Schedule of Investments - Treasury Bills and Affiliated Investments - USD ($) | 12 Months Ended |
Dec. 31, 2018 | Dec. 31, 2017 |
Schedule of Investments [Line Items] | | | | | |
Percentage of Shareholders' Equity | | 101.57% | | 98.90% | |
United States Treasury Obligations, Value | | $ 67,734,740 | | $ 142,797,721 | |
Affiliated Investments, Value | | 24,916,229 | | 33,284,413 | |
Investments in Securities, Value | | 92,650,969 | | 176,082,134 | |
Investments in Securities, cost | | $ 92,639,862 | | $ 176,104,892 | |
Affiliated Investments [Member] | | | | | |
Schedule of Investments [Line Items] | | | | | |
Percentage of Shareholders' Equity | | 27.31% | | 18.70% | |
Affiliated Investments, Value | | $ 24,916,229 | | $ 33,284,413 | |
Affiliated investments, at cost | | $ 24,903,778 | | $ 33,304,228 | |
U.S. Treasury Bills, 2.175% due January 3, 2019 [Member] | | | | | |
Schedule of Investments [Line Items] | | | | | |
Percentage of Shareholders' Equity | [1] | 18.64% | | | |
United States Treasury Obligations, Value | [1] | $ 16,998,940 | | | |
United States Treasury Obligations, Principal Value | [1] | $ 17,000,000 | | | |
Investment Interest Rate | [1] | 2.175% | | | |
Investment Maturity Date | [1] | Jan. 3, 2019 | | | |
U.S. Treasury Bills, 2.370% due February, 28, 2019 [Member] | | | | | |
Schedule of Investments [Line Items] | | | | | |
Percentage of Shareholders' Equity | [1] | 19.66% | | | |
United States Treasury Obligations, Value | [1] | $ 17,932,277 | | | |
United States Treasury Obligations, Principal Value | [1] | $ 18,000,000 | | | |
Investment Interest Rate | [1] | 2.37% | | | |
Investment Maturity Date | [1] | Feb. 28, 2019 | | | |
U.S. Treasury Bills, 2.465% due April 4, 2019 [Member] | | | | | |
Schedule of Investments [Line Items] | | | | | |
Percentage of Shareholders' Equity | [1] | 8.72% | | | |
United States Treasury Obligations, Value | [1] | $ 7,950,499 | | | |
United States Treasury Obligations, Principal Value | [1] | $ 8,000,000 | | | |
Investment Interest Rate | [1] | 2.465% | | | |
Investment Maturity Date | [1] | Apr. 4, 2019 | | | |
U.S. Treasury Bills, 2.415% due March 28, 2019 [Member] | | | | | |
Schedule of Investments [Line Items] | | | | | |
Percentage of Shareholders' Equity | [1],[2] | 23.98% | | | |
United States Treasury Obligations, Value | [1],[2] | $ 21,877,086 | | | |
United States Treasury Obligations, Principal Value | [1],[2] | $ 22,000,000 | | | |
Investment Interest Rate | [1] | 2.415% | | | |
Investment Maturity Date | [1] | Mar. 28, 2019 | | | |
Restricted for maintenance margin | | $ 19,213,740 | | | |
U.S. Treasury Bills, 2.430% due May 2, 2019 [Member] | | | | | |
Schedule of Investments [Line Items] | | | | | |
Percentage of Shareholders' Equity | [1] | 3.26% | | | |
United States Treasury Obligations, Value | [1] | $ 2,975,938 | | | |
United States Treasury Obligations, Principal Value | [1] | $ 3,000,000 | | | |
Investment Interest Rate | [1] | 2.43% | | | |
Investment Maturity Date | [1] | May 2, 2019 | | | |
United States Treasury Obligations [Member] | | | | | |
Schedule of Investments [Line Items] | | | | | |
Percentage of Shareholders' Equity | [1] | 74.26% | | 80.20% | |
United States Treasury Obligations, Value | [1] | $ 67,734,740 | | $ 142,797,721 | |
Investments in Securities, cost | | $ 67,736,084 | | $ 142,800,664 | |
Exchange-Traded Fund - Invesco Treasury Collateral ETF [Member] | Affiliated Investments [Member] | | | | | |
Schedule of Investments [Line Items] | | | | | |
Percentage of Shareholders' Equity | [3] | 21.94% | | 11.22% | |
