Annual report pursuant to Section 13 and 15(d)

Other Non-Current Assets - Equity Method Investments (Details)

v3.8.0.1
Other Non-Current Assets - Equity Method Investments (Details)
$ in Millions
12 Months Ended
Dec. 31, 2017
USD ($)
mi
Dec. 31, 2016
USD ($)
Dec. 31, 2015
USD ($)
Investment [Line Items]      
Equity method investment $ 64 $ 10  
Other—related party 3 0 $ 0
Accounts receivable—related party 2 $ 0  
Midship Holdings [Member]      
Investment [Line Items]      
Equity method investment 55    
O&M Services [Member] | Midship Pipeline [Member] | Service Agreements [Member]      
Investment [Line Items]      
Other—related party 3    
Accounts receivable—related party $ 2    
CCL [Member] | Midship Pipeline [Member] | Natural Gas Transportation Agreement [Member]      
Investment [Line Items]      
Long-term Purchase Commitment, Period 10 years    
EIG [Member] | Maximum [Member]      
Investment [Line Items]      
Investment Company, Financial Commitment to Investee, Future Amount $ 500    
Midship Pipeline [Member]      
Investment [Line Items]      
Length Of Natural Gas Pipeline | mi 230