XML 246 R225.htm IDEA: XBRL DOCUMENT
v3.25.1

Financial Instruments and Risk Management - Additional Information (Details) - BRL (R$) |  | 12 Months Ended |
--- | --- | --- | ---
Dec. 05, 2024 | Dec. 31, 2024 | Dec. 31, 2021 | Dec. 31, 2023
Financial instruments and risk management [line items] |  |  |  |
Interest on swap settled in cash flow |  | R$ (7,000,000) |  |
Percentage of fair value of loans and debentures on CDI rates |  | 111.43% |  |
Adjustment to fair value | R$ 381,110,000,000 |  |  |
Gain on cash flow hedge dismantled | 521,000,000 |  |  |
Hedge dismantled on cash inflow | R$ 443,000,000 |  |  |
Appreciation to excahange of foreign currencies, amount |  | R$ 5,700,000 |  |
Average foreign currencies exchange rate |  | 7.92 |  |
Estimated contract credits in arrears receivable |  | R$ 850,000,000 |  | R$ 868,000,000
Minimum equity required for concession of credit |  | R$ 800,000,000 |  |
Basel ratio percentage required above minimum set by regulating bank |  | 1.00% |  |
Percentage of estimated IPCA inflation index |  | 4.50% |  |
Percentage of estimated IGPM inflation index |  | 3.76% |  |
Percentage of maximum portfolio limit per bank entity |  | 30.00% |  |
Percentage of minimum fedreal risk concentrate |  | 50.00% |  |
Percentage of regulatory agent limits for consumer exposure |  | 100.00% |  |
Distribution service concession quality criteria period |  |  | three consecutive years |
Distribution service concession minimum parameters for economic and financial sustainability |  |  | two consecutive years |
Daily liquidity projection period |  | 180 days |  |
Minimum [Member] |  |  |  |
Financial instruments and risk management [line items] |  |  |  |
Percentage of fair value of loans and debentures on CDI rates |  | 0.47% |  |
Percentage of fair value of loans and debentures on IPCA |  | 4.10% |  |
Percentage of regulatory agent margin distributor supply |  | 95.00% |  |
Maximum [Member] |  |  |  |
Financial instruments and risk management [line items] |  |  |  |
Percentage of fair value of loans and debentures on CDI rates |  | 2.05% |  |
Percentage of fair value of loans and debentures on IPCA |  | 7.62% |  |
Percentage of regulatory agent margin distributor supply |  | 105.00% |  |
Probable Scenario [Member] |  |  |  |
Financial instruments and risk management [line items] |  |  |  |
Percentage of estimated IPCA inflation index |  | 4.50% |  |
Percentage of estimated IGPM inflation index |  | 3.76% |  |
Selic interest rate [Member] | Minimum [Member] |  |  |  |
Financial instruments and risk management [line items] |  |  |  |
Significant interest rate risk |  | 6.006% |  |
Selic interest rate [Member] | Maximum [Member] |  |  |  |
Financial instruments and risk management [line items] |  |  |  |
Significant interest rate risk |  | 9.009% |  |
Selic interest rate [Member] | Probable Scenario [Member] |  |  |  |
Financial instruments and risk management [line items] |  |  |  |
Significant interest rate risk |  | 15.00% |  |
TJLP interest rate [member] | Probable Scenario [Member] |  |  |  |
Financial instruments and risk management [line items] |  |  |  |
Significant interest rate risk |  | 7.94% |  |

X
- Definition Adjustment to fair value of options. + References No definition available. + Details
Name: | cig_AdjustmentToFairValueOfOptions
Namespace Prefix: | cig_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Basel ratio percentage required above minimum set by regulating bank. + References No definition available. + Details
Name: | cig_BaselRatioPercentageRequiredAboveMinimumSetByRegulatingBank
Namespace Prefix: | cig_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition The period of projection for daily liquidity. + References No definition available. + Details
Name: | cig_DailyLiquidityProjectionPeriod
Namespace Prefix: | cig_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Period of distribution service concession minimum parameters for economic and financial sustainability. + References No definition available. + Details
Name: | cig_DistributionServiceConcessionMinimumParametersForEconomicAndFinancialSustainabilityPeriod
Namespace Prefix: | cig_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Period of distribution service concession quality criteria. + References No definition available. + Details
Name: | cig_DistributionServiceConcessionQualityCriteriaPeriod
Namespace Prefix: | cig_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Estimated contract credits in arrears receivable. + References No definition available. + Details
Name: | cig_EstimatedContractCreditsInArrearsReceivable
Namespace Prefix: | cig_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Financial instruments and risk management. + References No definition available. + Details
Name: | cig_FinancialInstrumentsAndRiskManagementLineItems
Namespace Prefix: | cig_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Gain on cashflow hedge dismantled. + References No definition available. + Details
Name: | cig_GainOnCashflowHedgeDismantled
Namespace Prefix: | cig_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Hedge Dismantled on Cash Inflow + References No definition available. + Details
Name: | cig_HedgeDismantledOnCashInflow
Namespace Prefix: | cig_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Interest on swap settled in cash flow. + References No definition available. + Details
Name: | cig_InterestOnSwapSettledInCashFlow
Namespace Prefix: | cig_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Minimum equity required for concession of credit. + References No definition available. + Details
Name: | cig_MinimumEquityRequiredForConcessionOfCredit
Namespace Prefix: | cig_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Percentage of estimated general market prices index inflation index. + References No definition available. + Details
Name: | cig_PercentageOfEstimatedGeneralMarketPricesIndexInflationIndex
Namespace Prefix: | cig_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of estimated national consumer price index inflation index. + References No definition available. + Details
Name: | cig_PercentageOfEstimatedNationalConsumerPriceIndexInflationIndex
Namespace Prefix: | cig_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of reasonably possible unobservable input, assets and liabilities. + References No definition available. + Details
Name: | cig_PercentageOfEstimatedPossibleUnobservableInputAssetsAndLiabilities
Namespace Prefix: | cig_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Percentage of fair value of loans and debentures based on expanded national consumer price index rate. + References No definition available. + Details
Name: | cig_PercentageOfFairValueOfLoansAndDebenturesBasedOnExpandedNationalConsumerPriceIndexRate
Namespace Prefix: | cig_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of fair value of loans and debentures based on interbank deposit certificates rate. + References No definition available. + Details
Name: | cig_PercentageOfFairValueOfLoansAndDebenturesBasedOnInterbankDepositCertificatesRate
Namespace Prefix: | cig_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of maximum portfolio limit per bank entity. + References No definition available. + Details
Name: | cig_PercentageOfMaximumPortfolioLimitPerBankEntity
Namespace Prefix: | cig_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of minimum fedreal risk concentrate. + References No definition available. + Details
Name: | cig_PercentageOfMinimumFedrealRiskConcentrate
Namespace Prefix: | cig_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of regulatory agent limits for consumer exposure. + References No definition available. + Details
Name: | cig_PercentageOfRegulatoryAgentLimitsForConsumerExposure
Namespace Prefix: | cig_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of regulatory agent margin distributor supply. + References No definition available. + Details
Name: | cig_PercentageOfRegulatoryAgentMarginDistributorSupply
Namespace Prefix: | cig_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition The average exchange rate used by the entity. Exchange rate is the ratio of exchange for two currencies. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 1 -IssueDate 2024-01-01 -Paragraph 112 -Subparagraph c -URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2024-en-r&anchor=para_112_c&doctype=Standard -URIDate 2024-03-27 + Details
Name: | ifrs-full_AverageForeignExchangeRate
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:decimalItemType
Balance Type: | na
Period Type: | duration

X
- Definition The net gain arising from exchange differences recognised in profit or loss, excluding those arising on financial instruments measured at fair value through profit or loss in accordance with IFRS 9. [Refer: Foreign exchange gain (loss)] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 21 -IssueDate 2024-01-01 -Paragraph 52 -Subparagraph a -URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=21&code=ifrs-tx-2024-en-r&anchor=para_52_a&doctype=Standard -URIDate 2024-03-27 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 1 -IssueDate 2024-01-01 -Paragraph 35 -URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2024-en-r&anchor=para_35&doctype=Standard -URIDate 2024-03-27 + Details
Name: | ifrs-full_NetForeignExchangeGain
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | ifrs-full_RangeAxis=ifrs-full_BottomOfRangeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_RangeAxis=ifrs-full_TopOfRangeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_NonadjustingEventsAfterReportingPeriodAxis=cig_ProbableScenarioMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_UnobservableInputsAxis=cig_SelicInterestRateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_UnobservableInputsAxis=cig_TjlpInterestRateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |