Schedule I - Crestwood Equity Partners LP - Parent Only - Condensed Statement of Cash Flows (Detail) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Condensed Financial Statements, Captions [Line Items]
Cash flows from operating activities	$ 135.7	$ 105.7	$ 471.8	$ 437.3	$ 253.7
Cash flows from investing activities	(60.3)	(65.0)	(212.5)	(582.9)	(1,041.1)
Proceeds from the issuance of long-term debt	313.5	1,114.6	3,490.1	2,089.9	2,072.8
Principal payments on long-term debt	(286.0)	(970.4)	(2,960.9)	(1,950.0)	(1,634.5)
Payments for debt-related deferred costs	(0.1)	(11.1)	(17.3)	(0.1)	(32.0)
Distributions to partners	(101.0)	(111.4)	(819.5)	(470.5)	(419.7)
Change in intercompany balances	0.0	0.0
Other	0.0	(0.2)	(0.1)	(0.8)	0.0
Net cash used in financing activities	(74.7)	19.1	(266.8)	148.1	792.4
Net change in cash	0.7	59.8	(7.5)	2.5	5.0
Cash at beginning of period	0.1	7.6	7.6	5.1	0.1
Cash at end of period	0.8	67.4	0.1	7.6	5.1
Crestwood Equity Partners LP
Condensed Financial Statements, Captions [Line Items]
Cash flows from operating activities	134.3	156.6	440.7	283.0	188.3
Cash flows from investing activities	(60.3)	(65.2)	(212.7)	(483.0)	(1,042.9)
Proceeds from the issuance of long-term debt	313.5	1,252.7	4,261.8	2,823.9	2,466.9
Principal payments on long-term debt	(286.2)	(1,169.9)	(4,113.0)	(2,696.0)	(1,967.6)
Payments for debt-related deferred costs	(0.1)	(11.1)	(17.3)	(1.9)	(33.1)
Distributions to partners	(95.6)	(25.8)	(171.5)	(102.5)	(68.4)
Other	(0.1)	(0.3)	(1.3)	(0.7)	0.1
Net cash used in financing activities	(73.4)	(32.5)	(236.3)	203.6	859.7
Net change in cash	0.6	58.9	(8.3)	3.6	5.1
Cash at beginning of period	0.5	8.8	8.8	5.2	0.1
Cash at end of period	1.1	67.7	0.5	8.8	5.2
Crestwood Equity Partners LP \| Parent Company
Condensed Financial Statements, Captions [Line Items]
Cash flows from operating activities			(14.7)	(25.3)	(12.3)
Cash flows from investing activities			593.8	170.8	20.7
Proceeds from the issuance of long-term debt			771.7	734.0	394.1
Principal payments on long-term debt			(1,152.1)	(746.2)	(333.3)
Payments for debt-related deferred costs			0.0	(1.8)	0.0
Distributions to partners			(171.5)	(102.5)	(68.4)
Change in intercompany balances			(30.5)	(25.4)	0.4
Other			0.0	0.0	(1.1)
Net cash used in financing activities			(582.4)	(141.9)	(8.3)
Net change in cash			(3.3)	3.6	0.1
Cash at beginning of period	$ 0.4	$ 3.7	3.7	0.1	0.0
Cash at end of period			$ 0.4	$ 3.7	$ 0.1

Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.

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