Segment Information - Financial Information and Assets (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Segment Reporting
Revenue from contracts with customers	$ 1,331.8	$ 1,136.9
Cost of sales, exclusive of operating expenses and depreciation and amortization	(934.7)	(755.3)
Realized gain (loss) on derivatives	(7.8)	18.0
Change in fair value of derivatives	(7.9)	13.0
Adjusted gross margin	313.7	400.8
Operating expenses	(56.3)	(100.7)
Segment profit	257.4	300.1
Depreciation and amortization	(151.0)	(162.8)
Impairments	0.0	(353.0)
Gain (loss) on disposition of assets	0.0	0.6
General and administrative	(26.0)	(30.4)
Interest expense, net of interest income	(60.0)	(55.6)
Gain on extinguishment of debt	0.0	5.3
Loss from unconsolidated affiliates	(6.3)	1.7
Other expense	(0.1)	0.0
Income (loss) before non-controlling interest and income taxes	14.0	(294.1)
Capital expenditures	20.8	114.8
Related parties amount in cost of sales	3.2	2.9
Other depreciation and amortization	149.0	160.8
Commodity swaps
Segment Reporting
Realized gain (loss) on derivatives	(75.5)	6.2
Permian
Segment Reporting
Revenue from contracts with customers	418.8	371.7
Cost of sales, exclusive of operating expenses and depreciation and amortization	(325.6)	(313.9)
Change in fair value of derivatives	(5.3)	9.4
Adjusted gross margin	31.0	68.1
Operating expenses	11.8	(25.5)
Segment profit	42.8	42.6
Depreciation and amortization	(33.5)	(29.2)
Impairments		(184.6)
Gain (loss) on disposition of assets	0.1	0.4
General and administrative	0.0	0.0
Interest expense, net of interest income	0.0	0.0
Gain on extinguishment of debt		0.0
Loss from unconsolidated affiliates	0.0	0.0
Other expense	0.0
Income (loss) before non-controlling interest and income taxes	9.4	(170.8)
Capital expenditures	13.3	86.0
Permian | Commodity swaps
Segment Reporting
Realized gain (loss) on derivatives	(56.9)	0.9
Louisiana
Segment Reporting
Revenue from contracts with customers	862.9	563.5
Cost of sales, exclusive of operating expenses and depreciation and amortization	(740.4)	(459.7)
Change in fair value of derivatives	(0.4)	(1.0)
Adjusted gross margin	111.4	107.1
Operating expenses	(29.2)	(31.8)
Segment profit	82.2	75.3
Depreciation and amortization	(36.1)	(37.8)
Impairments		(168.4)
Gain (loss) on disposition of assets	(0.1)	0.0
General and administrative	0.0	0.0
Interest expense, net of interest income	0.0	0.0
Gain on extinguishment of debt		0.0
Loss from unconsolidated affiliates	0.0	0.0
Other expense	0.0
Income (loss) before non-controlling interest and income taxes	46.0	(130.9)
Capital expenditures	2.8	15.2
Louisiana | Commodity swaps
Segment Reporting
Realized gain (loss) on derivatives	(10.7)	4.3
Oklahoma
Segment Reporting
Revenue from contracts with customers	234.0	220.0
Cost of sales, exclusive of operating expenses and depreciation and amortization	(151.0)	(93.7)
Change in fair value of derivatives	(1.8)	3.8
Adjusted gross margin	75.2	130.9
Operating expenses	(19.7)	(22.9)
Segment profit	55.5	108.0
Depreciation and amortization	(50.7)	(56.6)
Impairments		0.0
Gain (loss) on disposition of assets	0.0	0.2
General and administrative	0.0	0.0
Interest expense, net of interest income	0.0	0.0
Gain on extinguishment of debt		0.0
Loss from unconsolidated affiliates	0.0	0.0
Other expense	0.0
Income (loss) before non-controlling interest and income taxes	4.8	51.6
Capital expenditures	1.9	8.5
Oklahoma | Commodity swaps
Segment Reporting
Realized gain (loss) on derivatives	(6.0)	0.8
North Texas
Segment Reporting
Revenue from contracts with customers	202.5	120.7
Cost of sales, exclusive of operating expenses and depreciation and amortization	(104.1)	(27.0)
Change in fair value of derivatives	(0.4)	0.8
Adjusted gross margin	96.1	94.7
Operating expenses	(19.2)	(20.5)
Segment profit	76.9	74.2
Depreciation and amortization	(28.7)	(37.2)
Impairments		0.0
Gain (loss) on disposition of assets	0.0	0.0
General and administrative	0.0	0.0
Interest expense, net of interest income	0.0	0.0
Gain on extinguishment of debt		0.0
Loss from unconsolidated affiliates	0.0	0.0
Other expense	0.0
Income (loss) before non-controlling interest and income taxes	48.2	37.0
Capital expenditures	2.4	4.7
North Texas | Commodity swaps
Segment Reporting
Realized gain (loss) on derivatives	(1.9)	0.2
Corporate
Segment Reporting
Revenue from contracts with customers	(386.4)	(139.0)
Cost of sales, exclusive of operating expenses and depreciation and amortization	386.4	139.0
Change in fair value of derivatives	0.0	0.0
Adjusted gross margin	0.0	0.0
Operating expenses	0.0	0.0
Segment profit	0.0	0.0
Depreciation and amortization	(2.0)	(2.0)
Impairments		0.0
Gain (loss) on disposition of assets	0.0	0.0
General and administrative	(26.0)	(30.4)
Interest expense, net of interest income	(60.0)	(55.6)
Gain on extinguishment of debt		5.3
Loss from unconsolidated affiliates	(6.3)	1.7
Other expense	(0.1)
Income (loss) before non-controlling interest and income taxes	(94.4)	(81.0)
Capital expenditures	0.4	0.4
Corporate | Commodity swaps
Segment Reporting
Realized gain (loss) on derivatives	0.0	0.0
Product sales
Segment Reporting
Revenue from contracts with customers	1,122.9	892.9
Product sales | Permian
Segment Reporting
Revenue from contracts with customers	232.3	300.3
Product sales | Louisiana
Segment Reporting
Revenue from contracts with customers	788.3	513.7
Product sales | Oklahoma
Segment Reporting
Revenue from contracts with customers	50.1	58.5
Product sales | North Texas
Segment Reporting
Revenue from contracts with customers	52.2	20.4
Product sales | Corporate
Segment Reporting
Revenue from contracts with customers	0.0	0.0
Product sales, Natural gas sales
Segment Reporting
Revenue from contracts with customers	333.1	157.9
Product sales, Natural gas sales | Permian
Segment Reporting
Revenue from contracts with customers	125.0	15.1
Product sales, Natural gas sales | Louisiana
Segment Reporting
Revenue from contracts with customers	121.2	81.6
Product sales, Natural gas sales | Oklahoma
Segment Reporting
Revenue from contracts with customers	35.9	41.1
Product sales, Natural gas sales | North Texas
Segment Reporting
Revenue from contracts with customers	51.0	20.1
Product sales, Natural gas sales | Corporate
Segment Reporting
Revenue from contracts with customers	0.0	0.0
Product sales, NGL sales
Segment Reporting
Revenue from contracts with customers	627.8	375.4
Product sales, NGL sales | Permian
Segment Reporting
Revenue from contracts with customers	0.0	0.2
Product sales, NGL sales | Louisiana
Segment Reporting
Revenue from contracts with customers	626.0	373.7
Product sales, NGL sales | Oklahoma
Segment Reporting
Revenue from contracts with customers	0.6	1.2
Product sales, NGL sales | North Texas
Segment Reporting
Revenue from contracts with customers	1.2	0.3
Product sales, NGL sales | Corporate
Segment Reporting
Revenue from contracts with customers	0.0	0.0
Product sales, Crude oil and condensate sales
Segment Reporting
Revenue from contracts with customers	162.0	359.6
Product sales, Crude oil and condensate sales | Permian
Segment Reporting
Revenue from contracts with customers	107.3	285.0
Product sales, Crude oil and condensate sales | Louisiana
Segment Reporting
Revenue from contracts with customers	41.1	58.4
Product sales, Crude oil and condensate sales | Oklahoma
Segment Reporting
Revenue from contracts with customers	13.6	16.2
Product sales, Crude oil and condensate sales | North Texas
Segment Reporting
Revenue from contracts with customers	0.0	0.0
Product sales, Crude oil and condensate sales | Corporate
Segment Reporting
Revenue from contracts with customers	0.0	0.0
Product sales—related parties
Segment Reporting
Revenue from contracts with customers	0.0	0.0
Product sales—related parties | Permian
Segment Reporting
Revenue from contracts with customers	164.9	46.0
Product sales—related parties | Louisiana
