfolio [Member]
Principal Amount			$ 1,000,000
Market Value			$ 1,000,000
% of Partners' Capital			12.00%
Cash Equivalents [Member] \| United States - Money Market Funds [Member] \| Goldman Sachs Financial Square Funds - Government Fund - Class FS [Member]
Principal Amount	$ 1,500,000		$ 1,000,000
Market Value	$ 1,500,000		$ 1,000,000
% of Partners' Capital	26.58%		12.00%
Cash Equivalents [Member] \| United States - Money Market Funds [Member] \| Morgan Stanley Institutional Liquidity Funds - Government Portfolio [Member]
Principal Amount	$ 100,000		$ 500,000
Market Value	$ 100,000		$ 500,000
% of Partners' Capital	1.77%		6.00%

[1]	Collateral amounted to $596,555 on open futures contracts.
[2]	Collateral amounted to $1,701,275 on open futures contracts.

Schedule of Investments (Parent

Schedule of Investments (Parenthetical) - USD ($)	12 Months Ended
Schedule of Investments (Parenthetical) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Collateral Amount on Open Futures Contracts	$ 596,555	$ 1,701,275
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 2.10%, 1/03/2019 [Member]
Expiration date	1/03/2019
Interest Rate	2.10%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 2.10%, 1/10/2019 [Member]
Expiration date	1/10/2019
Interest Rate	2.10%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 2.13%, 1/17/2019 [Member]
Expiration date	1/17/2019
Interest Rate	2.13%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 2.15%, 1/24/2019 [Member]
Expiration date	1/24/2019
Interest Rate	2.15%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 2.18%, 1/31/2019 [Member]
Expiration date	1/31/2019
Interest Rate	2.18%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 2.20%, 2/07/2019 [Member]
Expiration date	2/07/2019
Interest Rate	2.20%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 2.19%, 2/14/2019 [Member]
Expiration date	2/14/2019
Interest Rate	2.19%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 2.20%, 2/21/2019 [Member]
Expiration date	2/21/2019
Interest Rate	2.20%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 2.24%, 2/28/2019 [Member]
Expiration date	2/28/2019
Interest Rate	2.24%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 2.38%, 3/07/2019 [Member]
Expiration date	3/07/2019
Interest Rate	2.38%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 2.28%, 3/14/2019 [Member]
Expiration date	3/14/2019
Interest Rate	2.28%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 2.33%, 3/21/2019 [Member]
Expiration date	3/21/2019
Interest Rate	2.33%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 2.34%, 3/28/2019 [Member]
Expiration date	3/28/2019
Interest Rate	2.34%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 2.37%, 4/04/2019 [Member]
Expiration date	4/04/2019
Interest Rate	2.37%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 2.41%, 4/11/2019 [Member]
Expiration date	4/11/2019
Interest Rate	2.41%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 2.42%, 4/18/2019 [Member]
Expiration date	4/18/2019
Interest Rate	2.42%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 2.43%, 4/25/2019 [Member]
Expiration date	4/25/2019
Interest Rate	2.43%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 2.46%, 5/02/2019 [Member]
Expiration date	5/02/2019
Interest Rate	2.46%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 2.47%, 5/09/2019 [Member]
Expiration date	5/09/2019
Interest Rate	2.47%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 2.48%, 5/16/2019 [Member]
Expiration date	5/16/2019
Interest Rate	2.48%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 2.50%, 5/23/2019 [Member]
Expiration date	5/23/2019
Interest Rate	2.50%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 2.49%, 5/30/2019 [Member]
Expiration date	5/30/2019
Interest Rate	2.49%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 2.51%, 6/06/2019 [Member]
Expiration date	6/06/2019
Interest Rate	2.51%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 2.51%, 6/13/2019 [Member]
Expiration date	6/13/2019
Interest Rate	2.51%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 2.49%, 6/20/2019 [Member]
Expiration date	6/20/2019
Interest Rate	2.49%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 2.49%, 6/27/2019 [Member]
Expiration date	6/27/2019
Interest Rate	2.49%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 1.12%, 1/04/2018 [Member]
Expiration date		1/04/2018
Interest Rate		1.12%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 1.11%, 1/11/2018 [Member]
Expiration date		1/11/2018
Interest Rate		1.11%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 1.10%, 1/18/2018 [Member]
Expiration date		1/18/2018
Interest Rate		1.10%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 1.12%, 1/25/2018 [Member]
Expiration date		1/25/2018
Interest Rate		1.12%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 1.12%, 2/01/2018 [Member]
Expiration date		2/01/2018
Interest Rate		1.12%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 1.13%, 2/08/2018 [Member]
Expiration date		2/08/2018
Interest Rate		1.13%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 1.12%, 2/15/2018 [Member]
Expiration date		2/15/2018
Interest Rate		1.12%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 1.10%, 2/22/2018 [Member]
Expiration date		2/22/2018
Interest Rate		1.10%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 1.09%, 3/01/2018 [Member]
Expiration date		3/01/2018
Interest Rate		1.09%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 1.14%, 3/08/2018 [Member]
Expiration date		3/08/2018
Interest Rate		1.14%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 1.14%, 3/15/2018 [Member]
Expiration date		3/15/2018
Interest Rate		1.14%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 1.16%, 3/22/2018 [Member]
Expiration date		3/22/2018
Interest Rate		1.16%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 1.17%, 3/29/2018 [Member]
Expiration date		3/29/2018
Interest Rate		1.17%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 1.19%, 4/05/2018 [Member]
Expiration date		4/05/2018
Interest Rate		1.19%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 1.22%, 4/12/2018 [Member]
Expiration date		4/12/2018
Interest Rate		1.22%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 1.23%, 4/19/2018 [Member]
Expiration date		4/19/2018
Interest Rate		1.23%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 1.25%, 4/26/2018 [Member]
Expiration date		4/26/2018
Interest Rate		1.25%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 1.27%, 5/03/2018 [Member]
Expiration date		5/03/2018
Interest Rate		1.27%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 1.32%, 5/10/2018 [Member]
Expiration date		5/10/2018
Interest Rate		1.32%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 1.37%, 5/17/2018 [Member]
Expiration date		5/17/2018
Interest Rate		1.37%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 1.43%, 5/24/2018 [Member]
Expiration date		5/24/2018
Interest Rate		1.43%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 1.43%, 5/31/2018 [Member]
Expiration date		5/31/2018
Interest Rate		1.43%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 1.45%, 6/07/2018 [member]
Expiration date		6/07/2018
Interest Rate		1.45%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 1.46%, 6/14/2018 [Member]
Expiration date		6/14/2018
Interest Rate		1.46%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 1.49%, 6/21/2018 [Member]
Expiration date		6/21/2018
Interest Rate		1.49%
Cash Equivalents [Member] \| United States Treasury Obligations [Member] \| U.S. Treasury Bills: 1.50%, 6/28/2018 [Member]
Expiration date		6/28/2018
Interest Rate		1.50%

Statements of Operations

Statements of Operations - USD ($)		12 Months Ended
Statements of Operations - USD ($)		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Gain (loss) on trading of commodity futures contracts:
Realized gain (loss) on closed futures contracts		$ (11,739)	$ 229,715	$ (2,271,270)
Change in unrealized gain (loss) on open futures contracts		522,819	(3,364,926)	5,217,980
Dividend income		24,807	27,445	10,786
Interest income	[1]	86,283	53,398	32,944
ETF transaction fees		2,800	2,450	1,750
Total income (loss)		624,970	(3,051,918)	2,992,190
Expenses
General Partner management fees (Note 3)		48,189	78,805	102,306
Professional fees		65,849	71,759	114,167
Brokerage commissions		1,334	2,209	3,451
Directors' fees and insurance		1,447	1,929	2,888
License fees		964	1,576	2,046
Total expenses		117,783	156,278	224,858
Expense waiver (Note 3)		(59,956)	(61,713)	(102,092)
Net expenses		57,827	94,565	122,766
Net income (loss)		$ 567,143	$ (3,146,483)	$ 2,869,424
Net income (loss) per limited partnership share		$ 1	$ (2.49)	$ 2.03
Net income (loss) per weighted average limited partnership share		$ 0.84	$ (3.06)	$ 2.07
Weighted average limited partnership shares outstanding		671,507	1,027,534	1,387,568

[1]	Interest income does not exceed paid in kind of 5%.

Statements of Changes in Partne

Statements of Changes in Partners' Capital - USD ($)	Total	General Partner [Member]	Limited Partners [Member]
Balances at Dec. 31, 2015	$ 13,125,103	$ 0	$ 13,125,103
Addition of partnership shares	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, beginning of year at Dec. 31, 2015	$ 9.72
Net asset value, end of year at Dec. 31, 2016	$ 11.75
Addition of partnership shares	$ 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
Addition of partnership shares	$ 584,722	0	584,722
Redemption of partnership shares	(3,843,434)	0	(3,843,434)
Net income (loss)	567,143	0	567,143
Balances at Dec. 31, 2018	$ 5,642,871	$ 0	$ 5,642,871
Net asset value, end of year at Dec. 31, 2018	$ 10.26

Statements of Changes in Part_2

Statements of Changes in Partners' Capital (Parenthetical) - shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Addition of partnership share	50,000	100,000	150,000
Redemption of partnership shares	400,000	600,000	100,000

Statements of Cash Flows

Statements of Cash Flows - USD ($)	12 Months Ended
Statements of Cash Flows - USD ($)	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash Flows from Operating Activities:
Net income (loss)	$ 567,143	$ (3,146,483)	$ 2,869,424
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Unrealized (gain) loss on open futures contracts	(522,819)	3,364,926	(5,217,980)
(Increase) decrease in receivable from General Partner	1,757	40,379	(12,970)
(Increase) decrease in dividends receivable	(260)	(831)	(1,337)
(Increase) decrease in interest receivable	(201)	(88)	0
(Increase) decrease in directors' fees and insurance receivable	66	(66)	1,197
(Increase) decrease in ETF transaction fees receivable	0	350	(350)
(Increase) decrease in other assets	(216)	0	0
Increase (decrease) in payable due to Broker	81,581	(2,099,689)	2,099,689
Increase (decrease) in General Partner management fees payable	(1,784)	(4,944)	2,510
Increase (decrease) in professional fees payable	(21,209)	(29,606)	27,360
Increase (decrease) in brokerage commissions payable	(610)	(620)	0
Increase (decrease) in directors' fees and insurance payable	641	(106)	106
Increase (decrease) in license fees payable	(331)	(413)	(84)
Net cash provided by (used in) operating activities	103,758	(1,877,191)	(232,435)
Cash Flows from Financing Activities:
Addition of partnership shares	584,722	1,021,619	1,418,858
Redemption of partnership shares	(3,843,434)	(5,986,374)	(967,707)
Net cash provided by (used in) financing activities	(3,258,712)	(4,964,755)	451,151
Net Increase (Decrease) in Cash and Cash Equivalents	(3,154,954)	(6,841,946)	218,716
Total Cash, Cash Equivalents and Equity in Trading Accounts, beginning of year	8,918,876	15,760,822	15,542,106
Total Cash, Cash Equivalents and Equity in Trading Accounts, end of year	$ 5,763,922	$ 8,918,876	$ 15,760,822

Statements of Cash Flows (Paren

Statements of Cash Flows (Parenthetical) - USD ($)	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Components of Cash and Cash Equivalents:
Cash and Cash Equivalents	$ 5,167,367	$ 7,217,601	$ 15,061,018
Equity in Trading Accounts:
Cash and Cash Equivalents	596,555	1,701,275	699,804
Total Cash, Cash Equivalents and Equity in Trading Accounts	$ 5,763,922	$ 8,918,876	$ 15,760,822

ORGANIZATION AND BUSINESS

ORGANIZATION AND BUSINESS	12 Months Ended
ORGANIZATION AND BUSINESS	Dec. 31, 2018
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 for its NAV or market price of shares to equal, in dollar terms, the spot price of natural gas or any particular futures contract based on natural gas, nor is UNL’s investment objective for the percentage change in its NAV to reflect the percentage change of the price of any particular futures contract as measured over a time period greater than one day . United States Commodity Funds LLC (“USCF”), the general partner of 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, 2018, UNL held 201 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 was in registration and had not commenced operations. UCCO filed to withdraw from registration on December 19, 2018. On August 7, 2018, the Board of Directors of USCF authorized and approved the closing and liquidation for each of USAG, DNO and UHN together with a plan of liquidation for each of USAG, DNO and UHN. Each of the United States Commodity Index Funds Trust (“USCIFT”), of which USAG is a series, DNO and UHN filed a current report on Form 8-K dated August 8, 2018 with the SEC that included, as an exhibit, the press release, the applicable plan of liquidation, and, in the case of DNO and UHN, a copy of the notice of required withdrawal from the limited partnership sent to shareholders. In addition, each of USAG, DNO and UHN filed a prospectus supplement with the SEC dated August 8, 2018. The liquidation date for each of USAG, DNO and UHN was September 12, 2018 and the proceeds of the liquidation were sent to all remaining shareholders of USAG, DNO and UHN, respectively, on or about September 13, 2018, with a subsequent distribution of additional liquidation proceeds sent to UHN shareholders on or about September 18, 2018. Each of USAG, DNO and UHN also filed a post-effective amendment to the registration statement with the SEC to terminate the offering of registered and unsold shares of USAG, DNO and UHN, respectively, and the NYSE Arca filed Forms 25 to effect the withdrawal of the listings for shares of each of USAG, DNO and UHN. In addition, USCF is the sponsor of the USCF Funds Trust, a Delaware statutory trust, and each of its series, 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 DNO, UHN and USAG, 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 shares (“Creation Baskets”) through ALPS Distributors, Inc., as the marketing agent (the “Marketing Agent”). The purchase price for a Creation Basket is based upon the NAV of a share calculated shortly after the close of the core trading session on the NYSE Arca on the day the order to create the basket is properly received. In addition, Authorized Participants pay UNL a $350 fee for each order placed to create one or more Creation Baskets or to redeem one or more baskets (“Redemption Baskets”), consisting of 50,000 shares. Shares may be purchased or sold on a nationally recognized securities exchange in smaller increments than a Creation Basket or Redemption Basket. Shares purchased or sold on a nationally recognized securities exchange are not purchased or sold at the per share NAV of UNL but rather at market prices quoted on such exchange. In November 2009, UNL initially registered 30,000,000 shares on Form S-1 with the U.S. Securities and Exchange Commission (the “SEC”). On November 18, 2009, UNL listed its shares on the NYSE Arca under the ticker symbol “UNL”. On that day, UNL established its initial per share NAV by setting the price at $50.00 and issued 200,000 shares in exchange for $10,000,000. UNL also commenced investment operations on November 18, 2009, by purchasing Futures Contracts traded on the NYMEX based on natural gas. As of December 31, 2018, UNL had registered a total of 30,000,000 shares.

