Schedule I - Crestwood Equity Partners LP - Parent Only - Balance Sheet (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Condensed Financial Statements, Captions [Line Items]
Cash	$ 25.7	$ 0.9
Total current assets	376.4	379.3
Property, plant and equipment, net	2,909.1	2,029.7
Total assets	5,349.3	4,294.5
Accrued expenses	161.7	112.4
Total current liabilities	357.8	332.1
Other long-term liabilities	301.6	173.6
Total partners’ capital	1,932.8	2,033.8
Total liabilities and partners’ capital	5,349.3	4,294.5
Parent Company
Condensed Financial Statements, Captions [Line Items]
Cash	0.2	0.2	$ 0.3	$ 0.3
Total current assets	0.2	0.2
Property, plant and equipment, net	1.0	1.1
Investments in subsidiaries	1,935.9	1,854.7
Other assets	3.1	2.8
Total assets	1,940.2	1,858.8
Accounts payable	0.1	2.6
Accrued expenses	1.3	1.1
Total current liabilities	1.4	3.7
Other long-term liabilities	6.0	2.6
Total partners’ capital	1,932.8	1,852.5
Total liabilities and partners’ capital	$ 1,940.2	$ 1,858.8