XML 196 R189.htm IDEA: XBRL DOCUMENT v3.8.0.1
Related Party Transactions - Summary of Cemig's Principal Balances and Transactions With Related Parties (Detail) - BRL (R$)
R$ in Millions
 12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Disclosure of transactions between related parties [line items]      
Current assets R$ 8,537 R$ 8,286  
Non-current assets 33,703 33,750  
Current liabilities 8,663 11,447  
Non-current liabilities 19,247 17,655  
Parent [member] | MINAS GERAIS STATE GOVT [member] | Current [member]      
Disclosure of transactions between related parties [line items]      
Current assets 235    
Revenue 42    
Parent [member] | MINAS GERAIS STATE GOVT [member] | Current [member] | Consumers and traders [member]      
Disclosure of transactions between related parties [line items]      
Current assets 55 71  
Revenue 136 152 R$ 150
Parent [member] | MINAS GERAIS STATE GOVT [member] | Current [member] | Public Lighting Contribution [member]      
Disclosure of transactions between related parties [line items]      
Current assets 1    
Parent [member] | MINAS GERAIS STATE GOVT [member] | Non current [member] | Consumers and traders [member]      
Disclosure of transactions between related parties [line items]      
Non-current assets 50    
Parent [member] | MINAS GERAIS STATE GOVT [member] | Non current [member] | Public Lighting Contribution [member]      
Disclosure of transactions between related parties [line items]      
Non-current assets 1    
Entities with joint control or significant influence over entity [member] | Alianca Geracao [member] | Current [member] | Transactions in electricity [member]      
Disclosure of transactions between related parties [line items]      
Current liabilities 7 7  
Expenses (147) (142) (106)
Entities with joint control or significant influence over entity [member] | Alianca Geracao [member] | Current [member] | Provision of services [member]      
Disclosure of transactions between related parties [line items]      
Current assets 2 4  
Revenue 13 14 6
Entities with joint control or significant influence over entity [member] | Alianca Geracao [member] | Current [member] | Interest on Equity, and dividends [member]      
Disclosure of transactions between related parties [line items]      
Current assets 72    
Entities with joint control or significant influence over entity [member] | Baguari Energia [member] | Current [member] | Transactions in electricity [member]      
Disclosure of transactions between related parties [line items]      
Current liabilities 1 1  
Expenses (7) (7) (6)
Entities with joint control or significant influence over entity [member] | Baguari Energia [member] | Current [member] | Interest on Equity, and dividends [member]      
Disclosure of transactions between related parties [line items]      
Current assets   6  
Entities with joint control or significant influence over entity [member] | Baguari Energia [member] | Current [member] | Services [Member]      
Disclosure of transactions between related parties [line items]      
Revenue 1 1  
Entities with joint control or significant influence over entity [member] | Madeira Energia [member] | Current [member] | Transactions in electricity [member]      
Disclosure of transactions between related parties [line items]      
Current liabilities 57 18  
Revenue 27 8  
Expenses (686) (574) (638)
Entities with joint control or significant influence over entity [member] | Madeira Energia [member] | Current [member] | Advance against future electricity supply [Member]      
Disclosure of transactions between related parties [line items]      
Current assets 66    
Revenue     12
Entities with joint control or significant influence over entity [member] | Madeira Energia [member] | Non current [member] | Advance for future power supply [member]      
Disclosure of transactions between related parties [line items]      
Non-current assets 7    
Entities with joint control or significant influence over entity [member] | Norte Energia [member] | Current [member] | Transactions in electricity [member]      
Disclosure of transactions between related parties [line items]      
Current liabilities 4 4  
Revenue 9 2  
Expenses (122) (49)  
Entities with joint control or significant influence over entity [member] | Lightger [member] | Current [member] | Transactions in electricity [member]      
Disclosure of transactions between related parties [line items]      
Expenses (19) (19) (17)
Entities with joint control or significant influence over entity [member] | Hidreletrica Pipoca [member] | Current [member] | Transactions in electricity [member]      
Disclosure of transactions between related parties [line items]      
Current liabilities   1  
Expenses (15) (16) (11)
Entities with joint control or significant influence over entity [member] | Hidreletrica Pipoca [member] | Current [member] | Interest on Equity, and dividends [member]      
Disclosure of transactions between related parties [line items]      
Current assets 1    
Entities with joint control or significant influence over entity [member] | Retiro Baixo [member] | Current [member] | Transactions in electricity [member]      
Disclosure of transactions between related parties [line items]      
Current assets   1  
Current liabilities 1    
Expenses (6) (6) (3)
Entities with joint control or significant influence over entity [member] | Retiro Baixo [member] | Current [member] | Interest on Equity, and dividends [member]      
Disclosure of transactions between related parties [line items]      
Current assets 3 2  
Entities with joint control or significant influence over entity [member] | Guanhaes energia [member] | Current [member] | Adjustment for losses [member]      
Disclosure of transactions between related parties [line items]      
Current liabilities   59  
Entities with joint control or significant influence over entity [member] | Renova [member] | Current [member] | Transactions in electricity [member]      
Disclosure of transactions between related parties [line items]      
Current liabilities 2    
Expenses (179) (159) (12)
Entities with joint control or significant influence over entity [member] | Renova [member] | Non current [member] | Accounts Receivable [member]      
Disclosure of transactions between related parties [line items]      
Non-current assets 350 74  
Revenue   14  
Entities with joint control or significant influence over entity [member] | Renova [member] | Non current [member] | Advance for future delivery of power supply [member]      
Disclosure of transactions between related parties [line items]      
Non-current assets   229  
Revenue   17  
Entities with joint control or significant influence over entity [member] | Empresa Amazonense de Transmissao de Energia EATE [member] | Current [member] | Transactions in electricity [member]      
Disclosure of transactions between related parties [line items]      
Current liabilities 3 3  
Expenses (26) (25) (28)
Entities with joint control or significant influence over entity [member] | Light [member] | Current [member] | Transactions in electricity [member]      
Disclosure of transactions between related parties [line items]      
Current assets 1    
Revenue 54 59 47
Expenses (1) (1) (1)
Entities with joint control or significant influence over entity [member] | Light [member] | Current [member] | Interest on Equity, and dividends [member]      
Disclosure of transactions between related parties [line items]      
Current assets   7  
Entities with joint control or significant influence over entity [member] | Taesa [member] | Current [member] | Transactions in electricity [member]      
Disclosure of transactions between related parties [line items]      
Current liabilities 12 10  
Expenses (127) (110) (94)
Entities with joint control or significant influence over entity [member] | Taesa [member] | Current [member] | Services [Member]      
Disclosure of transactions between related parties [line items]      
Revenue 1 1  
Entities with joint control or significant influence over entity [member] | Cia. Transirape de Transmissao [member] | Current [member] | Transactions in electricity [member]      
Disclosure of transactions between related parties [line items]      
Current liabilities 1 1  
Expenses (10) (9) (7)
Entities with joint control or significant influence over entity [member] | Cia. Transirape de Transmissao [member] | Current [member] | Provision of services [member]      
Disclosure of transactions between related parties [line items]      
Revenue 1 1 1
Entities with joint control or significant influence over entity [member] | Cia. Transirape de Transmissao [member] | Current [member] | Interest on Equity, and dividends [member]      
Disclosure of transactions between related parties [line items]      
Current assets 1 1  
Entities with joint control or significant influence over entity [member] | Axxiom [member] | Current [member] | Provision of services [member]      
Disclosure of transactions between related parties [line items]      
Current liabilities 3 7  
Entities with joint control or significant influence over entity [member] | Transudeste [member] | Current [member] | Transactions in electricity [member]      
Disclosure of transactions between related parties [line items]      
Expenses (2) (1) (1)
Entities with joint control or significant influence over entity [member] | Transudeste [member] | Current [member] | Provision of services [member]      
Disclosure of transactions between related parties [line items]      
Revenue 1 1 1
Entities with joint control or significant influence over entity [member] | Transleste [member] | Current [member] | Transactions in electricity [member]      
Disclosure of transactions between related parties [line items]      
Expenses (3) (2) (2)
Other related parties [member] | FIC Pampulha [member] | Current [member] | Cash and cash equivalents [Member]      
Disclosure of transactions between related parties [line items]      
Current assets 322 428  
Other related parties [member] | FIC Pampulha [member] | Current [member] | Securities [member]      
Disclosure of transactions between related parties [line items]      
Current assets 1,037 1,027  
Revenue 9 197 115
Other related parties [member] | FIC Pampulha [member] | Current [member] | Securities issued by subsidiary companies of Cemig [member]      
Disclosure of transactions between related parties [line items]      
Current assets (25) (49)  
Other related parties [member] | FIC Pampulha [member] | Non current [member] | Securities [member]      
Disclosure of transactions between related parties [line items]      
Non-current assets 30 46  
Other related parties [member] | FIC Pampulha [member] | Non current [member] | Securities issued by subsidiary companies of Cemig [member]      
Disclosure of transactions between related parties [line items]      
Non-current assets   (15)  
Other related parties [member] | FORLUZ [member] | Current [member] | Post-retirement obligations [member]      
Disclosure of transactions between related parties [line items]      
Current liabilities 109 86  
Expenses (174) (186) (129)
Other related parties [member] | FORLUZ [member] | Current [member] | Supplementary pension contributions [member]      
Disclosure of transactions between related parties [line items]      
Expenses (84) (100) (85)
Other related parties [member] | FORLUZ [member] | Current [member] | Administrative running costs [member]      
Disclosure of transactions between related parties [line items]      
Expenses (26) (25) (22)
Other related parties [member] | FORLUZ [member] | Current [member] | Operating leases [member]      
Disclosure of transactions between related parties [line items]      
Current liabilities 5 10  
Expenses (55) (39) (18)
Other related parties [member] | FORLUZ [member] | Non current [member] | Post-retirement obligations [member]      
Disclosure of transactions between related parties [line items]      
Non-current liabilities 1,960 1,593  
Other related parties [member] | CEMIG SAUDE [member] | Current [member] | Health and dental plans [member]      
Disclosure of transactions between related parties [line items]      
Current liabilities 115 102  
Expenses (193) (187) R$ (146)
Other related parties [member] | CEMIG SAUDE [member] | Non current [member] | Health and dental plans [member]      
Disclosure of transactions between related parties [line items]      
Non-current liabilities R$ 1,633 R$ 1,647