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	12 Months Ended
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	Dec. 31, 2018
Summary Of Significant Accounting Policies [Abstract]
Summary of Significant Accounting Policies	NOTE 2 — SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Basis of Presentation The financial statements have been prepared in conformity with 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 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 a futures commission merchant (“FCM”) at prevailing market rates earned on such investments. Brokerage Commissions Brokerage commissions on all open commodity futures contracts are accrued on a full-turn basis. 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 2015. 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, 2018. Creations and Redemptions Authorized Participants may purchase Creation Baskets or redeem Redemption Baskets only in blocks of 50,000 shares at a price equal to the NAV of the shares calculated shortly after the close of the core trading session on the NYSE Arca on the day the order is placed. 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 for each order placed to create one or more Creation Baskets or to redeem one or more Redemption Baskets. Partnership Capital and Allocation of Partnership Income and Losses Profit or loss shall be allocated among the partners of 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 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 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, 2018. 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 include money market funds and overnight deposits or time deposits with original maturity dates of six months or less. Reclassification Certain amounts in the accompanying financial statements were reclassified to conform to the current presentation. 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.

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, 2018
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, 2018, 2017 and 2016, 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, 2018 were $521,689 for UNL and the Related Public Funds. UNL's portion of such fees and expenses for the year ended December 31, 2018 was $1,447. For the year ended December 31, 2017, these fees and expenses were $536,375 for UNL and the Related Public Funds. UNL’s portion of such fees and expenses for the year ended December 31, 2017 was $1,929. For the year ended December 31, 2016, these fees and expenses were $582,050 for UNL and the Related Public Funds. UNL’s portion of such fees and expenses for the year ended December 31, 2016 was $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, USOU and USOD, pay a licensing fee that is equal to 0.015% on all net assets. During the years ended December 31, 2018, 2017 and 2016, UNL incurred $964, $1,576 and $2,046, respectively, under this arrangement. 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 $65,000 for the year ended December 31, 2018, approximately $72,000 for the year ended December 31, 2017 and approximately $76,000 for the year ended December 31, 2016. Tax reporting costs fluctuate between years due to the number of shareholders during any given year. 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 below. USCF paid certain expenses on a discretionary basis typically borne by UNL, where expenses exceed 0.15% (15 basis points) of UNL’s NAV, on an annualized basis. USCF has no obligation to continue such payments into subsequent periods. For the year ended December 31, 2018, USCF waived $59,956 of UNL’s expenses. This voluntary expense waiver is in addition to those amounts USCF is contractually obligated to pay as described in Note 4 – Contracts and Agreements .

