Segment Information - Financial Information and Assets (Details) - USD ($) $ in Millions		3 Months Ended												12 Months Ended
		Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Product sales														$ 4,358.4	$ 3,008.9	$ 3,253.7
Product sales—related parties														144.9	134.3	119.4
Midstream services														552.3	467.2	451.0
Midstream services—related parties														688.2	653.1	618.6
Cost of sales	[1]													(4,361.5)	(3,015.5)	(3,245.3)
Operating expenses														(418.7)	(398.5)	(419.9)
Gain (loss) on derivative activity														(4.2)	(11.1)	9.4
Segment profit (loss)														959.4	838.4	786.9
Depreciation and amortization														(545.3)	(503.9)	(387.3)
Impairments		$ (8.3)	$ (1.8)	$ 0.0	$ (7.0)	$ 0.0	$ 0.0	$ 0.0	$ (873.3)	$ (764.2)	$ (799.2)	$ 0.0	$ 0.0	(17.1)	(873.3)	(1,563.4)
Goodwill		1,542.2				1,542.2				2,413.9				1,542.2	1,542.2	2,413.9
Capital expenditures														768.1	676.1	570.5
Total assets		10,537.8				10,275.9				9,541.3				10,537.8	10,275.9	9,541.3
Corporate
Segment Reporting Information [Line Items]
Product sales														0.0	0.0	0.0
Product sales—related parties														(750.6)	(333.0)	(66.2)
Midstream services														0.0	0.0	0.0
Midstream services—related parties														(131.5)	(86.8)	(16.8)
Cost of sales														882.1	419.8	83.0
Operating expenses														0.0	0.0	0.0
Gain (loss) on derivative activity														(4.2)	(11.1)	9.4
Segment profit (loss)														(4.2)	(11.1)	9.4
Depreciation and amortization														(9.9)	(9.2)	(7.2)
Impairments														0.0	(307.0)	0.0
Goodwill		1,119.9				1,119.9				1,426.9				1,119.9	1,119.9	1,426.9
Capital expenditures														26.4	9.1	15.1
Total assets		1,268.3				1,422.7				1,751.1				1,268.3	1,422.7	1,751.1
Texas | Operating Segments
Segment Reporting Information [Line Items]
Product sales														325.0	237.2	320.0
Product sales—related parties														500.3	287.6	123.3
Midstream services														116.3	104.2	100.2
Midstream services—related parties														424.3	439.3	456.7
Cost of sales														(772.3)	(483.4)	(412.2)
Operating expenses														(172.7)	(168.5)	(181.8)
Gain (loss) on derivative activity														0.0	0.0	0.0
Segment profit (loss)														420.9	416.4	406.2
Depreciation and amortization														(215.2)	(196.9)	(169.7)
Impairments														0.0	(473.1)	(496.3)
Goodwill		232.0				232.0				703.5				232.0	232.0	703.5
Capital expenditures														145.4	217.9	268.0
Total assets		3,094.8				3,142.6				3,709.5				3,094.8	3,142.6	3,709.5
Louisiana | Operating Segments
Segment Reporting Information [Line Items]
Product sales														2,529.6	1,632.5	1,527.7
Product sales—related parties														45.0	57.8	48.5
Midstream services														220.6	215.4	244.1
Midstream services—related parties														136.4	95.8	20.0
Cost of sales														(2,618.1)	(1,729.0)	(1,567.6)
Operating expenses														(101.3)	(96.6)	(105.9)
Gain (loss) on derivative activity														0.0	0.0	0.0
Segment profit (loss)														212.2	175.9	166.8
Depreciation and amortization														(116.1)	(114.8)	(109.1)
Impairments														(0.8)	0.0	(787.3)
Goodwill		0.0				0.0				0.0				0.0	0.0	0.0
Capital expenditures														75.1	79.1	59.2
Total assets		2,408.5				2,349.3				2,309.3				2,408.5	2,349.3	2,309.3
Oklahoma | Operating Segments
Segment Reporting Information [Line Items]
Product sales														128.8	48.5	5.0
Product sales—related parties														349.4	120.4	13.0
Midstream services														155.0	82.2	28.3
Midstream services—related parties														241.6	185.9	140.7
Cost of sales														(522.9)	(184.9)	(17.9)
Operating expenses														(64.6)	(52.1)	(30.3)
Gain (loss) on derivative activity														0.0	0.0	0.0
Segment profit (loss)														287.3	200.0	138.8
Depreciation and amortization														(156.6)	(140.6)	(49.8)
Impairments														0.0	0.0	(0.6)
Goodwill		190.3				190.3				190.3				190.3	190.3	190.3
Capital expenditures														442.1	295.7	40.7
Total assets		2,836.7				2,524.5				873.4				2,836.7	2,524.5	873.4
Crude and Condensate | Operating Segments
Segment Reporting Information [Line Items]
Product sales														1,375.0	1,090.7	1,401.0
Product sales—related parties														0.8	1.5	0.8
Midstream services														60.4	65.4	78.4
Midstream services—related parties														17.4	18.9	18.0
Cost of sales														(1,330.3)	(1,038.0)	(1,330.6)
Operating expenses														(80.1)	(81.3)	(101.9)
Gain (loss) on derivative activity														0.0	0.0	0.0
Segment profit (loss)														43.2	57.2	65.7
Depreciation and amortization														(47.5)	(42.4)	(51.5)
Impairments														(16.3)	(93.2)	(279.2)
Goodwill		0.0				0.0				93.2				0.0	0.0	93.2
Capital expenditures														79.1	74.3	187.5
Total assets		$ 929.5				$ 836.8				$ 898.0				$ 929.5	$ 836.8	$ 898.0

[1] Includes related party cost of sales of $211.0 million, $150.1 million and $141.3 million for the years ended December 31, 2017, 2016 and 2015, respectively.