Statement of Changes in Shareholders' Equity (Unaudited) - USD ($) | Total | General Shares [Member] | Shares [Member] |
Balance - Value at Dec. 31, 2016 | $ 193,214,737 | $ 552 | $ 193,214,185 |
Balance - Shares at Dec. 31, 2016 | | 40 | 14,000,000 |
Purchases of Shares - Value | 42,456,525 | | $ 42,456,525 |
Purchases of Shares - Shares | | | 3,200,000 |
Redemption of Shares - Value | (107,909,734) | | $ (107,909,734) |
Redemption of Shares - Shares | | | (8,600,000) |
Net Increase (Decrease) due to Share Transactions, value | (65,453,209) | | $ (65,453,209) |
Net Increase (Decrease) due to Share Transactions, shares | | | (5,400,000) |
Net Income (Loss) | | | |
Net Investment Income (Loss) | (180,659) | $ (1) | $ (180,658) |
Net Realized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts | (5,311,867) | (16) | (5,311,851) |
Net Change in Unrealized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts | (22,564,953) | (71) | (22,564,882) |
Net Income (Loss) | (28,057,479) | (88) | (28,057,391) |
Net Change in Shareholders' Equity, value | (93,510,688) | (88) | $ (93,510,600) |
Net Change in Shareholders' Equity, shares | | | (5,400,000) |
Balance - Value at Jun. 30, 2017 | 99,704,049 | $ 464 | $ 99,703,585 |
Balance - Shares at Jun. 30, 2017 | | 40 | 8,600,000 |
Balance - Value at Mar. 31, 2017 | 146,006,760 | $ 504 | $ 146,006,256 |
Balance - Shares at Mar. 31, 2017 | | 40 | 11,600,000 |
Purchases of Shares - Value | 23,600,261 | | $ 23,600,261 |
Purchases of Shares - Shares | | | 1,800,000 |
Redemption of Shares - Value | (58,030,733) | | $ (58,030,733) |
Redemption of Shares - Shares | | | (4,800,000) |
Net Increase (Decrease) due to Share Transactions, value | (34,430,472) | | $ (34,430,472) |
Net Increase (Decrease) due to Share Transactions, shares | | | (3,000,000) |
Net Income (Loss) | | | |
Net Investment Income (Loss) | (45,619) | | $ (45,619) |
Net Realized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts | (7,406,253) | $ (22) | (7,406,231) |
Net Change in Unrealized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts | (4,420,367) | (18) | (4,420,349) |
Net Income (Loss) | (11,872,239) | (40) | (11,872,199) |
Net Change in Shareholders' Equity, value | (46,302,711) | (40) | $ (46,302,671) |
Net Change in Shareholders' Equity, shares | | | (3,000,000) |
Balance - Value at Jun. 30, 2017 | 99,704,049 | $ 464 | $ 99,703,585 |
Balance - Shares at Jun. 30, 2017 | | 40 | 8,600,000 |
Balance - Value at Dec. 31, 2017 | 178,048,939 | $ 584 | $ 178,048,355 |
Balance - Shares at Dec. 31, 2017 | | 40 | 12,200,000 |
Purchases of Shares - Value | 38,114,516 | | $ 38,114,516 |
Purchases of Shares - Shares | | | 2,400,000 |
Redemption of Shares - Value | (21,236,039) | | $ (21,236,039) |
Redemption of Shares - Shares | | | (1,400,000) |
Net Increase (Decrease) due to Share Transactions, value | 16,878,477 | | $ 16,878,477 |
Net Increase (Decrease) due to Share Transactions, shares | | | 1,000,000 |
Net Income (Loss) | | | |
Net Investment Income (Loss) | 637,680 | $ 2 | $ 637,678 |
Net Realized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts | 18,106,968 | 59 | 18,106,909 |
Net Change in Unrealized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts | 12,029,937 | 39 | 12,029,898 |
Net Income (Loss) | 30,774,585 | 100 | 30,774,485 |
Net Change in Shareholders' Equity, value | 47,653,062 | 100 | $ 47,652,962 |
Net Change in Shareholders' Equity, shares | | | 1,000,000 |
Balance - Value at Jun. 30, 2018 | 225,702,001 | $ 684 | $ 225,701,317 |
Balance - Shares at Jun. 30, 2018 | | 40 | 13,200,000 |
Balance - Value at Mar. 31, 2018 | 177,151,372 | $ 611 | $ 177,150,761 |
Balance - Shares at Mar. 31, 2018 | | 40 | 11,600,000 |
Purchases of Shares - Value | 32,289,762 | | $ 32,289,762 |
Purchases of Shares - Shares | | | 2,000,000 |
Redemption of Shares - Value | (6,556,686) | | $ (6,556,686) |
Redemption of Shares - Shares | | | (400,000) |
Net Increase (Decrease) due to Share Transactions, value | 25,733,076 | | $ 25,733,076 |
Net Increase (Decrease) due to Share Transactions, shares | | | 1,600,000 |
Net Income (Loss) | | | |
Net Investment Income (Loss) | 407,569 | $ 1 | $ 407,568 |
Net Realized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts | 10,270,774 | 32 | 10,270,742 |
Net Change in Unrealized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts | 12,139,210 | 40 | 12,139,170 |
Net Income (Loss) | 22,817,553 | 73 | 22,817,480 |
Net Change in Shareholders' Equity, value | 48,550,629 | 73 | $ 48,550,556 |
Net Change in Shareholders' Equity, shares | | | 1,600,000 |
Balance - Value at Jun. 30, 2018 | $ 225,702,001 | $ 684 | $ 225,701,317 |
Balance - Shares at Jun. 30, 2018 | | 40 | 13,200,000 |