XML 87 R80.htm IDEA: XBRL DOCUMENT
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Concessions and Authorizations - Schedule of Concession and Amount to Be Paid (Detail) R$ in Millions | 12 Months Ended
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Dec. 31, 2017 BRL (R$)
Irape enterprise [member] |
Disclosure of concession and amount to be paid [Line Items] |
Percentage interest | 100.00%
Nominal value in 2017 | R$ 33
Present value in 2017 | R$ 14
Inflation index to be used to adjust historical amounts | IGP-M
Queimadao Consortium Enterprise [member] |
Disclosure of concession and amount to be paid [Line Items] |
Percentage interest | 82.50%
Nominal value in 2017 | R$ 8
Present value in 2017 | R$ 4
Inflation index to be used to adjust historical amounts | IGP-M
Salto morais small hydro plant enterprise [member] |
Disclosure of concession and amount to be paid [Line Items] |
Percentage interest | 100.00%
Inflation index to be used to adjust historical amounts | IPCA
Rio de Pedras Small Hydro Plant Enterprise [member] |
Disclosure of concession and amount to be paid [Line Items] |
Percentage interest | 100.00%
Nominal value in 2017 | R$ 1
Inflation index to be used to adjust historical amounts | IPCA
Various Small Hydro Plants Enterprise [member] |
Disclosure of concession and amount to be paid [Line Items] |
Percentage interest | 100.00%
Nominal value in 2017 | R$ 3
Present value in 2017 | R$ 3
Inflation index to be used to adjust historical amounts | IPCA
Bottom of range [member] | Irape enterprise [member] |
Disclosure of concession and amount to be paid [Line Items] |
Amortization period | 03/2006
Bottom of range [member] | Queimadao Consortium Enterprise [member] |
Disclosure of concession and amount to be paid [Line Items] |
Amortization period | 01/2004
Bottom of range [member] | Salto morais small hydro plant enterprise [member] |
Disclosure of concession and amount to be paid [Line Items] |
Amortization period | 06/2013
Bottom of range [member] | Rio de Pedras Small Hydro Plant Enterprise [member] |
Disclosure of concession and amount to be paid [Line Items] |
Amortization period | 06/2013
Bottom of range [member] | Various Small Hydro Plants Enterprise [member] |
Disclosure of concession and amount to be paid [Line Items] |
Amortization period | 06/2013
Top of range [member] | Irape enterprise [member] |
Disclosure of concession and amount to be paid [Line Items] |
Amortization period | 02/2035
Top of range [member] | Queimadao Consortium Enterprise [member] |
Disclosure of concession and amount to be paid [Line Items] |
Amortization period | 12/2032
Top of range [member] | Salto morais small hydro plant enterprise [member] |
Disclosure of concession and amount to be paid [Line Items] |
Amortization period | 07/2020
Top of range [member] | Rio de Pedras Small Hydro Plant Enterprise [member] |
Disclosure of concession and amount to be paid [Line Items] |
Amortization period | 09/2024
Top of range [member] | Various Small Hydro Plants Enterprise [member] |
Disclosure of concession and amount to be paid [Line Items] |
Amortization period | 08/2025

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- Definition Amortization period. + References No definition available. + Details
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Namespace Prefix: | xcmig_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

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- Definition Concession nominal value. + References No definition available. + Details
Name: | xcmig_ConcessionNominalValue
Namespace Prefix: | xcmig_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

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- Definition Concession present value. + References No definition available. + Details
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Namespace Prefix: | xcmig_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

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- Definition Disclosure of concession and amount to be paid line items. + References No definition available. + Details
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Data Type: | xbrli:stringItemType
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- Definition Inflation index to be used to adjust historical amounts. + References No definition available. + Details
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Namespace Prefix: | xcmig_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

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- Definition Percentage of concession interest. + References No definition available. + Details
Name: | xcmig_PercentageOfConcessionInterest
Namespace Prefix: | xcmig_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

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- Details
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Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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- Details
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Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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- Details
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Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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- Details
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Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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- Details
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Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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- Details
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Namespace Prefix: |
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Period Type: |

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