Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenues:
Gathering and processing	$ 1,369.1	$ 825.5	$ 1,051.2
Marketing, supply and logistics	2,093.1	1,144.3	857.5
Total product revenue	3,462.2	1,969.8	1,908.7
Gathering and processing	317.3	290.7	325.9
Storage and transportation	37.2	165.3	266.3
Marketing, supply and logistics	62.4	92.1	128.0
Related party (Note 16)	1.8	2.6	3.9
Total services revenues	418.7	550.7	724.1
Total revenues	3,880.9	2,520.5	2,632.8
Costs of product/services sold (exclusive of items shown separately below):
Product costs	3,309.5	1,851.9	1,780.0
Product costs - related party (Note 16)	15.3	17.7	28.9
Service costs	49.9	55.5	74.6
Total costs of products/services sold	3,374.7	1,925.1	1,883.5
Expenses:
Operations and maintenance	136.0	158.1	190.2
General and administrative	96.5	88.2	116.3
Depreciation, amortization and accretion	191.7	229.6	300.1
Total expenses	424.2	475.9	606.6
Loss on long-lived assets, net	(65.6)	(65.6)	(821.2)
Goodwill impairment	(38.8)	(162.6)	(1,406.3)
Loss on contingent consideration	(57.0)	0.0	0.0
Operating income (loss)	(79.4)	(108.7)	(2,084.8)
Earnings (loss) from unconsolidated affiliates, net	47.8	31.5	(60.8)
Interest and debt expense, net	(99.4)	(125.1)	(140.1)
Gain (loss) on modification/extinguishment of debt	(37.7)	10.0	(20.0)
Other income, net	1.3	0.5	0.6
Loss before income taxes	(167.4)	(191.8)	(2,305.1)
(Provision) benefit for income taxes	0.8	(0.3)	1.4
Net loss	(166.6)	(192.1)	(2,303.7)
Net income (loss) attributable to non-controlling partners	(25.3)	(24.2)	636.8
Net income (loss) attributable to parent	(191.9)	(216.3)	(1,666.9)
Net income attributable to preferred units	62.5	28.7	6.2
Net loss attributable to partners	(254.4)	(245.0)	(1,673.1)
Common unitholders’ interest in net loss	$ (254.4)	$ (245.0)	$ (1,673.1)
Net loss per limited partner unit:
Basic (dollars per unit)	$ (3.64)	$ (3.55)	$ (54.00)
Diluted (dollars per unit)	$ (3.64)	$ (3.55)	$ (54.00)
Weighted-average limited partners’ units outstanding (in thousands):
Basic (units)	69,839	69,017	30,983
Dilutive units (units)	0	0	0
Diluted (units)	69,839	69,017	30,983
CMLP
Revenues:
Gathering and processing	$ 1,369.1	$ 825.5	$ 1,051.2
Marketing, supply and logistics	2,093.1	1,144.3	857.5
Total product revenue	3,462.2	1,969.8	1,908.7
Gathering and processing	317.3	290.7	325.9
Storage and transportation	37.2	165.3	266.3
Marketing, supply and logistics	62.4	92.1	128.0
Related party (Note 16)	1.8	2.6	3.9
Total services revenues	418.7	550.7	724.1
Total revenues	3,880.9	2,520.5	2,632.8
Costs of product/services sold (exclusive of items shown separately below):
Product costs	3,309.5	1,851.9	1,780.0
Product costs - related party (Note 16)	15.3	17.7	28.9
Service costs	49.9	55.5	74.6
Total costs of products/services sold	3,374.7	1,925.1	1,883.5
Expenses:
Operations and maintenance	136.0	155.0	188.7
General and administrative	93.1	85.6	105.6
Depreciation, amortization and accretion	202.7	240.5	278.5
Total expenses	431.8	481.1	572.8
Loss on long-lived assets, net	(65.6)	(65.6)	(227.8)
Goodwill impairment	(38.8)	(162.6)	(1,149.1)
Loss on contingent consideration	(57.0)	0.0	0.0
Operating income (loss)	(87.0)	(113.9)	(1,200.4)
Earnings (loss) from unconsolidated affiliates, net	47.8	31.5	(60.8)
Interest and debt expense, net	(99.4)	(125.1)	(130.5)
Gain (loss) on modification/extinguishment of debt	(37.7)	10.0	(18.9)
Other income, net	0.8	0.0	0.0
(Provision) benefit for income taxes	0.0	0.0	0.0
Net loss	(175.5)	(197.5)	(1,410.6)
Net income (loss) attributable to non-controlling partners	(25.3)	(24.2)	(23.1)
Net income (loss) attributable to parent	(200.8)	(221.7)	(1,433.7)
Net income attributable to preferred units	0.0	0.0	23.1
Net loss attributable to partners	$ (200.8)	$ (221.7)	$ (1,456.8)