Crestwood Equity Partners (CEQP+) 10-Q 7 Nov 14 2014 Q3 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	9 Months Ended
	Sep. 30, 2014	Nov. 03, 2014	Nov. 03, 2014
		Limited Partner Units	Preferred Units, Class A
Document Information [Line Items]	'	'	'
Entity Registrant Name	'Crestwood Midstream Partners LP	'	'
Trading Symbol	'CMLP	'	'
Entity Central Index Key	'0001304464	'	'
Current Fiscal Year End Date	'--12-31	'	'
Entity Filer Category	'Large Accelerated Filer	'	'
Document Type	'10-Q	'	'
Document Period End Date	30-Sep-14	'	'
Document Fiscal Year Focus	'2014	'	'
Document Fiscal Period Focus	'Q3	'	'
Amendment Flag	'false	'	'
Entity Common Stock, Shares Outstanding	'	187,979,748	14,940,238

CONSOLIDATED_BALANCE_SHEETS

CONSOLIDATED BALANCE SHEETS (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Current assets:	'	'
Cash and cash equivalents	$0.10	$2.70
Accounts receivable	312.8	205.1
Inventory	8.3	7
Prepaid expenses and other current assets	20.3	10.2
Total current assets	341.5	225
Property, plant and equipment (Note 3)	3,812.90	3,565.70
Less: accumulated depreciation and depletion	313.3	215.6
Property, plant and equipment, net	3,499.60	3,350.10
Intangible assets:	'	'
Intangible assets (Note 3)	1,034.40	1,025.10
Less: accumulated amortization	113.6	54.3
Intangible assets, net	920.8	970.8
Goodwill	1,681.40	1,682.80
Investment in unconsolidated affiliates (Note 5)	231.9	151.4
Other assets	19.4	21.7
Total assets	6,694.60	6,401.80
Current liabilities:	'	'
Accounts payable	193.2	154.5
Accounts payable - related party (Note 11)	7.4	8.7
Accrued expenses and other liabilities	165.1	148.4
Current portion of long-term debt (Note 7)	0.6	2.9
Total current liabilities	366.3	314.5
Long-term debt, less current portion (Note 7)	1,893	1,867.90
Other long-term liabilities	30	26.3
Commitments and contingencies (Note 10)	'	'
Partnersb capital (Note 8):	'	'
Class A preferred units (14,940,238 units issued and outstanding at September 30, 2014)	377	0
Partnersb capital (187,956,285 and 187,243,989 limited partner units issued and outstanding at September 30, 2014 and December 31, 2013)	3,862.10	4,092.10
Total Crestwood Midstream Partners LP partnersb capital	4,239.10	4,092.10
Interest of non-controlling partners in subsidiary	166.2	101
Total partnersb capital	4,405.30	4,193.10
Total liabilities and partnersb capital	$6,694.60	$6,401.80

CONSOLIDATED_BALANCE_SHEETS_Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical)	Sep. 30, 2014	Dec. 31, 2013
Statement of Financial Position [Abstract]	'	'
Preferred units, issued	14,940,238	'
Preferred units, outstanding	14,940,238	'
Common units, issued	187,956,285	187,243,989
Common units, outstanding	187,956,285	187,243,989

CONSOLIDATED_STATEMENTS_OF_OPE

CONSOLIDATED STATEMENTS OF OPERATIONS (USD $)	3 Months Ended		9 Months Ended
In Millions, except Share data in Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Revenues:	'	'	'	'
Gathering and processing	$83.90	$47	$245.20	$140.30
Storage and transportation	44.2	42.1	133.9	47.6
NGL and crude services	605.4	23.5	1,558.80	26.6
Related party (Note 11)	4.9	27.5	13.2	78.1
Revenues	738.4	140.1	1,951.10	292.6
Costs of product/services sold (excluding depreciation, amortization and accretion as shown below):	'	'	'	'
Gathering and processing	7.3	5.3	22.8	18.2
Storage and transportation	4.3	4	11.3	4.4
NGL and crude services	552.8	9.7	1,426.70	10.6
Related party (Note 11)	11.3	7.6	32.1	22.2
Cost of Revenue	575.7	26.6	1,492.90	55.4
Expenses:	'	'	'	'
Operations and maintenance	39.4	21.7	100.1	48.1
General and administrative	18.2	25.2	63.6	44
Depreciation, amortization and accretion	55.5	35.1	161.2	73.4
Costs and Expenses, Total	113.1	82	324.9	165.5
Other operating income (expense):	'	'	'	'
Goodwill impairment	0	4.1	0	4.1
Gain (loss) on long-lived assets, net	-0.9	4.4	0.7	4.4
Loss on contingent consideration (Note 10)	0	0	-8.6	0
Operating income	48.7	31.8	125.4	72
Earnings (loss) from unconsolidated affiliates, net	0.3	-0.4	-1.3	-0.4
Interest and debt expense, net	-27.7	-19.5	-84.8	-43.4
Income before income taxes	21.3	11.9	39.3	28.2
Provision for income taxes	0	0.3	0.8	1
Net income	21.3	11.6	38.5	27.2
Net income attributable to non-controlling partners	-4.5	-1.9	-11.3	-1.9
Net income attributable to Crestwood Midstream Partners LP	16.8	9.7	27.2	25.3
Net income attributable to Class A preferred units	-9.1	0	-10.2	0
Net income attributable to partners	7.7	9.7	17	25.3
Partnersb interest information:	'	'	'	'
General partner's interest in net income	7.5	6.3	22.5	19.3
Limited partnersb interest in net income (loss)	$0.20	$3.40	($5.50)	$6
Net income (loss) per limited partner unit:	'	'	'	'
Basic (usd per unit)	$0	$0.02	($0.03)	$0.06
Diluted (usd per unit)	$0	$0.02	($0.03)	$0.06
Weighted-average limited partnersb units outstanding:	'	'	'	'
Basic (units)	187,955	161,575	187,931	101,094
Diluted (units)	187,955	161,575	187,931	101,094

CONSOLIDATED_STATEMENT_OF_PART

CONSOLIDATED STATEMENT OF PARTNERS' CAPITAL (USD $)	Total	Preferred Units, Class A	Preferred Partner	Preferred Partner	Limited Partner	Limited Partner	Non Controlling Partners	Non Controlling Partners	Partners' Capital	Partners' Capital
In Millions, unless otherwise specified				Preferred Units, Class A		Preferred Units, Class A		Preferred Units, Class A		Preferred Units, Class A
Beginning Balance at Dec. 31, 2013	$4,092.10	'	$0	'	$4,092.10	'	$101	'	$4,193.10	'
Increase (Decrease) in Partners' Capital [Roll Forward]	'	'	'	'	'	'	'	'	'	'
Change in invested capital from Legacy Inergy, net of debt (Note 4)	'	'	0	'	-5	'	0	'	-5	'
Distributions to general partner	-31.4	'	0	'	-31.4	'	0	'	-31.4	'
Distributions to limited partners	-222.4	'	0	'	-222.4	'	0	'	-222.4	'
Unit-based compensation charges	'	'	0	'	13.9	'	0	'	13.9	'
Issuance of Class A preferred units	-366.8	-366.8	'	366.8	'	0	'	0	'	366.8
Issuance of preferred equity of subsidiary	'	'	0	'	0	'	-53.9	'	-53.9	'
Taxes paid for unit-based compensation vesting	1.5	'	0	'	-1.5	'	0	'	-1.5	'
Other	'	'	0	'	-0.6	'	0	'	-0.6	'
Net income	38.5	'	10.2	'	17	'	11.3	'	38.5	'
Ending Balance at Sep. 30, 2014	$4,239.10	'	$377	'	$3,862.10	'	$166.20	'	$4,405.30	'

