Segment Information - Financial Information and Assets (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Segment Reporting
Revenue from contracts with customers	$ 1,136.9	$ 1,777.4
Cost of sales	(755.3)	(1,363.4)
Operating expenses	(100.7)	(114.5)
Gain on derivative activity	19.2	1.8
Segment profit	300.1	301.3
Depreciation and amortization	(162.8)	(152.1)
Impairments	(353.0)	(186.5)
Goodwill	0.0	1,123.7	$ 184.6
Capital expenditures	114.8	251.0
Corporate
Segment Reporting
Revenue from contracts with customers	(139.0)	(257.3)
Cost of sales	139.0	257.3
Operating expenses	0.0	0.0
Gain on derivative activity	19.2	1.8
Segment profit	19.2	1.8
Depreciation and amortization	(2.0)	(2.0)
Impairments	0.0	0.0
Goodwill	0.0	0.0	0.0
Capital expenditures	0.4	1.6
Permian | Operating Segments
Segment Reporting
Revenue from contracts with customers	371.7	742.6
Cost of sales	(313.9)	(676.2)
Operating expenses	(25.5)	(27.8)
Gain on derivative activity	0.0	0.0
Segment profit	32.3	38.6
Depreciation and amortization	(29.2)	(27.9)
Impairments	(184.6)	0.0
Goodwill	0.0	184.6	184.6
Capital expenditures	86.0	95.9
North Texas | Operating Segments
Segment Reporting
Revenue from contracts with customers	120.7	174.3
Cost of sales	(27.0)	(73.7)
Operating expenses	(20.5)	(25.7)
Gain on derivative activity	0.0	0.0
Segment profit	73.2	74.9
Depreciation and amortization	(37.2)	(34.3)
Impairments	0.0	0.0
Goodwill	0.0	125.7	0.0
Capital expenditures	4.7	4.3
Oklahoma | Operating Segments
Segment Reporting
Revenue from contracts with customers	220.0	319.7
Cost of sales	(93.7)	(184.2)
Operating expenses	(22.9)	(25.4)
Gain on derivative activity	0.0	0.0
Segment profit	103.4	110.1
Depreciation and amortization	(56.6)	(46.1)
Impairments	0.0	0.0
Goodwill	0.0	813.4	0.0
Capital expenditures	8.5	108.2
Louisiana | Operating Segments
Segment Reporting
Revenue from contracts with customers	563.5	798.1
Cost of sales	(459.7)	(686.6)
Operating expenses	(31.8)	(35.6)
Gain on derivative activity	0.0	0.0
Segment profit	72.0	75.9
Depreciation and amortization	(37.8)	(41.8)
Impairments	(168.4)	(186.5)
Goodwill	0.0	0.0	$ 0.0
Capital expenditures	15.2	41.0
Product sales
Segment Reporting
Revenue from contracts with customers	892.9	1,530.9
Product sales | Corporate
Segment Reporting
Revenue from contracts with customers	0.0	0.0
Product sales | Permian | Operating Segments
Segment Reporting
Revenue from contracts with customers	300.3	616.7
Product sales | North Texas | Operating Segments
Segment Reporting
Revenue from contracts with customers	20.4	59.9
Product sales | Oklahoma | Operating Segments
Segment Reporting
Revenue from contracts with customers	58.5	100.2
Product sales | Louisiana | Operating Segments
Segment Reporting
Revenue from contracts with customers	513.7	754.1
Product sales, Natural gas sales
Segment Reporting
Revenue from contracts with customers	157.9	270.5
Product sales, Natural gas sales | Corporate
Segment Reporting
Revenue from contracts with customers	0.0	0.0
Product sales, Natural gas sales | Permian | Operating Segments
Segment Reporting
Revenue from contracts with customers	15.1	36.1
Product sales, Natural gas sales | North Texas | Operating Segments
Segment Reporting
Revenue from contracts with customers	20.1	50.6
Product sales, Natural gas sales | Oklahoma | Operating Segments
Segment Reporting
Revenue from contracts with customers	41.1	61.6
Product sales, Natural gas sales | Louisiana | Operating Segments
Segment Reporting
Revenue from contracts with customers	81.6	122.2
Product sales, NGL sales
Segment Reporting
Revenue from contracts with customers	375.4	591.1
Product sales, NGL sales | Corporate
Segment Reporting
Revenue from contracts with customers	0.0	0.0
Product sales, NGL sales | Permian | Operating Segments
Segment Reporting
Revenue from contracts with customers	0.2	(0.2)
Product sales, NGL sales | North Texas | Operating Segments
Segment Reporting
Revenue from contracts with customers	0.3	9.3
Product sales, NGL sales | Oklahoma | Operating Segments
Segment Reporting
Revenue from contracts with customers	1.2	8.9
Product sales, NGL sales | Louisiana | Operating Segments
Segment Reporting
Revenue from contracts with customers	373.7	573.1
Product sales, Crude oil and condensate sales
Segment Reporting
Revenue from contracts with customers	359.6	669.2
Product sales, Crude oil and condensate sales | Corporate
Segment Reporting
Revenue from contracts with customers	0.0	0.0
Product sales, Crude oil and condensate sales | Permian | Operating Segments
Segment Reporting
Revenue from contracts with customers	285.0	580.8
Product sales, Crude oil and condensate sales | North Texas | Operating Segments
Segment Reporting
Revenue from contracts with customers	0.0	0.0
Product sales, Crude oil and condensate sales | Oklahoma | Operating Segments
Segment Reporting
Revenue from contracts with customers	16.2	29.6
Product sales, Crude oil and condensate sales | Louisiana | Operating Segments
Segment Reporting
Revenue from contracts with customers	58.4	58.8
Product sales, other
Segment Reporting
Revenue from contracts with customers		0.1
Product sales, other | Corporate
Segment Reporting
Revenue from contracts with customers		0.0
Product sales, other | Permian | Operating Segments
Segment Reporting
Revenue from contracts with customers		0.0
Product sales, other | North Texas | Operating Segments
Segment Reporting
Revenue from contracts with customers		0.0
Product sales, other | Oklahoma | Operating Segments
Segment Reporting
Revenue from contracts with customers		0.1
Product sales, other | Louisiana | Operating Segments
Segment Reporting
Revenue from contracts with customers		0.0
Product sales—related parties
Segment Reporting
Revenue from contracts with customers	0.0	0.0
Product sales—related parties | Corporate
Segment Reporting
Revenue from contracts with customers	(138.9)	(260.0)
Product sales—related parties | Permian | Operating Segments
Segment Reporting
Revenue from contracts with customers	46.0	101.2
Product sales—related parties | North Texas | Operating Segments
Segment Reporting
Revenue from contracts with customers	18.7	29.5
Product sales—related parties | Oklahoma | Operating Segments
Segment Reporting
Revenue from contracts with customers	67.4	126.1
Product sales—related parties | Louisiana | Operating Segments
Segment Reporting
Revenue from contracts with customers	6.8	3.2
Product sales, NGL sales, related party
Segment Reporting
Revenue from contracts with customers	(0.1)	0.0
Product sales, NGL sales, related party | Corporate
Segment Reporting
Revenue from contracts with customers	(137.6)	(255.0)
Product sales, NGL sales, related party | Permian | Operating Segments
Segment Reporting
Revenue from contracts with customers	45.9	97.2
Product sales, NGL sales, related party | North Texas | Operating Segments
Segment Reporting
Revenue from contracts with customers	17.2	28.5
Product sales, NGL sales, related party | Oklahoma | Operating Segments
Segment Reporting
Revenue from contracts with customers	67.6	126.1
Product sales, NGL sales, related party | Louisiana | Operating Segments
Segment Reporting
Revenue from contracts with customers	6.8	3.2
Product sales, Crude oil and condensate sales, related party
Segment Reporting
Revenue from contracts with customers	0.1	0.0
Product sales, Crude oil and condensate sales, related party | Corporate
Segment Reporting
Revenue from contracts with customers	(1.3)	(5.0)
Product sales, Crude oil and condensate sales, related party | Permian | Operating Segments
Segment Reporting
Revenue from contracts with customers	0.1	4.0
Product sales, Crude oil and condensate sales, related party | North Texas | Operating Segments
Segment Reporting
Revenue from contracts with customers	1.5	1.0
Product sales, Crude oil and condensate sales, related party | Oklahoma | Operating Segments
Segment Reporting
Revenue from contracts with customers	(0.2)	0.0
Product sales, Crude oil and condensate sales, related party | Louisiana | Operating Segments
Segment Reporting
Revenue from contracts with customers	0.0	0.0
Midstream services
Segment Reporting
Revenue from contracts with customers	244.0	246.5
Midstream services | Corporate
Segment Reporting
Revenue from contracts with customers	0.0	0.0
Midstream services | Permian | Operating Segments
Segment Reporting
Revenue from contracts with customers	25.4	24.7
Midstream services | North Texas | Operating Segments
Segment Reporting
Revenue from contracts with customers	81.6	84.9
Midstream services | Oklahoma | Operating Segments
Segment Reporting
Revenue from contracts with customers	94.0	93.1
Midstream services | Louisiana | Operating Segments
Segment Reporting
Revenue from contracts with customers	43.0	43.8
Midstream services, Gathering and transportation
Segment Reporting
Revenue from contracts with customers	130.2	146.4
Midstream services, Gathering and transportation | Corporate
Segment Reporting
Revenue from contracts with customers	0.0	0.0
Midstream services, Gathering and transportation | Permian | Operating Segments
Segment Reporting
Revenue from contracts with customers	16.3	10.3
Midstream services, Gathering and transportation | North Texas | Operating Segments
Segment Reporting
Revenue from contracts with customers	45.9	63.6
Midstream services, Gathering and transportation | Oklahoma | Operating Segments
Segment Reporting
Revenue from contracts with customers	56.3	55.3
Midstream services, Gathering and transportation | Louisiana | Operating Segments
Segment Reporting
Revenue from contracts with customers	11.7	17.2
Midstream services, Processing
Segment Reporting
Revenue from contracts with customers	73.7	63.8
Midstream services, Processing | Corporate
Segment Reporting
Revenue from contracts with customers	0.0	0.0
Midstream services, Processing | Permian | Operating Segments
Segment Reporting
Revenue from contracts with customers	4.3	7.7
Midstream services, Processing | North Texas | Operating Segments
Segment Reporting
Revenue from contracts with customers	35.4	21.1
Midstream services, Processing | Oklahoma | Operating Segments
Segment Reporting
Revenue from contracts with customers	33.3	34.1
Midstream services, Processing | Louisiana | Operating Segments
Segment Reporting
Revenue from contracts with customers	0.7	0.9
Midstream services, NGL services
Segment Reporting
Revenue from contracts with customers	19.6	11.7
Midstream services, NGL services | Corporate
Segment Reporting
Revenue from contracts with customers	0.0	0.0
Midstream services, NGL services | Permian | Operating Segments
Segment Reporting
Revenue from contracts with customers	0.0	0.0
Midstream services, NGL services | North Texas | Operating Segments
Segment Reporting
Revenue from contracts with customers	0.0	0.0
Midstream services, NGL services | Oklahoma | Operating Segments
Segment Reporting
Revenue from contracts with customers	0.0	0.0
Midstream services, NGL services | Louisiana | Operating Segments
Segment Reporting
Revenue from contracts with customers	19.6	11.7
Midstream services, Crude services
Segment Reporting
Revenue from contracts with customers	19.1	23.0
Midstream services, Crude services | Corporate
Segment Reporting
Revenue from contracts with customers	0.0	0.0
Midstream services, Crude services | Permian | Operating Segments
Segment Reporting
Revenue from contracts with customers	4.2	5.2
Midstream services, Crude services | North Texas | Operating Segments
Segment Reporting
Revenue from contracts with customers	0.0	0.0
Midstream services, Crude services | Oklahoma | Operating Segments
Segment Reporting
Revenue from contracts with customers	4.3	4.0
Midstream services, Crude services | Louisiana | Operating Segments
Segment Reporting
Revenue from contracts with customers	10.6	13.8
Midstream services, Other services
Segment Reporting
Revenue from contracts with customers	1.4	1.6
Midstream services, Other services | Corporate
Segment Reporting
Revenue from contracts with customers	0.0	0.0
Midstream services, Other services | Permian | Operating Segments
Segment Reporting
Revenue from contracts with customers	0.6	1.5
Midstream services, Other services | North Texas | Operating Segments
Segment Reporting
Revenue from contracts with customers	0.3	0.2
Midstream services, Other services | Oklahoma | Operating Segments
Segment Reporting
Revenue from contracts with customers	0.1	(0.3)
Midstream services, Other services | Louisiana | Operating Segments
Segment Reporting
Revenue from contracts with customers	0.4	0.2
Midstream services—related parties
Segment Reporting
Revenue from contracts with customers	0.0	0.0
Midstream services—related parties | Corporate
Segment Reporting
Revenue from contracts with customers	(0.1)	2.7
Midstream services—related parties | Permian | Operating Segments
Segment Reporting
Revenue from contracts with customers	0.0	0.0
Midstream services—related parties | North Texas | Operating Segments
Segment Reporting
Revenue from contracts with customers	0.0	0.0
Midstream services—related parties | Oklahoma | Operating Segments
Segment Reporting
Revenue from contracts with customers	0.1	0.3
Midstream services—related parties | Louisiana | Operating Segments
Segment Reporting
Revenue from contracts with customers	0.0	(3.0)
Midstream services, NGL services, related party
Segment Reporting
Revenue from contracts with customers		0.0
Midstream services, NGL services, related party | Corporate
Segment Reporting
Revenue from contracts with customers		3.0
Midstream services, NGL services, related party | Permian | Operating Segments
Segment Reporting
Revenue from contracts with customers		0.0
Midstream services, NGL services, related party | North Texas | Operating Segments
Segment Reporting
Revenue from contracts with customers		0.0
Midstream services, NGL services, related party | Oklahoma | Operating Segments
Segment Reporting
Revenue from contracts with customers		0.0
Midstream services, NGL services, related party | Louisiana | Operating Segments
Segment Reporting
Revenue from contracts with customers		(3.0)
Midstream services, Crude services, related party
Segment Reporting
Revenue from contracts with customers	0.0	0.0
Midstream services, Crude services, related party | Corporate
Segment Reporting
Revenue from contracts with customers	(0.1)	(0.3)
Midstream services, Crude services, related party | Permian | Operating Segments
Segment Reporting
Revenue from contracts with customers	0.0	0.0
Midstream services, Crude services, related party | North Texas | Operating Segments
Segment Reporting
Revenue from contracts with customers	0.0	0.0
Midstream services, Crude services, related party | Oklahoma | Operating Segments
Segment Reporting
Revenue from contracts with customers	0.1	0.3
Midstream services, Crude services, related party | Louisiana | Operating Segments
Segment Reporting
Revenue from contracts with customers	$ 0.0	$ 0.0