XML 245 R238.htm IDEA: XBRL DOCUMENT v3.19.1
Financial Instruments and Risk Management - Summary of Exposure to Exchange Rates (Detail)
R$ in Millions, $ in Millions
Dec. 31, 2018
BRL (R$)
Dec. 31, 2018
USD ($)
Dec. 31, 2017
BRL (R$)
Dec. 31, 2017
USD ($)
Disclosure of risk management strategy related to hedge accounting [line items]        
Net liabilities exposed R$ 6,150   R$ 3,601  
US dollar [member]        
Disclosure of risk management strategy related to hedge accounting [line items]        
Net liabilities exposed 6,150   3,597  
US dollar [member] | Supply From Itaipu Binacional [member]        
Disclosure of risk management strategy related to hedge accounting [line items]        
Net liabilities exposed 268   240  
Foreign currency risk [member]        
Disclosure of risk management strategy related to hedge accounting [line items]        
Net liabilities exposed | $   $ 1,588   $ 1,089
Foreign currency risk [member] | Supply From Itaipu Binacional [member]        
Disclosure of risk management strategy related to hedge accounting [line items]        
Net liabilities exposed | $   70   74
Loans and Financings [member] | US dollar [member]        
Disclosure of risk management strategy related to hedge accounting [line items]        
Net liabilities exposed R$ 5,882   3,357  
Loans and Financings [member] | Other Currency [member]        
Disclosure of risk management strategy related to hedge accounting [line items]        
Net liabilities exposed     R$ 4  
Loans and Financings [member] | Foreign currency risk [member]        
Disclosure of risk management strategy related to hedge accounting [line items]        
Net liabilities exposed | $   $ 1,518   1,015
Loans and financings [member] | Foreign currency risk [member]        
Disclosure of risk management strategy related to hedge accounting [line items]        
Net liabilities exposed | $       $ 1