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CONTRACTS AND AGREEMENTS (Brokerage Commissions) (Details) - USD ($) | 3 Months Ended
--- | ---
Mar. 31, 2019 | Mar. 31, 2018
Long Duration Contracts Assumptions By Product And Guarantee [Line Items] |  |  |
Brokerage commissions | $ 1,872 | $ 574 |
Brokerage commissions as a percentage of average daily net assets | 0.01% | 0.00% | [1]
Rebalancing Investments Transaction [Member] |  |  |
Long Duration Contracts Assumptions By Product And Guarantee [Line Items] |  |  |
Brokerage commissions | $ 1,823 | $ 34 |
Brokerage commissions as a percentage of average daily net assets | 97.38% | 5.92% |
Trades Necessitated By Creation And Redemption Activity [Member] |  |  |
Long Duration Contracts Assumptions By Product And Guarantee [Line Items] |  |  |
Brokerage commissions | $ 49 | $ 540 |
Brokerage commissions as a percentage of average daily net assets | 2.62% | 94.08% |
[1] | Represents less than 0.005%.

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