XML 171 R128.htm IDEA: XBRL DOCUMENT
v3.20.1

18. INVESTMENTS (Details 4) - BRL (R$) R$ in Millions | 12 Months Ended |
--- | --- | ---
Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
Disclosure of detailed information about investment property [line items] |  |  |  |  |
Share capital |  | R$ 7,294 | R$ 7,294 | R$ 7,294 |
Equity |  | R$ 15,891 | R$ 15,939 | R$ 14,330 | R$ 12,934
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$ 2,600 | R$ 2,600 | R$ 1,838 |
Equity |  | R$ 5,136 | R$ 4,980 | R$ 4,794 |
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% | 18.13% |
Share capital |  | R$ 10,620 | R$ 10,620 | R$ 9,547 |
Equity |  | R$ 3,705 | R$ 4,657 | R$ 5,327 |
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$ 100 | R$ 118 |
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$ 396 | R$ 331 |
Equity |  | R$ 268 | R$ 228 | R$ 51 |
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$ 63 | R$ 63 | R$ 53 |
Baguari Energia [Member] |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |
Name of subsidiary | [1] | Baguari Energia |  |  |
Number of shares | [1] | 26,157,300,278 |  |  |
Cemig interest % | [1] | 69.39% | 69.39% | 69.39% |
Share capital | [1] | R$ 187 | R$ 187 | R$ 187 |
Equity | [1] | R$ 227 | R$ 234 | R$ 214 |
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 |  | 71,834,843 |  |  |
Cemig interest % |  | 100.00% | 100.00% | 49.00% |
Share capital |  | R$ 72 | R$ 72 | R$ 71 |
Equity |  | R$ 89 | R$ 80 | R$ 89 |
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 |  | 138,867,440 |  |  |
Cemig interest % |  | 100.00% | 100.00% | 49.00% |
Share capital |  | R$ 139 | R$ 139 | R$ 117 |
Equity |  | R$ 58 | R$ 84 | R$ 116 |
Central Eolica Praias De Morgado [Member] |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |
Number of shares |  |  |  |  |
Cemig interest % |  |  |  | 49.00% |
Share capital |  |  |  | R$ 53 |
Equity |  |  |  | R$ 54 |
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$ 95 | R$ 86 | R$ 83 |
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 |  | 41,893,675,837 |  |  |
Cemig interest % |  | 49.00% | 49.00% | 49.00% |
Share capital |  | R$ 1,208 | R$ 1,206 | R$ 1,119 |
Equity |  | R$ 1,266 | R$ 1,247 | R$ 1,066 |
Amazonia Energia (Belo Monte plant) [Member] |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |
Name of subsidiary | [1] | Amazônia Energia (Belo Monte plant) |  |  |
Number of shares | [1] | 1,322,597,723 |  |  |
Cemig interest % | [1] | 74.50% | 74.50% | 74.50% |
Share capital | [1] | R$ 1,323 | R$ 1,322 | R$ 1,230 |
Equity | [1] | R$ 1,380 | R$ 1,359 | R$ 1,163 |
Alianca Geracao [Member] |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |
Name of subsidiary |  | Aliança Geração |  |  |
Number of shares |  | 1,291,582 |  |  |
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$ 223 | R$ 223 |
Equity |  | R$ 300 | R$ 278 | R$ 258 |
Renova [Member] |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |
Name of subsidiary | [1],[2] | Renova |  |  |
Number of shares | [1],[2] | 41,719,724 |  |  |
Cemig interest % | [1],[2] | 36.23% | 36.23% | 36.23% |
Share capital | [1],[2] | R$ 2,961 | R$ 2,919 | R$ 2,919 |
Equity | [1],[2] | R$ (1,091) | R$ (76) | R$ 780 |
Usina Hidreletrica Itaocara S.A. [Member] |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |
Name of subsidiary | [3] | Usina Hidrelétrica Itaocara S.A |  |  |
Number of shares | [3] | 69,282,514 |  |  |
Cemig interest % | [3] | 49.00% | 49.00% | 49.00% |
Share capital | [3] | R$ 69 | R$ 22 | R$ 11 |
Equity | [3] | R$ (45) | R$ 10 | R$ 8 |
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$ 1,408 | R$ 1,396 | R$ 1,392 |
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$ 446 | R$ 440 | 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$ 184 | R$ 179 | R$ 171 |
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$ 136 | R$ 132 | R$ 130 |
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$ 179 | R$ 176 | R$ 168 |
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$ 121 | R$ 116 |
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$ 73 | R$ 70 | R$ 69 |
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$ 128 | R$ 125 | R$ 107 |
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$ 124 | R$ 94 | R$ 103 |
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$ 57 | R$ 55 | R$ 53 |
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$ 98 | R$ 93 | R$ 97 |
Cemig Geracao Poco Fundo S.A. [Member] |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |
Name of subsidiary | [4] | Cemig Geração Poço Fundo S.A. |  |  |
Number of shares | [4] | 1,402,000 |  |  |
Cemig interest % | [4] | 100.00% | 100.00% | 100.00% |
Share capital | [4] | R$ 1 | R$ 17 | R$ 17 |
Equity | [4] | R$ 4 | R$ 18 | 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$ 28 | R$ 27 | R$ 18 |
Cemig Comercializadora De Energia Incentivada S.A. [Member] |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |
Name of subsidiary |  | Cemig Comercializadora de Energia Incentivada S.A. |  |  |
Number of shares |  | 1,000,000 |  |  |
Cemig interest % |  | 100.00% | 100.00% | 100.00% |
Share capital |  | R$ 1 | R$ 1 | R$ 1 |
Equity |  | R$ 3 | R$ 3 | R$ 2 |
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$ 31 | R$ 28 | R$ 29 |
Cemig Distribuicao [Member] |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |
Name of subsidiary | [3] | Cemig Distribuição |  |  |
Number of shares | [3] | 2,359,113,452 |  |  |
Cemig interest % | [3] | 100.00% | 100.00% | 100.00% |
Share capital | [3] | R$ 5,372 | R$ 2,772 | R$ 2,772 |
Equity | [3] | R$ 4,708 | R$ 4,642 | R$ 3,737 |
Light [Member] |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |
Name of subsidiary |  | Light |  |  |
Number of shares |  | 303,934,060 |  |  |
Cemig interest % |  | 22.58% | 26.06% | 26.06% |
Share capital |  | R$ 4,051 | R$ 2,226 | R$ 2,226 |
Equity |  | R$ 5,983 | R$ 3,389 | R$ 3,462 |
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$ 4,927 | R$ 4,572 | R$ 4,347 |
Cemig Telecom [Member] |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |
Name of subsidiary |  | Cemig Telecom |  |  |
Number of shares |  |  |  |  |
Cemig interest % |  |  |  | 100.00% |
Share capital |  |  |  | R$ 292 |
Equity |  |  |  | R$ 247 |
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% |  |
Share capital |  | R$ 182 | R$ 182 |  |
Equity |  | 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$ 988 | R$ 1,001 | R$ 1,224 |
Cemig Geracao Distribuida [Member] |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |
Name of subsidiary |  | Cemig Geração Distribuída |  |  |
Number of shares |  | 174,281 |  |  |
Cemig interest % |  | 100.00% | 100.00% | 100.00% |
Share capital |  |  | R$ 0 | R$ 0 |
Equity |  | R$ 11 | R$ 3 | R$ 5 |
LEPSA [Member] |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |
Name of subsidiary | [5] | LEPSA |  |  |
Number of shares | [5] |  |  |  |
Cemig interest % | [5] |  | 100.00% | 100.00% |
Share capital | [5] |  | R$ 406 | R$ 406 |
Equity | [5] |  | R$ 447 | R$ 456 |
RME [Member] |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |
Name of subsidiary | [5] | RME |  |  |
Number of shares | [5] |  |  |  |
Cemig interest % | [5] |  | 100.00% | 75.00% |
Share capital | [5] |  | R$ 403 | R$ 403 |
Equity | [5] |  | R$ 423 | R$ 453 |
Efficientia [Member] |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |
Name of subsidiary |  | Efficientia |  |  |
Number of shares |  | 15,121,845 |  |  |
Cemig interest % |  | 100.00% | 100.00% | 100.00% |
Share capital |  | R$ 15 | R$ 15 | R$ 6 |
Equity |  | R$ 17 | R$ 18 | R$ 7 |
Companhia De Transmissao Centroeste De Minas [Member] |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |
Name of subsidiary |  | Companhia de Transmissão Centroeste de Minas |  |  |
Number of shares |  | 28,000,000 |  |  |
Cemig interest % |  | 51.00% | 51.00% | 51.00% |
Share capital |  | R$ 28 | R$ 28 | R$ 28 |
Equity |  | R$ 47 | R$ 39 | R$ 40 |
Axxiom Solucoes Tecnologicas [Member] |  |  |  |  |
Disclosure of detailed information about investment property [line items] |  |  |  |  |
Name of subsidiary |  | Axxiom Soluções Tecnológicas |  |  |
Number of shares |  | 58,365,000 |  |  |
Cemig interest % |  | 49.00% | 49.00% | 49.00% |
Share capital |  | R$ 58 | R$ 47 | R$ 47 |
Equity |  | R$ 27 | R$ 17 | R$ 24 |
[1] | Jointly-control under a Shareholders' Agreement.
[2] | 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.
[3] | 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.
[4] | 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.
[5] | These investees were merged on April 24, 2019.

X
- Definition Number of shares held in subsidiaries or jointly controlled entities. + References No definition available. + Details
Name: | cig_NumberOfSharesHeldInSubsidiariesOrJointlyControlledEntities
Namespace Prefix: | cig_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Proportion of ownership interest in subsidiaries and jointly controlled entities. + References No definition available. + Details
Name: | cig_ProportionOfOwnershipInterestInSubsidiariesAndJointlyControlledEntities
Namespace Prefix: | cig_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table. + References No definition available. + Details
Name: | ifrs-full_DisclosureOfInvestmentPropertyLineItems
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The amount of residual interest in the assets of the entity after deducting all its liabilities. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 1 -IssueDate 2019-01-01 -Paragraph 24 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=1&code=ifrs-tx-2019-en-r&anchor=para_24_a&doctype=Standard -URIDate 2019-03-27 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 1 -IssueDate 2019-01-01 -Paragraph 32 -Subparagraph a -Clause i -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=1&code=ifrs-tx-2019-en-r&anchor=para_32_a_i&doctype=Standard -URIDate 2019-03-27 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 13 -IssueDate 2019-01-01 -Paragraph 93 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2019-en-r&anchor=para_93_a&doctype=Standard -URIDate 2019-03-27 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 13 -IssueDate 2019-01-01 -Paragraph 93 -Subparagraph b -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2019-en-r&anchor=para_93_b&doctype=Standard -URIDate 2019-03-27 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 13 -IssueDate 2019-01-01 -Paragraph 93 -Subparagraph e -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2019-en-r&anchor=para_93_e&doctype=Standard -URIDate 2019-03-27 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 1 -IssueDate 2019-01-01 -Paragraph 55 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2019-en-r&anchor=para_55&doctype=Standard -URIDate 2019-03-27 Reference 7: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 1 -IssueDate 2019-01-01 -Paragraph 78 -Subparagraph e -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2019-en-r&anchor=para_78_e&doctype=Standard -URIDate 2019-03-27 + Details
Name: | ifrs-full_Equity
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The nominal value of capital issued. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Name IAS -Number 1 -IssueDate 2019-01-01 -Paragraph 78 -Subparagraph e -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2019-en-r&anchor=para_78_e&doctype=Standard -URIDate 2019-03-27 + Details
Name: | ifrs-full_IssuedCapital
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The name of a subsidiary. [Refer: Subsidiaries [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 27 -IssueDate 2019-01-01 -Paragraph 17 -Subparagraph b -Clause i -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=27&code=ifrs-tx-2019-en-r&anchor=para_17_b_i&doctype=Standard -URIDate 2019-03-27 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 27 -IssueDate 2019-01-01 -Paragraph 16 -Subparagraph b -Clause i -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=27&code=ifrs-tx-2019-en-r&anchor=para_16_b_i&doctype=Standard -URIDate 2019-03-27 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 12 -IssueDate 2019-01-01 -Paragraph 12 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2019-en-r&anchor=para_12_a&doctype=Standard -URIDate 2019-03-27 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 12 -IssueDate 2019-01-01 -Paragraph 19B -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2019-en-r&anchor=para_19B_a&doctype=Standard -URIDate 2019-03-27 + Details
Name: | ifrs-full_NameOfSubsidiary
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | ifrs-full_SignificantInvestmentsInSubsidiariesAxis=cig_CemigGeracaoETransmissaoMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_SignificantInvestmentsInSubsidiariesAxis=cig_MadeiraEnergia1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_SignificantInvestmentsInSubsidiariesAxis=cig_HidreletricaCachoeiraoMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_SignificantInvestmentsInSubsidiariesAxis=cig_GuanhaesEnergiaMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_SignificantInvestmentsInSubsidiariesAxis=cig_HidreletricaPipocaMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_SignificantInvestmentsInSubsidiariesAxis=cig_BaguariEnergiaMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_SignificantInvestmentsInSubsidiariesAxis=cig_CentralEolicaPraiasDeParajuruMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_SignificantInvestmentsInSubsidiariesAxis=cig_CentralEolicaVoltaDoRioMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_SignificantInvestmentsInSubsidiariesAxis=cig_CentralEolicaPraiasDeMorgadoMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_SignificantInvestmentsInSubsidiariesAxis=cig_LightgerMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_SignificantInvestmentsInSubsidiariesAxis=cig_AliancaNorteMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_SignificantInvestmentsInSubsidiariesAxis=cig_AmazoniaEnergiaMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_SignificantInvestmentsInSubsidiariesAxis=cig_AliancaGeracaoMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_SignificantInvestmentsInSubsidiariesAxis=cig_RetiroBaixoMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_SignificantInvestmentsInSubsidiariesAxis=cig_RenovaMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_SignificantInvestmentsInSubsidiariesAxis=cig_UsinaHidreletricaItaocaraSAMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_SignificantInvestmentsInSubsidiariesAxis=cig_CemigGerTresMariasSAMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_SignificantInvestmentsInSubsidiariesAxis=cig_CemigGerSaltoGrandeSAMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_SignificantInvestmentsInSubsidiariesAxis=cig_CemigGerItutingaSAMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_SignificantInvestmentsInSubsidiariesAxis=cig_CemigGeracaoCamargosSAMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_SignificantInvestmentsInSubsidiariesAxis=cig_CemigGeracaoSulSAMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_SignificantInvestmentsInSubsidiariesAxis=cig_CemigGeracaoLesteSAMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_SignificantInvestmentsInSubsidiariesAxis=cig_CemigGeracaoOesteSAMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_SignificantInvestmentsInSubsidiariesAxis=cig_RosalEnergiaSAMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_SignificantInvestmentsInSubsidiariesAxis=cig_SaCarvalhoSAMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_SignificantInvestmentsInSubsidiariesAxis=cig_HorizontesEnergiaSAMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_SignificantInvestmentsInSubsidiariesAxis=cig_CemigPCHSAMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_SignificantInvestmentsInSubsidiariesAxis=cig_CemigGeracaoPocoFundoSAMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_SignificantInvestmentsInSubsidiariesAxis=cig_EmpresaDeServicosDeComercializacaoDeEnergiaEletricaSAMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_SignificantInvestmentsInSubsidiariesAxis=cig_CemigComercializadoraDeEnergiaIncentivadaSAMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_SignificantInvestmentsInSubsidiariesAxis=cig_CemigTradingSAMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_SignificantInvestmentsInSubsidiariesAxis=cig_CemigDistribuicaoMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_SignificantInvestmentsInSubsidiariesAxis=cig_LightMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_SignificantInvestmentsInSubsidiariesAxis=cig_TaesaMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_SignificantInvestmentsInSubsidiariesAxis=cig_CemigTelecomMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_SignificantInvestmentsInSubsidiariesAxis=cig_AtivasDataCenterMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_SignificantInvestmentsInSubsidiariesAxis=cig_GasmigMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_SignificantInvestmentsInSubsidiariesAxis=cig_CemigGeracaoDistribuidaMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_SignificantInvestmentsInSubsidiariesAxis=cig_LepsaMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_SignificantInvestmentsInSubsidiariesAxis=cig_RMEMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_SignificantInvestmentsInSubsidiariesAxis=cig_EfficientiaMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_SignificantInvestmentsInSubsidiariesAxis=cig_CompanhiadeTransmissaoCentroestedeMinasMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_SignificantInvestmentsInSubsidiariesAxis=cig_AxxiomSolucoesTecnologicasMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |