Segments (Reconciliation of Net Income (Loss) to EBITDA) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2020 USD ($) segment	Mar. 31, 2019 USD ($)
Segment Reporting, Other Significant Reconciling Item [Line Items]
Number of Operating Segments | segment	3
Net income (loss)	$ (23.4)	$ 14.1
Interest and debt expense, net	32.6	24.9
Depreciation, amortization and accretion	56.1	39.8
EBITDA	65.3	78.8
Crestwood Midstream Partners LP
Segment Reporting, Other Significant Reconciling Item [Line Items]
Net income (loss)	(25.6)	11.6
Interest and debt expense, net	32.6	24.9
Depreciation, amortization and accretion	59.6	43.4
EBITDA	$ 66.6	$ 79.9