Basis of Presentation and Summary of Significant Accounting Policies (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended			9 Months Ended		12 Months Ended
	Jun. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Mar. 31, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Summary Of Significant Accounting Policies [Line Items]
Net proceeds from sale of assets	$ 945.0				$ 1.3	$ 943.1
Deferred finance costs, net		$ 30.2			30.2		$ 34.0
Goodwill [Roll Forward]
Goodwill at December 31, 2015					199.0
Goodwill impairment		0.0	$ 0.0		0.0	109.7
Goodwill at September 30, 2016		199.0			199.0		199.0
Marcellus
Goodwill [Roll Forward]
Goodwill impairment						8.6
COLT
Goodwill [Roll Forward]
Goodwill impairment						13.7
Supply and Logistics
Goodwill [Roll Forward]
Goodwill impairment						65.5
Storage and Terminals
Goodwill [Roll Forward]
Goodwill impairment						14.1
Trucking
Goodwill [Roll Forward]
Goodwill impairment						7.8
Minimum
Summary Of Significant Accounting Policies [Line Items]
New Accounting Pronouncement, change in balance sheet classification		60.0			60.0
New Accounting Pronouncement, effect of adoption					15.0
Discount rate				10.00%
Maximum
Summary Of Significant Accounting Policies [Line Items]
New Accounting Pronouncement, change in balance sheet classification		70.0			70.0
New Accounting Pronouncement, effect of adoption					25.0
Discount rate				19.00%
Crestwood Midstream Partners LP
Summary Of Significant Accounting Policies [Line Items]
Net proceeds from sale of assets					1.3	943.1
Goodwill [Roll Forward]
Goodwill at December 31, 2015					199.0
Goodwill impairment		0.0	$ 0.0		0.0	$ 109.7
Goodwill at September 30, 2016		$ 199.0			$ 199.0		$ 199.0
Performance Shares
Summary Of Significant Accounting Policies [Line Items]
Units outstanding		404,847			404,847
Goodwill [Roll Forward]
Share-based compensation		$ 0.9			$ 2.9
Crestwood LTIP | Performance Shares
Summary Of Significant Accounting Policies [Line Items]
Compensation cost not yet recognized		$ 7.6			$ 7.6