XML 107 R100.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Restricted Cash - Additional Information (Detail) - BRL (R$) R$ in Millions | Dec. 31, 2017 | Dec. 31, 2016
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Disclosure Of Restricted Cash And Cash Equivalents [Abstract] |  |
Restricted cash | R$ 106 | R$ 367

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- Definition The amount of cash and cash equivalents whose use or withdrawal is restricted. [Refer: Cash and cash equivalents] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 1 -IssueDate 2017-01-01 -Paragraph 55 -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2017-03-01&anchor=para_55&doctype=Standard -URIDate 2017-03-09 + Details
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Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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- Definition Disclosure of restricted cash and cash equivalents abstract. + References No definition available. + Details
Name: | xcmig_DisclosureOfRestrictedCashAndCashEquivalentsAbstract
Namespace Prefix: | xcmig_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration