XML 147 R140.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Loans, Financings and Debentures - Summary of Changes in Loans, Financings and Debentures (Parenthetical) (Detail) R$ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2017 BRL (R$)
Disclosure of detailed information about borrowings [abstract] |
Taxes with no cash effect | R$ 10

X
- References No definition available. + Details
Name: | ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsAbstract
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:stringItemType
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