XML 167 R146.htm IDEA: XBRL DOCUMENT
v3.21.1

19. LEASING TRANSACTIONS (Details) | 12 Months Ended
--- | ---
Dec. 31, 2020
Up to two years [member] |
LeasingTransactionsLineItems [Line Items] |
Annual rate | 7.96%
Monthly rate | 0.64%
Three to five years [member] |
LeasingTransactionsLineItems [Line Items] |
Annual rate | 10.64%
Monthly rate | 0.85%
Six to twenty years [member] |
LeasingTransactionsLineItems [Line Items] |
Annual rate | 13.17%
Monthly rate | 1.04%
Up to three years [member] |
LeasingTransactionsLineItems [Line Items] |
Annual rate | 6.87%
Monthly rate | 0.56%
Three to four years [member] |
LeasingTransactionsLineItems [Line Items] |
Annual rate | 7.33%
Monthly rate | 0.59%
Four to twenty years [member] |
LeasingTransactionsLineItems [Line Items] |
Annual rate | 8.08%
Monthly rate | 0.65%

X
- Definition Represent information about the annual rate. + References No definition available. + Details
Name: | cig_AnnualRate
Namespace Prefix: | cig_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | cig_LeasingTransactionsLineItems
Namespace Prefix: | cig_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represent information about the monthly rate. + References No definition available. + Details
Name: | cig_MonthlyRate
Namespace Prefix: | cig_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | ifrs-full_MaturityAxis=cig_UpToTwoYearsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_MaturityAxis=cig_ThreeToFiveYearsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_MaturityAxis=cig_SixToTwentyYearsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_MaturityAxis=cig_UpToThreeYearsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_MaturityAxis=cig_ThreeToFourYearsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_MaturityAxis=cig_FourToTwentyYearsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |