Segment Information - Reconciliation of Reportable Segment Operating Margin to Income (Loss) Before Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Reconciliation of reportable segment operating margin to income (loss) before income taxes:
Operating margin	$ 479.5	$ 423.5	$ 1,145.5	$ 806.6
Depreciation and amortization expense	(204.5)	(237.2)	(443.6)	(474.6)
General and administrative expense	(61.5)	(72.8)	(121.9)	(153.6)
Impairment of long-lived assets			(2,442.8)
Interest expense, net	(96.7)	(72.1)	(194.7)	(152.7)
Equity earnings (loss)	14.9	3.2	35.5	5.9
Gain (loss) on sale or disposition of business and assets	0.7	0.2		(3.1)
Gain (loss) from financing activities	21.8		61.1	(1.4)
Change in contingent considerations		0.8		(8.9)
Other, net	(0.3)		(0.8)	(0.2)
Income (loss) before income taxes	153.9	45.6	(1,961.7)	18.0
Gathering and Processing [Member]
Reconciliation of reportable segment operating margin to income (loss) before income taxes:
Operating margin	237.2	232.1	492.8	470.3
Logistics and Transportation [Member]
Reconciliation of reportable segment operating margin to income (loss) before income taxes:
Operating margin	231.5	184.4	525.5	$ 336.3
Other [Member]
Reconciliation of reportable segment operating margin to income (loss) before income taxes:
Operating margin	$ 10.8	$ 7.0	$ 127.2