Members' Equity - Computation and Distribution Activity (Details) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended
	May 15, 2017	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2016
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
ENLC interest in net income (loss)		$ 12.4		$ (1.9)
Distributed earnings allocated to:
Total distributed earnings		48.1		46.5
Undistributed loss allocated to:
Total undistributed loss		(35.7)		(48.4)
Net income (loss) allocated to:
Total net income (loss)		$ 12.4		$ (1.9)
Basic and diluted net income (loss) per unit:
Basic (in dollars per share)		$ 0.07		$ (0.01)
Diluted (in dollars per share)		0.07		(0.01)
Distribution declared/unit (in dollars per share)		$ 0.263	$ 0.259	$ 0.255	$ 0.255
Distribution paid per unit (in dollars per share)	$ 0.255
Unvested restricted units
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
ENLC interest in net income (loss)		$ 0.1		$ 0.0
Distributed earnings allocated to:
Total distributed earnings		0.5		0.6
Undistributed loss allocated to:
Total undistributed loss		(0.4)		(0.6)
Net income (loss) allocated to:
Total net income (loss)		0.1		0.0
Common units
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
ENLC interest in net income (loss)		12.3		(1.9)
Distributed earnings allocated to:
Total distributed earnings		47.6		45.9
Undistributed loss allocated to:
Total undistributed loss		(35.3)		(47.8)
Net income (loss) allocated to:
Total net income (loss)		$ 12.3		$ (1.9)