Investments in Unconsolidated Affiliates Distributions and Contributions (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended
	Apr. 30, 2020	Mar. 31, 2020	Mar. 31, 2019
Schedule of Equity Method Investments [Line Items]
Proceeds from equity method investments		$ 19.5	$ 26.9
Payments to acquire equity method investments		6.0	38.2
Payments to Acquire Equity Method Investments Cash and Noncash Consideration			38.2
Stagecoach Gas Services LLC
Schedule of Equity Method Investments [Line Items]
Proceeds from equity method investments		15.6	13.0
Payments to acquire equity method investments		0.0	0.0
Jackalope Gas Gathering Services, L.L.C.
Schedule of Equity Method Investments [Line Items]
Proceeds from equity method investments			11.6
Payments to acquire equity method investments			24.4
Crestwood Permian Basin Holdings LLC
Schedule of Equity Method Investments [Line Items]
Proceeds from equity method investments		3.8	2.3
Payments to acquire equity method investments		0.0
Payments to Acquire Equity Method Investments Cash and Noncash Consideration			7.5
Tres Palacios Holdings LLC
Schedule of Equity Method Investments [Line Items]
Proceeds from equity method investments		0.0	0.0
Payments to acquire equity method investments		6.0	6.3
Powder River Basin Industrial Complex, LLC
Schedule of Equity Method Investments [Line Items]
Proceeds from equity method investments		0.1	0.0
Payments to acquire equity method investments		$ 0.0	$ 0.0
Subsequent Event | Stagecoach Gas Services LLC
Schedule of Equity Method Investments [Line Items]
Proceeds from equity method investments	$ 14.4
Subsequent Event | Crestwood Permian Basin Holdings LLC
Schedule of Equity Method Investments [Line Items]
Proceeds from equity method investments	2.9
Subsequent Event | Tres Palacios Holdings LLC
Schedule of Equity Method Investments [Line Items]
Proceeds from equity method investments	$ 1.4