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33. FINANCIAL INSTRUMENTS AND RISK MANAGEMENT (Details) - BRL (R$) R$ in Millions | Dec. 31, 2019 | Dec. 31, 2018
--- | --- | ---
Disclosure of detailed information about financial instruments [line items] |  |  |
Financial assets at fair value | R$ 16,098 |  | R$ 16,183
Financial liabilities | 18,764 |  | (18,120)
Financial liabilities at fair value | (18,764) | [1] | (18,120)
Financial liabilities at amortised cost, class [Member] |  |  |
Disclosure of detailed information about financial instruments [line items] |  |  |
Financial liabilities | (18,281) |  | (17,701)
Financial liabilities at fair value | (18,281) |  | (17,701)
Financial liabilities at fair value through profit or loss, category [member] |  |  |
Disclosure of detailed information about financial instruments [line items] |  |  |
Financial liabilities | (483) |  | (419)
Financial liabilities at fair value | (483) |  | (419)
Suppliers [Member] | Level 2 of fair value hierarchy [Member] | Financial liabilities at amortised cost, class [Member] |  |  |
Disclosure of detailed information about financial instruments [line items] |  |  |
Financial liabilities | (2,080) |  | (1,801)
Financial liabilities at fair value | (2,080) |  | (1,801)
Debt Agreed With Pension Fund [Member] | Level 2 of fair value hierarchy [Member] | Financial liabilities at amortised cost, class [Member] |  |  |
Disclosure of detailed information about financial instruments [line items] |  |  |
Financial liabilities | (566) |  | (652)
Financial liabilities at fair value | (566) |  | (652)
Concessions Payable [Member] | Level 3 of fair value hierarchy [Member] | Financial liabilities at amortised cost, class [Member] |  |  |
Disclosure of detailed information about financial instruments [line items] |  |  |
Financial liabilities | (20) |  | (19)
Financial liabilities at fair value | (20) |  | (19)
Advances from clients [Member] | Level 2 of fair value hierarchy [Member] | Financial liabilities at amortised cost, class [Member] |  |  |
Disclosure of detailed information about financial instruments [line items] |  |  |
Financial liabilities |  |  | (79)
Financial liabilities at fair value |  |  | (79)
Solution for deficit of pension fund [Member] | Level 2 of fair value hierarchy [Member] | Financial liabilities at amortised cost, class [Member] |  |  |
Disclosure of detailed information about financial instruments [line items] |  |  |
Financial liabilities | (550) |  | (378)
Financial liabilities at fair value | (550) |  | (378)
Loans, financings and debentures [Member] | Level 2 of fair value hierarchy [Member] | Financial liabilities at amortised cost, class [Member] |  |  |
Disclosure of detailed information about financial instruments [line items] |  |  |
Financial liabilities | (14,777) |  | (14,772)
Financial liabilities at fair value | (14,777) |  | (14,772)
Derivative financial instrument liabilities, SAAG put options [Member] | Level 3 of fair value hierarchy [Member] | Financial liabilities at fair value through profit or loss, category [member] |  |  |
Disclosure of detailed information about financial instruments [line items] |  |  |
Financial liabilities | (483) |  | (419)
Financial liabilities at fair value | (483) |  | (419)
Leasing transactions [member] | Level 2 of fair value hierarchy [Member] | Financial liabilities at amortised cost, class [Member] |  |  |
Disclosure of detailed information about financial instruments [line items] |  |  |
Financial liabilities | (288) |  |
Financial liabilities at fair value | (288) |  |
Financial assets at amortised cost, class [Member] |  |  |
Disclosure of detailed information about financial instruments [line items] |  |  |
Financial assets | 12,128 |  | 12,675
Financial assets at fair value | 12,128 |  | 12,675
Financial assets at amortised cost, class [Member] | Securities cash investments one [Member] | Level 2 of fair value hierarchy [Member] |  |  |
Disclosure of detailed information about financial instruments [line items] |  |  |
Financial assets | 102 |  | 117
Financial assets at fair value | 102 |  | 117
Financial assets at amortised cost, class [Member] | Restricted cash [Member] | Level 2 of fair value hierarchy [Member] |  |  |
Disclosure of detailed information about financial instruments [line items] |  |  |
Financial assets | 12 |  | 91
Financial assets at fair value | 12 |  | 91
Financial assets at amortised cost, class [Member] | Accounts receivable from the State of Minas Gerais [Member] | Level 2 of fair value hierarchy [Member] |  |  |
Disclosure of detailed information about financial instruments [line items] |  |  |
Financial assets | 115 |  | 246
Financial assets at fair value | 115 |  | 246
Financial assets at amortised cost, class [Member] | Concession financial assets CVA Account and Other financial components in tariff adjustments [Member] | Level 3 of fair value hierarchy [Member] |  |  |
Disclosure of detailed information about financial instruments [line items] |  |  |
Financial assets | 882 |  | 1,081
Financial assets at fair value | 882 |  | 1,081
Financial assets at amortised cost, class [Member] | Reimbursement of tariff subsidy payments [Member] | Level 2 of fair value hierarchy [Member] |  |  |
Disclosure of detailed information about financial instruments [line items] |  |  |
Financial assets | 97 |  | 91
Financial assets at fair value | 97 |  | 91
Financial assets at amortised cost, class [Member] | Low income subsidy [Member] | Level 2 of fair value hierarchy [Member] |  |  |
Disclosure of detailed information about financial instruments [line items] |  |  |
Financial assets | 30 |  | 30
Financial assets at fair value | 30 |  | 30
Financial assets at amortised cost, class [Member] | Reimbursement for assignment of contract [Member] |  |  |
Disclosure of detailed information about financial instruments [line items] |  |  |
Financial assets |  |  | 10
Financial assets at fair value |  |  | 10
Financial assets at amortised cost, class [Member] | Accounts receivable - Renova [Member] | Level 2 of fair value hierarchy [Member] |  |  |
Disclosure of detailed information about financial instruments [line items] |  |  |
Financial assets |  |  | 532
Financial assets at fair value |  |  | 532
Financial assets at amortised cost, class [Member] | Indemnifiable receivable - Transmission [Member] |  |  |
Disclosure of detailed information about financial instruments [line items] |  |  |
Financial assets | 1,281 |  | 1,296
Financial assets at fair value | 1,281 |  | 1,296
Financial assets at amortised cost, class [Member] | Customers - Accounts receivable from the State of Minas Gerais [Member] |  |  |
Disclosure of detailed information about financial instruments [line items] |  |  |
Financial assets |  |  | 246
Financial assets at fair value |  |  | 246
Financial assets at amortised cost, class [Member] | Reimbursement for decontracted supply [Member] | Level 2 of fair value hierarchy [Member] |  |  |
Disclosure of detailed information about financial instruments [line items] |  |  |
Financial assets |  |  | 97
Financial assets at fair value |  |  | 97
Financial assets at amortised cost, class [Member] | Concession grant fee generation concessions [Member] | Level 3 of fair value hierarchy [Member] |  |  |
Disclosure of detailed information about financial instruments [line items] |  |  |
Financial assets | 2,468 |  | 2,409
Financial assets at fair value | 2,468 |  | 2,409
Financial assets at amortised cost, class [Member] | Escrow deposits [Member] | Level 2 of fair value hierarchy [Member] |  |  |
Disclosure of detailed information about financial instruments [line items] |  |  |
Financial assets | 2,540 |  | 2,502
Financial assets at fair value | 2,540 |  | 2,502
Financial assets at amortised cost, class [Member] | Accounts receivable from Customers and traders; Concession holders (transmission service) [Member] | Level 2 of fair value hierarchy [Member] |  |  |
Disclosure of detailed information about financial instruments [line items] |  |  |
Financial assets | 4,601 |  | 4,173
Financial assets at fair value | 4,601 |  | 4,173
Financial assets at amortised cost, class [Member] | Advances to suppliers [Member] | Level 2 of fair value hierarchy [Member] |  |  |
Disclosure of detailed information about financial instruments [line items] |  |  |
Financial assets |  |  | 94
Financial assets at fair value |  |  | 94
Derivative financial instruments [Member] |  |  |
Disclosure of detailed information about financial instruments [line items] |  |  |
Financial assets | 3,970 |  | 3,508
Financial assets at fair value | 3,970 |  | 3,508
Derivative financial instruments [Member] | Derivative financial instrument assets, Ativas and Sonda Put options [Member] | Level 3 of fair value hierarchy [Member] |  |  |
Disclosure of detailed information about financial instruments [line items] |  |  |
Financial assets | 3 |  | 4
Financial assets at fair value | 3 |  | 4
Derivative financial instruments [Member] | Derivative financial instrument assets, Swaps [Member] | Level 3 of fair value hierarchy [Member] |  |  |
Disclosure of detailed information about financial instruments [line items] |  |  |
Financial assets | 1,691 |  | 813
Financial assets at fair value | 1,691 |  | 813
Derivative financial instruments [Member] | Indemnifiable receivable from generation [Member] | Level 3 of fair value hierarchy [Member] |  |  |
Disclosure of detailed information about financial instruments [line items] |  |  |
Financial assets | 816 |  | 816
Financial assets at fair value | 816 |  | 816
Derivative financial instruments [Member] | Concession of distribution infrastructure [Member] | Level 3 of fair value hierarchy [Member] |  |  |
Disclosure of detailed information about financial instruments [line items] |  |  |
Financial assets | 483 |  | 396
Financial assets at fair value | 483 |  | 396
Financial assets at fair value through profit or loss, category [Member] |  |  |
Disclosure of detailed information about financial instruments [line items] |  |  |
Financial assets | 977 |  | 1,479
Financial assets at fair value | 977 |  | 1,479
Financial assets at fair value through profit or loss, category [Member] | Cash equivalents investments [Member] |  |  |
Disclosure of detailed information about financial instruments [line items] |  |  |
Financial assets | 326 |  | 783
Financial assets at fair value | 326 |  | 783
Financial assets at fair value through profit or loss, category [Member] | Debentures [Member] | Level 2 of fair value hierarchy [Member] |  |  |
Disclosure of detailed information about financial instruments [line items] |  |  |
Financial assets |  |  | 7
Financial assets at fair value |  |  | 7
Financial assets at fair value through profit or loss, category [Member] | Treasury Financial Notes [Member] | Level 1 of fair value hierarchy [member] |  |  |
Disclosure of detailed information about financial instruments [line items] |  |  |
Financial assets | 94 |  | 254
Financial assets at fair value | 94 |  | 254
Financial assets at fair value through profit or loss, category [Member] | Bank financial notes [member] | Level 2 of fair value hierarchy [Member] |  |  |
Disclosure of detailed information about financial instruments [line items] |  |  |
Financial assets | 557 |  | 435
Financial assets at fair value | R$ 557 |  | R$ 435
[1] | On December 31, 2019 and 2018, the book values of financial instruments reflect their fair values.

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