Schedule of Investments (Unaudited) - Treasury Bills and Money Market Fund - USD ($)		9 Months Ended	12 Months Ended
		Sep. 30, 2016	Dec. 31, 2015
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity		96.98%
Value		$ 2,161,739,945	$ 1,936,908,405
Affiliated investments, at value and cost		113,526,403
Total Investments		2,275,266,348	1,936,908,405
Investments, cost		$ 2,274,982,617	$ 1,936,918,775
U.S. Treasury Bills, 0.250% due October 6, 2016 [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity	[1]	22.21%
Value	[1]	$ 520,996,353
Principal Value	[1]	$ 521,000,000
Investment Interest Rate		0.25%
Investment Maturity Date		Oct. 06, 2016
U.S. Treasury Bills, 0.180% due October 20, 2016 [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity	[1]	19.09%
Value	[1]	$ 447,974,016
Principal Value	[1]	$ 448,000,000
Investment Interest Rate		0.18%
Investment Maturity Date		Oct. 20, 2016
U.S. Treasury Bills, 0.160% due October 27, 2016 [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity	[1],[2]	17.81%
Value	[1],[2]	$ 417,949,004
Principal Value	[1],[2]	$ 418,000,000
Investment Interest Rate	[2]	0.16%
Investment Maturity Date	[2]	Oct. 27, 2016
Restricted for maintenance margin		$ 264,947,000
U.S. Treasury Bills, 0.300% due November 17, 2016 [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity	[1]	15.17%
Value	[1]	$ 355,929,512
Principal Value	[1]	$ 356,000,000
Investment Interest Rate		0.30%
Investment Maturity Date		Nov. 17, 2016
U.S. Treasury Bills, 0.335% due December 1, 2016 [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity	[1]	17.86%
Value	[1]	$ 418,891,060
Principal Value	[1]	$ 419,000,000
Investment Interest Rate		0.335%
Investment Maturity Date		Dec. 01, 2016
US Treasury Bill Securities [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity	[1]	92.14%	97.47%
Value	[1]	$ 2,161,739,945	$ 1,936,908,405
Investments, cost		$ 2,161,456,214	$ 1,936,918,775	[3]
Money Market Mutual Fund [Member] | Premier Portfolio - Institutional Class [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity	[4]	4.84%
Affiliated investments, at value and cost	[4]	$ 113,526,403
Shares	[4]	113,526,403
Investment Interest Rate		0.34%
Investments, cost		$ 113,526,403
U.S. Treasury Bills, 0.235% due January 7, 2016 [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity	[1]		15.60%
Value	[1]		$ 309,998,760
Principal Value	[1]		$ 310,000,000
Investment Interest Rate	[3]		0.235%
Investment Maturity Date	[3]		Jan. 07, 2016
U.S. Treasury Bills, 0.205% due January 14, 2016 [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity	[1]		23.37%
Value	[1]		$ 464,486,994
Principal Value	[1]		$ 464,500,000
Investment Interest Rate	[3]		0.205%
Investment Maturity Date	[3]		Jan. 14, 2016
U.S. Treasury Bills, 0.195% due January 21, 2016 [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity	[1],[5]		25.16%
Value	[1],[5]		$ 499,979,500
Principal Value	[1],[5]		$ 500,000,000
Investment Interest Rate	[3],[5]		0.195%
Investment Maturity Date	[3],[5]		Jan. 21, 2016
Restricted for maintenance margin	[3]		$ 399,960,000
U.S. Treasury Bills, 0.170% due January 28, 2016 [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity	[1]		19.60%
Value	[1]		$ 389,468,061
Principal Value	[1]		$ 389,500,000
Investment Interest Rate	[3]		0.17%
Investment Maturity Date	[3]		Jan. 28, 2016
U.S. Treasury Bills, 0.200% due February 4, 2016 [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity	[1]		5.44%
Value	[1]		$ 107,991,576
Principal Value	[1]		$ 108,000,000
Investment Interest Rate	[3]		0.20%
Investment Maturity Date	[3]		Feb. 04, 2016
U.S. Treasury Bills, 0.135% due February 11, 2016 [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity	[1]		0.15%
Value	[1]		$ 2,999,604
Principal Value	[1]		$ 3,000,000
Investment Interest Rate	[3]		0.135%
Investment Maturity Date	[3]		Feb. 11, 2016
U.S. Treasury Bills, 0.140% due February 25, 2016 [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity	[1]		8.05%
Value	[1]		$ 159,984,320
Principal Value	[1]		$ 160,000,000
Investment Interest Rate	[3]		0.14%
Investment Maturity Date	[3]		Feb. 25, 2016
U.S. Treasury Bills, 0.280% due March 10, 2016 [Member]
Schedule of Investments [Line Items]
Percentage of Shareholders' Equity	[1]		0.10%
Value	[1]		$ 1,999,590
Principal Value	[1]		$ 2,000,000
Investment Interest Rate	[3]		0.28%
Investment Maturity Date	[3]		Mar. 10, 2016

[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 $264,947,000 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 September 30, 2016.

[5] United States Treasury Obligations of $399,960,000 are on deposit with the Commodity Broker and held as maintenance margin for open futures contracts.