Schedule of Investments - Treasury Bills and Money Market Fund - USD ($)		12 Months Ended
		Dec. 31, 2016		Dec. 31, 2015
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity		99.16%
Value		$ 30,970,236		$ 36,495,207
Affiliated investments, at value and cost		1,502,575
Total Investments		32,472,811		36,495,207
Investments, cost		$ 32,473,872		$ 36,491,937
U.S. Treasury Bills, 0.485% due January 26, 2017 [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity	[1]	18.32%
Value	[1]	$ 5,998,422
Principal Value	[1]	$ 6,000,000
Investment Interest Rate	[1]	0.485%
Investment Maturity Date	[1]	Jan. 26, 2017
U.S. Treasury Bills, 0.490% due March 2, 2017 [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity	[1]	33.56%
Value	[1]	$ 10,991,585
Principal Value	[1]	$ 11,000,000
Investment Interest Rate	[1]	0.49%
Investment Maturity Date	[1]	Mar. 02, 2017
U.S. Treasury Bills, 0.530% due April 6, 2017 [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity	[1],[2]	39.64%
Value	[1],[2]	$ 12,982,476
Principal Value	[1],[2]	$ 13,000,000
Investment Interest Rate	[1],[2]	0.53%
Investment Maturity Date	[1],[2]	Apr. 06, 2017
Restricted for maintenance margin		$ 4,293,980
U.S. Treasury Bills, 0.625% due May 18, 2017 [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity	[1]	3.05%
Value	[1]	$ 997,753
Principal Value	[1]	$ 1,000,000
Investment Interest Rate	[1]	0.625%
Investment Maturity Date	[1]	May 18, 2017
US Treasury Bill Securities [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity		94.57%	[1]	94.63%	[3]
Value		$ 30,970,236	[1]	$ 36,495,207	[3]
Investments, cost		$ 30,971,297	[1]	$ 36,491,937	[3]
Money Market Mutual Fund [Member] | Premier U.S. Government Money Portfolio - Institutional Class, 0.41% [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity	[4]	4.59%
Affiliated investments, at value and cost	[4]	$ 1,502,575
Shares	[4]	1,502,575
Investment Interest Rate	[4]	0.41%
Investments, cost	[4]	$ 1,502,575
U.S. Treasury Bills, 0.205% due January 14, 2016 [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity	[3]			9.07%
Value	[3]			$ 3,499,902
Principal Value	[3]			$ 3,500,000
Investment Interest Rate	[3]			0.205%
Investment Maturity Date	[3]			Jan. 14, 2016
U.S. Treasury Bills, 0.170% due January 28, 2016 [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity	[3]			19.45%
Value	[3]			$ 7,499,385
Principal Value	[3]			$ 7,500,000
Investment Interest Rate	[3]			0.17%
Investment Maturity Date	[3]			Jan. 28, 2016
U.S. Treasury Bills, 0.135% due February 11, 2016 [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity	[3]			20.74%
Value	[3]			$ 7,998,944
Principal Value	[3]			$ 8,000,000
Investment Interest Rate	[3]			0.135%
Investment Maturity Date	[3]			Feb. 11, 2016
U.S. Treasury Bills, 0.145% due February 18, 2016 [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity	[3]			11.67%
Value	[3]			$ 4,499,406
Principal Value	[3]			$ 4,500,000
Investment Interest Rate	[3]			0.145%
Investment Maturity Date	[3]			Feb. 18, 2016
U.S. Treasury Bills, 0.215% due March 3, 2016 [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity	[3]			12.96%
Value	[3]			$ 4,999,210
Principal Value	[3]			$ 5,000,000
Investment Interest Rate	[3]			0.215%
Investment Maturity Date	[3]			Mar. 03, 2016
U.S. Treasury Bills, 0.280% due March 10, 2016 [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity	[3],[5]			20.74%
Value	[3],[5]			$ 7,998,360
Principal Value	[3],[5]			$ 8,000,000
Investment Interest Rate	[3],[5]			0.28%
Investment Maturity Date	[3],[5]			Mar. 10, 2016
Restricted for maintenance margin				$ 1,999,597

[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 $4,293,980 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 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 December 31, 2016.

[5] United States Treasury Obligations of $1,999,597 are on deposit with the Commodity Broker and held as maintenance margin for open futures contracts.