Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Deferred:
Total deferred	$ 0.7	$ 2.1	$ 3.1
(Provision) benefit for income taxes	(0.1)	0.8	(0.3)
Crestwood Equity Partners LP
Current:
Federal	(0.5)	(1.1)	(3.2)
State	(0.3)	(0.2)	(0.2)
Total current	(0.8)	(1.3)	(3.4)
Deferred:
Federal	0.5	2.1	3.0
State	0.2	0.0	0.1
Total deferred	0.7	2.1	3.1
(Provision) benefit for income taxes	(0.1)	0.8	(0.3)
Deferred tax asset:
Basis difference in stock of company	0.2	0.2
Total deferred tax asset	0.2	0.2
Deferred Tax Liabilities, Other	2.8	3.5
Deferred tax liability:
Deferred Tax Liabilities, Gross	(2.8)	(3.5)
Total deferred tax liability	(2.6)	(3.3)
CMLP
Current:
Federal	0.1	0.0	0.0
State	(0.2)	0.0	0.2
Total current	(0.1)	0.0	0.2
Deferred:
Federal	0.0	0.0	0.0
State	0.1	0.0	(0.2)
Total deferred	0.1	0.0	(0.2)
(Provision) benefit for income taxes	0.0	0.0	$ 0.0
Deferred tax asset:
Basis difference in stock of company	0.0	0.0
Total deferred tax asset	0.0	0.0
Deferred Tax Liabilities, Other	0.6	0.7
Deferred tax liability:
Deferred Tax Liabilities, Gross	(0.6)	(0.7)
Total deferred tax liability	$ (0.6)	$ (0.7)