Members' Equity - Computation and Distribution Activity (Details) - USD ($) $ / shares in Units, $ in Millions				3 Months Ended							6 Months Ended
	May 15, 2018	Aug. 14, 2017	May 15, 2017	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Jun. 30, 2016	Jun. 30, 2018	Jun. 30, 2017
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
ENLC interest in net income				$ 28.0			$ 5.9				$ 40.4	$ 4.0
Distributed earnings allocated to:
Total distributed earnings				49.1			46.7				97.2	93.2
Undistributed loss allocated to:
Total undistributed loss				(21.1)			(40.8)				(56.8)	(89.2)
Net income allocated to:
Total net income				$ 28.0			$ 5.9				$ 40.4	$ 4.0
Basic and diluted net income per unit:
Basic (in dollars per share)				$ 0.15			$ 0.03				$ 0.22	$ 0.02
Diluted (in dollars per share)				0.15			0.03				0.22	$ 0.02
Distribution declared/unit (in dollars per share)				$ 0.267000000	$ 0.263	$ 0.259	$ 0.267	$ 0.255	$ 0.255	$ 0.255	$ 0.267000000
Distribution paid per unit (in dollars per share)	$ 0.263000000	$ 0.255000000	$ 0.255000000
Unvested restricted units
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
ENLC interest in net income				$ 0.5			$ 0.1				$ 0.6	$ 0.1
Distributed earnings allocated to:
Total distributed earnings				0.8			0.6				1.3	1.2
Undistributed loss allocated to:
Total undistributed loss				(0.3)			(0.5)				(0.7)	(1.1)
Net income allocated to:
Total net income				0.5			0.1				0.6	0.1
Common units
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
ENLC interest in net income				27.5			5.8				39.8	3.9
Distributed earnings allocated to:
Total distributed earnings				48.3			46.1				95.9	92.0
Undistributed loss allocated to:
Total undistributed loss				(20.8)			(40.3)				(56.1)	(88.1)
Net income allocated to:
Total net income				$ 27.5			$ 5.8				$ 39.8	$ 3.9