XML 146 R139.htm IDEA: XBRL DOCUMENT v3.19.1

Investments - Additional Information (Detail) R$ in Millions						12 Months Ended
	Nov. 30, 2018 BRL (R$)	Nov. 27, 2018 BRL (R$)	May 17, 2018 BRL (R$)	Apr. 23, 2018 BRL (R$)	Apr. 10, 2018 BRL (R$) Installments	Dec. 31, 2018 BRL (R$)	Dec. 31, 2017 BRL (R$)	Dec. 31, 2016 BRL (R$)	Dec. 31, 2014 BRL (R$)	Dec. 20, 2018
Disclosure of detailed information about investment property [line items]
Payment of debit related to FID					R$ 738
Number of FID payments installments | Installments					36
Investment Write Downs						R$ 183
Loss recognized						1,742	R$ 1,002	R$ 334
Accumulated loss						R$ (1,938)	(1,476)
Negative equity				R$ 999
RME [member]
Disclosure of detailed information about investment property [line items]
Fair value of shares acquired	R$ 104
Loss upon valuation put option	R$ 556
Parajuru, Volta do Rio and Morgado [member]
Disclosure of detailed information about investment property [line items]
Percentage Of Minority Interest						49.00%
Cemig GT [member] | Light SA [member]
Disclosure of detailed information about investment property [line items]
Percentage of equity interest acquired						49.99%
Cemig GT [member] | Parajuru and Volta do Rio [member]
Disclosure of detailed information about investment property [line items]
Percentage of equity interest acquired										51.00%
Cemig GT [member] | Morgado [member]
Disclosure of detailed information about investment property [line items]
Percentage of equity interest acquired										49.00%
Cemig GT [member] | Parajuru, Volta do Rio and Morgado [member]
Disclosure of detailed information about investment property [line items]
Percentage of interest in investment property			49.00%
Adjustment of acquisition price of investees			R$ 37
Cemig GT [member] | RME [member]
Disclosure of detailed information about investment property [line items]
Percentage of equity interest acquired	100.00%
SAAG Investimentos S.A. and Ceming GT [Member]
Disclosure of detailed information about investment property [line items]
Payments for claims									R$ 750
Adjustments for impairment									R$ 750
Cemig GT [member]
Disclosure of detailed information about investment property [line items]
Investment Write Downs							679
Belo Monte Plant Through Amaznia Energia SAA and Aliana Norte [member]
Disclosure of detailed information about investment property [line items]
Percentage of indirect equity interest						11.69%
Negative net working capital						R$ 2,762	2,651
Belo Monte Plant Through Amaznia Energia S A A And Alianca Norte[member]
Disclosure of detailed information about investment property [line items]
Loss contingencies						1,643	286
Madeira Energia SA Mesa and FIP Melbourne [member]
Disclosure of detailed information about investment property [line items]
Loss contingencies						1,743	1,091	617
Current liabilities in excess of consolidated current assets						663	1,474
Renova Energia SA [member]
Disclosure of detailed information about investment property [line items]
Current liabilities in excess of consolidated current assets						(458)	(1,607)
Loss recognized						(856)	(1,139)	R$ (1,101)
Accumulated loss						(3,051)	R$ (2,195)
Negative equity						76
Carrying value of equity interest						R$ 0
Light SA [member] | RME [member]
Disclosure of detailed information about investment property [line items]
Loss recognized		R$ 7
Aggregate direct and indirect equity position		48.90%
Percentage of equity interest sold	25.00%	2.13%
Aggregate direct and indirect equity position	R$ 659	R$ 65

X

- Definition

The amount of accumulated items of income and expense (including reclassification adjustments) that are not recognised in profit or loss as required or permitted by other IFRSs. [Refer: IFRSs [member]; Other comprehensive income]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2018-01-01
-Paragraph 55
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2018-03-01&anchor=para_55&doctype=Standard
-URIDate 2018-03-16

+ Details

Name:	ifrs-full_AccumulatedOtherComprehensiveIncome
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

The increase (decrease) in equity. [Refer: Equity]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2018-01-01
-Paragraph 106
-Subparagraph d
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2018-03-01&anchor=para_106_d&doctype=Standard
-URIDate 2018-03-16

+ Details

Name:	ifrs-full_ChangesInEquity
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Definition

The amount of current assets less the amount of current liabilities.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2018-01-01
-Paragraph 55
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2018-03-01&anchor=para_55&doctype=Standard
-URIDate 2018-03-16

+ Details

Name:	ifrs-full_CurrentAssetsLiabilities
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

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

X

- Definition

The fair value of receivables acquired in a business combination. [Refer: Business combinations [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 3
-IssueDate 2018-01-01
-Paragraph B64
-Subparagraph h
-Clause i
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=3&date=2018-03-01&anchor=para_B64_h_i&doctype=Appendix&seq=2
-URIDate 2018-03-16

+ Details

Name:	ifrs-full_FairValueOfAcquiredReceivables
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

The increase (decrease) in working capital.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 7
-IssueDate 2018-01-01
-Paragraph 20
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=7&date=2018-03-01&anchor=para_20&doctype=Standard
-URIDate 2018-03-16

+ Details

Name:	ifrs-full_IncreaseDecreaseInWorkingCapital
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Definition

The percentage of voting equity interests acquired in a business combination. [Refer: Business combinations [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 3
-IssueDate 2018-01-01
-Paragraph B64
-Subparagraph c
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=3&date=2018-03-01&anchor=para_B64_c&doctype=Appendix&seq=2
-URIDate 2018-03-16

+ Details

Name:	ifrs-full_PercentageOfVotingEquityInterestsAcquired
Namespace Prefix:	ifrs-full_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

X

- Definition

The total of income less expenses from continuing and discontinued operations, excluding the components of other comprehensive income. [Refer: Other comprehensive income]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 7
-IssueDate 2018-01-01
-Paragraph 18
-Subparagraph b
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=7&date=2018-03-01&anchor=para_18_b&doctype=Standard
-URIDate 2018-03-16

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 1
-IssueDate 2018-01-01
-Paragraph 24
-Subparagraph b
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=1&date=2018-03-01&anchor=para_24_b&doctype=Standard
-URIDate 2018-03-16

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 1
-IssueDate 2018-01-01
-Paragraph 32
-Subparagraph a
-Clause ii
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=1&date=2018-03-01&anchor=para_32_a_ii&doctype=Standard
-URIDate 2018-03-16

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 8
-IssueDate 2018-01-01
-Paragraph 28
-Subparagraph b
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=8&date=2018-03-01&anchor=para_28_b&doctype=Standard
-URIDate 2018-03-16

Reference 5: http://www.xbrl.org/2003/role/exampleRef
-Note Effective on first application of IFRS 9
-Name IFRS
-Number 4
-IssueDate 2018-01-01
-Paragraph 39L
-Subparagraph e
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=4&date=2018-03-02&anchor=para_39L_e&doctype=Standard&book=b
-URIDate 2018-03-16

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 8
-IssueDate 2018-01-01
-Paragraph 23
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=8&date=2018-03-01&anchor=para_23&doctype=Standard
-URIDate 2018-03-16

Reference 7: http://www.xbrl.org/2003/role/exampleRef
-Name IFRS
-Number 12
-IssueDate 2018-01-01
-Paragraph B10
-Subparagraph b
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=12&date=2018-03-01&anchor=para_B10_b&doctype=Appendix&seq=2
-URIDate 2018-03-16

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2018-01-01
-Paragraph 106
-Subparagraph d
-Clause i
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2018-03-01&anchor=para_106_d_i&doctype=Standard
-URIDate 2018-03-16

Reference 9: http://www.xbrl.org/2003/role/exampleRef
-Note Effective 2021-01-01
-Name IFRS
-Number 17
-IssueDate 2018-01-01
-Paragraph 113
-Subparagraph b
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=17&date=2018-03-01&anchor=para_113_b&doctype=Standard
-URIDate 2018-03-16

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2018-01-01
-Paragraph 81A
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2018-03-01&anchor=para_81A_a&doctype=Standard
-URIDate 2018-03-16

+ Details

Name:	ifrs-full_ProfitLoss
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Definition

The amount of regulatory deferral account debit balances. [Refer: Regulatory deferral account balances [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 14
-IssueDate 2018-01-01
-Paragraph 20
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=14&date=2018-03-01&anchor=para_20_a&doctype=Standard
-URIDate 2018-03-16

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 14
-IssueDate 2018-01-01
-Paragraph 33
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=14&date=2018-03-01&anchor=para_33_a&doctype=Standard
-URIDate 2018-03-16

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 14
-IssueDate 2018-01-01
-Paragraph 35
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=14&date=2018-03-01&anchor=para_35&doctype=Standard
-URIDate 2018-03-16

+ Details

Name:	ifrs-full_RegulatoryDeferralAccountDebitBalances
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

The amount of reversal of impairment loss recognised in profit or loss. [Refer: Reversal of impairment loss; Profit (loss)]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 36
-IssueDate 2018-01-01
-Paragraph 126
-Subparagraph b
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=36&date=2018-03-01&anchor=para_126_b&doctype=Standard
-URIDate 2018-03-16

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 36
-IssueDate 2018-01-01
-Paragraph 129
-Subparagraph b
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=36&date=2018-03-01&anchor=para_129_b&doctype=Standard
-URIDate 2018-03-16

+ Details

Name:	ifrs-full_ReversalOfImpairmentLossRecognisedInProfitOrLoss
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Definition

Adjustment of acquisition price of investees

+ References

No definition available.

+ Details

Name:	xcmig_AdjustmentOfAcquisitionPriceOfInvestees
Namespace Prefix:	xcmig_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Definition

Adjustments for impairment.

+ References

No definition available.

+ Details

Name:	xcmig_AdjustmentsForImpairment
Namespace Prefix:	xcmig_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

Equity interest, carrying value.

+ References

No definition available.

+ Details

Name:	xcmig_EquityInterestCarryingValue
Namespace Prefix:	xcmig_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

Gain (loss) upon valuation of put option.

+ References

No definition available.

+ Details

Name:	xcmig_GainLossUponValuationOfPutOption
Namespace Prefix:	xcmig_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Definition

Loss contingencies.

+ References

No definition available.

+ Details

Name:	xcmig_LossContingencies
Namespace Prefix:	xcmig_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

Number of FID payment installments.

+ References

No definition available.

+ Details

Name:	xcmig_NumberOfFIDPaymentInstallments
Namespace Prefix:	xcmig_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Payments for claims.

+ References

No definition available.

+ Details

Name:	xcmig_PaymentsForClaims
Namespace Prefix:	xcmig_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

Percentage of equity interest.

+ References

No definition available.

+ Details

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

X

- Definition

Percentage of equity interest sold.

+ References

No definition available.

+ Details

Name:	xcmig_PercentageOfEquityInterestSold
Namespace Prefix:	xcmig_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Percentage of indiret equity interest.

+ References

No definition available.

+ Details

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

X

- Definition

Percentage of interest in investment property.

+ References

No definition available.

+ Details

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

X

- Definition

Percentage of minority interest.

+ References

No definition available.

+ Details

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

X

- Definition

Value of equity interest sold.

+ References

No definition available.

+ Details

Name:	xcmig_ValueOfEquityInterestSold
Namespace Prefix:	xcmig_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Details

Name:	ifrs-full_TypesOfInvestmentPropertyAxis=xcmig_RmeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_TypesOfInvestmentPropertyAxis=xcmig_ParajuruVoltaDoRioAndMorgadoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

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

X

- Details

Name:	ifrs-full_BusinessCombinationsAxis=xcmig_LightSAMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_BusinessCombinationsAxis=xcmig_ParajuruAndVoltaDoRioMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_BusinessCombinationsAxis=xcmig_MorgadoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_BusinessCombinationsAxis=xcmig_ParajuruVoltaDoRioAndMorgadoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_CategoriesOfRelatedPartiesAxis=xcmig_SAAGInvestimentosSAAndCemingGTMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_CategoriesOfRelatedPartiesAxis=xcmig_CemigGTMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_CategoriesOfRelatedPartiesAxis=xcmig_BeloMontePlantThroughAmazniaEnergiaSaaAndAlianaNorteMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_CategoriesOfRelatedPartiesAxis=xcmig_BeloMontePlantThroughAmazniaEnergiaSAAAndAliancaNorteMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_CategoriesOfRelatedPartiesAxis=xcmig_MadeiraEnergiaSAMesaAndFIPMelbourneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_CategoriesOfRelatedPartiesAxis=xcmig_RenovaEnergiaSAMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_CategoriesOfRelatedPartiesAxis=xcmig_LightSAMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: