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16. CONCESSION FINANCIAL AND SECTOR ASSETS AND LIABILITIES (Details 4) - BRL (R$) R$ in Millions | Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
--- | --- | --- | --- | ---
Disclosure Of Financial Assets and Financial Liabilities [line items] |  |  |  |  |
Current assets |  | R$ 1,080 | R$ 1,071 |  |
Non-current assets |  | 4,851 | 4,927 |  |
Liabilities |  | 18,764 | (18,120) |  |
Current liabilities |  | 415 |  |  |
Financial assets (liabilities), net |  | 882 | 1,080 | R$ (46) | R$ (407)
CVA Account for Compensation Of Changes In Portion A Costs [Member] |  |  |  |  |
Disclosure Of Financial Assets and Financial Liabilities [line items] |  |  |  |  |
Assets |  | 3,430 | 3,729 |  |
Current assets |  | 2,555 | 2,689 |  |
Non-current assets |  | 875 | 1,040 |  |
Liabilities |  | (2,548) | (2,649) |  |
Current liabilities |  | (1,915) | (2,042) |  |
Non-current liabilities |  | (633) | (607) |  |
Total current, net |  | 640 | 647 |  |
Total non-current,net |  | 242 | 433 |  |
Financial assets (liabilities), net |  | 882 | 1,080 |  |
CVA Account for Compensation Of Changes In Portion A Costs [Member] | Quota For The Energy Development Account [Member] |  |  |  |  |
Disclosure Of Financial Assets and Financial Liabilities [line items] |  |  |  |  |
Financial assets (liabilities), net |  | 148 | 221 |  |
CVA Account for Compensation Of Changes In Portion A Costs [Member] | Tariff For Use Of Transmission Facilities Of Grid Participants [Member] |  |  |  |  |
Disclosure Of Financial Assets and Financial Liabilities [line items] |  |  |  |  |
Financial assets (liabilities), net |  | 96 | 18 |  |
CVA Account for Compensation Of Changes In Portion A Costs [Member] | Tariff For Transport Of Electricity Provided By Itaiputs [Member] |  |  |  |  |
Disclosure Of Financial Assets and Financial Liabilities [line items] |  |  |  |  |
Financial assets (liabilities), net |  | 25 | 18 |  |
CVA Account for Compensation Of Changes In Portion A Costs [Member] | Program To Encourage Alternative Sources Of Electricity Proinfa [Member] |  |  |  |  |
Disclosure Of Financial Assets and Financial Liabilities [line items] |  |  |  |  |
Financial assets (liabilities), net |  | 5 | 8 |  |
CVA Account for Compensation Of Changes In Portion A Costs [Member] | System Service Charges And Reserve Energy Charge [Member] |  |  |  |  |
Disclosure Of Financial Assets and Financial Liabilities [line items] |  |  |  |  |
Financial assets (liabilities), net |  | (297) | (533) |  |
CVA Account for Compensation Of Changes In Portion A Costs [Member] | Energy Purchased For Resale [Member] |  |  |  |  |
Disclosure Of Financial Assets and Financial Liabilities [line items] |  |  |  |  |
Financial assets (liabilities), net |  | 1,293 | 2,069 |  |
CVA Account for Compensation Of Changes In Portion A Costs [Member] | Overcontracting Of Supply [Member] |  |  |  |  |
Disclosure Of Financial Assets and Financial Liabilities [line items] |  |  |  |  |
Financial assets (liabilities), net | [1] | 132 | (217) |  |
CVA Account for Compensation Of Changes In Portion A Costs [Member] | Neutrality of Portion A [Member] |  |  |  |  |
Disclosure Of Financial Assets and Financial Liabilities [line items] |  |  |  |  |
Financial assets (liabilities), net |  | (42) | 38 |  |
CVA Account for Compensation Of Changes In Portion A Costs [Member] | Other Financial Items [Member] |  |  |  |  |
Disclosure Of Financial Assets and Financial Liabilities [line items] |  |  |  |  |
Financial assets (liabilities), net |  | (277) | (448) |  |
CVA Account for Compensation Of Changes In Portion A Costs [Member] | Tariff Flag [Member] |  |  |  |  |
Disclosure Of Financial Assets and Financial Liabilities [line items] |  |  |  |  |
Financial assets (liabilities), net | [2] | (103) | (11) |  |
CVA Account for Compensation Of Changes In Portion A Costs [Member] | Excess Demand and Reactive Power [Member] |  |  |  |  |
Disclosure Of Financial Assets and Financial Liabilities [line items] |  |  |  |  |
Financial assets (liabilities), net |  | (98) | (83) |  |
CVA Account for Compensation Of Changes In Portion A Costs [Member] | Amounts Ratified By Aneel In The Last Tariff Adjustment [Member] |  |  |  |  |
Disclosure Of Financial Assets and Financial Liabilities [line items] |  |  |  |  |
Assets |  | 1,286 | 1,184 |  |
Current assets |  | 1,286 | 1,184 |  |
Liabilities |  | (882) | (1,140) |  |
Current liabilities |  | (882) | (1,140) |  |
Total current, net |  | 404 | 44 |  |
Financial assets (liabilities), net |  | 404 | 44 |  |
CVA Account for Compensation Of Changes In Portion A Costs [Member] | Amounts Ratified By Aneel In The Last Tariff Adjustment [Member] | Quota For The Energy Development Account [Member] |  |  |  |  |
Disclosure Of Financial Assets and Financial Liabilities [line items] |  |  |  |  |
Current assets |  |  |  |  |
Liabilities |  |  |  |  |
Financial assets (liabilities), net |  | 119 | 1 |  |
CVA Account for Compensation Of Changes In Portion A Costs [Member] | Amounts Ratified By Aneel In The Last Tariff Adjustment [Member] | Tariff For Use Of Transmission Facilities Of Grid Participants [Member] |  |  |  |  |
Disclosure Of Financial Assets and Financial Liabilities [line items] |  |  |  |  |
Financial assets (liabilities), net |  | (18) | 24 |  |
CVA Account for Compensation Of Changes In Portion A Costs [Member] | Amounts Ratified By Aneel In The Last Tariff Adjustment [Member] | Tariff For Transport Of Electricity Provided By Itaiputs [Member] |  |  |  |  |
Disclosure Of Financial Assets and Financial Liabilities [line items] |  |  |  |  |
Financial assets (liabilities), net |  | 9 | 2 |  |
CVA Account for Compensation Of Changes In Portion A Costs [Member] | Amounts Ratified By Aneel In The Last Tariff Adjustment [Member] | Program To Encourage Alternative Sources Of Electricity Proinfa [Member] |  |  |  |  |
Disclosure Of Financial Assets and Financial Liabilities [line items] |  |  |  |  |
Financial assets (liabilities), net |  | 11 | 3 |  |
CVA Account for Compensation Of Changes In Portion A Costs [Member] | Amounts Ratified By Aneel In The Last Tariff Adjustment [Member] | System Service Charges And Reserve Energy Charge [Member] |  |  |  |  |
Disclosure Of Financial Assets and Financial Liabilities [line items] |  |  |  |  |
Financial assets (liabilities), net |  | (161) | (246) |  |
CVA Account for Compensation Of Changes In Portion A Costs [Member] | Amounts Ratified By Aneel In The Last Tariff Adjustment [Member] | Energy Purchased For Resale [Member] |  |  |  |  |
Disclosure Of Financial Assets and Financial Liabilities [line items] |  |  |  |  |
Financial assets (liabilities), net |  | 661 | 667 |  |
CVA Account for Compensation Of Changes In Portion A Costs [Member] | Amounts Ratified By Aneel In The Last Tariff Adjustment [Member] | Overcontracting Of Supply [Member] |  |  |  |  |
Disclosure Of Financial Assets and Financial Liabilities [line items] |  |  |  |  |
Financial assets (liabilities), net | [1] | (84) | (204) |  |
CVA Account for Compensation Of Changes In Portion A Costs [Member] | Amounts Ratified By Aneel In The Last Tariff Adjustment [Member] | Neutrality of Portion A [Member] |  |  |  |  |
Disclosure Of Financial Assets and Financial Liabilities [line items] |  |  |  |  |
Financial assets (liabilities), net |  | (30) | 53 |  |
CVA Account for Compensation Of Changes In Portion A Costs [Member] | Amounts Ratified By Aneel In The Last Tariff Adjustment [Member] | Other Financial Items [Member] |  |  |  |  |
Disclosure Of Financial Assets and Financial Liabilities [line items] |  |  |  |  |
Financial assets (liabilities), net |  | (71) | (236) |  |
CVA Account for Compensation Of Changes In Portion A Costs [Member] | Amounts Ratified By Aneel In The Last Tariff Adjustment [Member] | Tariff Flag [Member] |  |  |  |  |
Disclosure Of Financial Assets and Financial Liabilities [line items] |  |  |  |  |
Financial assets (liabilities), net | [2] |  |  |  |
CVA Account for Compensation Of Changes In Portion A Costs [Member] | Amounts Ratified By Aneel In The Last Tariff Adjustment [Member] | Excess Demand and Reactive Power [Member] |  |  |  |  |
Disclosure Of Financial Assets and Financial Liabilities [line items] |  |  |  |  |
Financial assets (liabilities), net |  | (32) | (21) |  |
CVA Account for Compensation Of Changes In Portion A Costs [Member] | Amounts Ratified By Aneel In The Next Tariff Adjustment [Member] |  |  |  |  |
Disclosure Of Financial Assets and Financial Liabilities [line items] |  |  |  |  |
Assets |  | 2,144 | 2,545 |  |
Current assets |  | 1,269 | 1,505 |  |
Non-current assets |  | 875 | 1,040 |  |
Liabilities |  | (1,666) | (1,509) |  |
Current liabilities |  | (1,033) | (902) |  |
Non-current liabilities |  | (633) | (607) |  |
Total current, net |  | 236 | 603 |  |
Total non-current,net |  | 242 | 433 |  |
Financial assets (liabilities), net |  | 478 | 1,036 |  |
CVA Account for Compensation Of Changes In Portion A Costs [Member] | Amounts Ratified By Aneel In The Next Tariff Adjustment [Member] | Quota For The Energy Development Account [Member] |  |  |  |  |
Disclosure Of Financial Assets and Financial Liabilities [line items] |  |  |  |  |
Financial assets (liabilities), net |  | 29 | 220 |  |
CVA Account for Compensation Of Changes In Portion A Costs [Member] | Amounts Ratified By Aneel In The Next Tariff Adjustment [Member] | Tariff For Use Of Transmission Facilities Of Grid Participants [Member] |  |  |  |  |
Disclosure Of Financial Assets and Financial Liabilities [line items] |  |  |  |  |
Financial assets (liabilities), net |  | 114 | (6) |  |
CVA Account for Compensation Of Changes In Portion A Costs [Member] | Amounts Ratified By Aneel In The Next Tariff Adjustment [Member] | Tariff For Transport Of Electricity Provided By Itaiputs [Member] |  |  |  |  |
Disclosure Of Financial Assets and Financial Liabilities [line items] |  |  |  |  |
Financial assets (liabilities), net |  | 16 | 16 |  |
CVA Account for Compensation Of Changes In Portion A Costs [Member] | Amounts Ratified By Aneel In The Next Tariff Adjustment [Member] | Program To Encourage Alternative Sources Of Electricity Proinfa [Member] |  |  |  |  |
Disclosure Of Financial Assets and Financial Liabilities [line items] |  |  |  |  |
Financial assets (liabilities), net |  | (6) | 5 |  |
CVA Account for Compensation Of Changes In Portion A Costs [Member] | Amounts Ratified By Aneel In The Next Tariff Adjustment [Member] | System Service Charges And Reserve Energy Charge [Member] |  |  |  |  |
Disclosure Of Financial Assets and Financial Liabilities [line items] |  |  |  |  |
Financial assets (liabilities), net |  | (136) | (287) |  |
CVA Account for Compensation Of Changes In Portion A Costs [Member] | Amounts Ratified By Aneel In The Next Tariff Adjustment [Member] | Energy Purchased For Resale [Member] |  |  |  |  |
Disclosure Of Financial Assets and Financial Liabilities [line items] |  |  |  |  |
Financial assets (liabilities), net |  | 632 | 1,402 |  |
CVA Account for Compensation Of Changes In Portion A Costs [Member] | Amounts Ratified By Aneel In The Next Tariff Adjustment [Member] | Overcontracting Of Supply [Member] |  |  |  |  |
Disclosure Of Financial Assets and Financial Liabilities [line items] |  |  |  |  |
Financial assets (liabilities), net | [1] | 216 | (13) |  |
CVA Account for Compensation Of Changes In Portion A Costs [Member] | Amounts Ratified By Aneel In The Next Tariff Adjustment [Member] | Neutrality of Portion A [Member] |  |  |  |  |
Disclosure Of Financial Assets and Financial Liabilities [line items] |  |  |  |  |
Financial assets (liabilities), net |  | (12) | (15) |  |
CVA Account for Compensation Of Changes In Portion A Costs [Member] | Amounts Ratified By Aneel In The Next Tariff Adjustment [Member] | Other Financial Items [Member] |  |  |  |  |
Disclosure Of Financial Assets and Financial Liabilities [line items] |  |  |  |  |
Financial assets (liabilities), net |  | (206) | (212) |  |
CVA Account for Compensation Of Changes In Portion A Costs [Member] | Amounts Ratified By Aneel In The Next Tariff Adjustment [Member] | Tariff Flag [Member] |  |  |  |  |
Disclosure Of Financial Assets and Financial Liabilities [line items] |  |  |  |  |
Financial assets (liabilities), net | [2] | (103) | (11) |  |
CVA Account for Compensation Of Changes In Portion A Costs [Member] | Amounts Ratified By Aneel In The Next Tariff Adjustment [Member] | Excess Demand and Reactive Power [Member] |  |  |  |  |
Disclosure Of Financial Assets and Financial Liabilities [line items] |  |  |  |  |
Financial assets (liabilities), net |  | R$ (66) | R$ (62) |  |
[1] | The wholly-owned subsidiary Cemig D was over contracted in 2017 and 2018 and the gain arising from the sale of the excess of energy in the spot market was provisionally passed through to customers by Aneel in the tariff adjustments of 2018 and 2019, including the portion in excess of the limit of 105% of the regulatory load - thus reducing the tariff that was determined. To establish whether this is a voluntary over contracting, the Company considers that the portion above the regulatory limit will be recovered in the subsequent tariff adjustment, when Aneel approves them. The Company has no expectation of loss in relation to realization of these amounts. The Company recognizes this right, in the amount of R$ 216,852, as 'Other financial components', to be approved by Aneel in the next forthcoming tariff adjustments.
[2] | Billing arising from the 'Flag' Tariff System (see below) not yet approved by the regulator (Aneel).

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