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16. INVESTMENTS (Details 4) - BRL (R$) R$ in Millions | 12 Months Ended
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Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Disclosure of detailed information about investment property [line items] |  |  |  |  |  |  |
Share capital |  | R$ 7,594 |  | R$ 7,294 | [1] | R$ 7,294 |
Equity |  | R$ 17,478 |  | R$ 15,891 | [1],[2] | R$ 15,939 | [3]
UFV janauba geracao de energia eletrica distribuida [member] |  |  |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |  |  |
Name of subsidiary |  | UFV Janaúba Geração de Energia Elétrica Distribuída |  |  |  |  |
Number of shares |  | 18,509,900 |  |  |  |  |
Cemig interest % |  | 49.00% |  |  |  |  |
Share capital |  | R$ 19 |  |  |  |  |
Equity |  | R$ 21 |  |  |  |  |
UFV Corinto Geracao de Energia Eletrica Distribuida [member] |  |  |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |  |  |
Name of subsidiary |  | UFV Corinto Geração de Energia Elétrica Distribuída |  |  |  |  |
Number of shares |  | 18,000,000 |  |  |  |  |
Cemig interest % |  | 49.00% |  |  |  |  |
Share capital |  | R$ 18 |  |  |  |  |
Equity |  | R$ 20 |  |  |  |  |
UFV Manga Geracao de Energia Eletrica Distribuida [member] |  |  |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |  |  |
Name of subsidiary |  | UFV Manga Geração de Energia Elétrica Distribuída |  |  |  |  |
Number of shares |  | 21,235,933 |  |  |  |  |
Cemig interest % |  | 49.00% |  |  |  |  |
Share capital |  | R$ 21 |  |  |  |  |
Equity |  | R$ 24 |  |  |  |  |
UFV Bonfinopolis II Geracao de Energia Eletrica Distribuida [member] |  |  |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |  |  |
Name of subsidiary |  | UFV Bonfinópolis Geração de Energia Elétrica Distribuída |  |  |  |  |
Number of shares |  | 13,197,187 |  |  |  |  |
Cemig interest % |  | 49.00% |  |  |  |  |
Share capital |  | R$ 13 |  |  |  |  |
Equity |  | R$ 13 |  |  |  |  |
UFV lagoa grande geracao de energia eletrica distribuida [member] |  |  |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |  |  |
Name of subsidiary |  | UFV Lagoa Grande Geração de Energia Elétrica Distribuída |  |  |  |  |
Number of shares |  | 25,471,844 |  |  |  |  |
Cemig interest % |  | 49.00% |  |  |  |  |
Share capital |  | R$ 25 |  |  |  |  |
Equity |  | R$ 26 |  |  |  |  |
UFV lontra geracao de energia eletrica distribuida [member] |  |  |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |  |  |
Name of subsidiary |  | UFV Lontra Geração de Energia Elétrica Distribuída |  |  |  |  |
Number of shares |  | 29,010,219 |  |  |  |  |
Cemig interest % |  | 49.00% |  |  |  |  |
Share capital |  | R$ 29 |  |  |  |  |
Equity |  | R$ 29 |  |  |  |  |
UFV mato verde geracao de energia eletrica distribuida [member] |  |  |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |  |  |
Name of subsidiary |  | UFV Mato Verde Geração de Energia Elétrica Distribuída |  |  |  |  |
Number of shares |  | 11,030,391 |  |  |  |  |
Cemig interest % |  | 49.00% |  |  |  |  |
Share capital |  | R$ 11 |  |  |  |  |
Equity |  | R$ 11 |  |  |  |  |
UFV mirabela geracao de energia eletrica distribuida [member] |  |  |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |  |  |
Name of subsidiary |  | UFV Mirabela Geração de Energia Elétrica Distribuída |  |  |  |  |
Number of shares |  | 9,320,875 |  |  |  |  |
Cemig interest % |  | 49.00% |  |  |  |  |
Share capital |  | R$ 9 |  |  |  |  |
Equity |  | R$ 9 |  |  |  |  |
UFV porteirinha i geracao de energia eletrica distribuida [member] |  |  |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |  |  |
Name of subsidiary |  | UFV Porteirinha I Geração de Energia Elétrica Distribuída |  |  |  |  |
Number of shares |  | 12,348,392 |  |  |  |  |
Cemig interest % |  | 49.00% |  |  |  |  |
Share capital |  | R$ 12 |  |  |  |  |
Equity |  | R$ 12 |  |  |  |  |
UFV porteirinha ii geracao de energia eletrica distribuida [member] |  |  |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |  |  |
Name of subsidiary |  | UFV Porteirinha II Geração de Energia Elétrica Distribuída |  |  |  |  |
Number of shares |  | 11,702,733 |  |  |  |  |
Cemig interest % |  | 49.00% |  |  |  |  |
Share capital |  | R$ 12 |  |  |  |  |
Equity |  | R$ 12 |  |  |  |  |
Cemig Geracao E Transmissao [member] |  |  |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |  |  |
Name of subsidiary |  | Cemig Geração e Transmissão |  |  |  |  |
Number of shares |  | 2,896,785,358 |  |  |  |  |
Cemig interest % |  | 100.00% |  | 100.00% |  | 100.00% |
Share capital |  | R$ 4,000 |  | R$ 2,600 |  | R$ 2,600 |
Equity |  | R$ 5,842 |  | R$ 5,348 |  | R$ 5,125 |
Madeira Energia (Santo Antonio plant) [member] |  |  |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |  |  |
Name of subsidiary |  | Madeira Energia (Santo Antônio plant) |  |  |  |  |
Number of shares |  | 12,034,025,147 |  |  |  |  |
Cemig interest % |  | 15.51% |  | 15.51% |  | 15.51% |
Share capital |  | R$ 10,620 |  | R$ 10,620 |  | R$ 10,620 |
Equity |  | R$ 2,259 |  | R$ 3,705 |  | R$ 4,657 |
Hidreletrica cachoeirao [member] |  |  |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |  |  |
Name of subsidiary |  | Hidrelétrica Cachoeirão |  |  |  |  |
Number of shares |  | 35,000,000 |  |  |  |  |
Cemig interest % |  | 49.00% |  | 49.00% |  | 49.00% |
Share capital |  | R$ 35 |  | R$ 35 |  | R$ 35 |
Equity |  | R$ 110 |  | R$ 110 |  | R$ 100 |
Guanhaes energia [member] |  |  |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |  |  |
Name of subsidiary |  | Guanhães Energia |  |  |  |  |
Number of shares |  | 548,626,000 |  |  |  |  |
Cemig interest % |  | 49.00% |  | 49.00% |  | 49.00% |
Share capital |  | R$ 549 |  | R$ 549 |  | R$ 396 |
Equity |  | R$ 268 |  | R$ 268 |  | R$ 228 |
Hidreletrica pipoca [member] |  |  |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |  |  |
Name of subsidiary |  | Hidrelétrica Pipoca |  |  |  |  |
Number of shares |  | 41,360,000 |  |  |  |  |
Cemig interest % |  | 49.00% |  | 49.00% |  | 49.00% |
Share capital |  | R$ 41 |  | R$ 41 |  | R$ 41 |
Equity |  | R$ 73 |  | R$ 63 |  | R$ 63 |
Baguari energia [member] |  |  |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |  |  |
Name of subsidiary | [4] | Baguari Energia |  |  |  |  |
Number of shares | [4] | 26,157,300,278 |  |  |  |  |
Cemig interest % | [4] | 69.39% |  | 69.39% |  | 69.39% |
Share capital | [4] | R$ 187 |  | R$ 187 |  | R$ 187 |
Equity | [4] | R$ 229 |  | R$ 227 |  | R$ 234 |
Central eolica praias de parajuru [member] |  |  |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |  |  |
Name of subsidiary |  | Central Eólica Praias de Parajuru |  |  |  |  |
Number of shares |  | 70,560,000 |  |  |  |  |
Cemig interest % |  | 100.00% |  | 100.00% |  | 100.00% |
Share capital |  | R$ 71 |  | R$ 72 |  | R$ 72 |
Equity |  | R$ 107 |  | R$ 89 |  | R$ 80 |
Central eolica volta do rio [member] |  |  |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |  |  |
Name of subsidiary |  | Central Eólica Volta do Rio |  |  |  |  |
Number of shares |  | 117,230,000 |  |  |  |  |
Cemig interest % |  | 100.00% |  | 100.00% |  | 100.00% |
Share capital |  | R$ 117 |  | R$ 139 |  | R$ 139 |
Equity |  | R$ 171 |  | R$ 58 |  | R$ 84 |
Lightger [member] |  |  |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |  |  |
Name of subsidiary |  | Lightger |  |  |  |  |
Number of shares |  | 79,078,937 |  |  |  |  |
Cemig interest % |  | 49.00% |  | 49.00% |  | 49.00% |
Share capital |  | R$ 79 |  | R$ 79 |  | R$ 79 |
Equity |  | R$ 106 |  | R$ 95 |  | R$ 86 |
Alianca norte (belo monte plant) [member] |  |  |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |  |  |
Name of subsidiary |  | Aliança Norte (Belo Monte plant) |  |  |  |  |
Number of shares |  | 41,923,360,811 |  |  |  |  |
Cemig interest % |  | 49.00% |  | 49.00% |  | 49.00% |
Share capital |  | R$ 1,209 |  | R$ 1,208 |  | R$ 1,206 |
Equity |  | R$ 1,189 |  | R$ 1,266 |  | R$ 1,247 |
Amazonia energia (belo monte plant) [member] |  |  |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |  |  |
Name of subsidiary | [4] | Amazônia Energia (Belo Monte plant) |  |  |  |  |
Number of shares | [4] | 1,322,597,723 |  |  |  |  |
Cemig interest % | [4] | 74.50% |  | 74.50% |  | 74.50% |
Share capital | [4] | R$ 1,323 |  | R$ 1,323 |  | R$ 1,322 |
Equity | [4] | R$ 1,296 |  | R$ 1,380 |  | R$ 1,359 |
Alianca geracao [member] |  |  |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |  |  |
Name of subsidiary |  | Aliança Geração |  |  |  |  |
Number of shares |  | 1,291,500 |  |  |  |  |
Cemig interest % |  | 45.00% |  | 45.00% |  | 45.00% |
Share capital |  | R$ 1,291 |  | R$ 1,291 |  | R$ 1,291 |
Equity |  | R$ 1,858 |  | R$ 1,858 |  | R$ 1,858 |
Retiro baixo [member] |  |  |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |  |  |
Name of subsidiary |  | Retiro Baixo |  |  |  |  |
Number of shares |  | 225,350,000 |  |  |  |  |
Cemig interest % |  | 49.90% |  | 49.90% |  | 49.90% |
Share capital |  | R$ 225 |  | R$ 225 |  | R$ 223 |
Equity |  | R$ 325 |  | R$ 300 |  | R$ 278 |
Renova [member] |  |  |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |  |  |
Name of subsidiary | [4],[5] | Renova |  |  |  |  |
Number of shares | [4],[5] | 41,719,724 |  |  |  |  |
Cemig interest % | [4],[5] | 36.23% |  | 36.23% |  | 36.23% |
Share capital | [4],[5] | R$ 2,961 |  | R$ 2,961 |  | R$ 2,919 |
Equity | [4],[5] | R$ 1,108 |  | R$ (1,130) |  | R$ (76) |
Usina hidreletrica itaocara S.A. [member] |  |  |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |  |  |
Name of subsidiary | [6] | Usina Hidrelétrica Itaocara S.A |  |  |  |  |
Number of shares | [6] | 71,708,500 |  |  |  |  |
Cemig interest % | [6] | 49.00% |  | 49.00% |  | 49.00% |
Share capital |  | R$ 72 | [6] | R$ 69 |  | R$ 22 |
Equity |  | R$ (60) | [6] | R$ (45) |  | R$ 10 |
Cemig Ger.Tres Marias S.A. [member] |  |  |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |  |  |
Name of subsidiary |  | Cemig Ger.Três Marias S.A. |  |  |  |  |
Number of shares |  | 1,291,423,369 |  |  |  |  |
Cemig interest % |  | 100.00% |  | 100.00% |  | 100.00% |
Share capital |  | R$ 1,291 |  | R$ 1,291 |  | R$ 1,291 |
Equity |  | R$ 1,452 |  | R$ 1,408 |  | R$ 1,396 |
Cemig Ger.Salto Grande S.A [member] |  |  |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |  |  |
Name of subsidiary |  | Cemig Ger.Salto Grande S.A |  |  |  |  |
Number of shares |  | 405,267,607 |  |  |  |  |
Cemig interest % |  | 100.00% |  | 100.00% |  | 100.00% |
Share capital |  | R$ 405 |  | R$ 405 |  | R$ 405 |
Equity |  | R$ 455 |  | R$ 446 |  | R$ 440 |
Cemig Ger. Itutinga S.A. [member] |  |  |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |  |  |
Name of subsidiary |  | Cemig Ger. Itutinga S.A. |  |  |  |  |
Number of shares |  | 151,309,332 |  |  |  |  |
Cemig interest % |  | 100.00% |  | 100.00% |  | 100.00% |
Share capital |  | R$ 151 |  | R$ 151 |  | R$ 151 |
