Partners' Capital (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions								3 Months Ended
	Apr. 21, 2016	Feb. 12, 2016	Feb. 05, 2016	Feb. 13, 2015	Feb. 06, 2015	Feb. 14, 2014	Feb. 07, 2014	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Distribution Made to Limited Partner [Line Items]
Distribution Made to Limited Partner, Distribution Date		Feb. 12, 2016		Feb. 13, 2015
Distribution Made to Limited Partner, Date of Record			Feb. 05, 2016		Feb. 06, 2015
Incentive Distribution, Distribution								$ 95.6	$ 25.8
Limited Partners' Capital Account, Distribution Amount									10.5
Preferred Stock Dividends, Shares		1,404,317						1,400,000
Net Income (Loss) Attributable to Noncontrolling Interest								$ 5.9	9.8
Dividends, Paid-in-kind		$ 12.8						13.1
Payments of Ordinary Dividends, Noncontrolling Interest								3.8	74.3
Distribution Made to Limited Partner, Cash Distributions Paid		$ 95.6		$ 25.8				$ 97.2	26.6
Preferred Units, Issued								62,122,562		60,718,245
Crestwood Equity Partners LP
Distribution Made to Limited Partner [Line Items]
Incentive Distribution Rights, Ownership Percentage								100.00%
Crestwood Midstream Partners LP
Distribution Made to Limited Partner [Line Items]
Distribution Made to Limited Partner, Distribution Date						Feb. 13, 2015
Distribution Made to Limited Partner, Date of Record							Feb. 06, 2015
Incentive Distribution, Distribution								$ 101.0	$ 111.4
Preferred Stock Dividends, Shares									414,325
Net Income (Loss) Attributable to Noncontrolling Interest								5.9	$ 5.6
Dividends, Paid-in-kind									10.4
Payments of Ordinary Dividends, Noncontrolling Interest								0.0	0.0
Distribution Made to Limited Partner, Cash Distributions Paid						$ 74.3
Crestwood Niobrara LLC
Distribution Made to Limited Partner [Line Items]
Net Income (Loss) Attributable to Noncontrolling Interest								5.9	5.6
Payments of Ordinary Dividends, Noncontrolling Interest								3.8
Non-Controlling Partners
Distribution Made to Limited Partner [Line Items]
Net Income (Loss) Attributable to Noncontrolling Interest								5.9
Non-Controlling Partners | Crestwood Midstream Partners LP
Distribution Made to Limited Partner [Line Items]
Net Income (Loss) Attributable to Noncontrolling Interest								$ 5.9
Preferred Units | Crestwood Niobrara LLC
Distribution Made to Limited Partner [Line Items]
Distribution Made to Limited Partner, Unit Distribution								3,680,570
Subsequent Event
Distribution Made to Limited Partner [Line Items]
Distribution Made to Limited Partner, Distribution Date	May 13, 2016
Distribution Made to Limited Partner, Date of Record	May 06, 2016
Preferred Stock Dividends, Shares	1,436,797
Cash Distribution
Distribution Made to Limited Partner [Line Items]
Limited Partners' Capital Account, Distribution Amount									$ 74.3
Cash Distribution | Subsequent Event
Distribution Made to Limited Partner [Line Items]
Distribution Made to Limited Partner, Distributions Declared, Per Unit	$ 0.6