Goodwill and Intangible Assets - Changes in Carrying Value of Goodwill (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Dec. 31, 2018	Mar. 31, 2016	Dec. 31, 2018
Goodwill [Roll Forward]
Balance, beginning of period			$ 1,542.2
Impairment	$ (232.0)	$ (873.3)
Balance, end of period	1,310.2		1,310.2
Operating Segments | Texas
Goodwill [Roll Forward]
Balance, beginning of period			232.0
Balance, end of period	0.0		0.0
Operating Segments | Oklahoma
Goodwill [Roll Forward]
Balance, beginning of period			190.3
Balance, end of period	190.3		190.3
Operating Segments | Crude and Condensate
Goodwill [Roll Forward]
Balance, beginning of period			0.0
Balance, end of period	0.0		0.0
Corporate
Goodwill [Roll Forward]
Balance, beginning of period			1,119.9
Balance, end of period	1,119.9		1,119.9
EnLink Midstream Partners, LP
Goodwill [Roll Forward]
Balance, beginning of period			1,542.2
Impairment			(232.0)
Balance, end of period	1,310.2		1,310.2
EnLink Midstream Partners, LP | Operating Segments | Texas
Goodwill [Roll Forward]
Balance, beginning of period			232.0
Impairment			232.0
Balance, end of period	0.0		0.0
EnLink Midstream Partners, LP | Operating Segments | Oklahoma
Goodwill [Roll Forward]
Balance, beginning of period			190.3
Impairment			0.0
Balance, end of period	190.3		190.3
EnLink Midstream Partners, LP | Operating Segments | Crude and Condensate
Goodwill [Roll Forward]
Balance, beginning of period			1,119.9
Impairment			0.0
Balance, end of period	$ 1,119.9		$ 1,119.9