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Financial Highlights (Per Unit Performance Data and Other Supplemental Financial Data) (Parenthetical) (Details)
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12 Months Ended | 0 Months Ended | 12 Months Ended | 0 Months Ended | 12 Months Ended | 0 Months Ended | ||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
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Dec. 31, 2013
United States Copper Index Fund [Member]
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Dec. 31, 2012
United States Copper Index Fund [Member]
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Dec. 31, 2011
United States Copper Index Fund [Member]
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May 29, 2012
United States Copper Index Fund [Member]
Maximum [Member]
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May 29, 2012
United States Copper Index Fund [Member]
Minimum [Member]
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Dec. 31, 2013
United States Agriculture Index Fund [Member]
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Dec. 31, 2012
United States Agriculture Index Fund [Member]
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Dec. 31, 2011
United States Agriculture Index Fund [Member]
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May 29, 2012
United States Agriculture Index Fund [Member]
Maximum [Member]
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May 29, 2012
United States Agriculture Index Fund [Member]
Minimum [Member]
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Dec. 31, 2013
United States Metals Index Fund [Member]
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Dec. 31, 2012
United States Metals Index Fund [Member]
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Dec. 31, 2011
United States Metals Index Fund [Member]
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May 30, 2012
United States Metals Index Fund [Member]
Maximum [Member]
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May 30, 2012
United States Metals Index Fund [Member]
Minimum [Member]
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| Average Sales Price and Production Costs Per Unit of Production [Line Items] | ||||||||||||||||||||||||||||||
| Percentage of average daily net assets paid monthly, waiver expense | 3.56% | 3.78% | 3.95% | [1],[2] | 0.95% | 0.65% | 3.42% | [1] | 3.63% | [1],[3] | 0.00% | [1] | 0.95% | 0.80% | 3.26% | [1] | 3.88% | [1],[4] | 0.00% | [1] | 0.95% | 0.70% | ||||||||
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