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FINANCIAL HIGHLIGHTS (Per Unit Performance Data and Other Supplemental Financial Data) (Details) (USD $) | 9 Months Ended |
--- | --- | ---
Sep. 30, 2013 | Sep. 30, 2012 | Nov. 18, 2009
Per Unit Operating Performance: |  |  |  |  |
Net asset value, beginning of period | $ 17.23 |  | $ 21.21 |  | $ 50.00
Total loss | $ (0.19) |  | $ (2.40) |  |
Total expenses | $ (0.13) |  | $ (0.13) |  |
Net decrease in net asset value | $ (0.32) |  | $ (2.53) |  |
Net asset value, end of period | $ 16.91 |  | $ 18.68 |  | $ 50.00
Total Return | (1.86%) |  | (11.93%) |  |
Ratios to Average Net Assets |  |  |  |  |
Total income (loss) | 5.56% |  | (2.93%) |  |
Management fees | 0.75% | [1] | 0.75% | [1] |
Total expenses excluding management fees | 0.45% | [1] | 0.39% | [1] |
Expenses waived | (0.24%) | [1] | (0.16%) | [1] |
Net expenses excluding management fees | 0.21% | [1] | 0.23% | [1] |
Net income (loss) | 4.84% |  | (3.66%) |  |
[1] | Annualized

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