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 | 52,740,238 | | $ 52,740,238 |
Purchases of Shares - Shares | | | 1,400,000 |
Redemption of Shares - Value | (37,045,012) | | $ (37,045,012) |
Redemption of Shares - Shares | | | (1,000,000) |
Net Increase (Decrease) due to Share Transactions, value | 15,695,226 | | $ 15,695,226 |
Net Increase (Decrease) due to Share Transactions, shares | | | 400,000 |
Net Income (Loss) | | | |
Net Investment Income (Loss) | 46,315 | $ 1 | $ 46,314 |
Net Realized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts | (13,811,210) | (145) | (13,811,065) |
Net Change in Unrealized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts | 25,516,798 | 267 | 25,516,531 |
Net Income (Loss) | 11,751,903 | 123 | 11,751,780 |
Net Change in Shareholders' Equity, value | 27,447,129 | 123 | $ 27,447,006 |
Net Change in Shareholders' Equity, shares | | | 400,000 |
Balance - Value at Sep. 30, 2017 | 167,178,815 | $ 1,520 | $ 167,177,295 |
Balance - Shares at Sep. 30, 2017 | | 40 | 4,400,000 |
Balance - Value at Jun. 30, 2017 | 155,897,258 | $ 1,485 | $ 155,895,773 |
Balance - Shares at Jun. 30, 2017 | | 40 | 4,200,000 |
Purchases of Shares - Value | 15,135,379 | | $ 15,135,379 |
Purchases of Shares - Shares | | | 400,000 |
Redemption of Shares - Value | (7,567,689) | | $ (7,567,689) |
Redemption of Shares - Shares | | | (200,000) |
Net Increase (Decrease) due to Share Transactions, value | 7,567,690 | | $ 7,567,690 |
Net Increase (Decrease) due to Share Transactions, shares | | | 200,000 |
Net Income (Loss) | | | |
Net Investment Income (Loss) | 122,114 | $ 2 | $ 122,112 |
Net Realized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts | (11,611,123) | (121) | (11,611,002) |
Net Change in Unrealized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts | 15,202,876 | 154 | 15,202,722 |
Net Income (Loss) | 3,713,867 | 35 | 3,713,832 |
Net Change in Shareholders' Equity, value | 11,281,557 | 35 | $ 11,281,522 |
Net Change in Shareholders' Equity, shares | | | 200,000 |
Balance - Value at Sep. 30, 2017 | 167,178,815 | $ 1,520 | $ 167,177,295 |
Balance - Shares at Sep. 30, 2017 | | 40 | 4,400,000 |
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 | (68,681,120) | | $ (68,681,120) |
Redemption of Shares - Shares | | | (1,800,000) |
Net Increase (Decrease) due to Share Transactions, value | (29,956,419) | | $ (29,956,419) |
Net Increase (Decrease) due to Share Transactions, shares | | | (800,000) |
Net Income (Loss) | | | |
Net Investment Income (Loss) | 1,026,506 | $ 12 | $ 1,026,494 |
Net Realized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts | (3,385,299) | (39) | (3,385,260) |
Net Change in Unrealized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts | (12,047,350) | (140) | (12,047,210) |
Net Income (Loss) | (14,406,143) | (167) | (14,405,976) |
Net Change in Shareholders' Equity, value | (44,362,562) | (167) | $ (44,362,395) |
Net Change in Shareholders' Equity, shares | | | (800,000) |
Balance - Value at Sep. 30, 2018 | 110,368,430 | $ 1,380 | $ 110,367,050 |
Balance - Shares at Sep. 30, 2018 | | 40 | 3,200,000 |
Balance - Value at Jun. 30, 2018 | 132,165,797 | $ 1,468 | $ 132,164,329 |
Balance - Shares at Jun. 30, 2018 | | 40 | 3,600,000 |
Redemption of Shares - Value | (14,419,567) | | $ (14,419,567) |
Redemption of Shares - Shares | | | (400,000) |
Net Increase (Decrease) due to Share Transactions, value | (14,419,567) | | $ (14,419,567) |
Net Increase (Decrease) due to Share Transactions, shares | | | (400,000) |
Net Income (Loss) | | | |
Net Investment Income (Loss) | 363,772 | $ 5 | $ 363,767 |
Net Realized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts | (6,067,921) | (69) | (6,067,852) |
Net Change in Unrealized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts | (1,673,651) | (24) | (1,673,627) |
Net Income (Loss) | (7,377,800) | (88) | (7,377,712) |
Net Change in Shareholders' Equity, value | (21,797,367) | (88) | $ (21,797,279) |
Net Change in Shareholders' Equity, shares | | | (400,000) |
Balance - Value at Sep. 30, 2018 | $ 110,368,430 | $ 1,380 | $ 110,367,050 |
Balance - Shares at Sep. 30, 2018 | | 40 | 3,200,000 |