Partners' Capital (Components of Net Income (Loss) Attributable to Non-Controlling Interests) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Distribution Made to Limited Partner [Line Items]
Payments of Ordinary Dividends, Noncontrolling Interest			$ 7.6	$ 7.6
Net income attributable to non-controlling partners in subsidiaries	$ (6.3)	$ (6.0)	(12.4)	(11.9)
Crestwood Midstream Partners LP
Distribution Made to Limited Partner [Line Items]
Net income attributable to non-controlling partners in subsidiaries	(6.3)	(6.0)	(12.4)	(11.9)
Crestwood Niobrara LLC
Distribution Made to Limited Partner [Line Items]
Payments of Ordinary Dividends, Noncontrolling Interest			7.6	7.6
Net income attributable to non-controlling partners in subsidiaries	$ 6.3	$ 6.0	$ 12.4	$ 11.9