Goodwill and Intangible Assets - Changes in Carrying Value of Intangible Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Finite-lived Intangible Assets [Roll Forward]
Accumulated amortization, beginning of period	$ (545.9)
Retirements, gross carrying amount	(1.6)
Retirements, accumulated amortization	0.6
Retirements, net carrying amount	(1.0)
Accumulated amortization, end of period	(668.8)	$ (545.9)
EnLink Midstream Partners, LP
Finite-lived Intangible Assets [Roll Forward]
Amortization expense	123.5	123.7	$ 123.5
Customer relationships, end of period, net	1,125.4
Customer Relationships | EnLink Midstream Partners, LP
Finite-lived Intangible Assets [Roll Forward]
Customer relationships, beginning of period, gross	1,795.8	1,795.8	1,795.8
Accumulated amortization, beginning of period	(545.9)	(422.2)	(298.7)
Customer relationships, beginning of period, net	1,249.9	1,373.6	1,497.1
Amortization expense	(123.5)	(123.7)	(123.5)
Customer relationships, end of period, gross	1,794.2	1,795.8	1,795.8
Accumulated amortization, end of period	(668.8)	(545.9)	(422.2)
Customer relationships, end of period, net	$ 1,125.4	$ 1,249.9	$ 1,373.6