Schedule of Investments (Unaudited) - Treasury Bills and Money Market Fund - USD ($)		Sep. 30, 2020	Dec. 31, 2019
Schedule Of Investments [Line Items]
Percentage of Shareholders' Equity		105.33%	123.79%
United States Treasury Obligations, Value		$ 42,994,518	$ 28,910,162
Affiliated investments, value		40,676,310	21,851,133
Investments in Securities, Value		83,670,828	50,761,295
Investments in Securities, cost		83,669,503	50,756,983
Affiliated Investments [Member]
Schedule Of Investments [Line Items]
Affiliated investments, value		$ 40,676,310	$ 21,851,133
U.S. Treasury Bills, 0.085% due November 12, 2020 [Member]
Schedule Of Investments [Line Items]
Percentage of Shareholders' Equity	[1],[2]	23.92%
United States Treasury Obligations, Value	[1],[2]	$ 18,998,199
United States Treasury Obligations, Principal Value	[1],[2]	$ 19,000,000
Investment Interest Rate	[1],[2]	0.085%
Investment Maturity Date	[1],[2]	Nov. 12, 2020
U.S. Treasury Bills, 0.105% due December 3, 2020 [Member]
Schedule Of Investments [Line Items]
Percentage of Shareholders' Equity	[1]	25.17%
United States Treasury Obligations, Value	[1]	$ 19,997,025
United States Treasury Obligations, Principal Value	[1]	$ 20,000,000
Investment Interest Rate	[1]	0.105%
Investment Maturity Date	[1]	Dec. 03, 2020
U.S. Treasury Bills, 0.110% due December 17, 2020 [Member]
Schedule Of Investments [Line Items]
Percentage of Shareholders' Equity	[1]	5.03%
United States Treasury Obligations, Value	[1]	$ 3,999,294
United States Treasury Obligations, Principal Value	[1]	$ 4,000,000
Investment Interest Rate		0.11%
Investment Maturity Date		Dec. 17, 2020
United State Treasury Obligation [Member]
Schedule Of Investments [Line Items]
Percentage of Shareholders' Equity	[1]	54.12%	70.50%
United States Treasury Obligations, Value	[1]	$ 42,994,518	$ 28,910,162
Investments in Securities, cost	[1]	$ 42,993,193	$ 28,905,850
Money Market Mutual Fund - Invesco Government and Agency Portfolio - Institutional Class [Member] | Affiliated Investments [Member]
Schedule Of Investments [Line Items]
Percentage of Shareholders' Equity	[3],[4]	51.21%
Affiliated investments, value	[3],[4]	$ 40,676,310
Shares	[3],[4]	40,676,310
Investment Interest Rate	[3]	0.02%
Investments in Securities, cost	[3]	$ 40,676,310
U.S. Treasury Bills, 1.520% due February 6, 2020 [Member]
Schedule Of Investments [Line Items]
Percentage of Shareholders' Equity	[1]		21.92%
United States Treasury Obligations, Value	[1]		$ 8,987,006
United States Treasury Obligations, Principal Value	[1]		$ 9,000,000
Investment Interest Rate	[1]		1.52%
Investment Maturity Date	[1]		Feb. 06, 2020
U.S. Treasury Bills, 1.520% due April 2, 2020 [Member]
Schedule Of Investments [Line Items]
Percentage of Shareholders' Equity	[1],[5]		48.58%
United States Treasury Obligations, Value	[1],[5]		$ 19,923,156
United States Treasury Obligations, Principal Value	[1],[5]		$ 20,000,000
Investment Interest Rate	[1],[5]		1.52%
Investment Maturity Date	[1],[5]		Apr. 02, 2020
Restricted for maintenance margin		$ 3,999,600	$ 1,105,671
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	[3],[6]		53.29%
Affiliated investments, value	[3],[6]		$ 21,851,133
Shares	[3],[6]		21,851,133
Investment Interest Rate	[3]		1.47%
Investments in Securities, cost	[3]		$ 21,851,133

[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 $3,999,600 are on deposit with the Commodity Broker and held as maintenance margin for open futures contracts.

[3] Affiliated issuer. The issuer and/or the Fund is a wholly-owned subsidiary of Invesco Ltd., or is affiliated by having an investment adviser that is under common control of Invesco Ltd. See Note 8.

[4] The rate shown is the 7-day SEC standardized yield as of September 30, 2020.

[5] United States Treasury Obligations of $1,105,671 are on deposit with the Commodity Broker and held as maintenance margin for open futures contracts.

[6] The rate shown is the 7-day SEC standardized yield as of December 31, 2019