Schedule of Investments (Unaudited) - Treasury Bills and Money Market Fund - USD ($)		Sep. 30, 2019		Dec. 31, 2018
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity		98.80%		101.51%
United States Treasury Obligations, Value		$ 161,642,102		$ 88,687,386
Affiliated Investments, Value		6,434,764		7,355,184
Investments in Securities, Value		168,076,866		96,042,570
Investments in Securities, Cost		$ 168,039,707		$ 96,050,614
U.S. Treasury Bills, 2.025% due October 8, 2019 [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity	[1]	16.45%
United States Treasury Obligations, Value	[1]	$ 27,990,499
United States Treasury Obligations, Principal Value	[1]	$ 28,000,000
Investment Interest Rate	[1]	2.025%
Investment Maturity Date	[1]	Oct. 08, 2019
Restricted for maintenance margin		$ 22,115,640
U.S. Treasury Bills, 2.210% due October 10, 2019 [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity	[1]	34.67%
United States Treasury Obligations, Value	[1]	$ 58,974,003
United States Treasury Obligations, Principal Value	[1]	$ 59,000,000
Investment Interest Rate	[1]	2.21%
Investment Maturity Date	[1]	Oct. 10, 2019
U.S. Treasury Bills, 1.945% due December 19, 2019 [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity	[1],[2]	38.07%
United States Treasury Obligations, Value	[1],[2]	$ 64,754,625
United States Treasury Obligations, Principal Value	[1],[2]	$ 65,000,000
Investment Interest Rate	[1]	1.945%
Investment Maturity Date	[1]	Dec. 19, 2019
U.S. Treasury Bills, 1.825% due March 5, 2020 [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity	[1]	5.83%
United States Treasury Obligations, Value	[1]	$ 9,922,975
United States Treasury Obligations, Principal Value	[1]	$ 10,000,000
Investment Interest Rate	[1],[2]	1.825%
Investment Maturity Date	[1],[2]	Mar. 05, 2020
United States Treasury Obligations [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity		95.02%	[1]	93.74%	[3]
United States Treasury Obligations, Value		$ 161,642,102	[1]	$ 88,687,386	[3]
Investments in Securities, Cost		$ 161,604,943	[1]	$ 88,695,430	[3]
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		3.78%	[4]	7.77%	[5]
Affiliated Investments, Value		$ 6,434,764	[4]	$ 7,355,184	[5]
Affiliated Investments, Shares		6,434,764	[4]	7,355,184	[5]
Investment Interest Rate		1.81%	[1],[4]	2.30%	[3],[5]
Investments in Securities, Cost		$ 6,434,764	[4]	$ 7,355,184	[5]
U.S. Treasury Bills, 2.175% due January 3, 2019 [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity	[3]			19.03%
United States Treasury Obligations, Value	[3]			$ 17,998,877
United States Treasury Obligations, Principal Value	[3]			$ 18,000,000
Investment Interest Rate	[3]			2.175%
Investment Maturity Date	[3]			Jan. 03, 2019
U.S. Treasury Bills, 2.370% due February 28, 2019 [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity	[3],[6]			61.07%
United States Treasury Obligations, Value	[3],[6]			$ 57,781,781
United States Treasury Obligations, Principal Value	[3],[6]			$ 58,000,000
Investment Interest Rate	[3],[6]			2.37%
Investment Maturity Date	[3],[6]			Feb. 28, 2019
Restricted for maintenance margin	[6]			$ 11,157,440
U.S. Treasury Bills, 2.465% due April 4, 2019 [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity	[3]			6.30%
United States Treasury Obligations, Value	[3]			$ 5,962,874
United States Treasury Obligations, Principal Value	[3]			$ 6,000,000
Investment Interest Rate	[3]			2.465%
Investment Maturity Date	[3]			Apr. 04, 2019
U.S. Treasury Bills, 2.430% due May 2, 2019 [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity	[3]			7.34%
United States Treasury Obligations, Value	[3]			$ 6,943,854
United States Treasury Obligations, Principal Value	[3]			$ 7,000,000
Investment Interest Rate	[3]			2.43%
Investment Maturity Date	[3]			May 02, 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 $22,115,640 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 period end

[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 September 30, 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 $11,157,440 are on deposit with the Commodity Broker and held as maintenance margin for open futures contracts.