XML 231 R210.htm IDEA: XBRL DOCUMENT v3.21.1

31. FINANCIAL INSTRUMENTS AND RISK MANAGEMENT (Details 1) - BRL (R$) R$ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Disclosure of detailed information about financial instruments [line items]
Options in shares	R$ 533	R$ 480
SAAG [member]
Disclosure of detailed information about financial instruments [line items]
Options in shares	536	483
Sonda [member]
Disclosure of detailed information about financial instruments [line items]
Options in shares	R$ (3)	R$ (3)

X

- Definition

Options in shares amount.

+ References

No definition available.

+ Details

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

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

X

- Details

Name:	ifrs-full_BorrowingsByNameAxis=cig_SAAGMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_BorrowingsByNameAxis=cig_SondaMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: