Summary of Significant Accounting Policies (Tables)

6 Months Ended

Jun. 30, 2016

Accounting Policies [Abstract]

Summary of the Tiered Valuation Input Levels

The following is a summary of the tiered valuation input levels as of June 30, 2016:

	Level 1		Level 2		Level 3		Total
United States Treasury Obligations	$	—	$	2,384,228,085	$	—	$	2,384,228,085
Commodity Futures Contracts (a)	$	219,699,793	$	—	$	—	$	219,699,793

(a) Unrealized appreciation (depreciation).

The following is a summary of the tiered valuation input levels as of December 31, 2015:

	Level 1			Level 2		Level 3		Total
United States Treasury Obligations	$	—		$	1,936,908,405	$	—	$	1,936,908,405
Commodity Futures Contracts (a)	$	(351,279,993	)	$	—	$	—	$	(351,279,993	)

(a) Unrealized appreciation (depreciation).

Fair Value of Derivative Instruments and Effect of Derivative Instruments on Statements of Income and Expenses

The Fair Value of Derivative Instruments is as follows:

	June 30, 2016					December 31, 2015
Risk Exposure/Derivative Type (a)	Assets		Liabilities			Assets		Liabilities
Commodity risk
Commodity Futures Contracts	$	260,815,126	$	(41,115,333	)	$	21,760,386	$	(373,040,379	)

(a) Includes cumulative appreciation (depreciation) of commodity futures contracts. Only current day’s variation margin receivable (payable) is reported in the June 30, 2016 and December 31, 2015 Statements of Financial Condition for non-LME commodity futures contracts.

The Effect of Derivative Instruments on the Statements of Income and Expenses is as follows:

		For the Three Months  Ended
	Location of Gain or (Loss) on Derivatives	June 30,
Risk Exposure/Derivative Type	Recognized in Income	2016			2015
Commodity risk
Commodity Futures Contracts	Net Realized Gain (Loss)	$	(66,087,932	)	$	(301,640,755	)
	Net Change in Unrealized Gain (Loss)		381,444,063			468,319,830
Total		$	315,356,131		$	166,679,075

		For the Six Months Ended
	Location of Gain or (Loss) on Derivatives	June 30,
Risk Exposure/Derivative Type	Recognized in Income	2016			2015
Commodity risk
Commodity Futures Contracts	Net Realized Gain (Loss)	$	(265,281,304	)	$	(727,075,762	)
	Net Change in Unrealized Gain (Loss)		570,979,786			647,818,126
Total		$	305,698,482		$	(79,257,636	)

Summary of Average Monthly Notional Value of Future Contracts Outstanding

The table below summarizes the average monthly notional value of futures contracts outstanding during the period:

	For the Three Months Ended				For the Six Months Ended
	June 30,				June 30,
	2016		2015		2016		2015
Average Notional Value	$	2,280,292,516	$	3,117,486,144	$	2,121,983,429	$	3,489,983,946

Summary of Gross and Net Amounts of Offsetting Assets and Liabilities

The following table presents derivative instruments that are either subject to an enforceable netting agreement or offset by collateral arrangements as of June 30, 2016, net by contract:

				GrossAmounts Offset in the			Net Amounts Presented in			Gross Amounts Not Offset in the Statement of Financial Condition
	Gross Amounts Recognized			Statement of Financial Condition			the Statement of Financial Condition			Financial Instruments (a)		Cash Collateral Pledged (a)		Net Amount
Assets
Commodity Futures Contracts	$	260,815,126		$	(222,604,813	)	$	38,210,313		$	—	$	—	$	38,210,313
Liabilities
Commodity Futures Contracts	$	(256,806,819	)	$	222,604,813		$	(34,202,006	)	$	34,202,006	$	—	$	—

The following table presents derivative instruments that are either subject to an enforceable netting agreement or offset by collateral arrangements as of December 31, 2015, net by contract:

				Gross Amounts Offset in the			Net Amounts Presented in			Gross Amounts Not Offset in the Statement of Financial Condition
	Gross Amounts Recognized			Statement of Financial Condition			the Statement of Financial Condition			Financial Instruments (a)		Cash Collateral Pledged (a)		Net Amount
Assets
Commodity Futures Contracts	$	355,260,235		$	(338,594,323	)	$	16,665,912		$	—	$	—	$	16,665,912
Liabilities
Commodity Futures Contracts	$	(373,040,379	)	$	338,594,323		$	(34,446,056	)	$	34,446,056	$	—	$	—

(a) As of June 30, 2016 and December 31, 2015, a portion of the Fund’s U.S. Treasury Obligations were required to be deposited as maintenance margin in support of the Fund’s futures positions.