XML 139 R132.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Taxes, Income Tax and Social Contribution - Additional Information (Detail) R$ in Millions, $ in Millions | 1 Months Ended | 12 Months Ended
--- | --- | ---
Oct. 31, 2017 BRL (R$) | Dec. 31, 2017 BRL (R$) Installment | Dec. 31, 2017 USD ($) Installment | Dec. 31, 2016 BRL (R$) | Dec. 31, 2015 BRL (R$)
Disclosure of taxes payable [line items] |  |  |  |  |
Tax credits regularization amout | $ |  |  | $ 532 |  |
Taxes on revenues |  | R$ 8,547 |  | R$ 7,702 | R$ 7,247
PRCT [member] |  |  |  |  |
Disclosure of taxes payable [line items] |  |  |  |  |
Tax credits regularization amout |  | 595 |  |  |
Installments settlement paid |  | 282 |  |  |
Installments settlement unpaid |  | 283 |  |  |
ICMS [member] |  |  |  |  |
Disclosure of taxes payable [line items] |  |  |  |  |
Tax credits regularization amout |  | 214 |  |  |
Taxes on revenues |  | 5,847 |  | R$ 5,211 | R$ 4,487
Cemig D [member] |  |  |  |  |
Disclosure of taxes payable [line items] |  |  |  |  |
Write down tax expense |  | 1,087 |  |  |
Escrow deposits |  | 1,110 |  |  |
Taxes on revenues |  | 23 |  |  |
Cemig D [member] | PRCT [member] |  |  |  |  |
Disclosure of taxes payable [line items] |  |  |  |  |
Tax credits regularization amout |  | R$ 558 |  |  |
Percentage of reduction in interest and penalty payments |  | 90.00% | 90.00% |  |
Number of installments | Installment |  | 6 | 6 |  |
Selic rate |  | 50.00% | 50.00% |  |
Cemig GT [member] |  |  |  |  |
Disclosure of taxes payable [line items] |  |  |  |  |
Provision for income tax |  | R$ 101 |  |  |
Cemig GT [member] | PRCT [member] |  |  |  |  |
Disclosure of taxes payable [line items] |  |  |  |  |
Tax credits regularization amout | R$ 30 |  |  |  |
Percentage of reduction in interest and penalty payments | 95.00% |  |  |  |

X
- Definition Amount in escrow deposits + References No definition available. + Details
Name: | xcmig_AmountInEscrowDeposits
Namespace Prefix: | xcmig_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Disclosure of taxes payable [line items]. + References No definition available. + Details
Name: | xcmig_DisclosureOfTaxesPayableLineItems
Namespace Prefix: | xcmig_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of installments + References No definition available. + Details
Name: | xcmig_NumberOfInstallments
Namespace Prefix: | xcmig_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of tax liability excluding interest and penalty. + References No definition available. + Details
Name: | xcmig_PercentageOfTaxLiabilityExcludingInterestAndPenalty
Namespace Prefix: | xcmig_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Provision for income tax. + References No definition available. + Details
Name: | xcmig_ProvisionForIncomeTax
Namespace Prefix: | xcmig_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Selic rate. + References No definition available. + Details
Name: | xcmig_SelicRate
Namespace Prefix: | xcmig_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tax credits regularization plan amount. + References No definition available. + Details
Name: | xcmig_TaxCreditsRegularizationPlanAmount
Namespace Prefix: | xcmig_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Tax liabilities settlement paid. + References No definition available. + Details
Name: | xcmig_TaxLiabilitiesSettlementPaid
Namespace Prefix: | xcmig_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Tax settlement amount payable. + References No definition available. + Details
Name: | xcmig_TaxSettlementAmountPayable
Namespace Prefix: | xcmig_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Taxes on revenues. + References No definition available. + Details
Name: | xcmig_TaxesOnRevenues
Namespace Prefix: | xcmig_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Wrote-down other income and expenses + References No definition available. + Details
Name: | xcmig_WrotedownOtherIncomeAndExpenses
Namespace Prefix: | xcmig_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | xcmig_DeferredTaxAssetsAndLiabilitiesAxis=xcmig_PrctMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_TypesOfRateregulatedActivitiesAxis=xcmig_ICMSTaxesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_BorrowingsByNameAxis=xcmig_CemigDMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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