Schedule of Investments (Unaudited) - Treasury Bills and Money Market Fund - USD ($)		3 Months Ended		12 Months Ended
		Mar. 31, 2017		Dec. 31, 2016
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity		99.68%		100.48%
Value		$ 700,599,334		$ 846,158,812
Affiliated investments, at value and cost		33,096,938		3,786,312
Total Investments		733,696,272		849,945,124
Investments, cost		$ 733,746,100		$ 849,976,394
U.S. Treasury Bills, 0.570% due April 6, 2017 [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity		33.56%
Value		$ 246,988,638
Principal Value		$ 247,000,000
Investment Interest Rate		0.57%
Investment Maturity Date		Apr. 06, 2017
U.S. Treasury Bills, 0.745% due April 27, 2017 [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity		21.45%
Value		$ 157,923,686
Principal Value		$ 158,000,000
Investment Interest Rate		0.745%
Investment Maturity Date		Apr. 27, 2017
U.S. Treasury Bills, 0.540% due May 18, 2017 [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity		13.98%
Value		$ 102,907,609
Principal Value		$ 103,000,000
Investment Interest Rate		0.54%
Investment Maturity Date		May 18, 2017
U.S. Treasury Bills, 0.515% due June 1, 2017 [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity	[1]	26.19%
Value	[1]	$ 192,779,401
Principal Value	[1]	$ 193,000,000
Investment Interest Rate	[1]	0.515%
Investment Maturity Date	[1]	Jun. 01, 2017
Restricted for maintenance margin	[1]	$ 18,977,200
United States Treasury Obligations [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity		95.18%	[2]	100.03%	[3]
Value		$ 700,599,334	[2]	$ 846,158,812	[3]
Investments, cost		$ 700,649,162	[2]	$ 846,190,082	[3]
Money Market Mutual Fund [Member] | Affiliated Investments [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity		4.50%	[4]	0.45%	[5]
Affiliated investments, at value and cost		$ 33,096,938	[4]	$ 3,786,312	[5]
Shares		33,096,938	[4]	3,786,312	[5]
Investment Interest Rate		0.60%	[4]	0.41%	[5]
Investments, cost		$ 33,096,938	[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, 2016
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 $18,977,200 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 March 31, 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.