Statement of Changes in Shareholders' Equity (Unaudited) - USD ($) | Total | General Shares [Member] | Shares [Member] |
Balance - Value at Dec. 31, 2016 | $ 139,731,686 | $ 1,397 | $ 139,730,289 |
Balance - Shares at Dec. 31, 2016 | | 40 | 4,000,000 |
Purchases of Shares - Value | 37,604,859 | | $ 37,604,859 |
Purchases of Shares - Shares | | | 1,000,000 |
Redemption of Shares - Value | (29,477,323) | | $ (29,477,323) |
Redemption of Shares - Shares | | | (800,000) |
Net Increase (Decrease) due to Share Transactions, value | 8,127,536 | | $ 8,127,536 |
Net Increase (Decrease) due to Share Transactions, shares | | | 200,000 |
Net Income (Loss) | | | |
Net Investment Income (Loss) | (75,799) | $ (1) | $ (75,798) |
Net Realized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts | (2,200,087) | (24) | (2,200,063) |
Net Change in Unrealized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts | 10,313,922 | 113 | 10,313,809 |
Net Income (Loss) | 8,038,036 | 88 | 8,037,948 |
Net Change in Shareholders' Equity, value | 16,165,572 | 88 | $ 16,165,484 |
Net Change in Shareholders' Equity, shares | | | 200,000 |
Balance - Value at Jun. 30, 2017 | 155,897,258 | $ 1,485 | $ 155,895,773 |
Balance - Shares at Jun. 30, 2017 | | 40 | 4,200,000 |
Balance - Value at Mar. 31, 2017 | 160,209,307 | $ 1,526 | $ 160,207,781 |
Balance - Shares at Mar. 31, 2017 | | 40 | 4,200,000 |
Purchases of Shares - Value | 15,460,772 | | $ 15,460,772 |
Purchases of Shares - Shares | | | 400,000 |
Redemption of Shares - Value | (14,701,678) | | $ (14,701,678) |
Redemption of Shares - Shares | | | (400,000) |
Net Increase (Decrease) due to Share Transactions, value | 759,094 | | $ 759,094 |
Net Income (Loss) | | | |
Net Investment Income (Loss) | 2,611 | | 2,611 |
Net Realized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts | (1,651,254) | $ (19) | (1,651,235) |
Net Change in Unrealized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts | (3,422,500) | (22) | (3,422,478) |
Net Income (Loss) | (5,071,143) | (41) | (5,071,102) |
Net Change in Shareholders' Equity, value | (4,312,049) | (41) | (4,312,008) |
Balance - Value at Jun. 30, 2017 | 155,897,258 | $ 1,485 | $ 155,895,773 |
Balance - Shares at Jun. 30, 2017 | | 40 | 4,200,000 |
Balance - Value at Dec. 31, 2017 | 154,730,992 | $ 1,547 | $ 154,729,445 |
Balance - Shares at Dec. 31, 2017 | | 40 | 4,000,000 |
Purchases of Shares - Value | 38,724,701 | | $ 38,724,701 |
Purchases of Shares - Shares | | | 1,000,000 |
Redemption of Shares - Value | (54,261,553) | | $ (54,261,553) |
Redemption of Shares - Shares | | | (1,400,000) |
Net Increase (Decrease) due to Share Transactions, value | (15,536,852) | | $ (15,536,852) |
Net Increase (Decrease) due to Share Transactions, shares | | | (400,000) |
Net Income (Loss) | | | |
Net Investment Income (Loss) | 662,734 | $ 7 | $ 662,727 |
Net Realized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts | 2,682,622 | 30 | 2,682,592 |
Net Change in Unrealized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts | (10,373,699) | (116) | (10,373,583) |
Net Income (Loss) | (7,028,343) | (79) | (7,028,264) |
Net Change in Shareholders' Equity, value | (22,565,195) | (79) | $ (22,565,116) |
Net Change in Shareholders' Equity, shares | | | (400,000) |
Balance - Value at Jun. 30, 2018 | 132,165,797 | $ 1,468 | $ 132,164,329 |
Balance - Shares at Jun. 30, 2018 | | 40 | 3,600,000 |
Balance - Value at Mar. 31, 2018 | 177,525,272 | $ 1,544 | $ 177,523,728 |
Balance - Shares at Mar. 31, 2018 | | 40 | 4,600,000 |
Redemption of Shares - Value | (38,532,392) | | $ (38,532,392) |
Redemption of Shares - Shares | | | (1,000,000) |
Net Increase (Decrease) due to Share Transactions, value | (38,532,392) | | $ (38,532,392) |
Net Increase (Decrease) due to Share Transactions, shares | | | (1,000,000) |
Net Income (Loss) | | | |
Net Investment Income (Loss) | 341,208 | $ 2 | $ 341,206 |
Net Realized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts | 1,691,061 | 15 | 1,691,046 |
Net Change in Unrealized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts | (8,859,352) | (93) | (8,859,259) |
Net Income (Loss) | (6,827,083) | (76) | (6,827,007) |
Net Change in Shareholders' Equity, value | (45,359,475) | (76) | $ (45,359,399) |
Net Change in Shareholders' Equity, shares | | | (1,000,000) |
Balance - Value at Jun. 30, 2018 | $ 132,165,797 | $ 1,468 | $ 132,164,329 |
Balance - Shares at Jun. 30, 2018 | | 40 | 3,600,000 |