Schedule I - Crestwood Equity Partners LP - Parent Only - Balance Sheet (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Jun. 30, 2012
Condensed Financial Statements, Captions [Line Items]
Cash	$ 1.6	$ 0.5	$ 8.8	$ 5.2
Accounts receivable	289.8	236.5
Total current assets	373.4	335.8
Property, plant and equipment, net	2,097.6	3,310.8
Total assets	4,448.9	5,762.8
Accrued expenses	90.5	105.6
Current portion of long-term debt	1.0	1.1
Total current liabilities	337.3	258.2
Long-term debt, less current portion	1,522.7	2,501.8
Other long-term liabilities	44.6	47.5
Total partners’ capital	2,539.0	2,946.9	5,584.5	5,508.6
Total liabilities and partners’ capital	4,448.9	5,762.8
Parent Company
Condensed Financial Statements, Captions [Line Items]
Cash	0.3	0.4	$ 3.7	$ 0.1
Accounts receivable	0.0	1.8
Total current assets	0.3	2.2
Property, plant and equipment, net	1.4	1.5
Intangible assets, net	4.5	7.8
Investment in subsidiaries	2,342.7	2,757.7
Other assets	4.3	3.5
Total assets	2,353.2	2,772.7
Accounts payable	2.7	2.6
Accrued expenses	1.4	2.3
Current portion of long-term debt	0.0	0.2
Total current liabilities	4.1	$ 5.1
Other long-term liabilities	2.6				$ 4.2
Total partners’ capital	2,346.5				2,763.4
Total liabilities and partners’ capital	$ 2,353.2				$ 2,772.7