Affiliated Investments, Value | [3] | $ 20,012,512 | | $ 19,980,246 | |
Affiliated Investments, Shares | [3] | 189,800 | | 189,800 | |
Affiliated investments, at cost | [3] | $ 20,000,061 | | $ 20,000,061 | |
Money Market Mutual Fund - Invesco Premier U.S. Government Money Portfolio - Institutional Class [Member] | Affiliated Investments [Member] | | | | | |
Schedule of Investments [Line Items] | | | | | |
Percentage of Shareholders' Equity | | 5.37% | [4] | 7.48% | [3],[5] |
Affiliated Investments, Value | | $ 4,903,717 | [4] | $ 13,304,167 | [3],[5] |
Affiliated Investments, Shares | | 4,903,717 | [4] | 13,304,167 | [3],[5] |
Investment Interest Rate | | 2.30% | [4] | 1.15% | [5] |
Affiliated investments, at cost | | $ 4,903,717 | [4] | $ 13,304,167 | [5] |
U.S. Treasury Bills, 1.180% due January 4, 2018 [Member] | | | | | |
Schedule of Investments [Line Items] | | | | | |
Percentage of Shareholders' Equity | [1] | | | 27.52% | |
United States Treasury Obligations, Value | [1] | | | $ 48,996,927 | |
United States Treasury Obligations, Principal Value | [1] | | | $ 49,000,000 | |
Investment Interest Rate | [1] | | | 1.18% | |
Investment Maturity Date | [1] | | | Jan. 4, 2018 | |
U.S. Treasury Bills, 1.245% due January 18, 2018 [Member] | | | | | |
Schedule of Investments [Line Items] | | | | | |
Percentage of Shareholders' Equity | [1] | | | 10.10% | |
United States Treasury Obligations, Value | [1] | | | $ 17,990,130 | |
United States Treasury Obligations, Principal Value | [1] | | | $ 18,000,000 | |
Investment Interest Rate | [1] | | | 1.245% | |
Investment Maturity Date | [1] | | | Jan. 18, 2018 | |
U.S. Treasury Bills, 1.285% due February 22, 2018 [Member] | | | | | |
Schedule of Investments [Line Items] | | | | | |
Percentage of Shareholders' Equity | [1] | | | 28.59% | |
United States Treasury Obligations, Value | [1] | | | $ 50,908,965 | |
United States Treasury Obligations, Principal Value | [1] | | | $ 51,000,000 | |
Investment Interest Rate | [1] | | | 1.285% | |
Investment Maturity Date | [1] | | | Feb. 22, 2018 | |
U.S. Treasury Bills, 1.285% due March 1, 2018 [Member] | | | | | |
Schedule of Investments [Line Items] | | | | | |
Percentage of Shareholders' Equity | [1],[6] | | | 7.85% | |
United States Treasury Obligations, Value | [1],[6] | | | $ 13,971,411 | |
United States Treasury Obligations, Principal Value | [1],[6] | | | $ 14,000,000 | |
Investment Interest Rate | [1],[6] | | | 1.285% | |
Investment Maturity Date | [1],[6] | | | Mar. 1, 2018 | |
Restricted for maintenance margin | | | | $ 13,970,600 | |
U.S. Treasury Bills, 1.450% due June 7, 2018 [Member] | | | | | |
Schedule of Investments [Line Items] | | | | | |
Percentage of Shareholders' Equity | [1] | | | 6.14% | |
United States Treasury Obligations, Value | [1] | | | $ 10,930,288 | |
United States Treasury Obligations, Principal Value | [1] | | | $ 11,000,000 | |
Investment Interest Rate | [1] | | | 1.45% | |
Investment Maturity Date | [1] | | | Jun. 7, 2018 | |
| |
[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 $19,213,740 are on deposit with the Commodity Broker and held as maintenance margin for open futures contracts. | |
[3] | Affiliated company. The security and the Fund are affiliated by having the same investment adviser. See Note 8. | |
[4] | 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, 2018. | |
[5] | 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, 2017. | |
[6] | United States Treasury Obligations of $13,970,600 are on deposit with the Commodity Broker and held as maintenance margin for open futures contracts. | |