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Loans, Financings and Debentures - Transferred to Intangible Assets the Costs of Loans and Financings Linked to Working in Progress (Detail) - BRL (R$) R$ in Millions | 12 Months Ended
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Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
Disclosure of detailed information about borrowings [abstract] |  |  |
Costs of loans and financings | R$ 1,604 | R$ 2,070 | R$ 1,545
Financing costs on Intangible assets | (71) | (142) | (159)
Net effect in Profit or loss | R$ 1,533 | R$ 1,928 | R$ 1,386

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