Equity |  | R$ 180 |  | R$ 180 |  | R$ 179 |
Cemig geracao camargos s.a. [member] |  |  |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |  |  |
Name of subsidiary |  | Cemig Geração Camargos S.A. |  |  |  |  |
Number of shares |  | 113,499,102 |  |  |  |  |
Cemig interest % |  | 100.00% |  | 100.00% |  | 100.00% |
Share capital |  | R$ 113 |  | R$ 113 |  | R$ 113 |
Equity |  | R$ 144 |  | R$ 136 |  | R$ 132 |
Cemig geracao sul s.a. [member] |  |  |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |  |  |
Name of subsidiary |  | Cemig Geração Sul S.A. |  |  |  |  |
Number of shares |  | 148,146,505 |  |  |  |  |
Cemig interest % |  | 100.00% |  | 100.00% |  | 100.00% |
Share capital |  | R$ 148 |  | R$ 148 |  | R$ 148 |
Equity |  | R$ 174 |  | R$ 179 |  | R$ 176 |
Cemig geracao leste s.a. [member] |  |  |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |  |  |
Name of subsidiary |  | Cemig Geração Leste S.A. |  |  |  |  |
Number of shares |  | 100,568,929 |  |  |  |  |
Cemig interest % |  | 100.00% |  | 100.00% |  | 100.00% |
Share capital |  | R$ 101 |  | R$ 101 |  | R$ 101 |
Equity |  | R$ 127 |  | R$ 127 |  | R$ 121 |
Cemig geracao oeste s.a. [member] |  |  |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |  |  |
Name of subsidiary |  | Cemig Geração Oeste S.A. |  |  |  |  |
Number of shares |  | 60,595,484 |  |  |  |  |
Cemig interest % |  | 100.00% |  | 100.00% |  | 100.00% |
Share capital |  | R$ 61 |  | R$ 61 |  | R$ 61 |
Equity |  | R$ 84 |  | R$ 73 |  | R$ 70 |
Rosal energia s.a. [member] |  |  |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |  |  |
Name of subsidiary |  | Rosal Energia S.A. (‘Rosal’) |  |  |  |  |
Number of shares |  | 46,944,467 |  |  |  |  |
Cemig interest % |  | 100.00% |  | 100.00% |  | 100.00% |
Share capital |  | R$ 47 |  | R$ 47 |  | R$ 47 |
Equity |  | R$ 127 |  | R$ 128 |  | R$ 125 |
Sa carvalho s.a. [member] |  |  |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |  |  |
Name of subsidiary |  | Sá Carvalho S.A. (‘Sá Carvalho’) |  |  |  |  |
Number of shares |  | 361,200,000 |  |  |  |  |
Cemig interest % |  | 100.00% |  | 100.00% |  | 100.00% |
Share capital |  | R$ 37 |  | R$ 37 |  | R$ 37 |
Equity |  | R$ 115 |  | R$ 124 |  | R$ 94 |
Horizontes energia s.a [member] |  |  |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |  |  |
Name of subsidiary |  | Horizontes Energia S.A. (‘Horizontes’) |  |  |  |  |
Number of shares |  | 39,257,563 |  |  |  |  |
Cemig interest % |  | 100.00% |  | 100.00% |  | 100.00% |
Share capital |  | R$ 39 |  | R$ 39 |  | R$ 39 |
Equity |  | R$ 55 |  | R$ 57 |  | R$ 55 |
Cemig PCH s.a. [member] |  |  |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |  |  |
Name of subsidiary |  | Cemig PCH S.A. (‘PCH’) |  |  |  |  |
Number of shares |  | 45,952,000 |  |  |  |  |
Cemig interest % |  | 100.00% |  | 100.00% |  | 100.00% |
Share capital |  | R$ 46 |  | R$ 46 |  | R$ 36 |
Equity |  | R$ 90 |  | R$ 98 |  | R$ 93 |
Cemig Geracao Poco Fundo S.A. [member] |  |  |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |  |  |
Name of subsidiary | [7] | Cemig Geração Poço Fundo S.A. |  |  |  |  |
Number of shares | [7] | 1,402,000 |  |  |  |  |
Cemig interest % | [7] | 100.00% |  | 100.00% |  | 100.00% |
Share capital | [7] | R$ 1 |  | R$ 1 |  | R$ 17 |
Equity | [7] | R$ 4 |  | R$ 4 |  | R$ 18 |
Empresa De Servicos De Comercializacao De Energia Eletrica S.A. [member] |  |  |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |  |  |
Name of subsidiary |  | Empresa de Serviços de Comercialização de Energia Elétrica S.A. |  |  |  |  |
Number of shares |  | 486,000 |  |  |  |  |
Cemig interest % |  | 100.00% |  | 100.00% |  | 100.00% |
Share capital |  |  |  |  |  |  |
Equity |  | R$ 57 |  | R$ 28 |  | R$ 27 |
Cemig Comercializadora De Energia Incentivada S.A. [member] |  |  |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |  |  |
Name of subsidiary | [8] | Cemig Comercializadora de Energia Incentivada S.A. |  |  |  |  |
Number of shares | [8] |  |  |  |  |  |
Cemig interest % | [8] |  |  | 100.00% |  | 100.00% |
Share capital | [8] |  |  | R$ 1 |  | R$ 1 |
Equity | [8] |  |  | R$ 3 |  | R$ 3 |
Cemig trading s.a. [member] |  |  |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |  |  |
Name of subsidiary |  | Cemig Trading S.A. (‘Cemig Trading’) |  |  |  |  |
Number of shares |  | 1,000,000 |  |  |  |  |
Cemig interest % |  | 100.00% |  | 100.00% |  | 100.00% |
Share capital |  | R$ 1 |  | R$ 1 |  | R$ 1 |
Equity |  | R$ 30 |  | R$ 31 |  | R$ 28 |
Cemig distribuicao [member] |  |  |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |  |  |
Name of subsidiary |  | Cemig Distribuição |  |  |  |  |
Number of shares |  | 2,359,113,452 |  |  |  |  |
Cemig interest % |  | 100.00% |  | 100.00% |  | 100.00% |
Share capital |  | R$ 5,372 |  | R$ 5,372 |  | R$ 2,772 |
Equity |  | R$ 6,022 |  | R$ 4,708 |  | R$ 4,708 |
TAESA [member] |  |  |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |  |  |
Name of subsidiary |  | TAESA |  |  |  |  |
Number of shares |  | 1,033,496,721 |  |  |  |  |
Cemig interest % |  | 21.68% |  | 21.68% |  | 21.68% |
Share capital |  | R$ 3,042 |  | R$ 3,042 |  | R$ 3,042 |
Equity |  | R$ 6,026 |  | R$ 4,927 |  | R$ 4,572 |
Ativas data center [member] |  |  |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |  |  |
Name of subsidiary |  | Ativas Data Center |  |  |  |  |
Number of shares |  | 456,540,718 |  |  |  |  |
Cemig interest % |  | 19.60% |  | 19.60% |  | 19.60% |
Share capital |  | R$ 182 |  | R$ 182 |  | R$ 182 |
Equity |  | R$ 86 |  | R$ 82 |  | R$ 84 |
Gasmig [member] |  |  |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |  |  |
Name of subsidiary |  | Gasmig |  |  |  |  |
Number of shares |  | 409,255,483 |  |  |  |  |
Cemig interest % |  | 99.57% |  | 99.57% |  | 99.57% |
Share capital |  | R$ 665 |  | R$ 665 |  | R$ 665 |
Equity |  | R$ 1,079 |  | R$ 988 |  | R$ 1,001 |
Cemig Geracao Distribuida [member] |  |  |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |  |  |
Name of subsidiary | [9] | Cemig Geração Distribuída |  |  |  |  |
Number of shares | [9] |  |  |  |  |  |
Cemig interest % | [9] |  |  | 100.00% |  | 100.00% |
Share capital | [9] |  |  |  |  |  |
Equity | [9] |  |  | R$ 11 |  | R$ 3 |
LEPSA [member] |  |  |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |  |  |
Name of subsidiary |  | LEPSA |  |  |  |  |
Number of shares |  |  |  |  |  |  |
Cemig interest % |  |  |  |  |  | 100.00% |
Share capital |  |  |  |  |  | R$ 406 |
Equity |  |  |  |  |  | R$ 447 |
RME [member] |  |  |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |  |  |
Name of subsidiary |  | RME |  |  |  |  |
Number of shares |  |  |  |  |  |  |
Cemig interest % |  |  |  |  |  | 100.00% |
Share capital |  |  |  |  |  | R$ 403 |
Equity |  |  |  |  |  | R$ 423 |
Cemig Sim (Efficientia) [member] |  |  |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |  |  |
Name of subsidiary | [10] | Cemig Sim (Efficientia) |  |  |  |  |
Number of shares | [10] | 24,431,845 |  |  |  |  |
Cemig interest % | [10] | 100.00% |  | 100.00% |  | 100.00% |
Share capital | [10] | R$ 24 |  | R$ 15 |  | R$ 15 |
Equity | [10] | R$ 94 |  | R$ 17 |  | R$ 18 |
Companhia de transmissao centroeste de minas [member] |  |  |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |  |  |
Name of subsidiary | [11] | Companhia de Transmissão Centroeste de Minas |  |  |  |  |
Number of shares | [11] | 28,000,000 |  |  |  |  |
Cemig interest % | [11] | 51.00% |  | 51.00% |  | 51.00% |
Share capital | [11] | R$ 28 |  | R$ 28 |  | R$ 28 |
Equity | [11] | R$ 118 |  | R$ 47 |  | R$ 39 |
Axxiom solucoes tecnologicas [member] |  |  |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |  |  |
Name of subsidiary |  | Axxiom Soluções Tecnológicas |  |  |  |  |
Number of shares |  | 65,165,000 |  |  |  |  |
Cemig interest % |  | 49.00% |  | 49.00% |  | 49.00% |
Share capital |  | R$ 65 |  | R$ 58 |  | R$ 47 |
Equity |  | R$ 9 |  | R$ 27 |  | R$ 17 |
[1] | See note 2.8.
[2] | For further details of restatement of comparative balances, see Note 2.8
[3] | 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. On August 27, 2020, Aneel published the Dispatch 2,508/2020-SRM-SGT, which set new amounts for distributors' over contracting for the years 2016 and 2017, based on a new valuation criterion established by Aneel Technical Note 97/2020-SRM-SGT - not contained in the regulatory rules which were currently in force. As a result, Cemig D filed an appeal with the Council of Aneel, for the amounts of distribution agents' over contracting to be reset in accordance with the calculation criteria based on maximum effort contained in Aneel Normative Resolution 453/2011. The Company's position on this case is reinforced by the fact that the Brazilian Energy Distributors' Association (Abradee) filed a similar appeal, supported by the opinion of contracted legal advisersadvisors. The Company has no expectation of loss in relation to realization of these amounts. The Company recognizes this receivable asset, in the amount of R$222 on December 31, 2020, as Other financial components' to be ratified. At the reporting date for this financial statements, this matter was still pending analysis by Aneel.
[4] | Jointly-control under a Shareholders' Agreement.
[5] | In view of Renova's negative net equity, the Company reduced to zero the carrying value of its equity interests in this investee, at December 31, 2018.
[6] | An Extraordinary General Shareholders' Meeting held on August 7, 2019 approved increase in the share capital of Cemig D by R$2,600, through subscription of funds from Advances for Future Capital Increase (AFACs), paid in by the Company, without issuance of new shares.
[7] | The Extraordinary General Meeting of Shareholders held on August 29, 2019 approved changes to the bylaws of the subsidiary, changing its name and its corporate objects. With the alteration, the name of Usina Termeletrica Barreiro S.A. was changed to Cemig Geracao Poco Fundo S.A.
[8] | On October 1, 2020, Cemig GT completed the merger of its subsidiary Cemig Comercializadora de Energia Incentivada S.A., at book value, with consequent extinction of this investee, and the Cemig GT becoming its successor in all its assets, rights and obligations.
[9] | On October 19, 2020, the Cemig Geracao Distribuida was merged with the Company, at book value, with consequent extinction of this investee, and the Company becoming its successor in all its assets, rights and obligations.
[10] | On April 14, 2020, the minute of the Annual General Meeting that decided about changes in this subsidiary's By-laws was registered in the commercial registry authority, changing the name of this subsidiary to Cemig Solucoes Inteligentes em Energia S.A.-CEMIG SIM.
[11] | On January 13, 2020, the Company concluded acquisition of the equity interest of 49% of the share capital held by Eletrobras in Centroeste.

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