Statement of Changes in Shareholders' Equity (Unaudited) - USD ($) | Total | General Shares [Member] | Shares [Member] |
Balance - Value at Dec. 31, 2016 | $ 192,602,616 | $ 1,482 | $ 192,601,134 |
Balance - Shares at Dec. 31, 2016 | | 40 | 5,200,000 |
Purchases of Shares - Value | 105,529,537 | | $ 105,529,537 |
Purchases of Shares - Shares | | | 2,600,000 |
Redemption of Shares - Value | (155,956,971) | | $ (155,956,971) |
Redemption of Shares - Shares | | | (4,000,000) |
Net Increase (Decrease) due to Share Transactions, value | (50,427,434) | | $ (50,427,434) |
Net Increase (Decrease) due to Share Transactions, shares | | | (1,400,000) |
Net Income (Loss) | | | |
Net Investment Income (Loss) | (81,285) | $ (1) | $ (81,284) |
Net Realized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts | (18,318,933) | (224) | (18,318,709) |
Net Change in Unrealized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts | 26,895,060 | 329 | 26,894,731 |
Net Income (Loss) | 8,494,842 | 104 | 8,494,738 |
Net Change in Shareholders' Equity, value | (41,932,592) | 104 | $ (41,932,696) |
Net Change in Shareholders' Equity, shares | | | (1,400,000) |
Balance - Value at Jun. 30, 2017 | 150,670,024 | $ 1,586 | $ 150,668,438 |
Balance - Shares at Jun. 30, 2017 | | 40 | 3,800,000 |
Balance - Value at Mar. 31, 2017 | 144,118,784 | $ 1,601 | $ 144,117,183 |
Balance - Shares at Mar. 31, 2017 | | 40 | 3,600,000 |
Purchases of Shares - Value | 105,529,537 | | $ 105,529,537 |
Purchases of Shares - Shares | | | 2,600,000 |
Redemption of Shares - Value | (95,844,560) | | $ (95,844,560) |
Redemption of Shares - Shares | | | (2,400,000) |
Net Increase (Decrease) due to Share Transactions, value | 9,684,977 | | $ 9,684,977 |
Net Increase (Decrease) due to Share Transactions, shares | | | 200,000 |
Net Income (Loss) | | | |
Net Investment Income (Loss) | 3,963 | | $ 3,963 |
Net Realized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts | (8,038,869) | $ (119) | (8,038,750) |
Net Change in Unrealized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts | 4,901,169 | 104 | 4,901,065 |
Net Income (Loss) | (3,133,737) | (15) | (3,133,722) |
Net Change in Shareholders' Equity, value | 6,551,240 | (15) | $ 6,551,255 |
Net Change in Shareholders' Equity, shares | | | 200,000 |
Balance - Value at Jun. 30, 2017 | 150,670,024 | $ 1,586 | $ 150,668,438 |
Balance - Shares at Jun. 30, 2017 | | 40 | 3,800,000 |
Balance - Value at Dec. 31, 2017 | 141,151,352 | $ 1,660 | $ 141,149,692 |
Balance - Shares at Dec. 31, 2017 | | 40 | 3,400,000 |
Purchases of Shares - Value | 59,503,800 | | $ 59,503,800 |
Purchases of Shares - Shares | | | 1,400,000 |
Redemption of Shares - Value | (49,183,525) | | $ (49,183,525) |
Redemption of Shares - Shares | | | (1,200,000) |
Net Increase (Decrease) due to Share Transactions, value | 10,320,275 | | $ 10,320,275 |
Net Increase (Decrease) due to Share Transactions, shares | | | 200,000 |
Net Income (Loss) | | | |
Net Investment Income (Loss) | 742,175 | $ 9 | $ 742,166 |
Net Realized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts | 2,571,666 | 22 | 2,571,644 |
Net Change in Unrealized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts | (12,516,308) | (110) | (12,516,198) |
Net Income (Loss) | (9,202,467) | (79) | (9,202,388) |
Net Change in Shareholders' Equity, value | 1,117,808 | (79) | $ 1,117,887 |
Net Change in Shareholders' Equity, shares | | | 200,000 |
Balance - Value at Jun. 30, 2018 | 142,269,160 | $ 1,581 | $ 142,267,579 |
Balance - Shares at Jun. 30, 2018 | | 40 | 3,600,000 |
Balance - Value at Mar. 31, 2018 | 192,689,550 | $ 1,676 | $ 192,687,874 |
Balance - Shares at Mar. 31, 2018 | | 40 | 4,600,000 |
Purchases of Shares - Value | 8,517,714 | | $ 8,517,714 |
Purchases of Shares - Shares | | | 200,000 |
Redemption of Shares - Value | (49,183,525) | | $ (49,183,525) |
Redemption of Shares - Shares | | | (1,200,000) |
Net Increase (Decrease) due to Share Transactions, value | (40,665,811) | | $ (40,665,811) |
Net Increase (Decrease) due to Share Transactions, shares | | | (1,000,000) |
Net Income (Loss) | | | |
Net Investment Income (Loss) | 441,149 | | $ 441,149 |
Net Realized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts | 2,571,575 | $ 22 | 2,571,553 |
Net Change in Unrealized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts | (12,767,303) | (117) | (12,767,186) |
Net Income (Loss) | (9,754,579) | (95) | (9,754,484) |
Net Change in Shareholders' Equity, value | (50,420,390) | (95) | $ (50,420,295) |
Net Change in Shareholders' Equity, shares | | | (1,000,000) |
Balance - Value at Jun. 30, 2018 | $ 142,269,160 | $ 1,581 | $ 142,267,579 |
Balance - Shares at Jun. 30, 2018 | | 40 | 3,600,000 |