Schedule of Investments (Unaudited) - Treasury Bills and Affiliated Investments - USD ($) | 6 Months Ended | 12 Months Ended |
Jun. 30, 2017 | Dec. 31, 2016 |
Schedule of Investments [Line Items] | | | | | |
Percentage of Shareholders' Equity | | 96.32% | | 99.78% | |
Value | | $ 566,443,393 | | $ 702,215,941 | |
Affiliated Investments, at Value | | 102,424,959 | | 19,456,137 | |
Total Investments | | 668,868,352 | | 721,672,078 | |
Investments, cost | | $ 668,653,083 | | 721,689,108 | |
Affiliated Investments [Member] | | | | | |
Schedule of Investments [Line Items] | | | | | |
Percentage of Shareholders' Equity | | 14.75% | | | |
Affiliated Investments, at Value | | $ 102,424,959 | | | |
Affiliated Investments, at Cost | | $ 102,255,827 | | $ 19,456,137 | |
U.S. Treasury Bills, 0.840% due July 6, 2017 [Member] | | | | | |
Schedule of Investments [Line Items] | | | | | |
Percentage of Shareholders' Equity | [1] | 19.01% | | | |
Value | [1] | $ 131,991,684 | | | |
Principal Value | [1] | $ 132,000,000 | | | |
Investment Interest Rate | [1] | 0.84% | | | |
Investment Maturity Date | [1] | Jul. 6, 2017 | | | |
U.S. Treasury Bills, 0.890% due July 27, 2017 [Member] | | | | | |
Schedule of Investments [Line Items] | | | | | |
Percentage of Shareholders' Equity | [1],[2] | 24.03% | | | |
Value | [1],[2] | $ 166,909,319 | | | |
Principal Value | [1],[2] | $ 167,000,000 | | | |
Investment Interest Rate | [1],[2] | 0.89% | | | |
Investment Maturity Date | [1],[2] | Jul. 27, 2017 | | | |
Restricted for maintenance margin | | $ 104,937,000 | | | |
U.S. Treasury Bills, 0.960% due August 31, 2017 [Member] | | | | | |
Schedule of Investments [Line Items] | | | | | |
Percentage of Shareholders' Equity | [1] | 19.27% | | | |
Value | [1] | $ 133,798,464 | | | |
Principal Value | [1] | $ 134,000,000 | | | |
Investment Interest Rate | [1] | 0.96% | | | |
Investment Maturity Date | [1] | Aug. 31, 2017 | | | |
U.S. Treasury Bills, 0.990% due September 14, 2017 [Member] | | | | | |
Schedule of Investments [Line Items] | | | | | |
Percentage of Shareholders' Equity | [1] | 19.26% | | | |
Value | [1] | $ 133,743,926 | | | |
Principal Value | [1] | $ 134,000,000 | | | |
Investment Interest Rate | [1] | 0.99% | | | |
Investment Maturity Date | [1] | Sep. 14, 2017 | | | |
United States Treasury Obligations [Member] | | | | | |
Schedule of Investments [Line Items] | | | | | |
Percentage of Shareholders' Equity | | 81.57% | [1] | 97.09% | [3] |
Value | | $ 566,443,393 | [1] | $ 702,215,941 | [3] |
Investments, cost | | $ 566,397,256 | | $ 702,232,971 | |
Exchange-Traded Fund - PowerShares Treasury Collateral Portfolio [Member] | Affiliated Investments [Member] | | | | | |
Schedule of Investments [Line Items] | | | | | |
Percentage of Shareholders' Equity | [4],[5] | 11.40% | | | |
Affiliated Investments, at Value | [4],[5] | $ 79,168,320 | | | |
Affiliated Investments, Shares | [4],[5] | 749,700 | | | |
Affiliated Investments, at Cost | [4],[5] | $ 78,999,188 | | | |
Money Market Mutual Fund - Premier U.S. Government Money Portfolio - Institutional Class [Member] | Affiliated Investments [Member] | | | | | |
Schedule of Investments [Line Items] | | | | | |
Percentage of Shareholders' Equity | | 3.35% | [6] | 2.69% | [7] |
Affiliated Investments, at Value | | $ 23,256,639 | [6] | $ 19,456,137 | [7] |
Affiliated Investments, Shares | | 23,256,639 | [6] | 19,456,137 | [7] |
Investment Interest Rate | | 0.86% | [1],[6] | 0.41% | [3],[7] |
Affiliated Investments, at Cost | | $ 23,256,639 | [6] | $ 19,456,137 | [7] |
U.S. Treasury Bills, 0.490% due January 19, 2017 [Member] | | | | | |
Schedule of Investments [Line Items] | | | | | |
Percentage of Shareholders' Equity | [3] | | | 17.56% | |
Value | [3] | | | $ 126,977,013 | |
Principal Value | [3] | | | $ 127,000,000 | |
Investment Interest Rate | [3] | | | 0.49% | |
Investment Maturity Date | [3] | | | Jan. 19, 2017 | |
U.S. Treasury Bills, 0.485% due January 26, 2017 [Member] | | | | | |
Schedule of Investments [Line Items] | | | | | |
Percentage of Shareholders' Equity | [3] | | | 9.81% | |
Value | [3] | | | $ 70,981,327 | |
Principal Value | [3] | | | $ 71,000,000 | |
Investment Interest Rate | [3] | | | 0.485% | |
Investment Maturity Date | [3] | | | Jan. 26, 2017 | |
U.S. Treasury Bills, 0.490% due March 2, 2017 [Member] | | | | | |
Schedule of Investments [Line Items] | | | | | |
Percentage of Shareholders' Equity | [3] | | | 17.13% | |
Value | [3] | | | $ 123,905,140 | |
Principal Value | [3] | | | $ 124,000,000 | |
Investment Interest Rate | [3] | | | 0.49% | |
Investment Maturity Date | [3] | | | Mar. 2, 2017 | |
U.S. Treasury Bills, 0.530% due April 6, 2017 [Member] | | | | | |
Schedule of Investments [Line Items] | | | | | |
Percentage of Shareholders' Equity | [3],[8] | | | 32.03% | |
Value | [3],[8] | | | $ 231,687,264 | |
Principal Value | [3],[8] | | | $ 232,000,000 | |
Investment Interest Rate | [3],[8] | | | 0.53% | |
Investment Maturity Date | [3],[8] | | | Apr. 6, 2017 | |
Restricted for maintenance margin | | | | $ 104,853,000 | |
U.S. Treasury Bills, 0.625% due May 18, 2017 [Member] | | | | | |
Schedule of Investments [Line Items] | | | | | |
Percentage of Shareholders' Equity | [3] | | | 20.56% | |
Value | [3] | | | $ 148,665,197 | |
Principal Value | [3] | | | $ 149,000,000 | |
Investment Interest Rate | [3] | | | 0.625% | |
Investment Maturity Date | [3] | | | May 18, 2017 | |
| |
[1] | Security may be traded on a discount basis. The interest rate shown represents the discount rate at the most recent auction date of the security prior to period end. | |
[2] | United States Treasury Obligations of $104,937,000 are on deposit with the Commodity Broker and held as maintenance margin for open futures contracts. | |
[3] | Security may be traded on a discount basis. The interest rate shown represents the discount rate at the most recent auction date of the security prior to year end. | |
[4] | Affiliated company. The security and the Fund are affiliated by having the same investment adviser. See Note 8. | |
[5] | Non-income producing security. | |
[6] | The security and the Fund are advised by wholly-owned subsidiaries of Invesco Ltd. and are therefore considered to be affiliated. The rate shown is the 7-day SEC standardized yield as of June 30, 2017. | |
[7] | The security and the Fund are advised by wholly-owned subsidiaries of Invesco Ltd. and are therefore considered to be affiliated. The rate shown is the 7-day SEC standardized yield as of December 31, 2016. | |
[8] | United States Treasury Obligations of $104,853,000 are on deposit with the Commodity Broker and held as maintenance margin for open futures contracts. | |