Partners' Capital (Components of Net Income (Loss) Attributable to Non-Controlling Interests) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Distribution Made to Limited Partner [Line Items]
Net income attributable to non-controlling partners in subsidiaries	$ 6.1	$ (396.5)	$ 18.0	$ (642.7)
Crestwood Midstream Partners LP
Distribution Made to Limited Partner [Line Items]
Net income attributable to non-controlling partners in subsidiaries	6.1	5.9	18.0	17.2
Crestwood Niobrara LLC
Distribution Made to Limited Partner [Line Items]
Net income attributable to non-controlling partners in subsidiaries	6.1	5.9	18.0	17.2
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	6.4	0.0	23.1
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	$ (408.8)	$ 0.0	$ (683.0)