XML 191 R170.htm IDEA: XBRL DOCUMENT v3.25.1

Post-Employment Obligations - Additional Information (Details) - BRL (R$) R$ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2022
IfrsStatementLineItems [Line Items]
Remuneratory interest applicable on outstanding balance			5.51%	5.70%	6.00%
Deficit paid			R$ 1,207	R$ 1,207	R$ 1,207
Finance expenses and monetary updating on debt	R$ 3	R$ 20
Expected contributions to pension plan for amortization of deficit	87
Expected contributions to defined contribution plan	R$ 93
Inflation index rate	6.00%
Net defined benefit liability (asset)	R$ 13,105	15,276	R$ 15,561			R$ 14,778
Funded Benefit Plan ('Plan A') [member]
IfrsStatementLineItems [Line Items]
Benefit amount payable	R$ 494	545
Description of monthly amortizations	The monthly amortizations, calculated by the constant installments system (Price Table), will be paid up to 2031 for the 2015 and 2016 deficits, in the amount of R$323, and up to 2033 for the 2017 deficit, in the amount of R$171.
Remuneratory interest applicable on outstanding balance	6.00%
Funded Benefit Plan ('Plan A') [member] | Forluz [Member]
IfrsStatementLineItems [Line Items]
Percentage of minimum amount payments into judicial deposit account	50.00%
Monthly amount of deposits percentage of deficit equalizations			50.00%	50.00%	50.00%
Forluz Pension Fund [member]
IfrsStatementLineItems [Line Items]
Inflation index rate	6.00%
Health plan [member]
IfrsStatementLineItems [Line Items]
Net defined benefit liability (asset)	R$ 2,559	3,007	R$ 3,469			3,314
Dental plan [member]
IfrsStatementLineItems [Line Items]
Net defined benefit liability (asset)	45	53	R$ 66			R$ 60
Life Insurance [Member]
IfrsStatementLineItems [Line Items]
Past service cost arising from cancellation of post-retirement obligation	R$ 485	R$ 591

X

- Definition

Deficit Paid

+ References

No definition available.

+ Details

Name:	cig_DeficitPaid
Namespace Prefix:	cig_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

Represent information about the description of monthly amortizations.

+ References

No definition available.

+ Details

Name:	cig_DescriptionOfMonthlyAmortizations
Namespace Prefix:	cig_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Expected contributions to be paid to defined contribution plan.

+ References

No definition available.

+ Details

Name:	cig_ExpectedContributionsToBePaidToDefinedContributionPlan
Namespace Prefix:	cig_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Definition

Expected contributions to be paid to plan for amortization of deficit.

+ References

No definition available.

+ Details

Name:	cig_ExpectedContributionsToBePaidToPlanForAmortizationOfDeficit
Namespace Prefix:	cig_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Definition

Finance expenses and monetary updating on debt, defined benefit plans.

+ References

No definition available.

+ Details

Name:	cig_FinanceExpensesAndMonetaryUpdatingOnDebtDefinedBenefitPlans
Namespace Prefix:	cig_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

Ifrs Statement Line Items

+ References

No definition available.

+ Details

Name:	cig_IfrsStatementLineItems
Namespace Prefix:	cig_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

The information represents the inflation index rate.

+ References

No definition available.

+ Details

Name:	cig_InflationIndexRate
Namespace Prefix:	cig_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

X

- Definition

The information represents the interest rate on benefit plan.

+ References

No definition available.

+ Details

Name:	cig_InterestRateOnBenefitPlan
Namespace Prefix:	cig_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Percentage monthly amount of deposits of deficit equalizations.

+ References

No definition available.

+ Details

Name:	cig_MonthlyAmountOfDepositsPercentageOfDeficitEqualizations
Namespace Prefix:	cig_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Percentage of minimum amount payments into judicial deposit account.

+ References

No definition available.

+ Details

Name:	cig_PercentageOfMinimumAmountPaymentsIntoJudicialDepositAccount
Namespace Prefix:	cig_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

X

- Definition

The amount of benefits paid or payable for retirement benefit plans.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 26
-IssueDate 2024-01-01
-Paragraph 35
-Subparagraph b
-Clause v
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=26&code=ifrs-tx-2024-en-r&anchor=para_35_b_v&doctype=Standard
-URIDate 2024-03-27

+ Details

Name:	ifrs-full_BenefitsPaidOrPayable
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

The amount of deficit or surplus in a defined benefit plan, adjusted for any effect of limiting a net defined benefit asset to the asset ceiling. [Refer: Defined benefit plans [domain]]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 19
-IssueDate 2024-01-01
-Paragraph 140
-Subparagraph a
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2024-en-r&anchor=para_140_a&doctype=Standard
-URIDate 2024-03-27

+ Details

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

X

- Definition

The amount of expense (income) resulting from past service cost. Past service cost is the change in the present value of the defined benefit obligation for employee service in prior periods, resulting from a plan amendment (the introduction or withdrawal of, or changes to, a defined benefit plan) or a curtailment (a significant reduction by the entity in the number of employees covered by a plan). [Refer: Post-employment benefit expense in profit or loss, defined benefit plans; Defined benefit plans [domain]] [Contrast: Increase (decrease) in net defined benefit liability (asset) resulting from past service cost]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 19
-IssueDate 2024-01-01
-Paragraph 135
-Subparagraph b
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2024-en-r&anchor=para_135_b&doctype=Standard
-URIDate 2024-03-27

+ Details

Name:	ifrs-full_PastServiceCostDefinedBenefitPlans
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Details

Name:	ifrs-full_DefinedBenefitPlansAxis=cig_FundedBenefitPlanPlanAMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	srt_CounterpartyNameAxis=cig_ForluzMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_DefinedBenefitPlansAxis=cig_ForluzPensionFundMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_DefinedBenefitPlansAxis=cig_HealthPlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_DefinedBenefitPlansAxis=cig_DentalPlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_DefinedBenefitPlansAxis=cig_LifeInsuranceMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: