XML 100 R79.htm IDEA: XBRL DOCUMENT
v3.21.1

2. BASIS OF PREPARATION (Details1) - BRL (R$) R$ / shares in Units, R$ in Millions |  |  | 12 Months Ended
--- | --- | --- | ---
Apr. 30, 2021 | Jan. 02, 2019 | Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
CONTINUING OPERATIONS |  |  |  |  |  |  |  |  |
NET REVENUE |  |  |  |  | R$ 25,228 | R$ 25,487 | [1] | R$ 22,266 |
TOTAL COST |  |  |  |  | (19,845) |  |  |  |
GROSS PROFIT |  |  |  |  | 5,383 |  |  |  |
OPERATING EXPENSES |  |  |  |  | (1,587) |  |  |  |
Share of profit (loss), net, of affiliates and jointly-controlled entities |  |  |  |  | 357 | 125 | [1] | (104) |
Dividends declared by investee classified as held for sale |  |  |  |  |  |  |  |  |
Remeasurement of previously held equity interest in subsidiaries acquired |  |  |  |  |  |  |  | (119) |
Impairment loss on investments |  |  |  |  |  |  |  | (127) |
Net finance income |  |  |  |  | 2,445 | 3,207 | [1] | 1,706 |
Income before income tax and social contribution tax |  |  |  |  | 3,801 | 4,469 | [1] | 2,011 |
Current income tax and social contribution tax |  |  |  |  | (684) |  |  |  |
Deferred income tax and social contribution tax |  |  |  |  | (252) |  |  |  |
Net income for the year from continuing operations |  |  |  |  | 2,865 | 2,969 | [1] | 1,401 | [1]
DISCONTINUED OPERATIONS |  |  |  |  |  |  |  |  |
Net income after tax for the year from discontinued operations |  |  |  |  |  | 224 | [1] | 363 | [1]
NET INCOME FOR THE YEAR |  | R$ 2,864 |  |  | 2,865 | 3,194 | [1] | 1,764 | [1]
Equity holders of the parent |  |  |  |  |  |  |  |  |
Net income from continuing operations |  |  |  |  | 2,864 |  |  |  |
Net income for the year attributed to equity holders of the parent |  |  |  |  | 2,864 |  |  |  |
Non-controlling interests |  |  |  |  |  |  |  |  |
Net income from continuing operations |  |  |  |  | 1 |  |  |  |
NET INCOME FOR THE YEAR |  |  |  |  | R$ 1 | 1 | [1] | 42 |
Basic and diluted earnings per preferred share - R$ |  |  |  |  | R$ 1.69 |  |  |  |
Basic and diluted earnings per common share - R$ |  |  |  |  | 1.69 |  |  |  |
Basic and diluted earnings per preferred share from continuing operations - R$ |  |  |  |  | 1.69 |  |  |  |
Basic and diluted earnings per common share from continuing operations - R$ |  |  |  |  | 1.69 |  |  |  |
Basic and diluted earnings per preferred share from discontinued operations - R$ |  |  |  |  |  |  |  |  |
Basic and diluted earnings per common share from discontinued operations - R$ |  |  |  |  |  |  |  |  |
As presented [member] |  |  |  |  |  |  |  |  |
CONTINUING OPERATIONS |  |  |  |  |  |  |  |  |
NET REVENUE | [2] |  | R$ 22,266 |  |  | 25,390 |  |  |
TOTAL COST |  |  | (17,677) |  |  | (19,598) |  |  |
GROSS PROFIT |  |  | 4,589 |  |  | 5,792 |  |  |
OPERATING EXPENSES | [3] |  | (1,743) |  |  | (2,881) |  |  |
Share of profit (loss), net, of affiliates and jointly-controlled entities |  |  | (104) |  |  | 125 |  |  |
Dividends declared by investee classified as held for sale |  |  |  |  |  | 73 |  |  |
Remeasurement of previously held equity interest in subsidiaries acquired |  |  | (119) |  |  |  |  |  |
Impairment loss on investments |  |  | (127) |  |  |  |  |  |
Net finance income |  |  | (518) |  |  | 1,360 |  |  |
Income before income tax and social contribution tax |  |  | 1,978 |  |  | 4,469 |  |  |
Current income tax and social contribution tax |  |  | (583) |  |  | (1,454) |  |  |
Deferred income tax and social contribution tax | [4] |  | (16) |  |  | (111) |  |  |
Net income for the year from continuing operations |  |  | 1,379 |  |  | 2,904 |  | 1,379 |
DISCONTINUED OPERATIONS |  |  |  |  |  |  |  |  |
Net income after tax for the year from discontinued operations |  |  | 363 |  |  | 224 |  | 363 |
NET INCOME FOR THE YEAR |  |  | 1,742 |  |  | 3,128 |  | 1,742 |
Equity holders of the parent |  |  |  |  |  |  |  |  |
Net income from continuing operations |  |  | 1,378 |  |  | 2,903 |  |  |
Net income from discontinued operations |  |  | 322 |  |  | 224 |  |  |
Net income for the year attributed to equity holders of the parent |  |  | 1,700 |  |  | 3,127 |  |  |
Non-controlling interests |  |  |  |  |  |  |  |  |
Net income from continuing operations |  |  | 1 |  |  | 1 |  |  |
Net income from discontinued operations |  |  | 41 |  |  |  |  |  |
NET INCOME FOR THE YEAR |  |  | R$ 1,742 |  |  | R$ 3,128 |  |  |
Basic and diluted earnings per preferred share - R$ | [5] |  | R$ 1.17 |  |  | R$ 2.06 |  |  |
Basic and diluted earnings per common share - R$ | [5] |  | 1.17 |  |  | 2.06 |  |  |
Basic and diluted earnings per preferred share from continuing operations - R$ | [5] |  | 0.95 |  |  | 1.91 |  |  |
Basic and diluted earnings per common share from continuing operations - R$ | [5] |  | 0.95 |  |  | 1.91 |  |  |
Basic and diluted earnings per preferred share from discontinued operations - R$ | [5] |  | 0.22 |  |  | 0.15 |  |  |
Basic and diluted earnings per common share from discontinued operations - R$ | [5] |  | R$ 0.22 |  |  | R$ 0.15 |  |  |
Adjustment [member] |  |  |  |  |  |  |  |  |
CONTINUING OPERATIONS |  |  |  |  |  |  |  |  |
NET REVENUE | [2] |  | R$ 33 |  |  | R$ 96 |  |  |
GROSS PROFIT |  |  | 33 |  |  | 96 |  |  |
OPERATING EXPENSES | [3] |  |  |  |  | 5 |  |  |
Share of profit (loss), net, of affiliates and jointly-controlled entities |  |  |  |  |  |  |  |  |
Dividends declared by investee classified as held for sale |  |  |  |  |  |  |  |  |
Remeasurement of previously held equity interest in subsidiaries acquired |  |  |  |  |  |  |  |  |
Impairment loss on investments |  |  |  |  |  |  |  |  |
Net finance income |  |  |  |  |  |  |  |  |
Income before income tax and social contribution tax |  |  | 33 |  |  | 101 |  |  |
Current income tax and social contribution tax |  |  |  |  |  |  |  |  |
Deferred income tax and social contribution tax | [4] |  | (11) |  |  | (34) |  |  |
Net income for the year from continuing operations |  |  | 22 |  |  | 65 |  | 22 |
DISCONTINUED OPERATIONS |  |  |  |  |  |  |  |  |
Net income after tax for the year from discontinued operations |  |  |  |  |  |  |  |  |
NET INCOME FOR THE YEAR |  |  | 22 |  |  | 65 |  | 22 |
Equity holders of the parent |  |  |  |  |  |  |  |  |
Net income from continuing operations |  |  | 22 |  |  | 67 |  |  |
Net income from discontinued operations |  |  |  |  |  |  |  |  |
Net income for the year attributed to equity holders of the parent |  |  | 22 |  |  | 67 |  |  |
Non-controlling interests |  |  |  |  |  |  |  |  |
Net income from continuing operations |  |  |  |  |  |  |  |  |
Net income from discontinued operations |  |  |  |  |  |  |  |  |
NET INCOME FOR THE YEAR |  |  | R$ 22 |  |  | R$ 65 |  |  |
Basic and diluted earnings per preferred share - R$ | [5] |  | R$ (0.15) |  |  | R$ 0.17 |  |  |
Basic and diluted earnings per common share - R$ | [5] |  | (0.15) |  |  | 0.17 |  |  |
Basic and diluted earnings per preferred share from continuing operations - R$ | [5] |  | (0.12) |  |  | 0.14 |  |  |
Basic and diluted earnings per common share from continuing operations - R$ | [5] |  | (0.12) |  |  | 0.14 |  |  |
Basic and diluted earnings per preferred share from discontinued operations - R$ | [5] |  | (0.03) |  |  | 0.01 |  |  |
Basic and diluted earnings per common share from discontinued operations - R$ | [5] |  | R$ (0.03) |  |  | R$ 0.01 |  |  |
Restated [member] |  |  |  |  |  |  |  |  |
CONTINUING OPERATIONS |  |  |  |  |  |  |  |  |
NET REVENUE |  |  | R$ 22,299 | [1] |  | R$ 25,486 | [2],[6] | 22,299 | [6]
TOTAL COST |  |  | (17,677) | [1] |  | (19,598) | [6] | (17,677) | [6]
GROSS PROFIT |  |  | 4,622 | [1] |  | 5,888 | [6] | 4,622 | [6]
OPERATING EXPENSES |  |  | (1,743) | [1] |  | (2,876) | [3],[6] | (1,743) | [6]
Share of profit (loss), net, of affiliates and jointly-controlled entities |  |  | (104) | [1] |  | 125 | [6] | (104) | [6]
Dividends declared by investee classified as held for sale | [6] |  |  |  |  | (73) |  |  |
Remeasurement of previously held equity interest in subsidiaries acquired |  |  | (119) | [1] |  |  | [6] | (119) | [6]
Impairment loss on investments |  |  | (127) | [1] |  |  | [6] | (127) | [6]
Net finance income | [1] |  | (518) |  |  | 1,360 |  |  |
Income before income tax and social contribution tax |  |  | 2,011 | [1] |  | 4,570 | [6] | 2,011 | [6]
Current income tax and social contribution tax |  |  | (583) | [1] |  | (1,454) | [6] | (583) | [6]
Deferred income tax and social contribution tax |  |  | (27) | [1] |  | (145) | [5],[6] | (27) | [6]
Net income for the year from continuing operations |  |  | 1,401 | [1] |  | 2,971 | [6] | 1,401 | [6]
DISCONTINUED OPERATIONS |  |  |  |  |  |  |  |  |
Net income after tax for the year from discontinued operations |  |  | 363 | [1] |  | 224 | [6] | 363 | [6]
NET INCOME FOR THE YEAR |  |  | 1,764 | [1] |  | 3,195 | [6] | 1,764 | [6]
Equity holders of the parent |  |  |  |  |  |  |  |  |
Net income from continuing operations |  |  | 1,400 | [1] |  | 2,970 | [6] | 1,400 | [6]
Net income from discontinued operations |  |  | 322 | [1] |  | 224 | [6] | 322 | [6]
Net income for the year attributed to equity holders of the parent |  |  | 1,722 | [1] |  | 3,194 | [6] | 1,722 | [6]
Non-controlling interests |  |  |  |  |  |  |  |  |
Net income from continuing operations |  |  | 1 | [1] |  | 1 | [6] | 1 | [6]
Net income from discontinued operations |  |  | 41 | [1] |  |  | [6] | 41 | [6]
NET INCOME FOR THE YEAR |  |  | R$ 42 | [1] |  | R$ 1 | [6] | R$ 42 | [6]
Basic and diluted earnings per preferred share - R$ |  |  | R$ 1.02 | [5] |  | R$ 1.89 | [6] | R$ 1.02 | [6]
Basic and diluted earnings per common share - R$ |  |  | 1.02 | [5] |  | 1.89 | [6] | 1.02 | [6]
Basic and diluted earnings per preferred share from continuing operations - R$ |  |  | 0.83 | [5] |  | 1.75 | [6] | 0.83 | [6]
Basic and diluted earnings per common share from continuing operations - R$ |  |  | 0.83 | [5] |  | 1.75 | [6] | 0.83 | [6]
Basic and diluted earnings per preferred share from discontinued operations - R$ |  |  | 0.19 | [5] |  | 0.14 | [5],[6] | 0.19 | [6]
Basic and diluted earnings per common share from discontinued operations - R$ |  |  | R$ 0.19 | [5] |  | R$ 0.14 | [6] | R$ 0.19 | [6]
[1] | See note 2.8.
[2] | Recognition of the profit margin associated to the performance obligation to construct and upgrade the transmission infrastructure, as well as the interest revenue resulting from the financing component;
[3] | Reversal of expected losses recorded in others expenses in prior periods.
[4] | Deferral of income tax and social contribution tax over the adjustments
[5] | The basic and diluted earnings per share for the years ended in December 31, 2019 and 2018 were also adjusted retrospectively in order to reflect the increase in the number of shares in 2021. For more information, see Note 26.
[6] | For further details of restatement of comparative balances, see Note 2.8

X
- Definition Basic and diluted earnings (loss) per share from continuing operations. [Refer: Basic and diluted earnings (loss) per share] + References No definition available. + Details
Name: | cig_BasicAndDilutedEarningsLossPerShareFromContinuingOperation
Namespace Prefix: | cig_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | duration

X
- Definition Basic and diluted earnings (loss) per share from discontinued operations. [Refer: Basic and diluted earnings (loss) per share] + References No definition available. + Details
Name: | cig_BasicAndDilutedEarningsLossPerShareFromDiscontinuedOperation
Namespace Prefix: | cig_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | duration

X
- Definition The amount of earnings per share when the basic and diluted measurements are equal. [Refer: Basic earnings (loss) per share; Diluted earnings (loss) per share] + References No definition available. + Details
Name: | cig_BasicAndDilutedEarningsLossPerShares
Namespace Prefix: | cig_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | duration

X
- Definition Continuing Operations [abstract] + References No definition available. + Details
Name: | cig_ContinuingOperationsAbstract
Namespace Prefix: | cig_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Discontinued Operations [abstract] + References No definition available. + Details
Name: | cig_DiscontinuedOperationsAbstract
Namespace Prefix: | cig_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Gain (loss) recognized as result of remeasuring to fair value equity interest in subsidiaries acquired. + References No definition available. + Details
Name: | cig_GainLossRecognisedAsResultOfRemeasuringToFairValueEquityInterestInSubsidiariesAcquired
Namespace Prefix: | cig_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Non Controlling Interests [abstract] + References No definition available. + Details
Name: | cig_NonControllingInterestsAbstract
Namespace Prefix: | cig_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The amount of earnings per share when the basic and diluted measurements are equal. [Refer: Basic earnings (loss) per share; Diluted earnings (loss) per share] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 1 -IssueDate 2020-01-01 -Paragraph 85 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_85&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_BasicAndDilutedEarningsLossPerShare
Namespace Prefix: | ifrs-full_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | duration

X
- Definition Basic and diluted earnings (loss) per share from continuing operations. [Refer: Basic and diluted earnings (loss) per share] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 1 -IssueDate 2020-01-01 -Paragraph 85 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_85&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_BasicAndDilutedEarningsLossPerShareFromContinuingOperations
Namespace Prefix: | ifrs-full_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | duration

X
- Definition Basic and diluted earnings (loss) per share from discontinued operations. [Refer: Basic and diluted earnings (loss) per share] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 1 -IssueDate 2020-01-01 -Paragraph 85 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_85&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_BasicAndDilutedEarningsLossPerShareFromDiscontinuedOperations
Namespace Prefix: | ifrs-full_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | duration

X
- Definition The amount of costs relating to expenses directly or indirectly attributed to the goods or services sold, which may include, but are not limited to, costs previously included in the measurement of inventory that has now been sold, unallocated production overheads and abnormal amounts of production costs of inventories. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 1 -IssueDate 2020-01-01 -Paragraph 99 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_99&doctype=Standard -URIDate 2020-01-01 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 1 -IssueDate 2020-01-01 -Paragraph 103 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_103&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_CostOfSales
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The amount of income taxes payable (recoverable) in respect of the taxable profit (tax loss) for a period. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Name IAS -Number 12 -IssueDate 2020-01-01 -Paragraph 80 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=12&code=ifrs-tx-2020-en-r&anchor=para_80_a&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_CurrentTaxExpenseIncome
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The amount of tax expense (income) relating to changes in deferred tax liabilities and deferred tax assets. [Refer: Deferred tax assets; Deferred tax liabilities] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 12 -IssueDate 2020-01-01 -Paragraph 81 -Subparagraph g -Clause ii -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=12&code=ifrs-tx-2020-en-r&anchor=para_81_g_ii&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_DeferredTaxExpenseIncome
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The amount of dividends classified as an expense. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Name IAS -Number 32 -IssueDate 2020-01-01 -Paragraph 40 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=32&code=ifrs-tx-2020-en-r&anchor=para_40&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_DividendsClassifiedAsExpense
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The amount of income associated with interest and other financing activities of the entity. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 1 -IssueDate 2020-01-01 -Paragraph 85 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_85&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_FinanceIncome
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The amount of revenue less cost of sales. [Refer: Cost of sales; Revenue] + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Name IAS -Number 1 -IssueDate 2020-01-01 -Paragraph 103 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_103&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_GrossProfit
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The amount of impairment loss recognised in profit or loss for trade receivables. [Refer: Impairment loss recognised in profit or loss; Trade receivables] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 1 -IssueDate 2020-01-01 -Paragraph 112 -Subparagraph c -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_112_c&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_ImpairmentLossRecognisedInProfitOrLossTradeReceivables
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The amount of income from continuing operations attributable to owners of the parent. [Refer: Continuing operations [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 5 -IssueDate 2020-01-01 -Paragraph 33 -Subparagraph d -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=5&code=ifrs-tx-2020-en-r&anchor=para_33_d&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_IncomeFromContinuingOperationsAttributableToOwnersOfParent
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The amount of income from discontinued operations attributable to owners of the parent. [Refer: Discontinued operations [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 5 -IssueDate 2020-01-01 -Paragraph 33 -Subparagraph d -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=5&code=ifrs-tx-2020-en-r&anchor=para_33_d&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_IncomeFromDiscontinuedOperationsAttributableToOwnersOfParent
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The amount of all operating expenses. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 1 -IssueDate 2020-01-01 -Paragraph 85 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_85&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_OperatingExpense
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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 2020-01-01 -Paragraph 18 -Subparagraph b -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2020-en-r&anchor=para_18_b&doctype=Standard -URIDate 2020-01-01 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 1 -IssueDate 2020-01-01 -Paragraph 24 -Subparagraph b -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=1&code=ifrs-tx-2020-en-r&anchor=para_24_b&doctype=Standard -URIDate 2020-01-01 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 1 -IssueDate 2020-01-01 -Paragraph 32 -Subparagraph a -Clause ii -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=1&code=ifrs-tx-2020-en-r&anchor=para_32_a_ii&doctype=Standard -URIDate 2020-01-01 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 8 -IssueDate 2020-01-01 -Paragraph 28 -Subparagraph b -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2020-en-r&anchor=para_28_b&doctype=Standard -URIDate 2020-01-01 Reference 5: http://www.xbrl.org/2003/role/exampleRef -Note Effective on first application of IFRS 9 -Name IFRS -Number 4 -IssueDate 2020-01-01 -Paragraph 39L -Subparagraph e -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=4&code=ifrs-tx-2020-en-b&anchor=para_39L_e&doctype=Standard -URIDate 2020-01-01 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 8 -IssueDate 2020-01-01 -Paragraph 23 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2020-en-r&anchor=para_23&doctype=Standard -URIDate 2020-01-01 Reference 7: http://www.xbrl.org/2003/role/exampleRef -Name IFRS -Number 12 -IssueDate 2020-01-01 -Paragraph B10 -Subparagraph b -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2020-en-r&anchor=para_B10_b&doctype=Appendix&subtype=B -URIDate 2020-01-01 Reference 8: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 1 -IssueDate 2020-01-01 -Paragraph 106 -Subparagraph d -Clause i -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_106_d_i&doctype=Standard -URIDate 2020-01-01 Reference 9: http://www.xbrl.org/2003/role/exampleRef -Note Effective 2021-01-01 -Name IFRS -Number 17 -IssueDate 2020-01-01 -Paragraph 113 -Subparagraph b -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=17&code=ifrs-tx-2020-en-r&anchor=para_113_b&doctype=Standard -URIDate 2020-01-01 Reference 10: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 1 -IssueDate 2020-01-01 -Paragraph 81A -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_81A_a&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_ProfitLoss
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The profit (loss) from continuing and discontinued operations attributable to non-controlling interests. [Refer: Profit (loss); Non-controlling interests] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 12 -IssueDate 2020-01-01 -Paragraph 12 -Subparagraph e -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2020-en-r&anchor=para_12_e&doctype=Standard -URIDate 2020-01-01 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 1 -IssueDate 2020-01-01 -Paragraph 81B -Subparagraph a -Clause i -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_81B_a_i&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_ProfitLossAttributableToNoncontrollingInterests
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- References No definition available. + Details
Name: | ifrs-full_ProfitLossAttributableToOrdinaryEquityHoldersOfParentEntityAbstract
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The profit (loss) from continuing and discontinued operations attributable to owners of the parent. [Refer: Profit (loss)] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 1 -IssueDate 2020-01-01 -Paragraph 81B -Subparagraph a -Clause ii -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_81B_a_ii&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_ProfitLossAttributableToOwnersOfParent
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The profit (loss) before tax expense or income. [Refer: Profit (loss)] + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Name IFRS -Number 8 -IssueDate 2020-01-01 -Paragraph 28 -Subparagraph b -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2020-en-r&anchor=para_28_b&doctype=Standard -URIDate 2020-01-01 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Name IFRS -Number 8 -IssueDate 2020-01-01 -Paragraph 23 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2020-en-r&anchor=para_23&doctype=Standard -URIDate 2020-01-01 Reference 3: http://www.xbrl.org/2003/role/exampleRef -Name IAS -Number 1 -IssueDate 2020-01-01 -Paragraph 103 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_103&doctype=Standard -URIDate 2020-01-01 Reference 4: http://www.xbrl.org/2003/role/exampleRef -Name IAS -Number 1 -IssueDate 2020-01-01 -Paragraph 102 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_102&doctype=Standard -URIDate 2020-01-01 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 5 -IssueDate 2020-01-01 -Paragraph 33 -Subparagraph b -Clause i -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=5&code=ifrs-tx-2020-en-r&anchor=para_33_b_i&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_ProfitLossBeforeTax
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The profit (loss) from continuing operations. [Refer: Continuing operations [member]; Profit (loss)] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 8 -IssueDate 2020-01-01 -Paragraph 28 -Subparagraph b -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2020-en-r&anchor=para_28_b&doctype=Standard -URIDate 2020-01-01 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 8 -IssueDate 2020-01-01 -Paragraph 23 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2020-en-r&anchor=para_23&doctype=Standard -URIDate 2020-01-01 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 12 -IssueDate 2020-01-01 -Paragraph B12 -Subparagraph b -Clause vi -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2020-en-r&anchor=para_B12_b_vi&doctype=Appendix&subtype=B -URIDate 2020-01-01 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 1 -IssueDate 2020-01-01 -Paragraph 81A -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_81A_a&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_ProfitLossFromContinuingOperations
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The profit (loss) from continuing operations attributable to non-controlling interests. [Refer: Profit (loss) from continuing operations; Non-controlling interests] + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Name IFRS -Number 5 -IssueDate 2020-01-01 -Section Example 11 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=5&code=ifrs-tx-2020-en-r&doctype=Implementation%20Guidance&dita_xref=IFRS05_ex11_TI -URIDate 2020-01-01 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Name IFRS -Number 5 -IssueDate 2020-01-01 -Paragraph 33 -Subparagraph d -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=5&code=ifrs-tx-2020-en-r&anchor=para_33_d&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_ProfitLossFromContinuingOperationsAttributableToNoncontrollingInterests
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The profit (loss) from discontinued operations. [Refer: Discontinued operations [member]; Profit (loss)] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 5 -IssueDate 2020-01-01 -Paragraph 33 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=5&code=ifrs-tx-2020-en-r&anchor=para_33_a&doctype=Standard -URIDate 2020-01-01 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 12 -IssueDate 2020-01-01 -Paragraph B12 -Subparagraph b -Clause vii -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2020-en-r&anchor=para_B12_b_vii&doctype=Appendix&subtype=B -URIDate 2020-01-01 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 1 -IssueDate 2020-01-01 -Paragraph 82 -Subparagraph ea -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_82_ea&doctype=Standard -URIDate 2020-01-01 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 1 -IssueDate 2020-01-01 -Paragraph 98 -Subparagraph e -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_98_e&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_ProfitLossFromDiscontinuedOperations
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The profit (loss) from discontinued operations attributable to non-controlling interests. [Refer: Profit (loss) from discontinued operations; Non-controlling interests] + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Name IFRS -Number 5 -IssueDate 2020-01-01 -Section Example 11 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=5&code=ifrs-tx-2020-en-r&doctype=Implementation%20Guidance&dita_xref=IFRS05_ex11_TI -URIDate 2020-01-01 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Name IFRS -Number 5 -IssueDate 2020-01-01 -Paragraph 33 -Subparagraph d -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=5&code=ifrs-tx-2020-en-r&anchor=para_33_d&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_ProfitLossFromDiscontinuedOperationsAttributableToNoncontrollingInterests
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The income arising in the course of an entity's ordinary activities. Income is increases in assets, or decreases in liabilities, that result in increases in equity, other than those relating to contributions from holders of equity claims. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 8 -IssueDate 2020-01-01 -Paragraph 28 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2020-en-r&anchor=para_28_a&doctype=Standard -URIDate 2020-01-01 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 8 -IssueDate 2020-01-01 -Paragraph 23 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2020-en-r&anchor=para_23_a&doctype=Standard -URIDate 2020-01-01 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 8 -IssueDate 2020-01-01 -Paragraph 32 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2020-en-r&anchor=para_32&doctype=Standard -URIDate 2020-01-01 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 8 -IssueDate 2020-01-01 -Paragraph 33 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2020-en-r&anchor=para_33_a&doctype=Standard -URIDate 2020-01-01 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 8 -IssueDate 2020-01-01 -Paragraph 34 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2020-en-r&anchor=para_34&doctype=Standard -URIDate 2020-01-01 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 1 -IssueDate 2020-01-01 -Paragraph 82 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_82_a&doctype=Standard -URIDate 2020-01-01 Reference 7: http://www.xbrl.org/2003/role/exampleRef -Name IAS -Number 1 -IssueDate 2020-01-01 -Paragraph 103 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_103&doctype=Standard -URIDate 2020-01-01 Reference 8: http://www.xbrl.org/2003/role/exampleRef -Name IAS -Number 1 -IssueDate 2020-01-01 -Paragraph 102 -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_102&doctype=Standard -URIDate 2020-01-01 Reference 9: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 5 -IssueDate 2020-01-01 -Paragraph 33 -Subparagraph b -Clause i -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=5&code=ifrs-tx-2020-en-r&anchor=para_33_b_i&doctype=Standard -URIDate 2020-01-01 Reference 10: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 12 -IssueDate 2020-01-01 -Paragraph B12 -Subparagraph b -Clause v -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2020-en-r&anchor=para_B12_b_v&doctype=Appendix&subtype=B -URIDate 2020-01-01 Reference 11: http://www.xbrl.org/2003/role/exampleRef -Name IFRS -Number 12 -IssueDate 2020-01-01 -Paragraph B10 -Subparagraph b -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2020-en-r&anchor=para_B10_b&doctype=Appendix&subtype=B -URIDate 2020-01-01 + Details
Name: | ifrs-full_Revenue
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The entity's share of the profit (loss) of associates and joint ventures accounted for using the equity method. [Refer: Associates [member]; Investments accounted for using equity method; Joint ventures [member]; Profit (loss)] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 8 -IssueDate 2020-01-01 -Paragraph 23 -Subparagraph g -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2020-en-r&anchor=para_23_g&doctype=Standard -URIDate 2020-01-01 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 8 -IssueDate 2020-01-01 -Paragraph 28 -Subparagraph e -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2020-en-r&anchor=para_28_e&doctype=Standard -URIDate 2020-01-01 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Note Effective on first application of IFRS 9 -Name IFRS -Number 4 -IssueDate 2020-01-01 -Paragraph 39M -Subparagraph b -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=4&code=ifrs-tx-2020-en-b&anchor=para_39M_b&doctype=Standard -URIDate 2020-01-01 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 1 -IssueDate 2020-01-01 -Paragraph 82 -Subparagraph c -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_82_c&doctype=Standard -URIDate 2020-01-01 + Details
Name: | ifrs-full_ShareOfProfitLossOfAssociatesAndJointVenturesAccountedForUsingEquityMethod
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | ifrs-full_RetrospectiveApplicationAndRetrospectiveRestatementAxis=ifrs-full_PreviouslyStatedMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_RetrospectiveApplicationAndRetrospectiveRestatementAxis=cig_AdjustmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_RetrospectiveApplicationAndRetrospectiveRestatementAxis=cig_Restated1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |