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CONTRACTS AND AGREEMENTS (Brokerage Commissions) (Details) - USD ($) | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2018 | Jun. 30, 2017 | Jun. 30, 2018 | Jun. 30, 2017
Long Duration Contracts Assumptions By Product And Guarantee [Line Items] |  |  |  |
Brokerage commissions | $ 2,645 | $ 4,709 | $ 3,219 | $ 8,841
Brokerage commissions as a percentage of average daily net assets | 0.01% | 0.02% | 0.01% | 0.02%
Rebalancing Investments Transaction [Member] |  |  |  |
Long Duration Contracts Assumptions By Product And Guarantee [Line Items] |  |  |  |
Brokerage commissions |  |  | $ 2,439 | $ 7,074
Brokerage commissions as a percentage of average daily net assets | 75.77% | 80.01% | 75.77% | 80.01%
Trades Necessitated By Creation And Redemption Activity [Member] |  |  |  |
Long Duration Contracts Assumptions By Product And Guarantee [Line Items] |  |  |  |
Brokerage commissions |  |  | $ 780 | $ 1,767
Brokerage commissions as a percentage of average daily net assets | 24.23% | 19.99% | 24.23% | 19.99%

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