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24. Equity (Details) - shares | 12 Months Ended
--- | ---
Dec. 31, 2018 | Dec. 31, 2017
SummaryOfEquityLineItems [Line Items] |  |  |
Number of shares |  | 683,509,869 | 683,509,869
Percentage of shares |  | 1.0000 | 1.0000
State Department of Finance |  |  |
SummaryOfEquityLineItems [Line Items] |  |  |
Number of shares |  | 343,524,285 | 343,524,285
Percentage of shares |  | .5026 | 0.5026
Companhia Brasileira de Liquidacao e Custodia |  |  |
SummaryOfEquityLineItems [Line Items] |  |  |
Number of shares | [1] | 212,612,143 | 201,026,895
Percentage of shares | [1] | .3110 | 0.2941
The Bank of New York ADR Department |  |  |
SummaryOfEquityLineItems [Line Items] |  |  |
Number of shares | [1],[2] | 125,278,967 | 136,790,413
Percentage of shares | [1],[2] | .1833 | 0.2001
Other |  |  |
SummaryOfEquityLineItems [Line Items] |  |  |
Number of shares |  | 2,094,474 | 2,168,276
Percentage of shares |  | .0031 | 0.0032
[1] | Each ADR corresponds to 1 share.
[2] | Custodians

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