Goodwill and Intangible Assets - Narrative (Details) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Goodwill impairment loss recognized			$ 184,600,000	$ 1,125,600,000	$ 232,000,000.0
Goodwill		$ 1,310,200,000	$ 0	184,600,000	1,310,200,000	$ 1,542,200,000
Intangible asset, useful life			15 years
Minimum
Finite-Lived Intangible Assets [Line Items]
Intangible asset, useful life			10 years
Maximum
Finite-Lived Intangible Assets [Line Items]
Intangible asset, useful life			20 years
EnLink Midstream Partners, LP
Finite-Lived Intangible Assets [Line Items]
Amortization expense			$ (123,500,000)	(123,700,000)	(123,500,000)
Corporate | EnLink Midstream Partners, LP
Finite-Lived Intangible Assets [Line Items]
Goodwill impairment loss recognized			0	0	0
Goodwill		1,119,900,000	0	0	1,119,900,000	1,119,900,000
Corporate | Louisiana | EnLink Midstream Partners, LP
Finite-Lived Intangible Assets [Line Items]
Goodwill impairment loss recognized	$ 186,500,000
Operating Segments | Louisiana | EnLink Midstream Partners, LP
Finite-Lived Intangible Assets [Line Items]
Goodwill impairment loss recognized			0	186,500,000	0
Goodwill		0	0	0	0	0
Operating Segments | North Texas
Finite-Lived Intangible Assets [Line Items]
Goodwill impairment loss recognized		202,700,000
Operating Segments | North Texas | EnLink Midstream Partners, LP
Finite-Lived Intangible Assets [Line Items]
Goodwill impairment loss recognized			0	125,700,000	202,700,000
Goodwill		0	0	0	0	202,700,000
Operating Segments | Oklahoma | EnLink Midstream Partners, LP
Finite-Lived Intangible Assets [Line Items]
Goodwill impairment loss recognized			0	813,400,000	0
Goodwill		190,300,000	0	0	190,300,000	190,300,000
Operating Segments | Permian
Finite-Lived Intangible Assets [Line Items]
Goodwill impairment loss recognized		29,300,000
Operating Segments | Permian | EnLink Midstream Partners, LP
Finite-Lived Intangible Assets [Line Items]
Goodwill impairment loss recognized			184,600,000	0	29,300,000
Goodwill		$ 0	$ 0	$ 184,600,000	$ 0	$ 29,300,000