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EMPLOYEE BENEFITS - Defined benefit pension plan - Reconciliation of plan assets and liabilities (Details) - Defined benefit pension plan - BRL (R$) R$ in Thousands | Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
--- | --- | --- | --- | ---
Reconciliations of assets and liabilities of the plans |  |  |  |
Net | R$ (1,057,849) | R$ (1,084,758) |  |
Defined benefit obligation | (1,057,849) | (1,084,758) |  |
Present value of the defined benefit obligations |  |  |  |
Reconciliations of assets and liabilities of the plans |  |  |  |
Net | (4,391,251) | (4,314,592) | R$ (4,174,653) | R$ (4,739,299)
Plan assets |  |  |  |
Reconciliations of assets and liabilities of the plans |  |  |  |
Net | 3,568,934 | 3,456,613 | R$ 3,292,890 | R$ 3,865,411
Asset ceiling restrictions on recognition of net funded assets |  |  |  |
Reconciliations of assets and liabilities of the plans |  |  |  |
Net | R$ (235,532) | R$ (226,779) |  |

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