XML 152 R145.htm IDEA: XBRL DOCUMENT
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Loans, Financings and Debentures - Characteristics of Nonconvertible Debentures Issued by Company (Detail) - BRL (R$) R$ in Millions | 12 Months Ended |
--- | --- | ---
Dec. 31, 2017 | Dec. 31, 2016
Disclosure of detailed information about borrowings [line items] |  |
2016 | R$ 14,398 | R$ 15,179
Cemig GT third issue first series [member] | Unsecured guarantee [member] | Interbank rate for certificates of deposit plus zero point nine zero percentage [member] |  |
Disclosure of detailed information about borrowings [line items] |  |
Guarantee | Unsecured |
Annual cost % | 0.90 |
Maturity | 2017 |
2016 |  | 543
Cemig GT third issue second series [member] | Unsecured guarantee [member] | Expanded national consumer price index plus six point zero percentage [member] |  |
Disclosure of detailed information about borrowings [line items] |  |
Guarantee | Unsecured |
Annual cost % | 6.00 |
Maturity | 2019 |
2016 | R$ 301 | 293
Cemig GT third issue third series [member] | Unsecured guarantee [member] | Expanded national consumer price index plus six point two zero percentage [member] |  |
Disclosure of detailed information about borrowings [line items] |  |
Guarantee | Unsecured |
Annual cost % | 6.20 |
Maturity | 2022 |
2016 | R$ 1,011 | 984
Cemig GT fifth issue first series [member] | Unsecured guarantee [member] | Interbank Rate For Certificates Of Deposit Plus One Point Seven Zero Percentage [member] |  |
Disclosure of detailed information about borrowings [line items] |  |
Guarantee | Unsecured |
Annual cost % | 1.70 |
Maturity | 2018 |
2016 | R$ 703 | 1,411
Cemig GT - 6th Issue - 1st Series [member] | Surety guarantee [member] | Interbank rate for certificates of deposit plus one point six zero percentage [member] |  |
Disclosure of detailed information about borrowings [line items] |  |
Guarantee | Surety |
Annual cost % | 1.60 |
Maturity | 2018 |
2016 | R$ 508 | 1,041
Cemig GT - 6th Issue - 2nd Series [member] | Surety guarantee [member] | Expanded national consumer price index plus eight point zero seven percentage [member] |  |
Disclosure of detailed information about borrowings [line items] |  |
Guarantee | Surety |
Annual cost % | 8.07 |
Maturity | 2020 |
2016 | R$ 32 | 31
Cemig GT - 7th Issue - 1st Series [member] | Receivables revenue guarantee [member] | One four zero point zero percentage of interbank rate for certificates of deposit [member] |  |
Disclosure of detailed information about borrowings [line items] |  |
Guarantee | Receivables (Revenue) |
Annual cost % | 140.00 |
Maturity | 2021 |
2016 | R$ 1,683 | 2,242
Cemig D second issue [Member] | No guarantee [member] | Expanded national consumer price index plus seven point nine six percentage [member] |  |
Disclosure of detailed information about borrowings [line items] |  |
Guarantee | None |
Annual cost % | 7.96 |
Maturity | 2017 |
2016 |  | 235
Cemig D - 3rd Issue - 1st Series [member] | Surety guarantee [member] | Interbank rate for certificates of deposit plus zero point six nine percentage [member] |  |
Disclosure of detailed information about borrowings [line items] |  |
Guarantee | Surety |
Annual cost % | 0.69 |
Maturity | 2018 |
2016 | R$ 447 | 464
Cemig D - 3rd Issue - 2nd Series [member] | Surety guarantee [member] | Expanded national consumer price index plus four point seven zero percentage [member] |  |
Disclosure of detailed information about borrowings [line items] |  |
Guarantee | Surety |
Annual cost % | 4.70 |
Maturity | 2021 |
2016 | R$ 1,537 | 1,496
Cemig D - 3rd Issue - 3rd Series [member] | Surety guarantee [member] | Expanded national consumer price index plus five point one zero percentage [member] |  |
Disclosure of detailed information about borrowings [line items] |  |
Guarantee | Surety |
Annual cost % | 5.10 |
Maturity | 2025 |
2016 | R$ 921 | 896
Cemig D forth issue single series [member] | Surety guarantee [member] | Interbank rate for certificates of deposit plus four point zero five percentage [member] |  |
Disclosure of detailed information about borrowings [line items] |  |
Guarantee | Surety |
Annual cost % | 4.05 |
Maturity | 2018 |
2016 | R$ 20 | 1,627
Cemig D fifth issue single series [member] | Surety receivables guarantee [member] | One four six point five zero percentage of interbank rate for certificates of deposit [member] |  |
Disclosure of detailed information about borrowings [line items] |  |
Guarantee | Surety /Receivables |
Annual cost % | 146.50 |
Maturity | 2022 |
2016 | R$ 1,576 |
Gasmig [member] | Unsecured guarantee [member] | Interbank rate for certificates of deposit plus one point six zero percentage [member] |  |
Disclosure of detailed information about borrowings [line items] |  |
Guarantee | Unsecured |
Annual cost % | 1.60 |
Maturity | 2018 |
2016 | R$ 100 | 101
Gasmig [member] | Unsecured guarantee [member] | Interbank rate for certificates of deposit plus zero point seven four [member] |  |
Disclosure of detailed information about borrowings [line items] |  |
Guarantee | Unsecured |
Annual cost % | 0.74 |
Maturity | 2018 |
2016 | R$ 34 | 67
Gasmig [member] | Unsecured guarantee [member] | TJLP plus one point eight two and selic plus one point eight two percentage [member] |  |
Disclosure of detailed information about borrowings [line items] |  |
Guarantee | Unsecured |
Annual cost % | 116.50 |
Maturity | 2019 |
2016 | R$ 50 |
Cemig Telecom [member] | Receivables guarantee [member] | One two eight point five zero percentage of interbank rate for certificates of deposit [member] |  |
Disclosure of detailed information about borrowings [line items] |  |
Guarantee | Receivables |
Annual cost % | 128.50 |
Maturity | 2019 |
2016 | R$ 26 |
Subsidiary Securities [member] |  |
Disclosure of detailed information about borrowings [line items] |  |
2016 | (25) | (65)
Transaction costs [member] |  |
Disclosure of detailed information about borrowings [line items] |  |
2016 | (50) | (79)
Debentures [member] |  |
Disclosure of detailed information about borrowings [line items] |  |
2016 | R$ 9,029 | 11,420
Debentures [member] | Interbank rate for certificates of deposit plus zero point seven four [member] |  |
Disclosure of detailed information about borrowings [line items] |  |
Annual cost % | CDI + 0.74% |
Maturity | 2018 |
TJLP [member] | Gasmig [member] | Unsecured guarantee [member] | TJLP plus one point eight two and selic plus one point eight two percentage [member] |  |
Disclosure of detailed information about borrowings [line items] |  |
Guarantee | Unsecured |
Annual cost % | 75 |
Maturity | 2022 |
2016 | R$ 155 | R$ 133
Selic [member] | Gasmig [member] | Unsecured guarantee [member] | TJLP plus one point eight two and selic plus one point eight two percentage [member] |  |
Disclosure of detailed information about borrowings [line items] |  |
Annual cost % | 25 |

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