Basis of Presentation and Summary of Significant Accounting Policies (Details) - USD ($) $ in Millions		3 Months Ended			6 Months Ended
	Jan. 01, 2020	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Goodwill [Roll Forward]
Goodwill, beginning balance	$ 218.9		$ 218.9		$ 218.9
Goodwill impairment		$ 0.0		$ 0.0	80.3	$ 0.0
Goodwill, ending balance		138.6			138.6
Allowance for doubtful accounts		0.6			0.6		$ 0.3
Investments in unconsolidated affiliates		$ 961.9			$ 961.9		980.4
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201613Member
Crestwood Permian Basin Holdings LLC
Goodwill [Roll Forward]
Ownership percentage	50.00%	50.00%			50.00%
Investments in unconsolidated affiliates		$ 114.7			$ 114.7		$ 121.8
Arrow
Goodwill [Roll Forward]
Goodwill, beginning balance	$ 45.9		45.9		45.9
Goodwill impairment					0.0
Goodwill, ending balance		45.9			45.9
Powder River Basin
Goodwill [Roll Forward]
Goodwill, beginning balance	80.3		80.3		80.3
Goodwill impairment			80.3		80.3
Goodwill, ending balance		0.0			0.0
NGL Marketing and Logistics
Goodwill [Roll Forward]
Goodwill, beginning balance	92.7		$ 92.7		92.7
Goodwill impairment					0.0
Goodwill, ending balance		$ 92.7			$ 92.7
Cumulative Effect, Period of Adoption, Adjustment
Goodwill [Roll Forward]
Allowance for doubtful accounts	0.7
Partners' capital	0.7
Cumulative Effect, Period of Adoption, Adjustment | Crestwood Permian Basin Holdings LLC
Goodwill [Roll Forward]
Partners' capital	(0.2)
Investments in unconsolidated affiliates	$ 0.2