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Condensed Schedule of Investments	Jun. 30, 2017 USD ($) Number
Unrealized Gain (Loss) on Open Commodity Contracts	$ 5,291,350
Open Futures Contracts, Long [Member] | United States [Member] | ICE Natural Gas Futures LD1 H August 2017 contracts, expiring August 2017 [Member]
Number of Contracts | Number	20,000
Unrealized Gain (Loss) on Open Commodity Contracts	$ 1,078,750
% of Partners' Capital	0.24%
Open Futures Contracts, Long [Member] | United States [Member] | NYMEX Natural Gas Futures NG August 2017 contracts, expiring July 2017 [Member]
Number of Contracts | Number	9,745
Unrealized Gain (Loss) on Open Commodity Contracts	$ 4,212,600
% of Partners' Capital	0.94%
Total Open Futures Contracts [Member] | Open Futures Contracts, Long [Member] | United States [Member]
Number of Contracts | Number	29,745	[1]
Unrealized Gain (Loss) on Open Commodity Contracts	$ 5,291,350	[1]
% of Partners' Capital	1.18%	[1]
Cash Equivalents [Member] | United States [Member]
Market Value	$ 373,959,761
% of Partners' Capital	83.57%
Cash Equivalents [Member] | United States [Member] | US Treasury Securities [Member]
Market Value	$ 353,959,761
% of Partners' Capital	79.11%
Cash Equivalents [Member] | United States [Member] | US Treasury Securities [Member] | U.S. Treasury Bills 0.62%, 7/06/2017 [Member]
Principal Amount	$ 10,000,000
Market Value	$ 9,999,146
% of Partners' Capital	2.23%
Cash Equivalents [Member] | United States [Member] | US Treasury Securities [Member] | U.S. Treasury Bills 0.59%, 7/13/2017 [Member]
Principal Amount	$ 15,000,000
Market Value	$ 14,997,075
% of Partners' Capital	3.35%
Cash Equivalents [Member] | United States [Member] | US Treasury Securities [Member] | U.S. Treasury Bills 0.61%, 7/20/2017 [Member]
Principal Amount	$ 10,000,000
Market Value	$ 9,996,807
% of Partners' Capital	2.23%
Cash Equivalents [Member] | United States [Member] | US Treasury Securities [Member] | U.S. Treasury Bills 0.60%, 7/27/2017 [Member]
Principal Amount	$ 5,000,000
Market Value	$ 4,997,851
% of Partners' Capital	1.12%
Cash Equivalents [Member] | United States [Member] | US Treasury Securities [Member] | U.S. Treasury Bills 0.61%, 8/10/2017 [Member]
Principal Amount	$ 10,000,000
Market Value	$ 9,993,222
% of Partners' Capital	2.23%
Cash Equivalents [Member] | United States [Member] | US Treasury Securities [Member] | U.S. Treasury Bills 0.65%, 8/17/2017 [Member]
Principal Amount	$ 10,000,000
Market Value	$ 9,991,514
% of Partners' Capital	2.23%
Cash Equivalents [Member] | United States [Member] | US Treasury Securities [Member] | U.S. Treasury Bills 0.67%, 8/24/2017 [Member]
Principal Amount	$ 15,000,000
Market Value	$ 14,984,925
% of Partners' Capital	3.35%
Cash Equivalents [Member] | United States [Member] | US Treasury Securities [Member] | U.S. Treasury Bills 0.76%, 8/31/2017 [Member]
Principal Amount	$ 15,000,000
Market Value	$ 14,980,810
% of Partners' Capital	3.35%
Cash Equivalents [Member] | United States [Member] | US Treasury Securities [Member] | U.S. Treasury Bills 0.84%, 9/07/2017 [Member]
Principal Amount	$ 10,000,000
Market Value	$ 9,984,133
% of Partners' Capital	2.23%
Cash Equivalents [Member] | United States [Member] | US Treasury Securities [Member] | U.S. Treasury Bills 0.87%, 9/21/2017 [Member]
Principal Amount	$ 10,000,000
Market Value	$ 9,980,183
% of Partners' Capital	2.23%
Cash Equivalents [Member] | United States [Member] | US Treasury Securities [Member] | U.S. Treasury Bills 0.89%, 9/28/2017 [Member]
Principal Amount	$ 15,000,000
Market Value	$ 14,966,996
% of Partners' Capital	3.35%
Cash Equivalents [Member] | United States [Member] | US Treasury Securities [Member] | U.S. Treasury Bills 0.90%, 10/05/2017 [Member]
Principal Amount	$ 15,000,000
Market Value	$ 14,964,200
% of Partners' Capital	3.34%
Cash Equivalents [Member] | United States [Member] | US Treasury Securities [Member] | U.S. Treasury Bills 0.92%, 10/12/2017 [Member]
Principal Amount	$ 20,000,000
Market Value	$ 19,947,642
% of Partners' Capital	4.46%
Cash Equivalents [Member] | United States [Member] | US Treasury Securities [Member] | U.S. Treasury Bills 0.91%, 10/19/2017 [Member]
Principal Amount	$ 20,000,000
Market Value	$ 19,944,694
% of Partners' Capital	4.46%
Cash Equivalents [Member] | United States [Member] | US Treasury Securities [Member] | U.S. Treasury Bills 0.95%, 10/26/2017 [Member]
Principal Amount	$ 10,000,000
Market Value	$ 9,969,125
% of Partners' Capital	2.23%
Cash Equivalents [Member] | United States [Member] | US Treasury Securities [Member] | U.S. Treasury Bills 0.97%, 11/02/2017 [Member]
Principal Amount	$ 15,000,000
Market Value	$ 14,950,142
% of Partners' Capital	3.34%
Cash Equivalents [Member] | United States [Member] | US Treasury Securities [Member] | U.S. Treasury Bills 1.01%, 11/09/2017 [Member]
Principal Amount	$ 15,000,000
Market Value	$ 14,945,144
% of Partners' Capital	3.34%
Cash Equivalents [Member] | United States [Member] | US Treasury Securities [Member] | U.S. Treasury Bills 0.98%, 11/16/2017 [Member]
Principal Amount	$ 20,000,000
Market Value	$ 19,924,867
% of Partners' Capital	4.45%
Cash Equivalents [Member] | United States [Member] | US Treasury Securities [Member] | U.S. Treasury Bills 1.05%, 11/24/2017 [Member]
Principal Amount	$ 20,000,000
Market Value	$ 19,915,239
% of Partners' Capital	4.45%
Cash Equivalents [Member] | United States [Member] | US Treasury Securities [Member] | U.S. Treasury Bills 1.05%, 11/30/2017 [Member]
Principal Amount	$ 20,000,000
Market Value	$ 19,911,755
% of Partners' Capital	4.45%
Cash Equivalents [Member] | United States [Member] | US Treasury Securities [Member] | U.S. Treasury Bills 1.08%, 12/07/2017 [Member]
Principal Amount	$ 15,000,000
Market Value	$ 14,929,113
% of Partners' Capital	3.34%
Cash Equivalents [Member] | United States [Member] | US Treasury Securities [Member] | U.S. Treasury Bills 1.09%, 12/14/2017 [Member]
Principal Amount	$ 20,000,000
Market Value	$ 19,900,400
% of Partners' Capital	4.45%
Cash Equivalents [Member] | United States [Member] | US Treasury Securities [Member] | U.S. Treasury Bills 1.11%, 12/21/2017 [Member]
Principal Amount	$ 20,000,000
Market Value	$ 19,894,278
% of Partners' Capital	4.45%
Cash Equivalents [Member] | United States [Member] | US Treasury Securities [Member] | U.S. Treasury Bills 1.10%, 12/28/2017 [Member]
Principal Amount	$ 20,000,000
Market Value	$ 19,890,500
% of Partners' Capital	4.45%
Cash Equivalents [Member] | United States [Member] | Money Market Funds [Member]
Market Value	$ 20,000,000
% of Partners' Capital	4.46%
Cash Equivalents [Member] | United States [Member] | Money Market Funds [Member] | Fidelity Investments Money Market Funds - Government Portfolio [Member]
Principal Amount	$ 10,000,000
Market Value	$ 10,000,000
% of Partners' Capital	2.23%
Cash Equivalents [Member] | United States [Member] | Money Market Funds [Member] | Goldman Sachs Financial Square Funds - Government Fund - Class FS [Member]
Principal Amount	$ 10,000,000
Market Value	$ 10,000,000
% of Partners' Capital	2.23%
[1] Collateral amounted to $48,122,106 on open futures contracts.

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