Statement of Changes in Shareholders' Equity (Unaudited) - USD ($) | Total | General Shares [Member] | Shares [Member] |
Balance - Value at Dec. 31, 2016 | $ 452,757,654 | $ 387 | $ 452,757,267 |
Balance - Shares at Dec. 31, 2016 | | 40 | 46,800,000 |
Purchases of Shares - Value | 68,507,724 | | $ 68,507,724 |
Purchases of Shares - Shares | | | 8,400,000 |
Redemption of Shares - Value | (47,972,003) | | $ (47,972,003) |
Redemption of Shares - Shares | | | (5,400,000) |
Net Increase (Decrease) due to Share Transactions, value | 20,535,721 | | $ 20,535,721 |
Net Increase (Decrease) due to Share Transactions, shares | | | 3,000,000 |
Net Income (Loss) | | | |
Net Investment Income (Loss) | (434,236) | $ (1) | $ (434,235) |
Net Realized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts | 88,732,450 | 78 | 88,732,372 |
Net Change in Unrealized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts | (160,819,296) | (142) | (160,819,154) |
Net Income (Loss) | (72,521,082) | (65) | (72,521,017) |
Net Change in Shareholders' Equity, value | (51,985,361) | (65) | $ (51,985,296) |
Net Change in Shareholders' Equity, shares | | | 3,000,000 |
Balance - Value at Jun. 30, 2017 | 400,772,293 | $ 322 | $ 400,771,971 |
Balance - Shares at Jun. 30, 2017 | | 40 | 49,800,000 |
Balance - Value at Mar. 31, 2017 | 409,533,902 | $ 352 | $ 409,533,550 |
Balance - Shares at Mar. 31, 2017 | | 40 | 46,600,000 |
Purchases of Shares - Value | 57,997,228 | | $ 57,997,228 |
Purchases of Shares - Shares | | | 7,200,000 |
Redemption of Shares - Value | (35,051,986) | | $ (35,051,986) |
Redemption of Shares - Shares | | | (4,000,000) |
Net Increase (Decrease) due to Share Transactions, value | 22,945,242 | | $ 22,945,242 |
Net Increase (Decrease) due to Share Transactions, shares | | | 3,200,000 |
Net Income (Loss) | | | |
Net Investment Income (Loss) | (89,257) | $ (1) | $ (89,256) |
Net Realized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts | (2,803,783) | | (2,803,783) |
Net Change in Unrealized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts | (28,813,811) | (29) | (28,813,782) |
Net Income (Loss) | (31,706,851) | (30) | (31,706,821) |
Net Change in Shareholders' Equity, value | (8,761,609) | (30) | $ (8,761,579) |
Net Change in Shareholders' Equity, shares | | | 3,200,000 |
Balance - Value at Jun. 30, 2017 | 400,772,293 | $ 322 | $ 400,771,971 |
Balance - Shares at Jun. 30, 2017 | | 40 | 49,800,000 |
Balance - Value at Dec. 31, 2017 | 332,833,341 | $ 408 | $ 332,832,933 |
Balance - Shares at Dec. 31, 2017 | | 40 | 32,600,000 |
Purchases of Shares - Value | 699,852,343 | | $ 699,852,343 |
Purchases of Shares - Shares | | | 61,800,000 |
Redemption of Shares - Value | (736,807,311) | | $ (736,807,311) |
Redemption of Shares - Shares | | | (63,400,000) |
Net Increase (Decrease) due to Share Transactions, value | (36,954,968) | | $ (36,954,968) |
Net Increase (Decrease) due to Share Transactions, shares | | | (1,600,000) |
Net Income (Loss) | | | |
Net Investment Income (Loss) | 1,547,083 | $ 1 | $ 1,547,082 |
Net Realized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts | 116,345,657 | 120 | 116,345,537 |
Net Change in Unrealized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts | (26,194,719) | (29) | (26,194,690) |
Net Income (Loss) | 91,698,021 | 92 | 91,697,929 |
Net Change in Shareholders' Equity, value | 54,743,053 | 92 | $ 54,742,961 |
Net Change in Shareholders' Equity, shares | | | (1,600,000) |
Balance - Value at Jun. 30, 2018 | 387,576,394 | $ 500 | $ 387,575,894 |
Balance - Shares at Jun. 30, 2018 | | 40 | 31,000,000 |
Balance - Value at Mar. 31, 2018 | 343,935,691 | $ 447 | $ 343,935,244 |
Balance - Shares at Mar. 31, 2018 | | 40 | 30,800,000 |
Purchases of Shares - Value | 512,343,297 | | $ 512,343,297 |
Purchases of Shares - Shares | | | 44,000,000 |
Redemption of Shares - Value | (525,836,920) | | $ (525,836,920) |
Redemption of Shares - Shares | | | (43,800,000) |
Net Increase (Decrease) due to Share Transactions, value | (13,493,623) | | $ (13,493,623) |
Net Increase (Decrease) due to Share Transactions, shares | | | 200,000 |
Net Income (Loss) | | | |
Net Investment Income (Loss) | 1,014,367 | | $ 1,014,367 |
Net Realized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts | 56,686,880 | $ 53 | 56,686,827 |
Net Change in Unrealized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts | (566,921) | | (566,921) |
Net Income (Loss) | 57,134,326 | 53 | 57,134,273 |
Net Change in Shareholders' Equity, value | 43,640,703 | 53 | $ 43,640,650 |
Net Change in Shareholders' Equity, shares | | | 200,000 |
Balance - Value at Jun. 30, 2018 | $ 387,576,394 | $ 500 | $ 387,575,894 |
Balance - Shares at Jun. 30, 2018 | | 40 | 31,000,000 |