CONTRACTS AND AGREEMENTS

CONTRACTS AND AGREEMENTS	12 Months Ended
CONTRACTS AND AGREEMENTS	Dec. 31, 2018
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% on UNL's assets up to $3 billion and 0.04% on UNL's assets in excess of $3 billion. In no event may the aggregate compensation paid to the Marketing Agent and any affiliate of USCF for distribution-related services exceed 10% of the gross proceeds of UNL's offering. 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 annually for its custody, fund accounting and fund administration services rendered to UNL and each of the Related Public Funds, as well as a $20,000 annual fee for its transfer agency services. In addition, USCF pays BBH&Co. an asset-based charge of (a) 0.06% for the first $500 million of the Related Public Funds’ combined net assets, (b) 0.0465% for the Related Public Funds’ combined net assets greater than $500 million but less than $1 billion, and (c) 0.035% once the Related Public Funds’ combined net assets exceed $1 billion. The annual minimum amount will not apply if the asset-based charge for all accounts in the aggregate exceeds $75,000. USCF also pays BBH&Co. transaction fees ranging from $7 to $15 per transaction. Brokerage and Futures Commission Merchant Agreements On October 8, 2013, UNL entered into a brokerage agreement with RBC Capital 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 to $8 per round-turn trade, including applicable exchange, clearing and NFA fees for natural gas Futures Contracts and options on natural gas Futures Contracts. Such fees include those incurred when purchasing natural gas Futures Contracts and options on natural gas Futures Contracts when UNL issues shares as a result of a Creation Basket, as well as fees incurred when selling natural gas Futures Contracts and options on natural gas Futures Contracts when UNL redeems shares as a result of a Redemption Basket. Such fees are also incurred when natural gas Futures Contracts and options on natural gas Futures Contracts are purchased or redeemed for the purpose of rebalancing the portfolio. 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 December 31, 2018 For the Year Ended December 31, 2017 For the Year Ended December 31, 2016 Total commissions accrued to brokers $ 1,334 $ 2,209 $ 3,451 Total commissions as annualized percentage of average total net assets 0.02 % 0.02 % 0.03 % Commissions accrued as a result of rebalancing $ 823 $ 1,605 $ 3,305 Percentage of commissions accrued as a result of rebalancing 61.69 % 72.66 % 95.77 % Commissions accrued as a result of creation and redemption activity $ 511 $ 604 $ 146 Percentage of commissions accrued as a result of creation and redemption activity 38.31 % 27.34 % 4.23 % The decrease in total commissions accrued to brokers for the year ended December 31, 2018, compared to the year ended December 31, 2017, 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, 2017, compared to the year ended December 31, 2016, 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, 2018
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, 2018 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, 2018 and December 31, 2017, UNL held investments in money market funds in the amounts of $1,600,000 and $2,500,000, respectively. UNL also holds cash deposits with its custodian. Pursuant to a written agreement with BBH&Co., uninvested overnight cash balances are swept to offshore branches of U.S. regulated and domiciled banks located in Toronto, Canada; London, United Kingdom; Grand Cayman, Cayman Islands; and Nassau, Bahamas; which are subject to U.S. regulation and regulatory oversight. As of December 31, 2018 and December 31, 2017, UNL held cash deposits and investments in Treasuries in the amounts of $4,163,922 and $6,418,876, respectively, with the custodian and FCM. Some or all of these amounts may be subject to loss should UNL's custodian and/or FCM cease operations. 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
FINANCIAL HIGHLIGHTS	Dec. 31, 2018
Financial Highlights [Abstract]
Financial Highlights	NOTE 6 — FINANCIAL HIGHLIGHTS The following table presents per share performance data and other supplemental financial data for the years ended December 31, 2018, 2017 and 2016 for the shareholders. This information has been derived from information presented in the financial statements. Year ended December 31, 2018 Year ended December 31, 2017 Year ended December 31, 2016 Per Share Operating Performance: Net asset value, beginning of year $ 9.26 $ 11.75 $ 9.72 Total income (loss) 1.09 (2.40 ) 2.12 Net expenses (0.09 ) (0.09 ) (0.09 ) Net increase (decrease) in net asset value 1.00 (2.49 ) 2.03 Net asset value, end of year $ 10.26 $ 9.26 $ 11.75 Total Return 10.80 % (21.19 )% 20.88 % Ratios to Average Net Assets Total income (loss) 9.73 % (29.05 )% 21.94 % Management fees 0.75 % 0.75 % 0.75 % Total expenses excluding management fees* 1.08 % 0.74 % 0.90 % Expenses waived (0.93 )% (0.59 )% (0.75 )% Net expenses excluding management fees 0.15 % 0.15 % 0.15 % Net income (loss) 8.83 % (29.95 )% 21.04 % 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
QUARTERLY FINANCIAL DATA (Unaudited)	Dec. 31, 2018
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, 2018 and 2017. First Quarter 2018 Second Quarter 2018 Third Quarter 2018 Fourth Quarter 2018 Total Income (Loss) $ 68,119 $ 144,125 $ (21,437 ) $ 434,163 Total Expenses 35,055 29,326 25,180 28,222 Expense Waivers (17,762 ) (15,329 ) (11,999 ) (14,866 ) Net Expenses 17,293 13,997 13,181 13,356 Net Income (Loss) $ 50,826 $ 130,128 $ (34,618 ) $ 420,807 Net Income (Loss) per Share $ 0.03 $ 0.20 $ (0.04 ) $ 0.81 First Quarter 2017 Second Quarter 2017 Third Quarter 2017 Fourth Quarter 2017 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 )

FAIR VALUE OF FINANCIAL INSTRUM

FAIR VALUE OF FINANCIAL INSTRUMENTS	12 Months Ended
FAIR VALUE OF FINANCIAL INSTRUMENTS	Dec. 31, 2018
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 assets or liabilities that the reporting entity has the ability to access at the measurement date. Level II – Inputs other than quoted prices included within Level I that are observable for the asset or liability, either directly or indirectly. Level II assets include the following: quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the asset or liability, and inputs that are derived principally from or corroborated by observable market data by correlation or other means (market-corroborated inputs). Level III – Unobservable pricing input at the measurement date for the asset or liability. Unobservable inputs shall be used to measure fair value to the extent that observable inputs are not available. In some instances, the inputs used to measure fair value might fall within different levels of the fair value hierarchy. The level in the fair value hierarchy within which the fair value measurement in its entirety falls shall be determined based on the lowest input level that is significant to the fair value measurement in its entirety. The following table summarizes the valuation of UNL’s securities at December 31, 2018 using the fair value hierarchy: At December 31, 2018 Total Level I Level II Level III Short-Term Investments $ 5,577,527 $ 5,577,527 $ — $ — Exchange-Traded Futures Contracts United States Contracts (46,103 ) (46,103 ) — — During the year ended December 31, 2018, there were no transfers between Level I and Level II. 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. 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. Fair Value of Derivative Instruments Derivatives not Accounted for as Hedging Instruments Statements of Financial Condition Location Fair Value At December 31, 2018 Fair Value At December 31, 2017 Futures - Commodity Contracts Assets $ (46,103 ) $ (568,922 ) The Effect of Derivative Instruments on the Statements of Operations For the year ended December 31, 2018 For the year ended December 31, 2017 For the year ended December 31, 2016 Derivatives not Accounted for as Hedging Instruments Location of Gain (Loss) on Derivatives Recognized in Income Realized Gain (Loss) on Derivatives Recognized in Income Change in Unrealized Gain (Loss) on Derivatives Recognized in Income Realized Gain (Loss) on Derivatives Recognized in Income Change in Unrealized Gain (Loss) on Derivatives Recognized in Income Realized Gain (Loss) on Derivatives Recognized in Income Change in Unrealized Gain (Loss) on Derivatives Recognized in Income Futures - Commodity Contracts Realized gain (loss) on closed positions $ (11,739 ) $ 229,715 $ (2,271,270 ) Change in unrealized gain (loss) on open positions $ 522,819 $ (3,364,926 ) $ 5,217,980

RECENT ACCOUNTING PRONOUNCEMENT

RECENT ACCOUNTING PRONOUNCEMENTS	12 Months Ended
RECENT ACCOUNTING PRONOUNCEMENTS	Dec. 31, 2018
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. This standard became effective for fiscal years beginning after December 15, 2017, and interim periods within those annual periods. There were no material impacts to the Fund’s financial statements upon adoption. New Accounting Pronouncements In November 2016, the FASB issued Accounting Standards Update No. 2016-18, “Statement of Cash Flows (Topic 230): Restricted Cash” (“ASU 2016-18”), which amends ASC 230 to provide guidance on the classification and presentation of changes in restricted cash and restricted cash equivalents on the statement of cash flows. The ASU is effective for annual periods beginning after December 15, 2017, and interim periods within those annual periods. At this time, management has evaluated the implications of these changes on the financial statements and adopted with no material impact.

SUBSEQUENT EVENTS

SUBSEQUENT EVENTS	12 Months Ended
SUBSEQUENT EVENTS	Dec. 31, 2018
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 ACCOUN_2

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	12 Months Ended
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	Dec. 31, 2018
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 a 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 2015. 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, 2018.
Creations and Redemptions	Creations and Redemptions Authorized Participants may purchase Creation Baskets or redeem Redemption Baskets only in blocks of 50,000 shares at a price equal to the NAV of the shares calculated shortly after the close of the core trading session on the NYSE Arca on the day the order is placed. 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 for each order placed to create one or more Creation Baskets or to redeem one or more Redemption Baskets.
Partnership Capital and Allocation of Partnership Income and Losses	Partnership Capital and Allocation of Partnership Income and Losses Profit or loss shall be allocated among the partners of 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 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, 2018.
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
CONTRACTS AND AGREEMENTS (Tables)	Dec. 31, 2018
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 December 31, 2018 For the Year Ended December 31, 2017 For the Year Ended December 31, 2016 Total commissions accrued to brokers $ 1,334 $ 2,209 $ 3,451 Total commissions as annualized percentage of average total net assets 0.02 % 0.02 % 0.03 % Commissions accrued as a result of rebalancing $ 823 $ 1,605 $ 3,305 Percentage of commissions accrued as a result of rebalancing 61.69 % 72.66 % 95.77 % Commissions accrued as a result of creation and redemption activity $ 511 $ 604 $ 146 Percentage of commissions accrued as a result of creation and redemption activity 38.31 % 27.34 % 4.23 %

FINANCIAL HIGHLIGHTS (Tables)

FINANCIAL HIGHLIGHTS (Tables)	12 Months Ended
FINANCIAL HIGHLIGHTS (Tables)	Dec. 31, 2018
Financial Highlights [Abstract]
Per Unit Performance Data and Other Supplemental Financial Data	This information has been derived from information presented in the financial statements. Year ended December 31, 2018 Year ended December 31, 2017 Year ended December 31, 2016 Per Share Operating Performance: Net asset value, beginning of year $ 9.26 $ 11.75 $ 9.72 Total income (loss) 1.09 (2.40 ) 2.12 Net expenses (0.09 ) (0.09 ) (0.09 ) Net increase (decrease) in net asset value 1.00 (2.49 ) 2.03 Net asset value, end of year $ 10.26 $ 9.26 $ 11.75 Total Return 10.80 % (21.19 )% 20.88 % Ratios to Average Net Assets Total income (loss) 9.73 % (29.05 )% 21.94 % Management fees 0.75 % 0.75 % 0.75 % Total expenses excluding management fees* 1.08 % 0.74 % 0.90 % Expenses waived (0.93 )% (0.59 )% (0.75 )% Net expenses excluding management fees 0.15 % 0.15 % 0.15 % Net income (loss) 8.83 % (29.95 )% 21.04 %

QUARTERLY FINANCIAL DATA (Una_2

QUARTERLY FINANCIAL DATA (Unaudited) (Tables)	12 Months Ended
QUARTERLY FINANCIAL DATA (Unaudited) (Tables)	Dec. 31, 2018
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, 2018 and 2017. First Quarter 2018 Second Quarter 2018 Third Quarter 2018 Fourth Quarter 2018 Total Income (Loss) $ 68,119 $ 144,125 $ (21,437 ) $ 434,163 Total Expenses 35,055 29,326 25,180 28,222 Expense Waivers (17,762 ) (15,329 ) (11,999 ) (14,866 ) Net Expenses 17,293 13,997 13,181 13,356 Net Income (Loss) $ 50,826 $ 130,128 $ (34,618 ) $ 420,807 Net Income (Loss) per Share $ 0.03 $ 0.20 $ (0.04 ) $ 0.81 First Quarter 2017 Second Quarter 2017 Third Quarter 2017 Fourth Quarter 2017 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 )

FAIR VALUE OF FINANCIAL INSTR_2

FAIR VALUE OF FINANCIAL INSTRUMENTS (Tables)	12 Months Ended
FAIR VALUE OF FINANCIAL INSTRUMENTS (Tables)	Dec. 31, 2018
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, 2018 using the fair value hierarchy: At December 31, 2018 Total Level I Level II Level III Short-Term Investments $ 5,577,527 $ 5,577,527 $ — $ — Exchange-Traded Futures Contracts United States Contracts (46,103 ) (46,103 ) — — During the year ended December 31, 2018, there were no transfers between Level I and Level II. 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 ) — —
Fair Value of Derivative Instruments	Fair Value of Derivative Instruments Derivatives not Accounted for as Hedging Instruments Statements of Financial Condition Location Fair Value At December 31, 2018 Fair Value At December 31, 2017 Futures - Commodity Contracts Assets $ (46,103 ) $ (568,922 )
Effect of Derivative Instruments on the Condensed Statements of Operations	The Effect of Derivative Instruments on the Statements of Operations For the year ended December 31, 2018 For the year ended December 31, 2017 For the year ended December 31, 2016 Derivatives not Accounted for as Hedging Instruments Location of Gain (Loss) on Derivatives Recognized in Income Realized Gain (Loss) on Derivatives Recognized in Income Change in Unrealized Gain (Loss) on Derivatives Recognized in Income Realized Gain (Loss) on Derivatives Recognized in Income Change in Unrealized Gain (Loss) on Derivatives Recognized in Income Realized Gain (Loss) on Derivatives Recognized in Income Change in Unrealized Gain (Loss) on Derivatives Recognized in Income Futures - Commodity Contracts Realized gain (loss) on closed positions $ (11,739 ) $ 229,715 $ (2,271,270 ) Change in unrealized gain (loss) on open positions $ 522,819 $ (3,364,926 ) $ 5,217,980

ORGANIZATION AND BUSINESS (Addi

ORGANIZATION AND BUSINESS (Additional Information) (Details)	1 Months Ended
	Nov. 30, 2009	Nov. 18, 2009USD ($)$ / sharesshares	Dec. 31, 2018$ / shares$ / Basket	Dec. 31, 2017$ / shares	Dec. 31, 2016$ / shares	Dec. 31, 2015$ / shares	Dec. 31, 2014$ / 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			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	$ 10.26	$ 9.26	$ 11.75	$ 9.72	$ 9.72
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
Prior To July 1, 2011 [Member]
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			50,000

SUMMARY OF SIGNIFICANT ACCOUN_3

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Additional Information) (Details)	Dec. 31, 2018$ / Basket
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	350
Redemption Baskets [Member]
Significant Accounting Policies [Line Items]
Number of units per basket	50,000

FEES PAID BY THE FUND AND REL_2

FEES PAID BY THE FUND AND RELATED PARTY TRANSACTIONS (Additional Information) (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
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									$ 1,447	$ 1,929	$ 2,888
Licensing fee incurred									964	1,576	2,046
Expense waiver	$ (14,866)	$ (11,999)	$ (15,329)	$ (17,762)	$ (17,165)	$ (19,588)	$ (9,907)	$ (15,053)	$ 59,956	61,713	102,092
Licensing Agreements [Member]
Fees Paid and Related Party Transactions [Line Items]
Fee percentage									0.015%
Future Period - for the year ending December 31, 2018 [Member]
Fees Paid and Related Party Transactions [Line Items]
Estimated investor tax reporting cost									$ 65,000	72,000	76,000
Future Period - for the year ending December 31, 2018 [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									$ 1,447	$ 1,929	$ 2,888

CONTRACTS AND AGREEMENTS (Broke

CONTRACTS AND AGREEMENTS (Brokerage Commissions) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Total commissions accrued to brokers	$ 1,334	$ 2,209	$ 3,451
Total commissions as annualized percentage of average total net assets	0.02%	0.02%	0.03%
Rebalancing Investments Transaction [Member]
Total commissions accrued to brokers	$ 823	$ 1,605	$ 3,305
Total commissions as annualized percentage of average total net assets	61.69%	72.66%	95.77%
Creation And Redemption Activity [Member]
Total commissions accrued to brokers	$ 511	$ 604	$ 146
Total commissions as annualized percentage of average total net assets	38.31%	27.34%	4.23%

CONTRACTS AND AGREEMENTS (Addit

CONTRACTS AND AGREEMENTS (Additional Information) (Details)	12 Months Ended
CONTRACTS AND AGREEMENTS (Additional Information) (Details)	Dec. 31, 2018USD ($)$ / Basket
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]
Annual Fee for custody, fund accounting and fund administration services	$ 75,000
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 \| $ / Basket	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 \| $ / Basket	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-BA_2

