Property, Plant and Equipment, Other (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Mar. 29, 2018
Assets acquired:
Capital expenditures	$ 1,921.1	$ 1,113.1
Common units issued in connection with land acquisition (in units)	1,223,242
Land [Member]
Assets acquired:
Property, plant and equipment, additions	$ 85.2
Capital expenditures	$ 55.2
Delaware Basin Gas Processing LLC [Member]
Business Acquisition [Line Items]
Remaining membership interest acquired			50.00%
Assets acquired:
Property, plant, and equipment			$ 200.0