Revenues, Remaining Performance Obligations (Details) $ in Millions	3 Months Ended
	Mar. 31, 2018 USD ($)
Midstream Services [Member]
Remaining Performance Obligation to be Recognized in the Future [Abstract]
Remaining performance obligation	$ 12,579.5
Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2018-04-01
Remaining Performance Obligation to be Recognized in the Future [Abstract]
Expected timing of satisfaction, period	9 months
Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2018-04-01 | Midstream Services [Member]
Remaining Performance Obligation to be Recognized in the Future [Abstract]
Remaining performance obligation	$ 1,704.7
Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-01-01
Remaining Performance Obligation to be Recognized in the Future [Abstract]
Expected timing of satisfaction, period	1 year
Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-01-01 | Midstream Services [Member]
Remaining Performance Obligation to be Recognized in the Future [Abstract]
Remaining performance obligation	$ 2,155.1
Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Remaining Performance Obligation to be Recognized in the Future [Abstract]
Expected timing of satisfaction, period	1 year
Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01 | Midstream Services [Member]
Remaining Performance Obligation to be Recognized in the Future [Abstract]
Remaining performance obligation	$ 1,945.8
Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Remaining Performance Obligation to be Recognized in the Future [Abstract]
Expected timing of satisfaction, period	1 year
Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01 | Midstream Services [Member]
Remaining Performance Obligation to be Recognized in the Future [Abstract]
Remaining performance obligation	$ 1,484.3
Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Remaining Performance Obligation to be Recognized in the Future [Abstract]
Expected timing of satisfaction, period	1 year
Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01 | Midstream Services [Member]
Remaining Performance Obligation to be Recognized in the Future [Abstract]
Remaining performance obligation	$ 1,110.0
Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Remaining Performance Obligation to be Recognized in the Future [Abstract]
Expected timing of satisfaction, period
Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01 | Midstream Services [Member]
Remaining Performance Obligation to be Recognized in the Future [Abstract]
Remaining performance obligation	$ 4,179.6