CONSOLIDATED_STATEMENTS_OF_CAS

CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $)	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Operating activities	'	'
Net income	$38,500,000	$27,200,000
Adjustments to reconcile net income to net cash provided by operating activities:	'	'
Depreciation, amortization and accretion	161,200,000	73,400,000
Amortization of debt-related deferred costs and premiums	5,500,000	3,100,000
Unit-based compensation charges	13,900,000	6,500,000
Goodwill impairment	0	4,100,000
Gain on long-lived assets	-700,000	-4,400,000
Loss on contingent consideration	8,600,000	0
Loss from unconsolidated affiliates, net	1,300,000	400,000
Deferred income taxes	500,000	0
Changes in operating assets and liabilities, net of effects from acquisitions	-53,000,000	20,200,000
Net cash provided by operating activities	175,800,000	130,500,000
Investing activities	'	'
Acquisitions, net of cash acquired (Note 4)	-19,500,000	200,000
Purchases of property, plant and equipment	-259,300,000	-189,400,000
Investment in unconsolidated affiliates	-81,800,000	-152,500,000
Proceeds from sale of assets	0	11,000,000
Net cash used in investing activities	-360,600,000	-330,700,000
Financing activities	'	'
Proceeds from the issuance of long-term debt	1,410,900,000	577,200,000
Principal payments on long-term debt	-1,390,800,000	-568,500,000
Payments on capital leases	-2,600,000	-3,000,000
Payments for debt-related deferred costs	-100,000	-100,000
Distributions to limited partners	-222,400,000	-110,100,000
Distributions to general partner	-31,400,000	-17,100,000
Distributions for additional interest in Crestwood Marcellus Midstream LLC	0	-129,000,000
Contributions from general partner	0	5,400,000
Net proceeds from issuance of limited partner units	0	356,700,000
Net proceeds from issuance of preferred equity of subsidiary	53,900,000	96,100,000
Net proceeds from the issuance of Class A preferred units	366,800,000	'
Taxes paid for unit-based compensation vesting	-1,500,000	-700,000
Other	-600,000	100,000
Net cash provided by financing activities	182,200,000	207,000,000
Net change in cash	-2,600,000	6,800,000
Cash at beginning of period	2,700,000	100,000
Cash at end of period	100,000	6,900,000
Supplemental schedule of non-cash investing and financing activities	'	'
Net change to property, plant and equipment through accounts payable and accrued expenses	-8,100,000	31,900,000
Preferred Stock	'	'
Financing activities	'	'
Net proceeds from issuance of preferred equity of subsidiary	53,900,000	96,100,000
Preferred Units, Class A	'	'
Financing activities	'	'
Net proceeds from the issuance of Class A preferred units	$366,800,000	$0

Business_Description

Business Description	9 Months Ended
	Sep. 30, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Business Description	'
	Business Description
	Crestwood Midstream Partners LP (the Company or Crestwood) is a publicly-traded (NYSE: CMLP) Delaware limited partnership that provides midstream solutions to customers in the crude oil, natural gas liquids (NGLs) and natural gas sectors of the energy industry. We are engaged primarily in the gathering, processing, storage and transportation of natural gas and NGLs and the gathering, storage and transportation of crude oil.
	As of September 30, 2014, Crestwood Equity Partners LP (CEQP), which owns our general partner, owns our non-economic general partnership interest, approximately 4% of our common limited partnership units and 100% of our incentive distribution rights (IDRs), which entitle CEQP to receive 50% of all distributions paid to our common unit holders in excess of our initial quarterly distribution of $0.37 per common unit. CEQP is indirectly owned by Crestwood Holdings LLC (Crestwood Holdings), which is substantially owned and controlled by First Reserve Management, L.P. (First Reserve) and which owns approximately 11% of our common units as of September 30, 2014.
	Our financial statements reflect three operating and reporting segments, including:
	•	Gathering and Processing: our gathering and processing (G&P) operations provide natural gas gathering, processing, treating, compression, transportation services and sales of natural gas and the delivery of NGLs to producers in unconventional shale plays and tight-gas plays in West Virginia, Wyoming, Texas, Arkansas, New Mexico and Louisiana. This segment primarily includes our rich gas gathering systems and processing plants in the Marcellus, Powder River Basin (PRB) Niobrara, Barnett, and Permian Shale plays, and our dry gas gathering systems in the Barnett, Fayetteville, and Haynesville Shale plays;
	•	Storage and Transportation: our storage and transportation operations provide regulated natural gas storage and transportation services to producers, utilities and other customers. This segment primarily includes our natural gas storage facilities (Stagecoach, Thomas Corners, Steuben and Seneca Lake) in New York and Pennsylvania and our natural gas transmission facilities (the North-South Facilities, the MARC I Pipeline and the East Pipeline) in New York and Pennsylvania; and
	•	NGL and Crude Services: our NGL and crude services operations provide NGLs and crude oil gathering, storage, marketing and transportation services to producers, refiners, marketers and other customers in or near unconventional shale plays in North Dakota and New York. This segment primarily includes our integrated Bakken crude oil footprint in North Dakota, which consists of (i) the COLT Hub, a crude oil rail loading and storage terminal, (ii) the Arrow crude oil, natural gas and water gathering systems, and (iii) our fleet of over-the-road crude and produced water transportation assets. This segment also includes our Bath storage facility, an NGL underground storage facility under development in New York, and US Salt, a solution-mining and salt production company in New York.
	On October 7, 2013, we changed our name from Inergy Midstream, L.P. to Crestwood Midstream Partners LP. Unless otherwise indicated, references in this report to “we,” “us,” “our,” “ours,” “our company,” the “partnership,” the “Company,” “CMLP,” “Crestwood” and similar terms refer to either Crestwood Midstream Partners LP itself or Crestwood Midstream Partners LP and its consolidated subsidiaries, as the context requires. Unless otherwise indicated, references to (i) the Crestwood Merger refers to the October 7, 2013 merger of the Company’s wholly-owned subsidiary with and into Legacy Crestwood, with Legacy Inergy continuing as the surviving legal entity; (ii) Legacy Crestwood refers to either Crestwood Midstream Partners LP itself or Crestwood Midstream Partners LP and its consolidated subsidiaries prior to the Crestwood Merger; and (iii) Legacy Inergy refers to either Inergy Midstream, L.P. itself or Inergy Midstream, L.P. and its consolidated subsidiaries prior to the Crestwood Merger. See Note 4 for additional information on the Crestwood Merger.

Basis_of_Presentation_and_Summ

Basis of Presentation and Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2014
Accounting Policies [Abstract]	'
Basis of Presentation and Summary of Significant Accounting Policies	'
	Basis of Presentation and Summary of Significant Accounting Policies
	Basis of Presentation
	Our consolidated financial statements were originally the financial statements of Legacy Crestwood, prior to the Crestwood Merger and the merger of Legacy Crestwood with and into Legacy Inergy on October 7, 2013. Crestwood Holdings' acquisition of control of CEQP’s general partner on June 19, 2013 was accounted for as a reverse acquisition under the purchase method of accounting in accordance with accounting standards for business combinations.  CEQP’s accounting for this reverse acquisition resulted in the legal acquiree (Crestwood Gas Services GP LLC) being the acquirer for accounting purposes.  CEQP’s accounting acquiree (inclusive of Legacy Inergy) was subject to the purchase method of accounting and its balance sheet was adjusted to fair market value as of June 19, 2013.  Accordingly, the merger of Legacy Crestwood and Legacy Inergy on October 7, 2013 was accounted for as a reverse merger amongst entities under common control.  Although Legacy Crestwood was the surviving entity for accounting purposes, Legacy Inergy was the surviving entity for legal purposes, and consequently we changed our name from Inergy Midstream, L.P. to Crestwood Midstream Partners LP. As the reverse merger was amongst entities under common control, the financial statements have been recasted to reflect the operations of Legacy Inergy as being acquired by Legacy Crestwood on June 19, 2013, the date in which Legacy Inergy and Legacy Crestwood came under common control.
	The financial information as of September 30, 2014, and for the three and nine months ended September 30, 2014 and 2013, is unaudited. The consolidated balance sheet as of December 31, 2013, was derived from the audited balance sheet filed in our 2013 Annual Report on Form 10-K. Our consolidated financial statements are prepared in accordance with accounting principles generally accepted in the United States of America (GAAP) and include the accounts of all consolidated subsidiaries after the elimination of all intercompany accounts and transactions. In management’s opinion, all necessary adjustments to fairly present our results of operations, financial position and cash flows for the periods presented have been made and all such adjustments are of a normal and recurring nature. Certain information and footnote disclosures normally included in annual consolidated financial statements prepared in accordance with GAAP have been omitted pursuant to the rules and regulations of the Securities and Exchange Commission (SEC).
	Beginning in the first quarter of 2014, we began reflecting our operating and administrative expenses as operations and maintenance expenses and general and administrative expenses. In addition, we also reclassified our consolidated statements of operations for the three and nine months ended September 30, 2013 to reflect this change. This change had no impact on our previously reported net income, earnings per unit or partners' capital. The financial statements in our 2013 Annual Report on Form 10-K have not been recasted to reflect this change. The following table summarizes the reclassification of the amounts previously reported in operating and administrative expenses for the periods presented (in millions):
		Year Ended December 31,
		2013		2012		2011
	Operating and administrative expenses as previously reported	$	154	$	72.7	$	60.4
	Operations and maintenance expenses	73.3		43.1		36.3
	General and administrative expenses	80.7		29.6		24.1
	In addition to the reclassification described above, our consolidated financial statements for prior periods include reclassifications that were made to conform to the current period presentation. None of our reclassifications had an impact on our previously reported net income, earnings per unit or partners' capital.
	The accompanying consolidated financial statements should be read in conjunction with our 2013 Annual Report on Form 10-K filed with the SEC on February 28, 2014.
	Significant Accounting Policies
	There were no material changes in our significant accounting policies from those described in our 2013 Annual Report on Form 10-K.
	New Accounting Pronouncement Issued But Not Yet Adopted
	As of September 30, 2014, the following accounting standard had not yet been adopted by us.
	In May 2014, the Financial Accounting Standards Board issued Accounting Standards Update 2014-09, Revenue from Contracts with Customers, which outlines a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers and supersedes current revenue recognition guidance. We will adopt the provisions of this standard effective January 1, 2017 and are currently evaluating the impact that this standard will have on our financial statements.

