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LOANS AND FINANCING - By Currency (Details) - BRL (R$) R$ in Thousands | Dec. 31, 2017 | Dec. 31, 2016
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LOANS AND FINANCING |  |
Total Loans and Financing | R$ 16,461,656 | R$ 20,417,810
Brazilian Real (BRL) |  |
LOANS AND FINANCING |  |
Total Loans and Financing | 2,710,308 | 3,228,759
U.S. Dollar (USD) |  |
LOANS AND FINANCING |  |
Total Loans and Financing | 13,333,669 | 16,487,116
Other currencies |  |
LOANS AND FINANCING |  |
Total Loans and Financing | R$ 417,679 | R$ 701,935

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