Statement of Changes in Shareholders' Equity (Unaudited) - USD ($)	Total	General Shares [Member]	Shares [Member]
Balance - Value at Dec. 31, 2015	$ 1,987,223,012	$ 534	$ 1,987,222,478
Balance - Shares at Dec. 31, 2015		40	148,800,000
Purchases of Shares - Value	115,298,394		$ 115,298,394
Purchases of Shares - Shares			8,800,000
Redemption of Shares - Value	(92,427,206)		$ (92,427,206)
Redemption of Shares - Shares			(7,400,000)
Net Increase (Decrease) due to Share Transactions, value	22,871,188		$ 22,871,188
Net Increase (Decrease) due to Share Transactions, shares			1,400,000
Net Income (Loss)
Net Investment Income (Loss)	(3,297,906)	$ (1)	$ (3,297,905)
Net Realized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts	(199,192,741)	(31)	(199,192,710)
Net Change in Unrealized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts	189,713,833	30	189,713,803
Net Income (Loss)	(12,776,814)	(2)	(12,776,812)
Net Change in Shareholders' Equity, value	10,094,374	(2)	$ 10,094,376
Net Change in Shareholders' Equity, shares			1,400,000
Balance - Value at Mar. 31, 2016	1,997,317,386	$ 532	$ 1,997,316,854
Balance - Shares at Mar. 31, 2016		40	150,200,000
Balance - Value at Dec. 31, 2016	2,557,464,539	$ 633	$ 2,557,463,906
Balance - Shares at Dec. 31, 2016		40	161,600,000
Purchases of Shares - Value	136,024,461		$ 136,024,461
Purchases of Shares - Shares			8,600,000
Redemption of Shares - Value	(353,493,847)		$ (353,493,847)
Redemption of Shares - Shares			(23,000,000)
Net Increase (Decrease) due to Share Transactions, value	(217,469,386)		$ (217,469,386)
Net Increase (Decrease) due to Share Transactions, shares			(14,400,000)
Net Income (Loss)
Net Investment Income (Loss)	(2,466,466)	$ (1)	$ (2,466,465)
Net Realized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts	62,160,528	15	62,160,513
Net Change in Unrealized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts	(158,900,459)	(38)	(158,900,421)
Net Income (Loss)	(99,206,397)	(24)	(99,206,373)
Net Change in Shareholders' Equity, value	(316,675,783)	(24)	$ (316,675,759)
Net Change in Shareholders' Equity, shares			(14,400,000)
Balance - Value at Mar. 31, 2017	$ 2,240,788,756	$ 609	$ 2,240,788,147
Balance - Shares at Mar. 31, 2017		40	147,200,000