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CONTRACTS AND AGREEMENTS - Brokerage Commissions (Details) - USD ($) | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2019 | Sep. 30, 2018 | Sep. 30, 2019 | Sep. 30, 2018
Long Duration Contracts Assumptions By Product And Guarantee [Line Items] |  |  |  |
Brokerage commissions | $ 1,627 | $ 2,282 | $ 5,484 | $ 5,501
Brokerage commissions as a percentage of average daily net assets | 0.01% | 0.01% | 0.01% | 0.01%
Rebalancing Investments Transaction [Member] |  |  |  |
Long Duration Contracts Assumptions By Product And Guarantee [Line Items] |  |  |  |
Brokerage commissions |  |  | $ 5,021 | $ 4,520
Brokerage commissions as a percentage of average daily net assets | 91.56% | 82.17% | 91.56% | 82.17%
Trades Necessitated By Creation And Redemption Activity [Member] |  |  |  |
Long Duration Contracts Assumptions By Product And Guarantee [Line Items] |  |  |  |
Brokerage commissions |  |  | $ 463 | $ 981
Brokerage commissions as a percentage of average daily net assets | 8.44% | 17.83% | 8.44% | 17.83%

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