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FINANCIAL INSTRUMENTS - Swap Contracts (Details) R$ in Thousands, $ in Millions | 12 Months Ended |  |
--- | --- | --- | ---
Dec. 31, 2017 USD ($) | Dec. 31, 2016 USD ($) | Dec. 31, 2017 BRL (R$) | Dec. 31, 2016 BRL (R$)
Swap Contracts |  |  |  |
Notional value |  |  | R$ 16,207,120 | R$ 20,049,854
Financial assets at fair value |  |  |  |
Swap Contracts |  |  |  |
Amount receivable |  |  |  | 12,951
Amount payable |  |  | R$ (1,267) | (6,584)
Forward contract | Forward contracts Maturity at 2017, purchase |  |  |  |
Swap Contracts |  |  |  |
Notional value | $ |  | $ 84.8 |  |
Amount receivable |  |  |  | 734
Amount payable |  |  |  | (6,584)
Forward contract | Forward contracts Maturity at 2017, sell |  |  |  |
Swap Contracts |  |  |  |
Notional value | $ |  | $ 15.0 |  |
Amount receivable |  |  |  | R$ 1,823
Cross currency swap | Currency Swap Maturing In 2017, receivable | LIBOR |  |  |  |
Swap Contracts |  |  |  |
Interest Rate Basis |  | Libor 6M |  |
Derivative basis spread |  | 2.25% |  | 2.25%
Amount receivable |  |  |  | R$ 5,684
Cross currency swap | Currency Swap Maturing In 2017, payable |  |  |  |
Swap Contracts |  |  |  |
Fixed interest rate (as a percent) |  | 11.02% |  | 11.02%
Notional value | $ |  | $ 25.0 |  |
Cross currency swap | Currency Swap Maturing In 2018, receivable | LIBOR |  |  |  |
Swap Contracts |  |  |  |
Interest Rate Basis | Libor 6M | Libor 6M |  |
Derivative basis spread | 2.00% | 2.00% | 2.00% | 2.00%
Amount receivable |  |  |  | R$ 4,710
Amount payable |  |  | R$ (1,267) |
Cross currency swap | Currency Swap Maturing In 2018, payable |  |  |  |
Swap Contracts |  |  |  |
Fixed interest rate (as a percent) | 10.17% | 10.17% | 10.17% | 10.17%
Notional value | $ | $ 40.0 | $ 40.0 |  |

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