Schedule of Investments (Unaudited) - Treasury Bills and Money Market Fund - USD ($)		3 Months Ended		12 Months Ended
		Mar. 31, 2019		Dec. 31, 2018
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity		99.70%		103.98%
United States Treasury Obligations, Value		$ 1,447,699,255		$ 1,614,425,920
Affiliated Investments, Value		319,596,529		395,084,923
Investments in Securities, Value		1,767,295,784		2,009,510,843
Investments in Securities, Cost		$ 1,766,964,593		$ 2,009,415,674
Affiliated Investments [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity		18.03%		20.44%
Affiliated Investments, Value		$ 319,596,529		$ 395,084,923
Affiliated Investments, at Cost		$ 319,322,279		$ 394,929,293
U.S. Treasury Bills, 2.465% due April 4, 2019 [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity	[1]	28.94%		26.38%
United States Treasury Obligations, Value	[1]	$ 512,899,272		$ 509,825,741
United States Treasury Obligations, Principal Value	[1]	$ 513,000,000		$ 513,000,000
Investment Interest Rate		2.465%		2.465%
Investment Maturity Date		Apr. 04, 2019		Apr. 04, 2019
U.S. Treasury Bills, 2.470% due April 23, 2019 [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity	[1]	8.22%
United States Treasury Obligations, Value	[1]	$ 145,787,265
United States Treasury Obligations, Principal Value	[1]	$ 146,000,000
Investment Interest Rate		2.47%
Investment Maturity Date		Apr. 23, 2019
U.S. Treasury Bills, 2.375% due May 2, 2019 [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity	[1],[2]	27.64%
United States Treasury Obligations, Value	[1],[2]	$ 490,009,049
United States Treasury Obligations, Principal Value	[1],[2]	$ 491,000,000
Investment Interest Rate	[2]	2.375%
Investment Maturity Date	[2]	May 02, 2019
Restricted for maintenance margin		$ 266,339,510
U.S. Treasury Bills, 2.470% due July 11, 2019 [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity	[1]	16.87%
United States Treasury Obligations, Value	[1]	$ 299,003,669
United States Treasury Obligations, Principal Value	[1]	$ 301,000,000
Investment Interest Rate		2.47%
Investment Maturity Date		Jul. 11, 2019
United States Treasury Obligations [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity	[1]	81.67%		83.54%
United States Treasury Obligations, Value	[1]	$ 1,447,699,255		$ 1,614,425,920
Investments in Securities, Cost		$ 1,447,642,314		$ 1,614,486,381
Exchange-Traded Fund [Member] | Affiliated Investments [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity	[3]	14.12%		12.94%
Affiliated Investments, Value	[3]	$ 250,264,476		$ 250,145,856
Affiliated Investments, Shares	[3]	2,372,400		2,372,400
Affiliated Investments, at Cost		$ 249,990,226		$ 249,990,226
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		3.91%	[4]	7.50%	[5]
Affiliated Investments, Value		$ 69,332,053	[4]	$ 144,939,067	[5]
Affiliated Investments, Shares		69,332,053	[4]	144,939,067	[5]
Investment Interest Rate		2.33%		2.30%
Affiliated Investments, at Cost		$ 69,332,053		$ 144,939,067
U.S. Treasury Bills, 2.175% due January 3, 2019 [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity	[1]			4.87%
United States Treasury Obligations, Value	[1]			$ 93,994,138
United States Treasury Obligations, Principal Value	[1]			$ 94,000,000
Investment Interest Rate				2.175%
Investment Maturity Date				Jan. 03, 2019
U.S. Treasury Bills, 2.370% due February 28, 2019 [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity	[1]			33.35%
United States Treasury Obligations, Value	[1]			$ 644,565,727
United States Treasury Obligations, Principal Value	[1]			$ 647,000,000
Investment Interest Rate				2.37%
Investment Maturity Date				Feb. 28, 2019
U.S. Treasury Bills, 2.430% due May 2, 2019 [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity	[1],[6]			18.94%
United States Treasury Obligations, Value	[1],[6]			$ 366,040,314
United States Treasury Obligations, Principal Value	[1],[6]			$ 369,000,000
Investment Interest Rate	[6]			2.43%
Investment Maturity Date	[6]			May 02, 2019
Restricted for maintenance margin				$ 255,836,800

[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 $266,339,510 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 $255,836,800 are on deposit with the Commodity Broker and held as maintenance margin for open futures contracts.