Certain Balance Sheet Information (Property, Plant And Equipment) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 3,771.5	$ 3,759.6
Less: accumulated depreciation	992.1	842.5
Property, plant and equipment, net	2,779.4	2,917.1
Capitalized interests	0.4	2.7	$ 14.4
Crestwood Equity Partners LP
Property, Plant and Equipment [Line Items]
Property, plant and equipment	3,771.5	3,759.6
Less: accumulated depreciation	992.1	842.5
Property, plant and equipment, net	2,779.4	2,917.1
Depreciation	180.9	174.8	139.5
Crestwood Equity Partners LP | Gathering systems and pipelines and related assets
Property, Plant and Equipment [Line Items]
Property, plant and equipment	1,052.5	1,035.2
Crestwood Equity Partners LP | Facilities and equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment	2,200.6	2,193.5
Crestwood Equity Partners LP | Buildings, land, rights-of-way, storage rights and easements
Property, Plant and Equipment [Line Items]
Property, plant and equipment	391.8	389.0
Crestwood Equity Partners LP | Vehicles
Property, Plant and Equipment [Line Items]
Property, plant and equipment	17.0	13.9
Crestwood Equity Partners LP | Construction in process
Property, Plant and Equipment [Line Items]
Property, plant and equipment	64.7	83.6
Crestwood Equity Partners LP | Office furniture and fixtures
Property, Plant and Equipment [Line Items]
Property, plant and equipment	32.6	31.1
Crestwood Equity Partners LP | Finance leases
Property, Plant and Equipment [Line Items]
Property, plant and equipment	12.3	13.3
CMLP
Property, Plant and Equipment [Line Items]
Property, plant and equipment	4,100.8	4,089.6
Less: accumulated depreciation	1,193.0	1,028.3
Property, plant and equipment, net	2,907.8	3,061.3
Depreciation	195.1	188.9	$ 153.5
CMLP | Gathering systems and pipelines and related assets
Property, Plant and Equipment [Line Items]
Property, plant and equipment	1,195.2	1,178.0
CMLP | Facilities and equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment	2,385.8	2,378.6
CMLP | Buildings, land, rights-of-way, storage rights and easements
Property, Plant and Equipment [Line Items]
Property, plant and equipment	395.5	392.7
CMLP | Vehicles
Property, Plant and Equipment [Line Items]
Property, plant and equipment	14.5	12.1
CMLP | Construction in process
Property, Plant and Equipment [Line Items]
Property, plant and equipment	64.7	83.6
CMLP | Office furniture and fixtures
Property, Plant and Equipment [Line Items]
Property, plant and equipment	32.8	31.3
CMLP | Finance leases
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 12.3	$ 13.3