Statement of Changes in Shareholders' Equity (Unaudited) - USD ($) | Total | General Shares [Member] | Shares [Member] |
Balance - Value at Dec. 31, 2015 | $ 96,843,573 | $ 1,291 | $ 96,842,282 |
Balance - Shares at Dec. 31, 2015 | | 40 | 3,000,000 |
Purchases of Shares - Value | 232,200,317 | | $ 232,200,317 |
Purchases of Shares - Shares | | | 5,800,000 |
Redemption of Shares - Value | (62,910,904) | | $ (62,910,904) |
Redemption of Shares - Shares | | | (1,600,000) |
Net Increase (Decrease) due to Share Transactions, value | 169,289,413 | | $ 169,289,413 |
Net Increase (Decrease) due to Share Transactions, shares | | | 4,200,000 |
Net Income (Loss) | | | |
Net Investment Income (Loss) | (778,996) | $ (10) | $ (778,986) |
Net Realized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts | 24,237,930 | 312 | 24,237,618 |
Net Change in Unrealized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts | 2,201,929 | 28 | 2,201,901 |
Net Income (Loss) | 25,660,863 | 330 | 25,660,533 |
Net Change in Shareholders' Equity, value | 194,950,276 | 330 | $ 194,949,946 |
Net Change in Shareholders' Equity, shares | | | 4,200,000 |
Balance - Value at Sep. 30, 2016 | 291,793,849 | $ 1,621 | $ 291,792,228 |
Balance - Shares at Sep. 30, 2016 | | 40 | 7,200,000 |
Balance - Value at Jun. 30, 2016 | 219,596,394 | $ 1,627 | $ 219,594,767 |
Balance - Shares at Jun. 30, 2016 | | 40 | 5,400,000 |
Purchases of Shares - Value | 109,882,427 | | $ 109,882,427 |
Purchases of Shares - Shares | | | 2,600,000 |
Redemption of Shares - Value | (32,866,402) | | $ (32,866,402) |
Redemption of Shares - Shares | | | (800,000) |
Net Increase (Decrease) due to Share Transactions, value | 77,016,025 | | $ 77,016,025 |
Net Increase (Decrease) due to Share Transactions, shares | | | 1,800,000 |
Net Income (Loss) | | | |
Net Investment Income (Loss) | (394,086) | $ (6) | $ (394,080) |
Net Realized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts | 20,462,421 | 271 | 20,462,150 |
Net Change in Unrealized Gain (Loss) on United States Treasury Obligations, Affiliated Investments and Commodity Futures Contracts | (24,886,905) | (271) | (24,886,634) |
Net Income (Loss) | (4,818,570) | (6) | (4,818,564) |
Net Change in Shareholders' Equity, value | 72,197,455 | (6) | $ 72,197,461 |
Net Change in Shareholders' Equity, shares | | | 1,800,000 |
Balance - Value at Sep. 30, 2016 | 291,793,849 | $ 1,621 | $ 291,792,228 |
Balance - Shares at Sep. 30, 2016 | | 40 | 7,200,000 |
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 |