Net Asset Value and Financial Highlights (Tables)

6 Months Ended

Jun. 30, 2014

Earnings Per Share [Abstract]

Schedule of Net Asset Value Per Share

Net asset value per Share is the net asset value of the Fund divided by the number of outstanding Shares at the date of each respective period presented.

	Three Months Ended						Six Months Ended
	June 30, 2014			June 30, 2013			June 30, 2014			June 30, 2013
Net Asset Value
Net asset value per Share, beginning of period	$	29.27		$	29.13		$	29.16		$	27.99
Net realized and change in unrealized gain (loss) on United States Treasury Obligations and Futures		1.51			(1.86	)		1.67			(0.67	)
Net investment income (loss)		(0.06	)		(0.05	)		(0.11	)		(0.10	)
Net income (loss)		1.45			(1.91	)		1.56			(0.77	)
Net asset value per Share, end of period	$	30.72		$	27.22		$	30.72		$	27.22
Market value per Share, beginning of period	$	29.27		$	29.11		$	29.15		$	27.94
Market value per Share, end of period	$	30.75		$	27.17		$	30.75		$	27.17
Ratio to average Net Assets*
Net investment income (loss)		(0.74	)%		(0.73	)%		(0.73	)%		(0.72	)%
Total expenses		0.78	%		0.79	%		0.77	%		0.79	%
Total Return, at net asset value **		4.95	%		(6.56	)%		5.35	%		(2.75	)%
Total Return, at market value **		5.06	%		(6.66	)%		5.49	%		(2.76	)%

* Percentages are annualized.

** Percentages are not annualized.