FINANCIAL INSTRUMENTS, OFF-BALANCE SHEET RISKS AND CONTINGENCIES (Additional Information) (Details) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Carrying Amounts and Fair Values of Financial Instruments or Liabilities [Line Items]
Cash investments in money market funds	$ 1,600,000	$ 2,500,000
Deposits in domestic and foreign financial institutions	$ 4,163,922	$ 6,418,876

FINANCIAL HIGHLIGHTS (Per Unit

FINANCIAL HIGHLIGHTS (Per Unit Performance Data and Other Supplemental Financial Data) (Details) - $ / shares		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Per Share Operating Performance:
Net asset value, beginning of year		$ 9.26	$ 11.75	$ 9.72
Total income (loss)		1.09	(2.40)	2.12
Net expenses		(0.09)	(0.09)	(0.09)
Net increase (decrease) in net asset value		1	(2.49)	2.03
Net asset value, end of year		$ 10.26	$ 9.26	$ 11.75
Total Return		10.80%	(21.19%)	20.88%
Ratios to Average Net Assets
Total income (loss)		9.73%	(29.05%)	21.94%
Management fees		0.75%	0.75%	0.75%
Total expenses excluding management fees	[1]	1.08%	0.74%	0.90%
Expenses waived		(0.93%)	(0.59%)	(0.75%)
Net expenses excluding management fees		0.15%	0.15%	0.15%
Net income (loss)		8.83%	(29.95%)	21.04%

[1]	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 (Una_3

QUARTERLY FINANCIAL DATA (Unaudited) (Quarterly Financial Information Presents The Results Of Operations) (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Total Income (Loss)	$ 434,163	$ (21,437)	$ 144,125	$ 68,119	$ (645,188)	$ 9,809	$ (536,427)	$ (1,880,112)	$ 624,970	$ (3,051,918)	$ 2,992,190
Total Expenses	28,222	25,180	29,326	35,055	36,482	40,970	33,306	45,520	117,783	156,278	224,858
Expense Waivers	(14,866)	(11,999)	(15,329)	(17,762)	(17,165)	(19,588)	(9,907)	(15,053)	59,956	61,713	102,092
Net expenses	13,356	13,181	13,997	17,293	19,317	21,382	23,399	30,467	57,827	94,565	122,766
Net Income (Loss)	$ 420,807	$ (34,618)	$ 130,128	$ 50,826	$ (664,505)	$ (11,573)	$ (559,826)	$ (1,910,579)	$ 567,143	$ (3,146,483)	$ 2,869,424
Net Income (Loss) per Share	$ 0.81	$ (0.04)	$ 0.20	$ 0.03	$ (0.75)	$ (0.01)	$ (0.63)	$ (1.10)	$ 1	$ (2.49)	$ 2.03

FAIR VALUE OF FINANCIAL INSTR_3

FAIR VALUE OF FINANCIAL INSTRUMENTS (Valuation of Securities Using Fair Value Hierarchy) (Details) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Short-Term Investments [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Securities, fair value	$ 5,577,527	$ 7,683,698
Fair Value, Inputs, Level 1 [Member] \| Short-Term Investments [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Securities, fair value	5,577,527	7,683,698
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	(46,103)	(568,922)
United States Contracts [Member] \| Fair Value, Inputs, Level 1 [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Securities, fair value	(46,103)	(568,922)
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 INSTR_4

FAIR VALUE OF FINANCIAL INSTRUMENTS (Fair Value of Derivative Instruments) (Details) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Derivatives, Fair Value [Line Items]
Derivatives not Accounted for as Hedging Instruments	$ (46,103)	$ (568,922)
Commodity Contracts [Member] \| Futures [Member] \| Assets [Member]
Derivatives, Fair Value [Line Items]
Derivatives not Accounted for as Hedging Instruments	$ (46,103)	$ (568,922)

FAIR VALUE OF FINANCIAL INSTR_5

FAIR VALUE OF FINANCIAL INSTRUMENTS (Effect of Derivative Instruments on Condensed Statements of Operations) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Realized Gain (Loss) on Derivatives Recognized in Income	$ (11,739)	$ 229,715	$ (2,271,270)
Change in Unrealized Gain (Loss) on Derivatives Recognized in Income	522,819	(3,364,926)	5,217,980
Commodity Contracts [Member] \| Futures [Member] \| Realized gain (loss) on closed futures contracts
Derivative Instruments, Gain (Loss) [Line Items]
Realized Gain (Loss) on Derivatives Recognized in Income	(11,739)	229,715	(2,271,270)
Commodity Contracts [Member] \| Futures [Member] \| Change in unrealized gain (loss) on open positions
Derivative Instruments, Gain (Loss) [Line Items]
Change in Unrealized Gain (Loss) on Derivatives Recognized in Income	$ 522,819	$ (3,364,926)	$ 5,217,980