Schedule II - Crestwood Equity Partners LP - Valuation and Qualifying Accounts (Details) - Allowance for Doubtful Accounts - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
SEC Schedule, 12-09, Valuation Allowances and Reserves, Amount	$ 0.3	$ 2.4	$ 1.9
Valuation Allowances and Reserves, Charged to Cost and Expense	0.1	0.2	1.5
Valuation Allowances and Reserves, Charged to Other Accounts	0.0	0.0	0.0
SEC Schedule, 12-09, Valuation Allowances and Reserves, Deduction	(0.1)	(2.3)	(1.0)
SEC Schedule, 12-09, Valuation Allowances and Reserves, Amount	$ 0.3	$ 0.3	$ 2.4