XML 62 R51.htm IDEA: XBRL DOCUMENT v3.10.0.1
Financial Risk Management Activities - Gross and Net Fair Values (Detail) - USD ($)
$ in Millions
Jun. 30, 2018
Dec. 31, 2017
Derivatives Fair Value [Line Items]    
Assets - Gross fair value of derivative contracts $ 33 $ 1
Assets - Net Fair Value of Derivative Contracts 33 1
Liabilities - Gross fair value of derivative contracts (36) (13)
Liabilities - Net Fair Value of Derivative Contracts (36) (13)
Derivative Contracts Designated as Hedging Instruments    
Derivatives Fair Value [Line Items]    
Assets - Gross fair value of derivative contracts 33  
Liabilities - Gross fair value of derivative contracts (36) (11)
Derivative Contracts Designated as Hedging Instruments | Commodity | Accounts Receivable and Accounts Payable    
Derivatives Fair Value [Line Items]    
Assets - Gross fair value of derivative contracts 33  
Liabilities - Gross fair value of derivative contracts (31)  
Derivative Contracts Designated as Hedging Instruments | Commodity | Accounts Payable    
Derivatives Fair Value [Line Items]    
Liabilities - Gross fair value of derivative contracts   (7)
Derivative Contracts Designated as Hedging Instruments | Interest Rate | Other assets (noncurrent) and Accounts Payable    
Derivatives Fair Value [Line Items]    
Liabilities - Gross fair value of derivative contracts   (4)
Derivative Contracts Designated as Hedging Instruments | Interest Rate | Other Liabilities and Deferred Credits    
Derivatives Fair Value [Line Items]    
Liabilities - Gross fair value of derivative contracts $ (5)  
Derivative Contracts Not Designated as Hedging Instruments    
Derivatives Fair Value [Line Items]    
Assets - Gross fair value of derivative contracts   1
Liabilities - Gross fair value of derivative contracts   (2)
Derivative Contracts Not Designated as Hedging Instruments | Commodity | Accounts Payable    
Derivatives Fair Value [Line Items]    
Liabilities - Gross fair value of derivative contracts   (2)
Derivative Contracts Not Designated as Hedging Instruments | Foreign Exchange    
Derivatives Fair Value [Line Items]    
Assets - Gross fair value of derivative contracts   $ 1