Partners' Capital (Components of Net Income (Loss) Attributable to Non-Controlling Interests) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Distribution Made to Limited Partner [Line Items]
Net income attributable to non-controlling partners in subsidiaries	$ 5.9	$ 9.8
Crestwood Midstream Partners LP
Distribution Made to Limited Partner [Line Items]
Net income attributable to non-controlling partners in subsidiaries	5.9	5.6
Crestwood Niobrara LLC
Distribution Made to Limited Partner [Line Items]
Net income attributable to non-controlling partners in subsidiaries	5.9	5.6
Preferred Units, Class A | Crestwood Midstream Partners LP
Distribution Made to Limited Partner [Line Items]
Net income attributable to non-controlling partners in subsidiaries	0.0	9.2
Limited Partner [Member] | Crestwood Midstream Partners LP
Distribution Made to Limited Partner [Line Items]
Net income attributable to non-controlling partners in subsidiaries	$ 0.0	$ (5.0)