Schedule of Investments (Unaudited) - Treasury Bills (Parenthetical) - USD ($)		3 Months Ended		12 Months Ended
		Mar. 31, 2016		Dec. 31, 2015
U.S. Treasury Bills, 0.275% due April 7, 2016 [Member]
Schedule of Investments [Line Items]
Investment Interest Rate		0.275%
Investment Maturity Date		Apr. 07, 2016
U.S. Treasury Bills, 0.270% due April 21, 2016 [Member]
Schedule of Investments [Line Items]
Investment Interest Rate		0.27%
Investment Maturity Date		Apr. 21, 2016
U.S. Treasury Bills, 0.200% due April 28, 2016 [Member]
Schedule of Investments [Line Items]
Investment Interest Rate		0.20%
Investment Maturity Date		Apr. 28, 2016
U.S. Treasury Bills, 0.325% due June 2, 2016 [Member]
Schedule of Investments [Line Items]
Investment Interest Rate	[1]	0.325%
Investment Maturity Date	[1]	Jun. 02, 2016
U.S. Treasury Bills, 0.235% due July 7, 2016 [Member]
Schedule of Investments [Line Items]
Investment Interest Rate		0.235%
Investment Maturity Date		Jul. 07, 2016
United States Treasury Obligations [Member]
Schedule of Investments [Line Items]
United States Treasury Obligations, cost		$ 768,709,369	[2]	$ 1,077,885,299	[3],[4]
U.S. Treasury Bills, 0.235% due January 7, 2016 [Member]
Schedule of Investments [Line Items]
Investment Interest Rate				0.235%
Investment Maturity Date				Jan. 07, 2016
U.S. Treasury Bills, 0.205% due January 14, 2016 [Member]
Schedule of Investments [Line Items]
Investment Interest Rate				0.205%
Investment Maturity Date				Jan. 14, 2016
U.S. Treasury Bills, 0.195% due January 21, 2016 [Member]
Schedule of Investments [Line Items]
Investment Interest Rate				0.195%
Investment Maturity Date				Jan. 21, 2016
U.S. Treasury Bills, 0.170% due January 28, 2016 [Member]
Schedule of Investments [Line Items]
Investment Interest Rate				0.17%
Investment Maturity Date				Jan. 28, 2016
U.S. Treasury Bills, 0.200% due February 4, 2016 [Member]
Schedule of Investments [Line Items]
Investment Interest Rate				0.20%
Investment Maturity Date				Feb. 04, 2016
U.S. Treasury Bills, 0.135% due February 11, 2016 [Member]
Schedule of Investments [Line Items]
Investment Interest Rate				0.135%
Investment Maturity Date				Feb. 11, 2016
U.S. Treasury Bills, 0.145% due February 18, 2016 [Member]
Schedule of Investments [Line Items]
Investment Interest Rate				0.145%
Investment Maturity Date				Feb. 18, 2016
U.S. Treasury Bills, 0.140% due February 25, 2016 [Member]
Schedule of Investments [Line Items]
Investment Interest Rate				0.14%
Investment Maturity Date				Feb. 25, 2016
U.S. Treasury Bills, 0.215% due March 3, 2016 [Member]
Schedule of Investments [Line Items]
Investment Interest Rate				0.215%
Investment Maturity Date				Mar. 03, 2016
U.S. Treasury Bills, 0.280% due March 10, 2016 [Member]
Schedule of Investments [Line Items]
Investment Interest Rate				0.28%
Investment Maturity Date				Mar. 10, 2016

[1] All or a portion of United States Treasury Obligations 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] A portion of United States Treasury Obligations are on deposit with the Commodity Broker and held as maintenance margin for open futures contracts.

[4] 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.