Segment Reporting
Revenue from contracts with customers	23.6	6.8
Product sales—related parties | Oklahoma
Segment Reporting
Revenue from contracts with customers	113.1	67.4
Product sales—related parties | North Texas
Segment Reporting
Revenue from contracts with customers	82.4	18.7
Product sales—related parties | Corporate
Segment Reporting
Revenue from contracts with customers	(384.0)	(138.9)
Product sales, NGL sales, related party
Segment Reporting
Revenue from contracts with customers	0.0	(0.1)
Product sales, NGL sales, related party | Permian
Segment Reporting
Revenue from contracts with customers	164.9	45.9
Product sales, NGL sales, related party | Louisiana
Segment Reporting
Revenue from contracts with customers	23.6	6.8
Product sales, NGL sales, related party | Oklahoma
Segment Reporting
Revenue from contracts with customers	113.1	67.6
Product sales, NGL sales, related party | North Texas
Segment Reporting
Revenue from contracts with customers	80.9	17.2
Product sales, NGL sales, related party | Corporate
Segment Reporting
Revenue from contracts with customers	(382.5)	(137.6)
Product sales, Crude oil and condensate sales, related party
Segment Reporting
Revenue from contracts with customers	0.0	0.1
Product sales, Crude oil and condensate sales, related party | Permian
Segment Reporting
Revenue from contracts with customers	0.0	0.1
Product sales, Crude oil and condensate sales, related party | Louisiana
Segment Reporting
Revenue from contracts with customers	0.0	0.0
Product sales, Crude oil and condensate sales, related party | Oklahoma
Segment Reporting
Revenue from contracts with customers	0.0	(0.2)
Product sales, Crude oil and condensate sales, related party | North Texas
Segment Reporting
Revenue from contracts with customers	1.5	1.5
Product sales, Crude oil and condensate sales, related party | Corporate
Segment Reporting
Revenue from contracts with customers	(1.5)	(1.3)
Midstream services
Segment Reporting
Revenue from contracts with customers	208.9	244.0
Midstream services | Permian
Segment Reporting
Revenue from contracts with customers	21.6	25.4
Midstream services | Louisiana
Segment Reporting
Revenue from contracts with customers	48.7	43.0
Midstream services | Oklahoma
Segment Reporting
Revenue from contracts with customers	70.7	94.0
Midstream services | North Texas
Segment Reporting
Revenue from contracts with customers	67.9	81.6
Midstream services | Corporate
Segment Reporting
Revenue from contracts with customers	0.0	0.0
Midstream services, Gathering and transportation
Segment Reporting
Revenue from contracts with customers	117.2	130.2
Midstream services, Gathering and transportation | Permian
Segment Reporting
Revenue from contracts with customers	9.7	16.3
Midstream services, Gathering and transportation | Louisiana
Segment Reporting
Revenue from contracts with customers	15.8	11.7
Midstream services, Gathering and transportation | Oklahoma
Segment Reporting
Revenue from contracts with customers	51.3	56.3
Midstream services, Gathering and transportation | North Texas
Segment Reporting
Revenue from contracts with customers	40.4	45.9
Midstream services, Gathering and transportation | Corporate
Segment Reporting
Revenue from contracts with customers	0.0	0.0
Midstream services, Processing
Segment Reporting
Revenue from contracts with customers	51.7	73.7
Midstream services, Processing | Permian
Segment Reporting
Revenue from contracts with customers	8.2	4.3
Midstream services, Processing | Louisiana
Segment Reporting
Revenue from contracts with customers	0.5	0.7
Midstream services, Processing | Oklahoma
Segment Reporting
Revenue from contracts with customers	15.9	33.3
Midstream services, Processing | North Texas
Segment Reporting
Revenue from contracts with customers	27.1	35.4
Midstream services, Processing | Corporate
Segment Reporting
Revenue from contracts with customers	0.0	0.0
Midstream services, NGL services
Segment Reporting
Revenue from contracts with customers	22.1	19.6
Midstream services, NGL services | Permian
Segment Reporting
Revenue from contracts with customers	0.0	0.0
Midstream services, NGL services | Louisiana
Segment Reporting
Revenue from contracts with customers	22.0	19.6
Midstream services, NGL services | Oklahoma
Segment Reporting
Revenue from contracts with customers	0.0	0.0
Midstream services, NGL services | North Texas
Segment Reporting
Revenue from contracts with customers	0.1	0.0
Midstream services, NGL services | Corporate
Segment Reporting
Revenue from contracts with customers	0.0	0.0
Midstream services, Crude services
Segment Reporting
Revenue from contracts with customers	16.9	19.1
Midstream services, Crude services | Permian
Segment Reporting
Revenue from contracts with customers	3.5	4.2
Midstream services, Crude services | Louisiana
Segment Reporting
Revenue from contracts with customers	9.9	10.6
Midstream services, Crude services | Oklahoma
Segment Reporting
Revenue from contracts with customers	3.3	4.3
Midstream services, Crude services | North Texas
Segment Reporting
Revenue from contracts with customers	0.2	0.0
Midstream services, Crude services | Corporate
Segment Reporting
Revenue from contracts with customers	0.0	0.0
Midstream services, Other services
Segment Reporting
Revenue from contracts with customers	1.0	1.4
Midstream services, Other services | Permian
Segment Reporting
Revenue from contracts with customers	0.2	0.6
Midstream services, Other services | Louisiana
Segment Reporting
Revenue from contracts with customers	0.5	0.4
Midstream services, Other services | Oklahoma
Segment Reporting
Revenue from contracts with customers	0.2	0.1
Midstream services, Other services | North Texas
Segment Reporting
Revenue from contracts with customers	0.1	0.3
Midstream services, Other services | Corporate
Segment Reporting
Revenue from contracts with customers	0.0	0.0
Midstream services—related parties
Segment Reporting
Revenue from contracts with customers	0.0	0.0
Midstream services—related parties | Permian
Segment Reporting
Revenue from contracts with customers	0.0	0.0
Midstream services—related parties | Louisiana
Segment Reporting
Revenue from contracts with customers	2.3	0.0
Midstream services—related parties | Oklahoma
Segment Reporting
Revenue from contracts with customers	0.1	0.1
Midstream services—related parties | North Texas
Segment Reporting
Revenue from contracts with customers	0.0	0.0
Midstream services—related parties | Corporate
Segment Reporting
Revenue from contracts with customers	(2.4)	(0.1)
Midstream services, Crude services, related party
Segment Reporting
Revenue from contracts with customers	0.0	0.0
Midstream services, Crude services, related party | Permian
Segment Reporting
Revenue from contracts with customers	0.0	0.0
Midstream services, Crude services, related party | Louisiana
Segment Reporting
Revenue from contracts with customers	0.0	0.0
Midstream services, Crude services, related party | Oklahoma
Segment Reporting
Revenue from contracts with customers	0.1	0.1
Midstream services, Crude services, related party | North Texas
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)	$ (0.1)
Midstream services, Other services, related party
Segment Reporting
Revenue from contracts with customers	0.0
Midstream services, Other services, related party | Permian
Segment Reporting
Revenue from contracts with customers	0.0
Midstream services, Other services, related party | Louisiana
Segment Reporting
Revenue from contracts with customers	2.3
Midstream services, Other services, related party | Oklahoma
Segment Reporting
Revenue from contracts with customers	0.0
Midstream services, Other services, related party | North Texas
Segment Reporting
Revenue from contracts with customers	0.0
Midstream services, Other services, related party | Corporate
Segment Reporting
Revenue from contracts with customers	$ (2.3)