Certain Balance Sheet Information (Intangible Assets) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross	$ 1,076.3	$ 770.3
Less: accumulated amortization	271.1	216.5
Total intangible assets, net	805.2	553.8
Customer accounts
Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross	438.9	438.9
Less: accumulated amortization	134.4	112.1
Gathering systems and pipelines and related assets
Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross	631.2	325.2
Gathering systems and pipelines and related assets | Jackalope Gas Gathering Services, LLC
Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross	306.0
Acquired storage contracts
Finite-Lived Intangible Assets [Line Items]
Less: accumulated amortization	4.2	3.6
Trademarks
Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross	6.2	6.2
Less: accumulated amortization	132.5	100.8
Crestwood Equity Partners LP
Finite-Lived Intangible Assets [Line Items]
Amortization of Intangible Assets	54.6	43.5	$ 53.7
CMLP
Finite-Lived Intangible Assets [Line Items]
Amortization of Intangible Assets	54.6	42.1	$ 50.6
Less: accumulated amortization	$ 271.1	$ 216.5