Statements of Income and Expenses - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income
Interest Income	$ 14,035,908	$ 6,308,729	$ 715,663
Dividends from Affiliates	2,600,473	139,113
Total Income	16,636,381	6,447,842	715,663
Expenses
Management Fee	17,965,282	19,189,799	24,818,382
Brokerage Commissions and Fees	492,416	759,634	1,171,437
Interest Expense	68,451	141,261	277,439
Total Expenses	18,526,149	20,090,694	26,267,258
Less: Waivers	(432,451)	(68,552)	0
Net Expenses	18,093,698	20,022,142	26,267,258
Net Investment Income (Loss)	(1,457,317)	(13,574,300)	(25,551,595)
Net Realized Gain (Loss) on
United States Treasury Obligations	(44,293)	19,938	14,586
Commodity Futures Contracts	58,338,714	(72,730,527)	(1,272,167,944)
Net Realized Gain (Loss)	58,294,421	(72,710,589)	(1,272,153,358)
Net Change in Unrealized Gain (Loss) on
United States Treasury Obligations	(40,787)	(56,173)	(53,402)
Affiliated Investments	(247,678)
Commodity Futures Contracts	14,636,898	452,312,410	423,877,671
Net Change in Unrealized Gain (Loss)	14,348,433	452,256,237	423,824,269
Net Realized and Net Change in Unrealized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts	72,642,854	379,545,648	(848,329,089)
Net Income (Loss)	$ 71,185,537	$ 365,971,348	$ (873,880,684)