Consolidated Statement of Partners' Capital - USD ($) $ in Millions	Total	CMLP	Crestwood Marcellus Midstream LLC	Preferred Units	Preferred Units CMLP	Preferred Units Crestwood Marcellus Midstream LLC	Limited Partners	Limited Partners CMLP	Limited Partners Crestwood Marcellus Midstream LLC	Non-Controlling Partners	Non-Controlling Partners CMLP	Non-Controlling Partners Crestwood Marcellus Midstream LLC	Preferred Units, Class A	Preferred Units, Class A Preferred Units	Preferred Units, Class A Limited Partners	Preferred Units, Class A Non-Controlling Partners	Subordinated units	Common units	Preferred Units
Common Unit, Outstanding	18,100,000																400,000
Increase (Decrease) in Partners' Capital		$ (15.3)	$ 15.3	$ 0.0		$ 0.0		$ (15.3)	$ 10.5		$ 0.0	$ 4.8
Balance at the beginning of the period at Dec. 31, 2013	$ 5,508.6	5,291.3		0.0	$ 0.0		$ 831.6	5,190.3		$ 4,677.0	101.0
Increase (Decrease) in Partners' Capital [Roll Forward]
Proceeds from the issuance of common units													$ 430.5	$ 0.0	$ 0.0	$ 430.5
Unit-based compensation charges	$ 21.3	18.1		0.0	0.0		3.9	18.1		17.4	0.0
Partners' Capital Account, Units, Unit-based Compensation	100,000
Taxes paid for unit-based compensation vesting	$ (3.9)	(1.6)		0.0	0.0		(2.3)	(1.6)		(1.6)	0.0
Distributions to partners	(399.0)	(470.5)		0.0	0.0		(102.5)	(470.5)		(296.5)	0.0
Issuance of CMLP Class A preferred units		430.5			430.5			0.0			0.0
Issuance of preferred equity of subsidiary	53.9	53.9		0.0	0.0		0.0	0.0		53.9	53.9
Change in fair value of Suburban Propane Partners, LP units	(0.5)			0.0			(0.5)			0.0
Other	(0.7)	(0.7)		0.0	0.0		0.1	(0.7)		(0.8)	0.0
Net loss	(10.4)	14.7		0.0	17.2		56.4	(19.3)		(66.8)	16.8
Balance at the end of the period at Dec. 31, 2014	$ 5,584.5	5,320.4		0.0	447.7		776.2	4,701.0		4,808.3	171.7
Common Unit, Outstanding	18,200,000																400,000
Partners' Capital Account, Units, Acquisitions																		49,900,000	59,300,000
Increase (Decrease) in Partners' Capital [Roll Forward]
Unit-based compensation charges	$ 19.7	18.1		0.0	0.0		5.7	18.1		14.0	0.0
Partners' Capital Account, Units, Unit-based Compensation																		100,000
Taxes paid for unit-based compensation vesting	(3.7)	(2.1)		0.0	0.0		(1.6)	(2.1)		(2.1)	0.0
Distributions to partners	(405.7)	(819.5)		0.0	0.0		(171.5)	(808.2)		(234.2)	(11.3)
Issuance of CMLP Class A preferred units		58.8			58.8			0.0			0.0
Partners' Capital Account, Exchanges and Conversions		0.0		529.6	(529.6)		3,294.8	529.6		(3,824.4)	0.0
Issuance of preferred equity of subsidiary	0.0												$ 58.8	$ 0.0	$ 0.0	$ 58.8
Change in fair value of Suburban Propane Partners, LP units	(2.7)			0.0			(2.7)			0.0
Other	(0.3)			0.0			(0.2)			(0.1)
Net loss	(2,303.7)	(1,410.6)		6.2	23.1		(1,673.1)	(1,456.8)		(636.8)	23.1
Balance at the end of the period at Dec. 31, 2015	$ 2,946.9	3,165.1		535.8	0.0		2,227.6	2,981.6		183.5	183.5
Common Unit, Outstanding																	400,000	68,200,000
Preferred units, outstanding	60,718,245																		60,700,000
Increase (Decrease) in Partners' Capital [Roll Forward]
Preferred units, issued	60,718,245													1,400,000
Unit-based compensation charges	$ 19.2	19.2		0.0	0.0		19.2	19.2		0.0	0.0
Partners' Capital Account, Units, Unit-based Compensation																		900,000
Taxes paid for unit-based compensation vesting	(0.8)	(0.8)		0.0	0.0		(0.8)	(0.8)		0.0	0.0
Distributions to partners	(235.0)	(242.8)		0.0	0.0		(219.8)	(227.6)		(15.2)	(15.2)
Issuance of CMLP Class A preferred units		0.0
Preferred Stock Dividends, Shares																			5,800,000
Change in fair value of Suburban Propane Partners, LP units	0.8			0.0			0.8			0.0
Net loss	(192.1)	(197.5)		28.7	0.0		(245.0)	(221.7)		24.2	24.2
Balance at the end of the period at Dec. 31, 2016	$ 2,539.0	$ 2,743.2		$ 564.5	$ 0.0		$ 1,782.0	$ 2,550.7		$ 192.5	$ 192.5
Common Unit, Outstanding																	400,000	69,100,000
Preferred units, outstanding	66,533,415																		66,500,000
Increase (Decrease) in Partners' Capital [Roll Forward]
Preferred units, issued	66,533,415