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15. CONCESSION CONTRACT ASSETS (Details) - BRL (R$) R$ in Thousands | Dec. 31, 2020 | Dec. 31, 2019 | Jan. 02, 2019 | [1] | Dec. 31, 2018
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Disclosure of assets recognised from costs to obtain or fulfil contracts with customers [line items] |  |  |  |  |
Contract assets | R$ 4,980,000 |  |  |  |
Current | 737,000 |  |  |  |
Non current | 4,243,000 |  |  |  |
Restated [member] |  |  |  |  |
Disclosure of assets recognised from costs to obtain or fulfil contracts with customers [line items] |  |  |  |  |
Contract assets |  | R$ 3,884,000 |  |  | R$ 3,509,000
Current |  | 576,000 | [1] | R$ 482,000 | 482,000
Non current |  | 3,307,000 | [1] | R$ 3,026,000 | 3,026,000
Distribution - infrastructure assets under construction [member] |  |  |  |  |
Disclosure of assets recognised from costs to obtain or fulfil contracts with customers [line items] |  |  |  |  |
Contract assets | 1,142,000 |  |  |  |
Distribution - infrastructure assets under construction [member] | Restated [member] |  |  |  |  |
Disclosure of assets recognised from costs to obtain or fulfil contracts with customers [line items] |  |  |  |  |
Contract assets |  | 740,000 |  |  | 518,000
Gas - infrastructure assets under construction [member] |  |  |  |  |
Disclosure of assets recognised from costs to obtain or fulfil contracts with customers [line items] |  |  |  |  |
Contract assets | 94,000 |  |  |  |
Gas - infrastructure assets under construction [member] | Restated [member] |  |  |  |  |
Disclosure of assets recognised from costs to obtain or fulfil contracts with customers [line items] |  |  |  |  |
Contract assets |  | 68,000 |  |  | 81,000
Transmission - assets rrincorporated into the assets remuneration base [member] |  |  |  |  |
Disclosure of assets recognised from costs to obtain or fulfil contracts with customers [line items] |  |  |  |  |
Contract assets | 1,896,000 |  |  |  |
Transmission - assets rrincorporated into the assets remuneration base [member] | Restated [member] |  |  |  |  |
Disclosure of assets recognised from costs to obtain or fulfil contracts with customers [line items] |  |  |  |  |
Contract assets |  | 1,928,000 |  |  | 2,272,000
Transmission - assets remunerated by tariff [member] |  |  |  |  |
Disclosure of assets recognised from costs to obtain or fulfil contracts with customers [line items] |  |  |  |  |
Contract assets | R$ 1,848,000 |  |  |  |
Transmission - assets remunerated by tariff [member] | Restated [member] |  |  |  |  |
Disclosure of assets recognised from costs to obtain or fulfil contracts with customers [line items] |  |  |  |  |
Contract assets |  | R$ 1,147,000 |  |  | R$ 637,000
[1] | For further details of restatement of comparative balances, see Note 2.8

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- Definition The amount of an entity’s right to consideration in exchange for goods or services that the entity has transferred to a customer, when that right is conditioned on something other than the passage of time (for example, the entity’s future performance). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 15 -IssueDate 2020-01-01 -Paragraph 105 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=15&code=ifrs-tx-2020-en-r&anchor=para_105&doctype=Standard -URIDate 2020-01-01 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 15 -IssueDate 2020-01-01 -Paragraph 116 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=15&code=ifrs-tx-2020-en-r&anchor=para_116_a&doctype=Standard -URIDate 2020-01-01 + Details
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- Definition The amount of current contract assets. [Refer: Contract assets] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 15 -IssueDate 2020-01-01 -Paragraph 105 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=15&code=ifrs-tx-2020-en-r&anchor=para_105&doctype=Standard -URIDate 2020-01-01 + Details
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- Definition The amount of non-current contract assets. [Refer: Contract assets] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 15 -IssueDate 2020-01-01 -Paragraph 105 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=15&code=ifrs-tx-2020-en-r&anchor=para_105&doctype=Standard -URIDate 2020-01-01 + Details
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