Statement of Changes in Shareholders' Equity (Unaudited) - USD ($) | Total | General Shares [Member] | Shares [Member] |
Balance - Value at Dec. 31, 2016 | $ 284,135,889 | $ 598 | $ 284,135,291 |
Balance - Shares at Dec. 31, 2016 | | 40 | 19,000,000 |
Purchases of Shares - Value | 15,663,411 | | $ 15,663,411 |
Purchases of Shares - Shares | | | 1,000,000 |
Redemption of Shares - Value | (113,620,158) | | $ (113,620,158) |
Redemption of Shares - Shares | | | (7,200,000) |
Net Increase (Decrease) due to Share Transactions, value | (97,956,747) | | $ (97,956,747) |
Net Increase (Decrease) due to Share Transactions, shares | | | (6,200,000) |
Net Income (Loss) | | | |
Net Investment Income (Loss) | (309,657) | $ (1) | $ (309,656) |
Net Realized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts | 18,742,865 | 45 | 18,742,820 |
Net Change in Unrealized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts | 4,161,410 | 10 | 4,161,400 |
Net Income (Loss) | 22,594,618 | 54 | 22,594,564 |
Net Change in Shareholders' Equity, value | (75,362,129) | 54 | $ (75,362,183) |
Net Change in Shareholders' Equity, shares | | | (6,200,000) |
Balance - Value at Jun. 30, 2017 | 208,773,760 | $ 652 | $ 208,773,108 |
Balance - Shares at Jun. 30, 2017 | | 40 | 12,800,000 |
Balance - Value at Mar. 31, 2017 | 281,761,160 | $ 655 | $ 281,760,505 |
Balance - Shares at Mar. 31, 2017 | | 40 | 17,200,000 |
Purchases of Shares - Value | 6,230,325 | | $ 6,230,325 |
Purchases of Shares - Shares | | | 400,000 |
Redemption of Shares - Value | (75,153,345) | | $ (75,153,345) |
Redemption of Shares - Shares | | | (4,800,000) |
Net Increase (Decrease) due to Share Transactions, value | (68,923,020) | | $ (68,923,020) |
Net Increase (Decrease) due to Share Transactions, shares | | | (4,400,000) |
Net Income (Loss) | | | |
Net Investment Income (Loss) | (84,806) | | $ (84,806) |
Net Realized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts | 3,931,689 | $ 13 | 3,931,676 |
Net Change in Unrealized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts | (7,911,263) | (16) | (7,911,247) |
Net Income (Loss) | (4,064,380) | (3) | (4,064,377) |
Net Change in Shareholders' Equity, value | (72,987,400) | (3) | $ (72,987,397) |
Net Change in Shareholders' Equity, shares | | | (4,400,000) |
Balance - Value at Jun. 30, 2017 | 208,773,760 | $ 652 | $ 208,773,108 |
Balance - Shares at Jun. 30, 2017 | | 40 | 12,800,000 |
Balance - Value at Dec. 31, 2017 | 314,091,261 | $ 776 | $ 314,090,485 |
Balance - Shares at Dec. 31, 2017 | | 40 | 16,200,000 |
Purchases of Shares - Value | 84,326,361 | | $ 84,326,361 |
Purchases of Shares - Shares | | | 4,400,000 |
Redemption of Shares - Value | (59,582,168) | | $ (59,582,168) |
Redemption of Shares - Shares | | | (3,200,000) |
Net Increase (Decrease) due to Share Transactions, value | 24,744,193 | | $ 24,744,193 |
Net Increase (Decrease) due to Share Transactions, shares | | | 1,200,000 |
Net Income (Loss) | | | |
Net Investment Income (Loss) | 1,170,583 | $ 2 | $ 1,170,581 |
Net Realized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts | 18,006,132 | 40 | 18,006,092 |
Net Change in Unrealized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts | (51,294,528) | (113) | (51,294,415) |
Net Income (Loss) | (32,117,813) | (71) | (32,117,742) |
Net Change in Shareholders' Equity, value | (7,373,620) | (71) | $ (7,373,549) |
Net Change in Shareholders' Equity, shares | | | 1,200,000 |
Balance - Value at Jun. 30, 2018 | 306,717,641 | $ 705 | $ 306,716,936 |
Balance - Shares at Jun. 30, 2018 | | 40 | 17,400,000 |
Balance - Value at Mar. 31, 2018 | 348,906,652 | $ 727 | $ 348,905,925 |
Balance - Shares at Mar. 31, 2018 | | 40 | 19,200,000 |
Purchases of Shares - Value | 18,696,830 | | $ 18,696,830 |
Purchases of Shares - Shares | | | 1,000,000 |
Redemption of Shares - Value | (51,832,057) | | $ (51,832,057) |
Redemption of Shares - Shares | | | (2,800,000) |
Net Increase (Decrease) due to Share Transactions, value | (33,135,227) | | $ (33,135,227) |
Net Increase (Decrease) due to Share Transactions, shares | | | (1,800,000) |
Net Income (Loss) | | | |
Net Investment Income (Loss) | 723,851 | $ 1 | $ 723,850 |
Net Realized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts | (600,957) | 1 | (600,958) |
Net Change in Unrealized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts | (9,176,678) | (24) | (9,176,654) |
Net Income (Loss) | (9,053,784) | (22) | (9,053,762) |
Net Change in Shareholders' Equity, value | (42,189,011) | (22) | $ (42,188,989) |
Net Change in Shareholders' Equity, shares | | | (1,800,000) |
Balance - Value at Jun. 30, 2018 | $ 306,717,641 | $ 705 | $ 306,716,936 |
Balance - Shares at Jun. 30, 2018 | | 40 | 17,400,000 |