Schedule I - Crestwood Equity Partners LP - Parent Only - Statement of Comprehensive Income (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Condensed Financial Statements, Captions [Line Items]
Net loss	$ (166.6)	$ (192.1)	$ (2,303.7)
Change in fair value of Suburban Propane Partners, LP units	(0.8)	0.8	(2.7)
Comprehensive loss	(167.4)	(191.3)	(2,306.4)
Comprehensive income (loss) attributable to non-controlling partners	(25.3)	(24.2)	636.8
Comprehensive loss attributable to Crestwood Equity Partners LP	(192.7)	(215.5)	(1,669.6)
Parent Company
Condensed Financial Statements, Captions [Line Items]
Net loss	(166.6)	(192.1)	(2,303.7)
Change in fair value of Suburban Propane Partners, LP units	(0.8)	0.8	(2.7)
Comprehensive loss	(167.4)	(191.3)	(2,306.4)
Comprehensive income (loss) attributable to non-controlling partners	(25.3)	(24.2)	636.8
Comprehensive loss attributable to Crestwood Equity Partners LP	$ (192.7)	$ (215.5)	$ (1,669.6)

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income (loss) and other comprehensive income (loss), attributable to noncontrolling interests. Excludes changes in equity resulting from investments by owners and distributions to owners.

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Amount after tax, before reclassification adjustments, of unrealized holding gain (loss) on available-for-sale securities.

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