XML 236 R140.htm IDEA: XBRL DOCUMENT
v3.20.1

20. INTANGIBLE ASSETS (Details) - BRL (R$) R$ in Millions | Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
--- | --- | --- | --- | ---
Disclosure of detailed information about intangible assets [line items] |  |  |  |  |  |  |
Intangible assets |  | R$ 11,624 |  | R$ 10,777 |  | R$ 11,156 | R$ 10,820
Temporary Easement Intangible Assets [Member] |  |  |  |  |  |  |
Disclosure of detailed information about intangible assets [line items] |  |  |  |  |  |  |
Intangible assets |  | 8 |  | 8 |  |  |
Assets Of Concession [Member] |  |  |  |  |  |  |
Disclosure of detailed information about intangible assets [line items] |  |  |  |  |  |  |
Intangible assets |  | 11,517 | [1] | 10,680 | [1] | 10,435 | 9,248
Temporary Easements Intangible Assets [Member] |  |  |  |  |  |  |
Disclosure of detailed information about intangible assets [line items] |  |  |  |  |  |  |
Intangible assets |  | 8 |  | 8 |  | 10 | 10
Useful Life Defined Intangible Asset [Member] |  |  |  |  |  |  |
Disclosure of detailed information about intangible assets [line items] |  |  |  |  |  |  |
Intangible assets |  | 11,542 |  | 10,714 |  | 11,156 | 9,285
Onerous Concession [Member] |  |  |  |  |  |  |
Disclosure of detailed information about intangible assets [line items] |  |  |  |  |  |  |
Intangible assets |  | 7 |  | 7 |  | 8 | 9
Other Intangible Assets [Member] |  |  |  |  |  |  |
Disclosure of detailed information about intangible assets [line items] |  |  |  |  |  |  |
Intangible assets |  | 10 |  | 19 |  | R$ 17 | R$ 18
Intangible Assets Under Development [Member] |  |  |  |  |  |  |
Disclosure of detailed information about intangible assets [line items] |  |  |  |  |  |  |
Intangible assets |  | 82 |  | 63 |  |  |
Gross Carrying Amount [Member] |  |  |  |  |  |  |
Disclosure of detailed information about intangible assets [line items] |  |  |  |  |  |  |
Intangible assets |  | 20,230 |  | 18,852 |  |  |
Gross Carrying Amount [Member] | Temporary Easement Intangible Assets [Member] |  |  |  |  |  |  |
Disclosure of detailed information about intangible assets [line items] |  |  |  |  |  |  |
Intangible assets |  | 12 |  | 11 |  |  |
Gross Carrying Amount [Member] | Assets Of Concession [Member] |  |  |  |  |  |  |
Disclosure of detailed information about intangible assets [line items] |  |  |  |  |  |  |
Intangible assets | [1] | 20 |  | 18,674 |  |  |
Gross Carrying Amount [Member] | Useful Life Defined Intangible Asset [Member] |  |  |  |  |  |  |
Disclosure of detailed information about intangible assets [line items] |  |  |  |  |  |  |
Intangible assets |  | 20,148 |  | 18,789 |  |  |
Gross Carrying Amount [Member] | Onerous Concession [Member] |  |  |  |  |  |  |
Disclosure of detailed information about intangible assets [line items] |  |  |  |  |  |  |
Intangible assets |  | 20,039 |  | 19 | [1] |  |
Gross Carrying Amount [Member] | Other Intangible Assets [Member] |  |  |  |  |  |  |
Disclosure of detailed information about intangible assets [line items] |  |  |  |  |  |  |
Intangible assets |  | 82 |  | 85 |  |  |
Gross Carrying Amount [Member] | Intangible Assets Under Development [Member] |  |  |  |  |  |  |
Disclosure of detailed information about intangible assets [line items] |  |  |  |  |  |  |
Intangible assets |  | 82 |  | 63 |  |  |
Accumulated Depreciation and Amortisation [Member] |  |  |  |  |  |  |
Disclosure of detailed information about intangible assets [line items] |  |  |  |  |  |  |
Intangible assets |  | (8,606) |  | (8,075) |  |  |
Accumulated Depreciation and Amortisation [Member] | Temporary Easement Intangible Assets [Member] |  |  |  |  |  |  |
Disclosure of detailed information about intangible assets [line items] |  |  |  |  |  |  |
Intangible assets |  | (4) |  | (3) |  |  |
Accumulated Depreciation and Amortisation [Member] | Assets Of Concession [Member] |  |  |  |  |  |  |
Disclosure of detailed information about intangible assets [line items] |  |  |  |  |  |  |
Intangible assets | [1] | (8,522) |  | (7,994) |  |  |
Accumulated Depreciation and Amortisation [Member] | Useful Life Defined Intangible Asset [Member] |  |  |  |  |  |  |
Disclosure of detailed information about intangible assets [line items] |  |  |  |  |  |  |
Intangible assets |  | (8,606) |  | (8,075) |  |  |
Accumulated Depreciation and Amortisation [Member] | Onerous Concession [Member] |  |  |  |  |  |  |
Disclosure of detailed information about intangible assets [line items] |  |  |  |  |  |  |
Intangible assets |  | (8,522) |  | (12) |  |  |
Accumulated Depreciation and Amortisation [Member] | Other Intangible Assets [Member] |  |  |  |  |  |  |
Disclosure of detailed information about intangible assets [line items] |  |  |  |  |  |  |
Intangible assets |  | R$ (67) |  | R$ (66) |  |  |
[1] | The rights of authorization to generate wind power granted to the subsidiary Parajuru and Volta do Rio, valued at R$ 127, and of the gas distribution concession, granted to Gasmig, valued at R$ 426, are classified in the consolidated statement of financial position under intangibles assets and are amortized by the straight-line method, for the period of the concessions.

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_DisclosureOfIntangibleAssetsLineItems
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The amount of identifiable non-monetary assets without physical substance. This amount does not include goodwill. [Refer: Goodwill] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 38 -IssueDate 2019-01-01 -Paragraph 118 -Subparagraph e -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=38&code=ifrs-tx-2019-en-r&anchor=para_118_e&doctype=Standard -URIDate 2019-03-27 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 1 -IssueDate 2019-01-01 -Paragraph 54 -Subparagraph c -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2019-en-r&anchor=para_54_c&doctype=Standard -URIDate 2019-03-27 + Details
Name: | ifrs-full_IntangibleAssetsOtherThanGoodwill
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | ifrs-full_ClassesOfIntangibleAssetsOtherThanGoodwillAxis=cig_TemporaryEasementIntangibleAssetsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_ClassesOfIntangibleAssetsOtherThanGoodwillAxis=cig_AssetsOfConcessionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_ClassesOfIntangibleAssetsOtherThanGoodwillAxis=cig_TemporaryEasementsIntangibleAssetsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_ClassesOfIntangibleAssetsOtherThanGoodwillAxis=cig_UsefulLifeDefinedIntangibleAssetMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_ClassesOfIntangibleAssetsOtherThanGoodwillAxis=ifrs-full_ServiceConcessionRightsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_ClassesOfIntangibleAssetsOtherThanGoodwillAxis=ifrs-full_OtherIntangibleAssetsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_ClassesOfIntangibleAssetsOtherThanGoodwillAxis=ifrs-full_IntangibleAssetsUnderDevelopmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_CarryingAmountAccumulatedDepreciationAmortisationAndImpairmentAndGrossCarryingAmountAxis=ifrs-full_GrossCarryingAmountMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_CarryingAmountAccumulatedDepreciationAmortisationAndImpairmentAndGrossCarryingAmountAxis=ifrs-full_AccumulatedDepreciationAndAmortisationMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |