Segments (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Crestwood Equity Partners LP
Segment Reporting Information [Line Items]
Interest, taxes, depreciation and amortization included in earnings from equity method investments	$ 10.0	$ 8.3	$ 25.7	$ 15.3
Crestwood Midstream Partners LP
Segment Reporting Information [Line Items]
Interest, taxes, depreciation and amortization included in earnings from equity method investments	$ 10.0	$ 8.3	$ 25.7	$ 15.3

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

Name:	us-gaap_SegmentReportingInformationLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration