Consolidated Statement of Partners' Capital - USD ($) $ in Millions	Total	Preferred Units	Common unit	Non-Controlling Partners	Partners' Capital	Crestwood Midstream Partners LP	Crestwood Midstream Partners LP Common unit	Crestwood Midstream Partners LP Non-Controlling Partners	Crestwood Midstream Partners LP Partners' Capital	Preferred Units	Common Units	Subordinated Units
Increase (Decrease) in Partners' Capital [Roll Forward]
Common Unit, Outstanding											71,200,000	400,000
Preferred Units, Outstanding										71,300,000
Beginning balance at Dec. 31, 2018		$ 612.0	$ 1,240.5	$ 181.3	$ 2,033.8		$ 2,028.2	$ 181.3	$ 2,209.5
Increase (Decrease) in Partners' Capital [Roll Forward]
Distributions to partners		(15.0)	(43.1)	(3.3)	(61.4)		(57.8)	(3.3)	(61.1)
Unit-based compensation charges			17.3		17.3		17.3		17.3
Unit-based compensation charges (in shares)											900,000
Taxes paid for unit-based compensation vesting			(7.0)		(7.0)		(7.0)		(7.0)
Taxes paid for unit-based compensation vesting (in shares)											(200,000)
Change in fair value of Suburban Propane Partners, L.P. units	$ 0.4		0.4		0.4
Other		0.0	(0.7)		(0.7)		(0.3)		(0.3)
Net income (loss)	$ 14.1	15.0	(4.9)	4.0	14.1	$ 11.6	7.6	4.0	11.6
Ending Balance at Mar. 31, 2019		612.0	1,202.5	$ 182.0	1,996.5		$ 1,988.0	$ 182.0	2,170.0
Increase (Decrease) in Partners' Capital [Roll Forward]
Common Unit, Outstanding											71,900,000	400,000
Preferred Units, Outstanding										71,300,000
Common Unit, Outstanding											71,900,000	400,000
Preferred Units, Outstanding	71,257,445									71,300,000
Beginning balance at Dec. 31, 2019		612.0	1,320.8		1,932.8	2,099.3			2,099.3
Increase (Decrease) in Partners' Capital [Roll Forward]
Distributions to partners		(15.0)	(45.3)		(60.3)				(57.0)
Unit-based compensation charges			0.2		0.2				(4.4)
Unit-based compensation charges (in shares)											1,700,000
Taxes paid for unit-based compensation vesting			(15.1)		(15.1)				(15.1)
Taxes paid for unit-based compensation vesting (in shares)											(500,000)
Change in fair value of Suburban Propane Partners, L.P. units	$ (1.1)		(1.1)		(1.1)
Other			3.5		3.5				(1.1)
Net income (loss)	$ (23.4)	15.0	(48.3)		(33.3)	(25.6)			(35.5)
Ending Balance at Mar. 31, 2020		$ 612.0	$ 1,214.7		$ 1,826.7	$ 1,986.2			$ 1,986.2
Increase (Decrease) in Partners' Capital [Roll Forward]
Common Unit, Outstanding											73,300,000	400,000
Preferred Units, Outstanding	71,257,445									71,300,000
Other (in shares)											200,000