XML 98 R91.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Customers, Traders and Power Transport Concession Holders - Summary of Advances from Customers (Detail) R$ in Millions | 12 Months Ended
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Dec. 31, 2017 BRL (R$)
Disclosure Of Advances From Customers [line items] |
Beginning Balance | R$ 181
Ending Balance | 233
Cemig GT [member] |
Disclosure Of Advances From Customers [line items] |
Beginning Balance | 181
Addition | 325
Supply completed | (318)
Monetary adjustment | 45
Ending Balance | R$ 233

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- Definition The amount of current payments received for goods or services to be provided in the future. [Refer: Advances received] + 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
Name: | ifrs-full_CurrentAdvances
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

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- Definition Additions to advances payable. + References No definition available. + Details
Name: | xcmig_AdditionsToAdvancesPayable
Namespace Prefix: | xcmig_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

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- Definition Disclosure Of Advances From Customers [line items] + References No definition available. + Details
Name: | xcmig_DisclosureOfAdvancesFromCustomersLineItems
Namespace Prefix: | xcmig_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

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- Definition Monetary adjustment on advance payable. + References No definition available. + Details
Name: | xcmig_MonetaryAdjustmentOnAdvancePayable
Namespace Prefix: | xcmig_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

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- Definition Supply of energy completed. + References No definition available. + Details
Name: | xcmig_SupplyOfEnergyCompleted
Namespace Prefix: | xcmig_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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- Details
Name: | ifrs-full_SignificantInvestmentsInSubsidiariesAxis=xcmig_CemigGTMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |