Statements of Operations (Unaudited) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Investment Income
Interest	$ 35,905	$ 99,328	$ 176,019	$ 414,341
Total investment income	35,905	99,328	176,019	414,341
Expenses
Sponsor’s fees	1,428,422	2,030,598	4,489,560	6,086,463
Brokerage commissions and fees	174,694	138,402	506,652	590,725
Total expenses	1,603,116	2,169,000	4,996,212	6,677,188
Net investment loss	(1,567,211)	(2,069,672)	(4,820,193)	(6,262,847)
Net realized gain (loss) from:
Short-term investments	14,776	8,576	29,232	29,121
Futures contracts	(152,499,032)	(99,275,900)	(222,057,163)	(138,661,150)
Net realized loss	(152,484,256)	(99,267,324)	(222,027,931)	(138,632,029)
Net change in unrealized appreciation/depreciation on:
Short-term investments	37,597	0	53,611	0
Futures contracts	(15,131,979)	(43,732,303)	52,483,833	49,609,765
Net change in unrealized appreciation/depreciation	(15,094,382)	(43,732,303)	52,537,444	49,609,765
Net realized and unrealized loss	(167,578,638)	(142,999,627)	(169,490,487)	(89,022,264)
Net decrease in net assets resulting from operations	$ (169,145,849)	$ (145,069,299)	$ (174,310,680)	$ (95,285,111)
Net decrease in net assets per Share (in Dollars per share)	$ (4.03)	$ (4.26)	$ (4.29)	$ (2.85)
Weighted-average Shares outstanding (in Shares)	41,949,457	34,042,391	40,666,300	33,490,842