Statements of Cash Flows - USD ($)		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash flows from operating activities:
Net Income (Loss)		$ 365,971,348	$ (873,880,684)	$ (1,604,013,483)
Adjustments to reconcile net income (loss) to net cash provided by (used for) operating activities:
Cost of securities purchased		(8,367,614,637)	(10,667,467,852)	(21,215,312,035)
Proceeds from securities sold and matured		7,906,957,513	12,810,168,648	22,688,974,945
Net sales (purchases) of affiliated investments		(131,029,805)
Net accretion of discount on United States Treasury Obligations		(6,308,729)	(715,663)	(1,860,082)
Net realized (gain) loss on United States Treasury Obligations		(19,938)	(14,586)	(39,941)
Net change in unrealized (gain) loss on United States Treasury Obligations and Commodity Futures Contracts		(50,991,385)	(423,824,269)	812,506,620
Cash transfer to Commodity Broker to satisfy variation margin requirements (Note 4)			(584,258,422)
Cash received (paid) to Commodity Broker to satisfy open variation margin, net (Note 4)			267,424,485
Change in operating receivables and liabilities:
Dividends from affiliates		(42,071)
Variation margin		16,211,441	(16,665,912)
LME contracts		(24,721,084)	12,568,839	(466,044)
Management fee		239,375	(1,508,466)	(1,241,158)
Brokerage commissions and fees		14	425	3,110
Net cash provided by (used for) operating activities		(291,347,958)	521,826,543	678,551,932
Cash flows from financing activities:
Proceeds from purchases of Shares		852,904,825	316,102,530	1,121,198,095
Redemption of Shares		(648,634,646)	(1,491,423,279)	(1,177,235,663)
Net cash provided by (used for) financing activities		204,270,179	(1,175,320,749)	(56,037,568)
Net change in cash		(87,077,779)	(653,494,206)	622,514,364
Cash at beginning of period	[1],[2]	92,092,936	745,587,142	123,072,778
Cash at end of period	[1],[2]	5,015,157	92,092,936	745,587,142
Supplemental disclosure of cash flow information
Cash paid for interest		$ 141,261	$ 277,439	$ 19,365

[1] Cash at December 31, 2014 and prior reflects cash held by Predecessor Commodity Broker

[2] Cash at December 31, 2016 and 2015 reflects cash held by the Custodian.