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Summary of Significant Accounting Policies (Additional Information) (Details) |  |  | 12 Months Ended
--- | --- | --- | ---
Dec. 31, 2013 | Feb. 29, 2012 Creation Baskets | Feb. 29, 2012 Redemption Baskets | Dec. 31, 2013 Maximum
Significant Accounting Policies [Line Items] |  |  |  |
Minimum likelihood of tax benefits being recognized upon ultimate settlement | 50.00% |  |  |
Cash equivalents maturity period |  |  |  | 6 months
Number of Shares per basket |  | 50,000 | 100,000 |

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- Details
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