Segments (Reconciliation of Net Income (Loss) to EBITDA) (Details) $ in Millions	1 Months Ended	3 Months Ended		9 Months Ended
	Jun. 30, 2016 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2017 USD ($) segment	Sep. 30, 2016 USD ($)
Segment Reporting, Other Significant Reconciling Item [Line Items]
Number of Operating Segments | segment				3
Net income (loss)		$ (27.9)	$ 3.0	$ (47.0)	$ (127.8)
Interest and debt expense, net		24.2	27.5	74.8	97.9
Gains (Losses) on Extinguishment of Debt	$ 10.0	0.0	0.0	37.7	(10.0)
Benefit for income taxes		0.1	0.2	0.0	0.2
Depreciation, amortization and accretion		48.1	50.3	145.2	177.0
EBITDA		44.5	81.0	210.7	137.3
Crestwood Midstream Partners LP
Segment Reporting, Other Significant Reconciling Item [Line Items]
Net income (loss)		(29.8)	0.6	(53.1)	(130.3)
Interest and debt expense, net		24.2	27.5	74.8	97.9
Gains (Losses) on Extinguishment of Debt		0.0	0.0	37.7	(10.0)
Benefit for income taxes		0.1	0.0	0.0	0.0
Depreciation, amortization and accretion		50.9	53.2	153.5	185.2
EBITDA		$ 45.4	$ 81.3	$ 212.9	$ 142.8