Schedule I - Crestwood Equity Partners LP - Parent Only - Statement of Operations (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Condensed Financial Statements, Captions [Line Items]
Revenues	$ 4,569.0	$ 2,254.3	$ 3,181.9
Operating income	222.7	86.8	402.2
Other income (expense), net	0.1	(0.7)	0.6
Net income (loss)	(37.4)	(15.3)	319.9
Net income (loss) attributable to parent	(78.5)	(56.1)	285.1
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	(37.4)	(15.3)	320.2
Parent Company
Condensed Financial Statements, Captions [Line Items]
Revenues	0.0	0.0	0.0
Costs and Expenses	7.7	4.9	5.3
Operating income	(7.7)	(4.9)	(5.3)
Loss from unconsolidated affiliates	(70.9)	(50.5)	290.0
Other income (expense), net	0.1	(0.7)	0.4
Net income (loss) attributable to parent	(78.5)	(56.1)	285.1
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	$ (78.5)	$ (56.1)	$ 285.4