Statements of Changes in Shareholders' Equity (Deficit) (USD $) In Thousands, unless otherwise specified	6 Months Ended	12 Months Ended
	Jun. 30, 2013	Dec. 31, 2012
Shareholders' equity (deficit) - beginning of period	$ (2,332,728)	$ (1,846,637)
Net income (loss)	(700,273)	136,332
Adjustment of redeemable capital Shares to redemption value	3,033,001	(622,423)
Shareholders' equity (deficit) - end of period		$ (2,332,728)