Statements of Financial Condition - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Assets
United States Treasury Obligations, at value (cost $405,208,278 and $514,764,046, respectively)	$ 405,215,093	$ 514,714,860
Affiliated Investments, at value (cost $94,692,742 and $124,826,575, respectively)	94,741,922	124,748,306
Other investments:
Variation margin receivable- Commodity Futures Contracts		442,552
Cash held by custodian	0	2,260,923
Receivable for:
Dividends from affiliates	44,281	33,612
Total assets	500,001,296	642,200,253
Other investments:
Variation margin payable- Commodity Futures Contracts	1,623,523
Payable for:
Due to custodian	3,213,714
Management fees	379,135	444,415
Brokerage commissions and fees	3,263	4,091
Total liabilities	5,219,635	448,506
Commitments and Contingencies (Note 10)
Equity
Shareholder's equity—General Shares	678	750
Shareholders' equity—Shares	494,780,983	641,750,997
Total shareholders' equity	494,781,661	641,751,747
Total liabilities and equity	$ 500,001,296	$ 642,200,253
General Shares outstanding	40	40
Shares outstanding	29,200,000	34,200,000
Net asset value per share	$ 16.94	$ 18.76
Market value per share	$ 16.95	$ 18.75