Intangible Assets - Changes in Carrying Value (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Finite-lived Intangible Assets [Roll Forward]
Accumulated Amortization, Beginning Balance	$ (298.7)
Accumulated Amortization, Amortization expense	(30.8)	$ (29.5)
Accumulated Amortization, Ending Balance	(329.5)
EnLink Midstream Partners, LP
Finite-lived Intangible Assets [Roll Forward]
Net Carrying Amount, Ending Balance	1,466.3
Customer relationships | EnLink Midstream Partners, LP
Finite-lived Intangible Assets [Roll Forward]
Gross Carrying Amount, Beginning Balance	1,795.8
Accumulated Amortization, Beginning Balance	(298.7)
Net Carrying Amount, Beginning Balance	1,497.1
Accumulated Amortization, Amortization expense	(30.8)
Gross Carrying Amount, Ending Balance	1,795.8
Accumulated Amortization, Ending Balance	(329.5)
Net Carrying Amount, Ending Balance	$ 1,466.3