Certain_Balance_Sheet_Informat

Certain Balance Sheet Information	9 Months Ended
	Sep. 30, 2014
Balance Sheet Related Disclosures [Abstract]	'
Certain Balance Sheet Information	'
	Certain Balance Sheet Information
	Property, Plant and Equipment
	Property, plant and equipment consisted of the following at September 30, 2014 and December 31, 2013 (in millions):
		September 30,		December 31,
		2014		2013
	Gathering systems and pipelines	1,251.90		1,231.10
	Facilities and equipment	1,378.50		1,041.00
	Buildings, land, rights-of-way, storage contracts and easements	783.4		766.2
	Vehicles	13.8		4.1
	Construction in process	221.3		360.5
	Base gas	37.3		36.3
	Salt deposits	120.5		120.5
	Office furniture and fixtures	6.2		6
		3,812.90		3,565.70
	Less: accumulated depreciation and depletion	313.3		215.6
	Total property, plant and equipment, net	$	3,499.60	$	3,350.10
	Capital Leases. We have a treating facility and certain auto leases which are accounted for as capital leases. Our treating facility lease is reflected in facilities and equipment in the above table. We had capital lease assets of $3.0 million and $5.0 million included in property, plant and equipment, net at September 30, 2014 and December 31, 2013.
	Intangible Assets
	Intangible assets consisted of the following at September 30, 2014 and December 31, 2013 (in millions):
		September 30,		December 31,
		2014		2013
	Customer accounts	$	483.2	$	476.4
	Covenants not to compete	5.5		3
	Gas gathering, compression and processing contracts	451.4		451.4
	Acquired storage contracts	29		29
	Trademarks	11		11
	Deferred financing and other costs	54.3		54.3
		1,034.40		1,025.10
	Less: accumulated amortization	113.6		54.3
	Total intangible assets, net	$	920.8	$	970.8
	Accrued Expenses and Other Liabilities
	Accrued expenses and other liabilities consisted of the following at September 30, 2014 and December 31, 2013 (in millions):
		September 30,		December 31, 2013
		2014
	Accrued expenses	$	31.9	$	20
	Accrued property taxes	5.6		7.6
	Accrued product purchases payable	1.4		1.6
	Tax payable	0.9		10.6
	Interest payable	27.4		14.9
	Accrued additions to property, plant and equipment	45.8		58.1
	Commitments and contingent liabilities (Note 10)	40		31.4
	Capital leases	1.5		2.6
	Deferred revenue	10.6		1.6
	Total accrued expenses and other liabilities	$	165.1	$	148.4

