XML 150 R143.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Loans, Financings and Debentures - Consolidated Totals of Funds Raised (Parenthetical) (Detail) - BRL (R$) R$ in Millions |  | 12 Months Ended
--- | --- | ---
Dec. 14, 2017 | Dec. 31, 2017
Disclosure of detailed information about borrowings [line items] |  |
Taxes with no cash effect |  | R$ 10
Non-convertible debentures amortisation period | 36 months |
Cemig Telecom [member] |  |
Disclosure of detailed information about borrowings [line items] |  |
Non-convertible debentures maturity period | 4 years 6 months |
Annual remuneration percentage | 146.50% |

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

X
- Definition Annual remuneration percentage + References No definition available. + Details
Name: | xcmig_AnnualRemunerationPercentage
Namespace Prefix: | xcmig_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Non-convertible debentures amortisation period + References No definition available. + Details
Name: | xcmig_NonconvertibleDebenturesAmortisationPeriod
Namespace Prefix: | xcmig_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Non-convertible debentures maturity period + References No definition available. + Details
Name: | xcmig_NonconvertibleDebenturesMaturityPeriod
Namespace Prefix: | xcmig_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Taxes with no cash effect. + References No definition available. + Details
Name: | xcmig_TaxesWithNoCashEffect
Namespace Prefix: | xcmig_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | ifrs-full_BorrowingsByNameAxis=xcmig_CemigTelecomMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |