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	510,008,432		$ 510,008,432
Purchases of Shares - Shares			36,200,000
Redemption of Shares - Value	(212,304,739)		$ (212,304,739)
Redemption of Shares - Shares			(16,200,000)
Net Increase (Decrease) due to Share Transactions, value	297,703,693		$ 297,703,693
Net Increase (Decrease) due to Share Transactions, shares			20,000,000
Net Income (Loss)
Net Investment Income (Loss)	(6,781,815)	$ (2)	$ (6,781,813)
Net Realized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts	(265,280,041)	(69)	(265,279,972)
Net Change in Unrealized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts	571,353,854	149	571,353,705
Net Income (Loss)	299,291,998	78	299,291,920
Net Change in Shareholders' Equity, value	596,995,691	78	$ 596,995,613
Net Change in Shareholders' Equity, shares			20,000,000
Balance - Value at Jun. 30, 2016	2,584,218,703	$ 612	$ 2,584,218,091
Balance - Shares at Jun. 30, 2016		40	168,800,000
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
Purchases of Shares - Value	394,710,038		$ 394,710,038
Purchases of Shares - Shares			27,400,000
Redemption of Shares - Value	(119,877,533)		$ (119,877,533)
Redemption of Shares - Shares			(8,800,000)
Net Increase (Decrease) due to Share Transactions, value	274,832,505		$ 274,832,505
Net Increase (Decrease) due to Share Transactions, shares			18,600,000
Net Income (Loss)
Net Investment Income (Loss)	(3,483,909)	$ (1)	$ (3,483,908)
Net Realized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts	(66,087,300)	(38)	(66,087,262)
Net Change in Unrealized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts	381,640,021	119	381,639,902
Net Income (Loss)	312,068,812	80	312,068,732
Net Change in Shareholders' Equity, value	586,901,317	80	$ 586,901,237
Net Change in Shareholders' Equity, shares			18,600,000
Balance - Value at Jun. 30, 2016	2,584,218,703	$ 612	$ 2,584,218,091
Balance - Shares at Jun. 30, 2016		40	168,800,000
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	142,251,533		$ 142,251,533
Purchases of Shares - Shares			9,000,000
Redemption of Shares - Value	(708,495,377)		$ (708,495,377)
Redemption of Shares - Shares			(47,000,000)
Net Increase (Decrease) due to Share Transactions, value	(566,243,844)		$ (566,243,844)
Net Increase (Decrease) due to Share Transactions, shares			(38,000,000)
Net Income (Loss)
Net Investment Income (Loss)	(3,590,921)	$ (1)	$ (3,590,920)
Net Realized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts	(1,224,684)		(1,224,684)
Net Change in Unrealized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts	(200,381,016)	(54)	(200,380,962)
Net Income (Loss)	(205,196,621)	(55)	(205,196,566)
Net Change in Shareholders' Equity, value	(771,440,465)	(55)	$ (771,440,410)
Net Change in Shareholders' Equity, shares			(38,000,000)
Balance - Value at Jun. 30, 2017	1,786,024,074	$ 578	$ 1,786,023,496
Balance - Shares at Jun. 30, 2017		40	123,600,000
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
Purchases of Shares - Value	6,227,072		$ 6,227,072
Purchases of Shares - Shares			400,000
Redemption of Shares - Value	(355,001,530)		$ (355,001,530)
Redemption of Shares - Shares			(24,000,000)
Net Increase (Decrease) due to Share Transactions, value	(348,774,458)		$ (348,774,458)
Net Increase (Decrease) due to Share Transactions, shares			(23,600,000)
Net Income (Loss)
Net Investment Income (Loss)	(1,124,455)		$ (1,124,455)
Net Realized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts	(63,385,212)	$ (15)	(63,385,197)
Net Change in Unrealized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts	(41,480,557)	(16)	(41,480,541)
Net Income (Loss)	(105,990,224)	(31)	(105,990,193)
Net Change in Shareholders' Equity, value	(454,764,682)	(31)	$ (454,764,651)
Net Change in Shareholders' Equity, shares			(23,600,000)
Balance - Value at Jun. 30, 2017	$ 1,786,024,074	$ 578	$ 1,786,023,496
Balance - Shares at Jun. 30, 2017		40	123,600,000