Condensed Schedule of Investments [Parenthetical]	9 Months Ended
Sep. 30, 2015 USD ($)
Collateral amount on open futures contracts	$ 14,928,031
Cash Equivalents [Member] \| U.S. Treasury Bill 0.10%, 10/01/2015 [Member] \| Us Treasury Securities [Member]
Interest rate	0.10%
Expiration date	10/01/2015
Cash Equivalents [Member] \| U.S. Treasury Bills,0.08%, 10/08/2015 [Member] \| Us Treasury Securities [Member]
Interest rate	0.08%
Expiration date	10/08/2015
Cash Equivalents [Member] \| U.S. Treasury Bills,0.09%, 10/15/2015 [Member] \| Us Treasury Securities [Member]
Interest rate	0.09%
Expiration date	10/15/2015
Cash Equivalents [Member] \| U.S. Treasury Bills,0.09%, 10/22/2015 [Member] \| Us Treasury Securities [Member]
Interest rate	0.09%
Expiration date	10/22/2015
Cash Equivalents [Member] \| U.S. Treasury Bills,0.06%, 10/29/2015 [Member] \| Us Treasury Securities [Member]
Interest rate	0.06%
Expiration date	10/29/2015
Cash Equivalents [Member] \| U.S. Treasury Bills,0.07%, 11/05/2015 [Member] \| Us Treasury Securities [Member]
Interest rate	0.07%
Expiration date	11/05/2015
Cash Equivalents [Member] \| U.S. Treasury Bills,0.08%, 11/12/2015 [Member] \| Us Treasury Securities [Member]
Interest rate	0.08%
Expiration date	11/12/2015
Cash Equivalents [Member] \| U.S. Treasury Bills,0.08%, 11/19/2015 [Member] \| Us Treasury Securities [Member]
Interest rate	0.08%
Expiration date	11/19/2015
Cash Equivalents [Member] \| U.S. Treasury Bills,0.09%, 11/27/2015 [Member] \| Us Treasury Securities [Member]
Interest rate	0.09%
Expiration date	11/27/2015
Cash Equivalents [Member] \| U.S. Treasury Bills,0.07%, 12/03/2015 [Member] \| Us Treasury Securities [Member]
Interest rate	0.07%
Expiration date	12/03/2015
Cash Equivalents [Member] \| U.S. Treasury Bills,0.08%, 12/10/2015 [Member] \| Us Treasury Securities [Member]
Interest rate	0.08%
Expiration date	12/10/2015
Cash Equivalents [Member] \| U.S. Treasury Bills,0.11%, 12/31/2015 [Member] \| Us Treasury Securities [Member]
Interest rate	0.11%
Expiration date	12/31/2015
Cash Equivalents [Member] \| U.S. Treasury Bills,0.11%, 1/14/2016 [Member] \| Us Treasury Securities [Member]
Interest rate	0.11%
Expiration date	1/14/2016
Cash Equivalents [Member] \| U.S. Treasury Bills,0.13%, 1/21/2016 [Member] \| Us Treasury Securities [Member]
Interest rate	0.13%
Expiration date	1/21/2016
Cash Equivalents [Member] \| U.S. Treasury Bills,0.15%, 1/28/2016 [Member] \| Us Treasury Securities [Member]
Interest rate	0.15%
Expiration date	1/28/2016
Cash Equivalents [Member] \| U.S. Treasury Bills,0.19%, 2/04/2016 [Member] \| Us Treasury Securities [Member]
Interest rate	0.19%
Expiration date	02/04/2016
Cash Equivalents [Member] \| U.S. Treasury Bills,0.22%, 2/11/2016 [Member] \| Us Treasury Securities [Member]
Interest rate	0.22%
Expiration date	02/11/2016
Cash Equivalents [Member] \| U.S. Treasury Bills,0.20%, 2/18/2016 [Member] \| Us Treasury Securities [Member]
Interest rate	0.20%
Expiration date	2/18/2016
Cash Equivalents [Member] \| U.S. Treasury Bills,0.23%, 3/03/2016 [Member] \| Us Treasury Securities [Member]
Interest rate	0.23%
Expiration date	03/03/2016
Cash Equivalents [Member] \| U.S. Treasury Bills,0.26%, 3/10/2016 [Member] \| Us Treasury Securities [Member]
Interest rate	0.26%
Expiration date	3/10/2016
Cash Equivalents [Member] \| U.S. Treasury Bills,0.24%, 3/17/2016 [Member] \| Us Treasury Securities [Member]
Interest rate	0.24%
Expiration date	3/17/2016
Cash Equivalents [Member] \| U.S. Treasury Bills,0.09%, 3/24/2016 [Member] \| Us Treasury Securities [Member]
Interest rate	0.09%
Expiration date	3/24/2016
Open Futures Contracts - Long [Member] \| United States [Member] \| ICE Brent Crude Oil Futures CO November 2015 contracts, expiring October 2015 [Merber]
Expiration date	October 2015