Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ (39.6)	$ 4.6	$ (116.0)	$ (43.1)
Change in fair value of Suburban Propane Partners, L.P. units	0.0	0.3	0.0	(0.8)
Comprehensive income (loss)	(39.6)	4.9	(116.0)	(43.9)
Comprehensive income attributable to non-controlling partner	10.3	10.3	30.7	30.4
Comprehensive loss attributable to Crestwood Equity Partners LP	$ (49.9)	$ (5.4)	$ (146.7)	$ (74.3)