Acquisitions_and_Divestitures

Acquisitions and Divestitures	9 Months Ended
	Sep. 30, 2014
Business Combinations [Abstract]	'
Acquisitions	'
	Acquisitions and Divestitures
	2014 Acquisitions
	Crude Transportation Acquisitions (Bakken)
	Red Rock. On March 21, 2014, we purchased substantially all of the operating assets of Red Rock Transportation Inc. (Red Rock) for approximately $13.8 million, comprised of $12.1 million paid at closing plus deferred payments of $1.7 million. Red Rock is a trucking operation located in Watford City, North Dakota which provides crude oil and produced water hauling services to the oilfields of western North Dakota and eastern Montana. The acquired assets include a fleet of approximately 56 trailer tanks, 22 double bottom body tanks and 44 tractors with 28,000 barrels per day of transportation capacity. In the first quarter of 2014, we finalized the purchase price and allocated approximately $10.6 million of the purchase price to property, plant and equipment and intangible assets and approximately $3.2 million to goodwill. Goodwill recognized relates primarily to anticipated operating synergies between the assets acquired and our existing assets. These assets are included in our NGL and crude services segment.
	LT Enterprises. On May 9, 2014, we purchased substantially all of the operating assets of LT Enterprises, Inc. (LT Enterprises) for approximately $10.7 million, comprised of $9.0 million paid at closing plus deferred payments of $1.7 million. LT Enterprises is a trucking operation located in Watford City, North Dakota which provides crude oil and produced water hauling services primarily to the oilfields of western North Dakota. The acquired assets include a fleet of approximately 38 tractors, 51 crude trailers and 17 service vehicles with 20,000 barrels per day of transportation capacity. In addition, we acquired employee housing and 20 acres of greenfield real property located two miles south of Watford City. In the second quarter of 2014, we finalized the purchase price and allocated all of the purchase price to property, plant and equipment and intangible assets. These assets are included in our NGL and crude services segment.
	The acquisitions of Red Rock and LT Enterprises were not material to our NGL and crude services segment's results of operations for the three and nine months ended September 30, 2014. In addition, transaction costs related to these acquisitions were not material for the three and nine months ended September 30, 2014.
	2013 Acquisitions
	Crestwood Merger
	As described in Note 2, the merger of Legacy Crestwood with and into Legacy Inergy was accounted for as a reverse merger amongst entities under common control. This accounting treatment requires the accounting acquiree (Legacy Inergy) to have its assets and liabilities stated at fair value as well as any other purchase accounting adjustments as of June 19, 2013, the date in which Legacy Crestwood and Legacy Inergy came under common control. The fair value of Legacy Inergy was calculated based on the consolidated enterprise fair value of Legacy Inergy as of June 19, 2013. This consolidated enterprise fair value considered the discounted future cash flows of Legacy Inergy's operations and Legacy Inergy's NYSE-listed stock price, the value of its outstanding senior notes based on quoted market prices for same or similar issuances and the value of its outstanding floating rate debt.
	In June 2014, we finalized the Legacy Inergy purchase price allocation. The following table summarizes the final valuation of the assets acquired and liabilities assumed at the merger date (in millions):
	Current assets	$	49.1
	Property, plant and equipment	1,677.80
	Intangible assets	196
	Other assets	2.9
	Total identifiable assets acquired	1,925.80
	Current liabilities	30.9
	Long-term debt	745
	Other long-term liabilities	5.3
	Total liabilities assumed	781.2
	Net identifiable assets acquired	1,144.60
	Goodwill	1,532.70
	Net assets acquired	$	2,677.30
	Of the $1,532.7 million of goodwill, $806.4 million is reflected in our NGL and crude services segment and $726.3 million is reflected in our storage and transportation segment. Goodwill recognized relates primarily to synergies and new expansion opportunities expected to result from the combination of Legacy Crestwood and Legacy Inergy.  During the period from June 19, 2013 to September 30, 2013, we recognized $78.0 million of revenues and $7.1 million of net income related to this reverse merger.
	Arrow Acquisition
	On November 8, 2013, we acquired Arrow Midstream Holdings, LLC (Arrow) for approximately $750 million, subject to customary capital expenditures and working capital adjustments of approximately $11.3 million, representations, warranties and indemnifications.  The acquisition was consummated by merging one of our wholly-owned subsidiaries with and into Arrow (the Arrow Acquisition), with Arrow continuing as the surviving entity and our wholly-owned subsidiary. The base merger consideration consisted of $550 million in cash and 8,826,125 common units issued to the sellers, subject to adjustment for standard working capital provisions.
	In June 2014, we finalized the Arrow Acquisition purchase price allocation. The following table summarizes the final valuation of the assets acquired and liabilities assumed at the acquisition date (in millions):
	Current assets	$	192.7
	Property, plant and equipment	400.5
	Intangible assets	323.4
	Other assets	19.5
	Total identifiable assets acquired	936.1
	Current liabilities	215.8
	Assets retirement obligations	1.2
	Other long-term liabilities	3.7
	Total liabilities assumed	220.7
	Net identifiable assets acquired	715.4
	Goodwill	45.9
	Net assets acquired	$	761.3
	The $45.9 million of goodwill is reflected in our NGL and crude services segment. Goodwill recognized relates primarily to anticipated operating synergies between the assets acquired and our existing assets. During the three and nine months ended September 30, 2014, we also recognized approximately $0.2 million and $5.4 million of transaction-related fees primarily related to services provided in 2013 related to this acquisition.
	Unaudited Pro Forma Financial Information
	The following table represents the pro forma consolidated statement of operations as if the Arrow Acquisition had been included in our consolidated results for the full three and nine months ended September 30, 2013, and as if the results for Legacy Inergy reverse acquisition had been included for the entire nine months ended September 30, 2013 (in millions, except per unit information):
		Three Months Ended		Nine Months Ended
		30-Sep-13		30-Sep-13
	Revenues	$	601.2	$	1,526.80
	Net income	$	9.6	$	27.2
	Net income per limited partner unit(1):
	Basic	$	0.02	$	0.07
	Diluted	$	0.02	$	0.07
	(1) Basic and diluted net income per limited partner unit for the three and nine months ended September 30, 2013 were computed based on the number of
	Legacy Inergy common units outstanding plus the number of common units issued by Legacy Inergy to Legacy Crestwood unitholders as part of the
	Crestwood Merger and the number of units issued in conjunction with the Arrow Acquisition.
	These amounts have been calculated after applying our accounting policies and adjusting the results of the acquisitions to reflect the depreciation and amortization based on the estimated fair value adjustments to property, plant and equipment and intangible assets.
	Divestitures
	On July 25, 2013, we sold a cryogenic plant and associated equipment for approximately $11.0 million (net of fees) and recognized a gain of approximately $4.4 million during the three months ended September 30, 2013.

