Segment Information - Summary of Consolidated Revenues Disaggregated by Product and Service (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Revenue from External Customer [Line Items]
Revenue recognized		$ 1,212.3	$ 1,642.0	$ 2,832.1	$ 3,606.6
Non-customer revenue		68.3	42.2	228.1	54.1
Total revenues		1,523.5	1,995.3	3,572.4	4,294.7
Derivative Activities - Hedge [Member]
Revenue from External Customer [Line Items]
Non-customer revenue		60.2	43.3	120.3	64.6
Derivative Activities - Non-hedge [Member]
Revenue from External Customer [Line Items]
Non-customer revenue	[1]	8.1	(1.1)	107.8	(10.5)
Natural Gas [Member]
Revenue from External Customer [Line Items]
Revenue recognized		269.7	217.6	542.8	628.9
NGL [Member]
Revenue from External Customer [Line Items]
Revenue recognized		908.2	1,195.5	2,069.5	2,591.9
Condensate and Crude Oil [Member]
Revenue from External Customer [Line Items]
Revenue recognized		27.6	172.1	163.3	309.8
Petroleum Products [Member]
Revenue from External Customer [Line Items]
Revenue recognized		6.8	56.8	56.5	76.0
Gathering and Processing [Member]
Revenue from External Customer [Line Items]
Revenue recognized		107.4	177.5	223.3	371.9
Sales of Commodities [Member]
Revenue from External Customer [Line Items]
Total revenues		1,280.6	1,684.2	3,060.2	3,660.7
Other [Member]
Revenue from External Customer [Line Items]
Revenue recognized		13.5	3.1	27.3	15.8
NGL Transportation, Fractionation and Services [Member]
Revenue from External Customer [Line Items]
Revenue recognized		32.9	40.1	72.8	76.3
Storage Terminaling and Export [Member]
Revenue from External Customer [Line Items]
Revenue recognized		89.1	90.4	188.8	170.0
Fees from Midstream Services [Member]
Revenue from External Customer [Line Items]
Revenue recognized		242.9	311.1	512.2	634.0
Total revenues		$ 242.9	$ 311.1	$ 512.2	$ 634.0

[1] Represents derivative activities that are not designated as hedging instruments under ASC 815.