XML 119 R112.htm IDEA: XBRL DOCUMENT v3.19.1

Income and Social Contribution Taxes - Summary of Reconciliation of Statutory on Income and Social Contribution Taxes (Parenthetical) (Detail)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disclosure Of Reconciliation Of Expense On Income And Social Contribution Taxes [abstract]
Income tax and Social Contribution tax rate	34.00%	34.00%	34.00%

X

- Definition

Disclosure of reconciliation of expense on income and social contribution taxes.

+ References

No definition available.

+ Details

Name:	xcmig_DisclosureOfReconciliationOfExpenseOnIncomeAndSocialContributionTaxesAbstract
Namespace Prefix:	xcmig_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Income tax expense and social contribution tax rate

+ References

No definition available.

+ Details

Name:	xcmig_IncomeTaxExpenseAndSocialContributionTaxRate
Namespace Prefix:	xcmig_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration