XML 57 R191.htm IDEA: XBRL DOCUMENT
v3.20.1

29. REVENUE (Details 1) R$ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2019 BRL (R$) GW | Dec. 31, 2018 BRL (R$) GW | Dec. 31, 2017 BRL (R$) GW
Disclosure of revenue [line items] |  |  |  |  |
Supply of electricity in GWh | GW |  | 43,558 | 43,522 | [1] | 42,461
Own consumption | GW |  | 38 | 41 | [1] | 37
Unbilled revenue | GW |  | 0 | 0 | [1] | 0
Supply of electricity including own consumption and not invoiced | GW |  | 43,596 | 43,563 | [1] | 42,498
Wholesale supply to other concession holders | GW | [2] | 11,448 | 11,992 | [1] | 12,777
Wholesale supply unbilled, net | GW |  | 0 | 0 | [1] | 0
Total | GW |  | 55,044 | 55,555 | [1] | 55,275
Revenue from sale of electricity | R$ |  | R$ 23,918 | R$ 21,834 |  | R$ 20,378
Own consumption | R$ |  | 0 | 0 |  | 0
Unbilled revenue | R$ |  | 134 | 48 |  | 61
Supply of electricity including own consumption and not invoiced | R$ |  | 24,052 | 21,882 |  | 20,439
Wholesale supply to other concession holders | R$ | [2] | 2,943 | 3,002 |  | 1,727
Wholesale supply unbilled, net | R$ |  | (67) | (12) |  | 1,535
Revenue from sale of electricity | R$ |  | R$ 26,928 | R$ 24,872 |  | R$ 23,701
Residential [Member] | Electricity distribution [Member] |  |  |  |  |
Disclosure of revenue [line items] |  |  |  |  |
Supply of electricity in GWh | GW |  | 10,538 | 10,267 | [1] | 10,008
Revenue from sale of electricity | R$ |  | R$ 9,668 | R$ 8,658 |  | R$ 7,842
Industrial [Member] | Electricity distribution [Member] |  |  |  |  |
Disclosure of revenue [line items] |  |  |  |  |
Supply of electricity in GWh | GW |  | 16,024 | 17,689 | [1] | 17,761
Revenue from sale of electricity | R$ |  | R$ 4,760 | R$ 4,892 |  | R$ 4,907
Commercial, Services and Other [Member] | Electricity distribution [Member] |  |  |  |  |
Disclosure of revenue [line items] |  |  |  |  |
Supply of electricity in GWh | GW |  | 9,567 | 8,380 | [1] | 7,507
Revenue from sale of electricity | R$ |  | R$ 5,439 | R$ 4,683 |  | R$ 4,342
Rural [Member] | Electricity distribution [Member] |  |  |  |  |
Disclosure of revenue [line items] |  |  |  |  |
Supply of electricity in GWh | GW |  | 3,795 | 3,615 | [1] | 3,651
Revenue from sale of electricity | R$ |  | R$ 2,058 | R$ 1,794 |  | R$ 1,629
Public Authorities [Member] | Electricity distribution [Member] |  |  |  |  |
Disclosure of revenue [line items] |  |  |  |  |
Supply of electricity in GWh | GW |  | 905 | 871 | [1] | 866
Revenue from sale of electricity | R$ |  | R$ 654 | R$ 575 |  | R$ 532
Public Lighting [Member] | Electricity distribution [Member] |  |  |  |  |
Disclosure of revenue [line items] |  |  |  |  |
Supply of electricity in GWh | GW |  | 1,357 | 1,384 | [1] | 1,367
Revenue from sale of electricity | R$ |  | R$ 614 | R$ 585 |  | R$ 537
Public Service [Member] | Electricity distribution [Member] |  |  |  |  |
Disclosure of revenue [line items] |  |  |  |  |
Supply of electricity in GWh | GW |  | 1,372 | 1,316 | [1] | 1,301
Revenue from sale of electricity | R$ |  | R$ 725 | R$ 646 |  | R$ 589
[1] | Data not audited by external auditors.
[2] | Includes a CCEAR (Regulated Market Sales Contract), bilateral contracts with other agents, and the revenues from management of generation assets (GAG) for the 18 hydroelectric plants of Lot D of Auction no 12/2015.

X
- Definition Disclosure of revenue. + References No definition available. + Details
Name: | cig_DisclosureOfRevenueLineItems
Namespace Prefix: | cig_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Revenue from sale of electricity gross. + References No definition available. + Details
Name: | cig_RevenueFromSaleOfElectricityGross
Namespace Prefix: | cig_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Supply of electricity for own consumption. + References No definition available. + Details
Name: | cig_SupplyOfElectricityForOwnConsumption
Namespace Prefix: | cig_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Represent information about the supply of electricity gross. + References No definition available. + Details
Name: | cig_SupplyOfElectricityGross
Namespace Prefix: | cig_
Data Type: | num:powerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represent information about the supply of electricity in gwh for own consumptions. + References No definition available. + Details
Name: | cig_SupplyOfElectricityInGwhForOwnConsumptions
Namespace Prefix: | cig_
Data Type: | num:powerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represent information about the supply of electricity in gwh for unbilled revenues. + References No definition available. + Details
Name: | cig_SupplyOfElectricityInGwhForUnbilledRevenues
Namespace Prefix: | cig_
Data Type: | num:powerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Supply of electricity including own consumption and not invoiced. + References No definition available. + Details
Name: | cig_SupplyOfElectricityIncludingOwnConsumptionAndNotInvoiced
Namespace Prefix: | cig_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Represent information about the supply of electricity power including own consumption and not invoiced. + References No definition available. + Details
Name: | cig_SupplyOfElectricityPowerIncludingOwnConsumptionAndNotInvoiced
Namespace Prefix: | cig_
Data Type: | num:powerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represent information about the total supply of electricity. + References No definition available. + Details
Name: | cig_TotalSupplyOfElectricity
Namespace Prefix: | cig_
Data Type: | num:powerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Unbilled revenues. + References No definition available. + Details
Name: | cig_UnbilledRevenues
Namespace Prefix: | cig_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Represent information about the wholesale supply of electricity in gw to other concession holder. + References No definition available. + Details
Name: | cig_WholesaleSupplyOfElectricityInGwToOtherConcessionHolder
Namespace Prefix: | cig_
Data Type: | num:powerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represent information about the wholesale supply of electricity in gw to unbilled. + References No definition available. + Details
Name: | cig_WholesaleSupplyOfElectricityInGwToUnbilled
Namespace Prefix: | cig_
Data Type: | num:powerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Wholesale supply of electricity to other concession holder. + References No definition available. + Details
Name: | cig_WholesaleSupplyOfElectricityToOtherConcessionHolder
Namespace Prefix: | cig_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Wholesale supply of electricity unbilled. + References No definition available. + Details
Name: | cig_WholesaleSupplyOfElectricityUnbilled
Namespace Prefix: | cig_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The amount of revenue arising from the sale of electricity. [Refer: Revenue] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 1 -IssueDate 2019-01-01 -Paragraph 112 -Subparagraph c -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2019-en-r&anchor=para_112_c&doctype=Standard -URIDate 2019-03-27 + Details
Name: | ifrs-full_RevenueFromSaleOfElectricity
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | ifrs-full_TypesOfCustomersAxis=cig_ResidentialMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_TypesOfRateregulatedActivitiesAxis=ifrs-full_ElectricityDistributionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_TypesOfCustomersAxis=cig_IndustrialMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_TypesOfCustomersAxis=cig_CommercialServicesAndOtherMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_TypesOfCustomersAxis=cig_RuralMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_TypesOfCustomersAxis=cig_PublicAuthoritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_TypesOfCustomersAxis=cig_PublicLightingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_TypesOfCustomersAxis=cig_PublicServiceMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |