Segments (Reconciliation of Net Income (Loss) to EBITDA) (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($) segment	Jun. 30, 2019 USD ($)
Segment Reporting, Other Significant Reconciling Item [Line Items]
Number of Operating Segments | segment			3
Net income (loss)	$ (24.3)	$ 225.0	$ (47.7)	$ 239.1
Interest and debt expense, net	34.0	27.8	66.6	52.7
Income Tax Expense (Benefit)	(0.1)	0.3	(0.1)	0.3
Depreciation, amortization and accretion	61.0	49.3	117.1	89.1
EBITDA	70.6	302.4	135.9	381.2
Crestwood Midstream Partners LP
Segment Reporting, Other Significant Reconciling Item [Line Items]
Net income (loss)	(26.8)	222.9	(52.4)	234.5
Interest and debt expense, net	34.0	27.8	66.6	52.7
Income Tax Expense (Benefit)	(0.2)	0.3	(0.2)	0.3
Depreciation, amortization and accretion	64.6	52.7	124.2	96.1
EBITDA	$ 71.6	$ 303.7	$ 138.2	$ 383.6