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18. INTANGIBLE ASSETS (Details 3) | 12 Months Ended
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Dec. 31, 2020
Disclosure of detailed information about intangible assets [line items] |
Annual average amortization rate | 4.05%
Hydroelectric generation [member] |
Disclosure of detailed information about intangible assets [line items] |
Annual average amortization rate | 9.06%
Wind power generation [member] |
Disclosure of detailed information about intangible assets [line items] |
Annual average amortization rate | 8.88%
Administration [member] |
Disclosure of detailed information about intangible assets [line items] |
Annual average amortization rate | 15.74%
Distribution [member] |
Disclosure of detailed information about intangible assets [line items] |
Annual average amortization rate | 3.90%
Gas [member] |
Disclosure of detailed information about intangible assets [line items] |
Annual average amortization rate | 3.48%

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- Definition Amount refers to useful lives or amortisation rates intangible assets other than goodwill. + References No definition available. + Details
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Namespace Prefix: | cig_
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Balance Type: | na
Period Type: | duration

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- 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
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- Details
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Namespace Prefix: |
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- Details
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Namespace Prefix: |
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Period Type: |

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- Details
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Period Type: |

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- Details
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Period Type: |

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- Details
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Balance Type: |
Period Type: |