XML 200 R173.htm IDEA: XBRL DOCUMENT
v3.20.1

26. POST-EMPLOYMENT OBLIGATIONS (Details 10) | 12 Months Ended
--- | ---
Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
Disclosure of defined benefit plans [line items] |  |  |  |
Real growth in contributions above inflation (1) | [1] | 1.00% | 1.00% |
Pension And Retirement Supplement Plans [Member] |  |  |  |
Disclosure of defined benefit plans [line items] |  |  |  |
Annual discount rate for present value of the actuarial obligation |  | 6.87% | 9.02% | 9.48%
Annual expected return on plan assets |  | 6.87% | 9.02% | 9.48%
Long-term annual inflation rate |  | 3.61% | 4.01% | 4.00%
Estimated future annual salary increases |  | 3.61% | 4.01% | 4.00%
General mortality table |  | AT-2000 M S10% D10% | AT-2000 M S10% D10% | AT-2000 M S10% D10%
Disability table |  | Not applicable | Not applicable | Not applicable
Disabled mortality table |  | AT-49 M | AT 49 M | AT 49 M
Health Plan [Member] |  |  |  |
Disclosure of defined benefit plans [line items] |  |  |  |
Annual discount rate for present value of the actuarial obligation |  | 7.09% | 9.60% | 9.60%
Annual expected return on plan assets |  |  |  | 9.60%
Long-term annual inflation rate |  | 3.61% | 4.00% | 4.00%
General mortality table |  | AT-2000 M S10% D20% | AT-2000 M S10% D20% | AT-2000 M S10% D20%
Disability table |  | Álvaro Vindas D30% | Álvaro Vindas D30% | Álvaro Vindas D30%
Disabled mortality table |  | MI-85 F | Winklevoss D30% | Winklevoss D30%
Real growth in contributions above inflation (1) | [1] |  | 1.00% |
Life Insurance Plan [Member] |  |  |  |
Disclosure of defined benefit plans [line items] |  |  |  |
Annual discount rate for present value of the actuarial obligation |  | 7.19% | 9.57% | 9.57%
Annual expected return on plan assets |  | 3.61% | 9.16% | 9.57%
Long-term annual inflation rate |  |  | 4.00% | 4.00%
Estimated future annual salary increases |  | 4.85% | 6.08% | 6.08%
General mortality table |  | AT-2000 M S10% D20% | AT-2000 M S10% D20% | AT-2000 M S10% D20%
Disability table |  | Álvaro Vindas D30% | Álvaro Vindas D30% | Álvaro Vindas D30%
Disabled mortality table |  | MI-85 F | Winklevoss D30% | Winklevoss D30%
[1] | Starting in 2018, Company adopted the assumption of real growth of the contributions above inflation at the rate of 1% p.a.

X
- Definition Actuarial assumption annual expected return on plan assets. + References No definition available. + Details
Name: | cig_ActuarialAssumptionAnnualExpectedReturnOnPlanAssets
Namespace Prefix: | cig_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Actuarial assumption disability rate. + References No definition available. + Details
Name: | cig_ActuarialAssumptionDisabilityRate
Namespace Prefix: | cig_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Actuarial assumption disabled mortality rate. + References No definition available. + Details
Name: | cig_ActuarialAssumptionDisabledMortalityRate
Namespace Prefix: | cig_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Actuarial assumption mortality rate. + References No definition available. + Details
Name: | cig_ActuarialAssumptionMortalityRate
Namespace Prefix: | cig_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Real growth in contributions above inflation. + References No definition available. + Details
Name: | cig_RealGrowthInContributionsAboveInflation
Namespace Prefix: | cig_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition The discount rate used as the significant actuarial assumption to determine the present value of a defined benefit obligation. [Refer: Defined benefit obligation, at present value; Actuarial assumptions [member]] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 19 -IssueDate 2019-01-01 -Paragraph 144 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=19&code=ifrs-tx-2019-en-r&anchor=para_144&doctype=Standard -URIDate 2019-03-27 + Details
Name: | ifrs-full_ActuarialAssumptionOfDiscountRates
Namespace Prefix: | ifrs-full_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition The expected rate of inflation that is used as a significant actuarial assumption to determine the present value of a defined benefit obligation. [Refer: Defined benefit plans [member]; Defined benefit obligation, at present value; Actuarial assumptions [member]] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 19 -IssueDate 2019-01-01 -Paragraph 144 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=19&code=ifrs-tx-2019-en-r&anchor=para_144&doctype=Standard -URIDate 2019-03-27 + Details
Name: | ifrs-full_ActuarialAssumptionOfExpectedRatesOfInflation
Namespace Prefix: | ifrs-full_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition The expected rate of salary increases used as a significant actuarial assumption to determine the present value of a defined benefit obligation. [Refer: Defined benefit plans [member]; Defined benefit obligation, at present value; Actuarial assumptions [member]] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 19 -IssueDate 2019-01-01 -Paragraph 144 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=19&code=ifrs-tx-2019-en-r&anchor=para_144&doctype=Standard -URIDate 2019-03-27 + Details
Name: | ifrs-full_ActuarialAssumptionOfExpectedRatesOfSalaryIncreases
Namespace Prefix: | ifrs-full_
Data Type: | num:percentItemType
Balance Type: | na
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_DisclosureOfDefinedBenefitPlansLineItems
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | ifrs-full_DefinedBenefitPlansAxis=cig_PensionAndRetirementSupplementPlansMember
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_LifeInsurancePlanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |