Share-Based Compensation (Summary of Unrecognized Compensation Cost And Weighted Average Period For Recognition General Partner And EnLink) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017 USD ($)
Restricted Stock Awards And Units [Member]
Unrecognized Compensation And Weighted Average Recognition [Line Items]
Unrecognized compensation cost	$ 135
Weighted average period for recognition (years)	2 years 4 months 24 days
Performance Share Units [Member]
Unrecognized Compensation And Weighted Average Recognition [Line Items]
Unrecognized compensation cost	$ 28
Weighted average period for recognition (years)	1 year 10 months 25 days
General Partner [Member] | Restricted Stock Awards And Units [Member]
Unrecognized Compensation And Weighted Average Recognition [Line Items]
Unrecognized compensation cost	$ 11
Weighted average period for recognition (years)	1 year 8 months 12 days
General Partner [Member] | Performance Share Units [Member]
Unrecognized Compensation And Weighted Average Recognition [Line Items]
Unrecognized compensation cost	$ 5
Weighted average period for recognition (years)	1 year 9 months 18 days
EnLink [Member] | Restricted Stock Awards And Units [Member]
Unrecognized Compensation And Weighted Average Recognition [Line Items]
Unrecognized compensation cost	$ 12
Weighted average period for recognition (years)	1 year 8 months 12 days
EnLink [Member] | Performance Share Units [Member]
Unrecognized Compensation And Weighted Average Recognition [Line Items]
Unrecognized compensation cost	$ 5
Weighted average period for recognition (years)	1 year 9 months 18 days