Investments_in_Unconsolidated_

Investments in Unconsolidated Affiliates (Notes)	9 Months Ended
	Sep. 30, 2014
Equity Method Investments and Joint Ventures [Abstract]	'
Investments in Unconsolidated Affiliates	'
	Investments in Unconsolidated Affiliates
	Jackalope Gas Gathering Services, L.L.C.
	Crestwood Niobrara LLC (Crestwood Niobrara), our consolidated subsidiary, owns a 50% ownership interest in Jackalope Gas Gathering Services, L.L.C. (Jackalope) which we account for under the equity method of accounting. Our Jackalope investment is included in our gathering and processing segment.
	Crestwood Niobrara acquired its interest in Jackalope in July 2013 for approximately $107.5 million. During the nine months ended September 30, 2014 and 2013, Crestwood Niobrara contributed $78.3 million and $20.6 million to Jackalope to fund its construction projects.
	Our investment in Jackalope was $205.6 million and $127.2 million at September 30, 2014 and December 31, 2013. We have reflected the earnings from our investment in Jackalope in our consolidated statements of income, which includes our share of Jackalope's net earnings based on our ownership interest and other adjustments recorded by us as discussed below. Our share of Jackalope’s net earnings was approximately $1.2 million and $0.2 million for the three months ended September 30, 2014 and 2013 and $2.4 million and $0.2 million for the nine months ended September 30, 2014 and 2013. As of September 30, 2014, our investment balance in Jackalope exceeded our equity in the underlying net assets of Jackalope by approximately $54.5 million. We amortize and generally assess the recoverability of this amount based on the life of Jackalope’s gathering agreement with Chesapeake Energy Corporation (Chesapeake) and RKI Exploration and Production, LLC (RKI). The amortization is reflected as a reduction of our earnings from unconsolidated affiliates, and we recorded amortization expense of approximately $0.8 million and $0.6 million for the three months ended September 30, 2014 and 2013 and $2.3 million and $0.6 million for the nine months ended September 30, 2014 and 2013.
	Jackalope is required to make quarterly distributions of its available cash to its members based on their respective ownership percentage. During the nine months ended September 30, 2014 and 2013, Jackalope did not make any distributions to its members.
	Powder River Basin Industrial Complex, LLC
	Crestwood Crude Logistics LLC (Crude Logistics), our consolidated subsidiary, owns a 50% ownership interest in Powder River Basin Industrial Complex, LLC (PRBIC) which we account for under the equity method of accounting. Our PRBIC investment is included in our NGL and crude services segment.
	Crestwood Logistics acquired its interest in PRBIC in September 2013 for approximately $22.5 million. During the nine months ended September 30, 2014 and 2013, Crude Logistics contributed approximately $3.5 million and $1.9 million to PRBIC to fund its construction projects.
	Our investment in PRBIC was $26.3 million and $24.2 million at September 30, 2014 and December 31, 2013. During the three and nine months ended September 30, 2014, our share of PRBIC’s loss was approximately $0.1 million and $1.4 million. As of September 30, 2014, our investment balance in PRBIC approximated our equity in the underlying net assets of PRBIC. Our share of PRBIC’s net earnings was not material for the three months ended September 30, 2013.
	PRBIC is required to make quarterly distributions of its available cash to its members based on their respective ownership percentage. During the nine months ended September 30, 2014 and 2013, PRBIC did not make any distributions to its members.

