Schedule of Investments (Unaudited) - Treasury Bills and Money Market Fund - USD ($)		6 Months Ended		12 Months Ended
		Jun. 30, 2017		Dec. 31, 2016
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity		100.01%		100.48%
Value		$ 537,597,215		$ 846,158,812
Affiliated Investments, at value and cost		2,039,940		3,786,312
Total Investments		539,637,155		849,945,124
Investments, cost		$ 539,598,907		$ 849,976,394
U.S. Treasury Bills, 0.840% due July 6, 2017 [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity		42.25%
Value		$ 227,985,636
Principal Value		$ 228,000,000
Investment Interest Rate		0.84%
Investment Maturity Date		Jul. 06, 2017
U.S. Treasury Bills, 0.890% due July 27, 2017 [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity	[1]	19.08%
Value	[1]	$ 102,944,071
Principal Value	[1]	$ 103,000,000
Investment Interest Rate	[1]	0.89%
Investment Maturity Date	[1]	Jul. 27, 2017
Restricted for maintenance margin	[1]	$ 19,988,000
U.S. Treasury Bills, 0.960% due August 31, 2017 [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity		28.68%
Value		$ 154,766,880
Principal Value		$ 155,000,000
Investment Interest Rate		0.96%
Investment Maturity Date		Aug. 31, 2017
U.S. Treasury Bills, 0.990% due September 14, 2017 [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity		9.62%
Value		$ 51,900,628
Principal Value		$ 52,000,000
Investment Interest Rate		0.99%
Investment Maturity Date		Sep. 14, 2017
United States Treasury Obligations [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity		99.63%	[2]	100.03%	[3]
Value		$ 537,597,215	[2]	$ 846,158,812	[3]
Investments, cost		$ 537,558,967	[2]	$ 846,190,082	[3]
Money Market Mutual Fund [Member] | Affiliated Investments [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity		0.38%	[4]	0.45%	[5]
Affiliated Investments, at value and cost		$ 2,039,940	[4]	$ 3,786,312	[5]
Shares		2,039,940	[4]	3,786,312	[5]
Investment Interest Rate		0.86%	[4]	0.41%	[5]
Investments, cost		$ 2,039,940	[4]	$ 3,786,312	[5]
U.S. Treasury Bills, 0.490% due March 2, 2017 [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity				4.14%
Value				$ 34,993,665
Principal Value				$ 35,000,000
Investment Interest Rate				0.49%
Investment Maturity Date				Jan. 19, 2017
U S Treasury Bills Zero Point Four Eight Five Percentage Due January Twenty Six Two Thousand Seventeen
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity				26.95%
Value				$ 227,940,036
Principal Value				$ 228,000,000
Investment Interest Rate				0.485%
Investment Maturity Date				Jan. 26, 2017
U S Treasury Bills Zero Point Four Nine Zero Percentage Due March Two Two Thousand Seventeen
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity				21.26%
Value				$ 179,862,300
Principal Value				$ 180,000,000
Investment Interest Rate				0.49%
Investment Maturity Date				Mar. 02, 2017
U.S. Treasury Bills, 0.530% due April 6, 2016 [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity	[6]			35.53%
Value	[6]			$ 300,594,252
Principal Value	[6]			$ 301,000,000
Investment Interest Rate	[6]			0.53%
Investment Maturity Date	[6]			Apr. 06, 2017
Restricted for maintenance margin	[6]			$ 18,973,400
U.S. Treasury Bills, 0625% due May 18, 2017 [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity				12.15%
Value				$ 102,768,559
Principal Value				$ 103,000,000
Investment Interest Rate				0.625%
Investment Maturity Date				May 18, 2017

[1] United States Treasury Obligations of $19,988,000 are on deposit with the Commodity Broker and held as maintenance margin for open futures contracts.

[2] 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.

[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 year 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 June 30, 2017.

[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, 2016.

[6] United States Treasury Obligations of $18,973,400 are on deposit with the Commodity Broker and held as maintenance margin for open futures contracts.