Quarterly report pursuant to Section 13 or 15(d)

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

v3.8.0.1
Other Non-Current Assets - Equity Method Investments (Details)
$ in Millions
3 Months Ended
Mar. 31, 2018
USD ($)
mi
Mar. 31, 2017
USD ($)
Dec. 31, 2017
USD ($)
Investment [Line Items]      
Equity method investment $ 64   $ 64
Other—related party 1 $ 0  
Accounts receivable—related party 2   2
Midship Holdings [Member]      
Investment [Line Items]      
Equity method investment 55   55
O&M Services [Member] | Midship Pipeline [Member] | Service Agreements [Member]      
Investment [Line Items]      
Other—related party 1 $ 0  
Accounts receivable—related party $ 2   $ 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