Investments in Unconsolidated Affiliates Distributions and Contributions (Details) - USD ($) $ in Millions		1 Months Ended	9 Months Ended
	Jun. 21, 2017	Oct. 31, 2017	Sep. 30, 2017	Sep. 30, 2016
Schedule of Equity Method Investments [Line Items]
Proceeds from equity method investments			$ 62.0	$ 31.4
Payments to acquire equity method investments			46.5	6.2
Payments to acquire equity method investment, cash and non cash			115.9
Contribution of property	$ 69.4
Stagecoach Gas Services LLC
Schedule of Equity Method Investments [Line Items]
Proceeds from equity method investments			35.7	3.7
Payments to acquire equity method investments			0.0	0.0
Crestwood Permian Basin Holdings LLC
Schedule of Equity Method Investments [Line Items]
Proceeds from equity method investments			0.0	0.0
Payments to acquire equity method investments				0.0
Payments to acquire equity method investment, cash and non cash			113.0
Jackalope Gas Gathering Services, L.L.C.
Schedule of Equity Method Investments [Line Items]
Proceeds from equity method investments			19.4	19.9
Tres Palacios Holdings LLC
Schedule of Equity Method Investments [Line Items]
Proceeds from equity method investments			5.8	6.2
Payments to acquire equity method investments			0.0	5.5
Powder River Basin Industrial Complex, LLC
Schedule of Equity Method Investments [Line Items]
Proceeds from equity method investments			1.1	1.6
Payments to acquire equity method investments			0.0	0.0
Crestwood New Mexico Pipeline LLC
Schedule of Equity Method Investments [Line Items]
Equity interest	100.00%
Crestwood Niobrara LLC | Jackalope Gas Gathering Services, L.L.C.
Schedule of Equity Method Investments [Line Items]
Payments to acquire equity method investments			$ 2.9	$ 0.7
Subsequent Event | Stagecoach Gas Services LLC
Schedule of Equity Method Investments [Line Items]
Proceeds from equity method investments		$ 11.6
Subsequent Event | Crestwood Permian Basin Holdings LLC
Schedule of Equity Method Investments [Line Items]
Proceeds from equity method investments		4.5
Subsequent Event | Tres Palacios Holdings LLC
Schedule of Equity Method Investments [Line Items]
Proceeds from equity method investments		$ 3.1