XML 194 R212.htm IDEA: XBRL DOCUMENT v3.20.1

33. FINANCIAL INSTRUMENTS AND RISK MANAGEMENT (Details 3) - BRL (R$) R$ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Disclosure of detailed information about financial instruments [abstract]
Balance	R$ 507	R$ 1,150
Variation in fair value	48	187
Written down, due to exercise of Put	(555)	(830)
Balance		R$ 507

X

- Definition

The amount of options outstanding grant date fair value.

+ References

No definition available.

+ Details

Name:	cig_OptionsOutstandingGrantDateFairValue
Namespace Prefix:	cig_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

The amount of written down due to exercise of put in fair value of options.

+ References

No definition available.

+ Details

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

X

- References

No definition available.

+ Details

Name:	ifrs-full_DisclosureOfFinancialInstrumentsAbstract
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

The increase (decrease) in the fair value measurement of liabilities. [Refer: At fair value [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 13
-IssueDate 2019-01-01
-Paragraph 93
-Subparagraph e
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2019-en-r&anchor=para_93_e&doctype=Standard
-URIDate 2019-03-27

+ Details

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Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration