Partners' Capital (Components of Net Income (Loss) Attributable to Non-Controlling Interests) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Distribution Made to Limited Partner [Line Items]
Distributions to non-controlling partner			$ 18.5	$ 6.6
Net income attributable to non-controlling partners in subsidiaries	$ (10.2)	$ (10.6)	(20.1)	(14.6)
Crestwood Midstream Partners LP
Distribution Made to Limited Partner [Line Items]
Distributions to non-controlling partner			18.5	6.6
Net income attributable to non-controlling partners in subsidiaries	$ (10.2)	$ (10.6)	(20.1)	(14.6)
Crestwood Niobrara LLC
Distribution Made to Limited Partner [Line Items]
Distributions to non-controlling partner			$ 18.5	$ 6.6