Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities:
Net income (loss)	$ (999.6)	$ (32.8)	$ 320.0
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Impairments	1,133.5	365.8	17.1
Depreciation and amortization	617.0	577.3	545.3
Loss on secured term loan receivable	52.9	0.0	0.0
Non-cash revenue from contract restructuring	0.0	(45.5)	0.0
Non-cash unit-based compensation	39.4	41.1	48.1
Deferred tax expense (benefit)	6.9	16.3	(197.2)
(Gain) loss on derivative activity recognized in net income (loss)	(14.4)	(5.2)	4.2
Cash settlements on derivatives	16.9	(7.0)	(11.2)
Gain on extinguishment of debt	0.0	0.0	(9.0)
Amortization of debt issue costs, net (premium) discount of notes and installment payable	4.9	4.3	29.3
Distribution of earnings from unconsolidated affiliates	16.5	15.8	13.3
(Income) loss from unconsolidated affiliates	16.8	(13.3)	(9.6)
Other operating activities	(4.1)	(2.2)	0.6
Changes in assets and liabilities:
Accounts receivable, accrued revenue, and other	337.1	(113.1)	(189.4)
Natural gas and NGLs inventory, prepaid expenses, and other	13.6	(12.2)	(23.5)
Accounts payable, accrued product purchases, and other accrued liabilities	(245.5)	58.3	162.1
Net cash provided by operating activities	991.9	847.6	700.1
Cash flows from investing activities:
Additions to property and equipment	(754.9)	(843.1)	(790.8)
Proceeds from sale of unconsolidated affiliate investment	0.0	0.0	189.7
Proceeds from sale of property	14.3	1.9	2.3
Investment in unconsolidated affiliates	0.0	(0.1)	(12.6)
Distribution from unconsolidated affiliates in excess of earnings	3.7	6.9	0.2
Other investing activities	(4.6)	8.1	0.4
Net cash used in investing activities	(741.5)	(826.3)	(610.8)
Cash flows from financing activities:
Proceeds from borrowings	3,310.0	3,946.8	2,381.8
Payments on borrowings	(2,971.4)	(3,060.0)	(2,123.4)
Payment of installment payable for EOGP acquisition	0.0	(250.0)	(250.0)
Debt financing costs	(10.0)	(1.9)	(5.5)
Distributions to non-controlling interests	(220.5)	(517.2)	(433.7)
Distribution to members	(467.2)	(194.8)	(186.0)
Conversion of restricted units, net of units withheld for taxes	(7.8)	(5.7)	(4.8)
Proceeds from issuance of ENLK common units	0.0	46.1	106.9
Contributions by non-controlling interests	97.5	90.2	57.3
Other financing activities	(4.0)	(5.6)	(6.4)
Net cash provided by (used in) financing activities	(273.4)	47.9	(69.8)
Net increase (decrease) in cash and cash equivalents	(23.0)	69.2	19.5
Cash and cash equivalents, beginning of period	100.4	31.2	11.7
Cash and cash equivalents, end of period	77.4	100.4	31.2
Series C Preferred Units
Cash flows from financing activities:
Proceeds from issuance of Series C Preferred Units	$ 0.0	$ 0.0	$ 394.0