Goodwill and Intangible Assets - Narrative (Details) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Goodwill impairment loss recognized	$ 873,300,000			$ 1,328,200,000
Impairment of intangible assets			$ 0
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
Weighted average
Finite-Lived Intangible Assets [Line Items]
Intangible asset, useful life		14 years 11 months 20 days
EnLink Midstream Partners, LP
Finite-Lived Intangible Assets [Line Items]
Goodwill impairment loss recognized			873,300,000
Amortization expense		$ 127,100,000	$ 117,000,000	56,000,000
Crude and Condensate
Finite-Lived Intangible Assets [Line Items]
Impairment of intangible assets				$ 223,100,000