Statement of Changes in Shareholders' Equity (Unaudited) - USD ($)	Total	Shares [Member]	General Shares [Member]
Balance - Value at Dec. 31, 2017	$ 2,262,359,193	$ 2,262,358,528	$ 665
Balance - Shares at Dec. 31, 2017		136,000,000	40
Purchases of Shares - Value	1,103,001,369	$ 1,103,001,369
Purchases of Shares - Shares		64,000,000
Redemption of Shares - Value	(945,903,578)	$ (945,903,578)
Redemption of Shares - Shares		(55,400,000)
Net Increase (Decrease) due to Share Transactions, value	157,097,791	$ 157,097,791
Net Increase (Decrease) due to Share Transactions, shares		8,600,000
Net Income (Loss)
Net Investment Income (Loss)	17,247,379	$ 17,247,374	$ 5
Net Realized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts	93,825,791	93,825,763	28
Net Change in Unrealized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts	64,973,139	64,973,119	20
Net Income (Loss)	176,046,309	176,046,256	53
Net Change in Shareholders' Equity, value	333,144,100	$ 333,144,047	53
Net Change in Shareholders' Equity, shares		8,600,000
Balance - Value at Sep. 30, 2018	2,595,503,293	$ 2,595,502,575	$ 718
Balance - Shares at Sep. 30, 2018		144,600,000	40
Balance - Value at Jun. 30, 2018	3,014,880,027	$ 3,014,879,319	$ 708
Balance - Shares at Jun. 30, 2018		170,400,000	40
Purchases of Shares - Value	38,628,531	$ 38,628,531
Purchases of Shares - Shares		2,200,000
Redemption of Shares - Value	(477,260,682)	$ (477,260,682)
Redemption of Shares - Shares		(28,000,000)
Net Increase (Decrease) due to Share Transactions, value	(438,632,151)	$ (438,632,151)
Net Increase (Decrease) due to Share Transactions, shares		(25,800,000)
Net Income (Loss)
Net Investment Income (Loss)	8,971,619	$ 8,971,616	$ 3
Net Realized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts	(55,512,166)	(55,512,153)	(13)
Net Change in Unrealized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts	65,795,964	65,795,944	20
Net Income (Loss)	19,255,417	19,255,407	10
Net Change in Shareholders' Equity, value	(419,376,734)	$ (419,376,744)	10
Net Change in Shareholders' Equity, shares		(25,800,000)
Balance - Value at Sep. 30, 2018	2,595,503,293	$ 2,595,502,575	$ 718
Balance - Shares at Sep. 30, 2018		144,600,000	40
Balance - Value at Dec. 31, 2018	1,932,576,856	$ 1,932,576,278	$ 578
Balance - Shares at Dec. 31, 2018		133,800,000	40
Purchases of Shares - Value	51,179,193	$ 51,179,193
Purchases of Shares - Shares		3,400,000
Redemption of Shares - Value	(677,971,167)	$ (677,971,167)
Redemption of Shares - Shares		(43,600,000)
Net Increase (Decrease) due to Share Transactions, value	(626,791,974)	$ (626,791,974)
Net Increase (Decrease) due to Share Transactions, shares		(40,200,000)
Net Income (Loss)
Net Investment Income (Loss)	18,890,547	$ 18,890,542	$ 5
Net Realized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts	(101,973,925)	(101,973,902)	(23)
Net Change in Unrealized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts	182,657,599	182,657,559	40
Net Income (Loss)	99,574,221	99,574,199	22
Net Change in Shareholders' Equity, value	(527,217,753)	$ (527,217,775)	22
Net Change in Shareholders' Equity, shares		(40,200,000)
Balance - Value at Sep. 30, 2019	1,405,359,103	$ 1,405,358,503	$ 600
Balance - Shares at Sep. 30, 2019		93,600,000	40
Balance - Value at Jun. 30, 2019	1,608,783,674	$ 1,608,783,043	$ 631
Balance - Shares at Jun. 30, 2019		102,000,000	40
Purchases of Shares - Value	3,000,952	$ 3,000,952
Purchases of Shares - Shares		200,000
Redemption of Shares - Value	(130,451,567)	$ (130,451,567)
Redemption of Shares - Shares		(8,600,000)
Net Increase (Decrease) due to Share Transactions, value	(127,450,615)	$ (127,450,615)
Net Increase (Decrease) due to Share Transactions, shares		(8,400,000)
Net Income (Loss)
Net Investment Income (Loss)	5,261,389	$ 5,261,388	$ 1
Net Realized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts	(40,870,611)	(40,870,606)	(5)
Net Change in Unrealized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts	(40,364,734)	(40,364,707)	(27)
Net Income (Loss)	(75,973,956)	(75,973,925)	(31)
Net Change in Shareholders' Equity, value	(203,424,571)	$ (203,424,540)	(31)
Net Change in Shareholders' Equity, shares		(8,400,000)
Balance - Value at Sep. 30, 2019	$ 1,405,359,103	$ 1,405,358,503	$ 600
Balance - Shares at Sep. 30, 2019		93,600,000	40