Schedule of Investments (Unaudited) - Treasury Bills and Affiliated Investments - USD ($) | 3 Months Ended | 12 Months Ended |
Mar. 31, 2019 | Dec. 31, 2018 |
Schedule of Investments [Line Items] | | | | | |
Percentage of Shareholders' Equity | | 99.59% | | 101.57% | |
United States Treasury Obligations, Value | | $ 71,822,061 | | $ 67,734,740 | |
Affiliated Investments, Value | | 24,727,060 | | 24,916,229 | |
Investments in Securities, Value | | 96,549,121 | | 92,650,969 | |
Investments in Securities, cost | | $ 96,526,394 | | $ 92,639,862 | |
Affiliated Investments [Member] | | | | | |
Schedule of Investments [Line Items] | | | | | |
Percentage of Shareholders' Equity | | 25.51% | | 27.31% | |
Affiliated Investments, Value | | $ 24,727,060 | | $ 24,916,229 | |
Affiliated investments, at cost | | $ 24,705,119 | | $ 24,903,778 | |
U.S. Treasury Bills, 2.470% due April 4, 2019 [Member] | | | | | |
Schedule of Investments [Line Items] | | | | | |
Percentage of Shareholders' Equity | [1] | 8.25% | | | |
United States Treasury Obligations, Value | [1] | $ 7,998,429 | | | |
United States Treasury Obligations, Principal Value | [1] | $ 8,000,000 | | | |
Investment Interest Rate | [1] | 2.47% | | | |
Investment Maturity Date | [1] | Apr. 4, 2019 | | | |
U.S. Treasury Bills, 2.470% due April 23, 2019 [Member] | | | | | |
Schedule of Investments [Line Items] | | | | | |
Percentage of Shareholders' Equity | [1] | 31.93% | | | |
United States Treasury Obligations, Value | [1] | $ 30,954,830 | | | |
United States Treasury Obligations, Principal Value | [1] | $ 31,000,000 | | | |
Investment Interest Rate | [1] | 2.47% | | | |
Investment Maturity Date | [1] | Apr. 23, 2019 | | | |
U.S. Treasury Bills, 2.380% due May 2, 2019 [Member] | | | | | |
Schedule of Investments [Line Items] | | | | | |
Percentage of Shareholders' Equity | [1],[2] | 19.56% | | | |
United States Treasury Obligations, Value | [1],[2] | $ 18,961,654 | | | |
United States Treasury Obligations, Principal Value | [1],[2] | $ 19,000,000 | | | |
Investment Interest Rate | [1],[2] | 2.38% | | | |
Investment Maturity Date | [1],[2] | May 2, 2019 | | | |
Restricted for maintenance margin | | $ 18,960,100 | | | |
U.S. Treasury Bills, 2.470% due July 11, 2019 [Member] | | | | | |
Schedule of Investments [Line Items] | | | | | |
Percentage of Shareholders' Equity | [1] | 14.34% | | | |
United States Treasury Obligations, Value | [1] | $ 13,907,148 | | | |
United States Treasury Obligations, Principal Value | [1] | $ 14,000,000 | | | |
Investment Interest Rate | [1] | 2.47% | | | |
Investment Maturity Date | [1] | Jul. 11, 2019 | | | |
United States Treasury Obligations [Member] | | | | | |
Schedule of Investments [Line Items] | | | | | |
Percentage of Shareholders' Equity | [1] | 74.08% | | 74.26% | |
United States Treasury Obligations, Value | [1] | $ 71,822,061 | | $ 67,734,740 | |
Investments in Securities, cost | | $ 71,821,275 | | $ 67,736,084 | |
Exchange-Traded Fund - Invesco Treasury Collateral ETF [Member] | Affiliated Investments [Member] | | | | | |
Schedule of Investments [Line Items] | | | | | |
Percentage of Shareholders' Equity | | 20.65% | [3] | 21.94% | |
Affiliated Investments, Value | | $ 20,022,002 | [3] | $ 20,012,512 | |
Affiliated Investments, Shares | | 189,800 | [3] | 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 | | 4.86% | [4] | 5.37% | [3],[5] |
Affiliated Investments, Value | | $ 4,705,058 | [4] | $ 4,903,717 | [3],[5] |
Affiliated Investments, Shares | | 4,705,058 | [4] | 4,903,717 | [3],[5] |
Investment Interest Rate | | 2.33% | [4] | 2.30% | [5] |
Affiliated investments, at cost | | $ 4,705,058 | [4] | $ 4,903,717 | [5] |
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, 2.415% due March 28, 2019 [Member] | | | | | |
Schedule of Investments [Line Items] | | | | | |
Percentage of Shareholders' Equity | [1],[6] | | | 23.98% | |
United States Treasury Obligations, Value | [1],[6] | | | $ 21,877,086 | |
United States Treasury Obligations, Principal Value | [1],[6] | | | $ 22,000,000 | |
Investment Interest Rate | [1],[6] | | | 2.415% | |
Investment Maturity Date | [1],[6] | | | Mar. 28, 2019 | |
Restricted for maintenance margin | | | | $ 19,213,740 | |
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, 2.430% 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 | |
| |
[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 $18,960,100 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 March 31, 2019. | |
[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, 2018. | |
[6] | United States Treasury Obligations of $19,213,740 are on deposit with the Commodity Broker and held as maintenance margin for open futures contracts. | |