Earnings_Per_Limited_Partner_U

Earnings Per Limited Partner Unit Earnings Per Limited Partner Unit	9 Months Ended
	Sep. 30, 2014
Earnings Per Share [Abstract]	'
Earnings Per Limited Partner Unit	'
	Earnings Per Limited Partner Unit
	Prior to the Crestwood Merger, net income attributable to Legacy Crestwood was allocated to the general partner and the limited partners in accordance with their respective ownership percentages, after giving effect to incentive distributions earned by the general partner. To the extent cash distributions exceeded net income attributable to Legacy Crestwood, the excess distributions were allocated proportionately to all participating units outstanding based on their respective ownership percentages. As a result of the Crestwood Merger, CEQP, which owns our general partner, owns a non-economic general partner interest in us and 100% of our IDRs. We allocate net income attributable to CMLP to our limited partners after giving effect to the IDRs earned by CEQP and net income attributable to the Class A preferred units.
	Basic earnings per unit are calculated using the two-class method. Diluted earnings per unit are computed using the treasury stock method, which considers the impact to net income attributable to CMLP and limited partner units from the potential issuance of limited partner units as discussed below. The weighted average number of units outstanding is calculated based on the presumption that the number of common units issued by Legacy Inergy to Legacy Crestwood unitholders as part of the Crestwood Merger were outstanding for the entire period prior to Crestwood Merger.
	The tables below show the (i) allocation of net income attributable to CMLP and the (ii) net income attributable to CMLP per limited partner unit based on the number of basic and diluted limited partner units outstanding for the three and nine months ended September 30, 2014 and 2013 (in millions):
	Allocation of Net Income Attributable to CMLP
		Three Months Ended						Nine Months Ended
		September 30,						September 30,
		2014			2013			2014			2013
	Net income attributable to CMLP	$	16.8		$	9.7		$	27.2		$	25.3
	Class A preferred units interest in net income attributable to CMLP	(9.1		)	—			(10.2		)	—
	General partner’s incentive distributions	(7.5		)	(6.2		)	(22.5		)	(18.9		)
	General partner’s interest in net income attributable to CMLP	—			(0.1		)	—			(0.4		)
	Limited partners’ interest in net income (loss) attributable to CMLP	$	0.2		$	3.4		$	(5.5	)	$	6
	Earnings Per Limited Partner Unit
		Three Months Ended						Nine Months Ended
		September 30,						September 30,
		2014			2013			2014			2013
	Limited partners’ interest in net income (loss)	$	0.2		$	3.4		$	(5.5	)	$	6
	Weighted-average limited partner units - basic	188			161.6			187.9			101.1
	Effect of diluted units	—			—			—			—
	Weighted-average limited partner units - diluted	188			161.6			187.9			101.1
	Basic earnings per unit:
	Net income (loss) per limited partner	$	—		$	0.02		$	(0.03	)	$	0.06
	Diluted earnings per unit:
	Net income (loss) per limited partner	$	—		$	0.02		$	(0.03	)	$	0.06
	We exclude potentially dilutive securities from the determination of diluted earnings per unit (as well as their related income statement impacts) when their impact on net income attributable to CMLP per limited partner unit is anti-dilutive. During the three and nine months ended September 30, 2014, we excluded a weighted-average of 7,191,463 and 5,984,792 common units, representing Crestwood Niobrara's preferred units if converted to common units, from our diluted earnings per unit. During the three and nine months ended September 30, 2014, we also excluded a weighted-average of 12,244,500 and 4,739,285 common units, representing Class A preferred units if converted to common units, from our diluted earnings per unit. During the three and nine months ended September 30, 2013, we excluded a weighted-average of 3,262,275 and 1,099,375 common units, representing Crestwood Niobrara's preferred units if converted to common units, from our diluted earnings per unit. See Note 8 for additional information regarding the potential conversion of the preferred units to common units.

Financial_Instruments

Financial Instruments	9 Months Ended
	Sep. 30, 2014
Debt Disclosure [Abstract]	'
Financial Instruments	'
	Financial Instruments
	Fair Value
	We separate the fair values of our financial instruments into three levels (Levels 1, 2 and 3) based on our assessment of the availability of observable market data and the significance of non-observable data used to determine fair value. Our assessment and classification of an instrument within a level can change over time based on the maturity or liquidity of the instruments and would be reflected at the end of the period in which the change occurs. At September 30, 2014 and December 31, 2013, there were no changes to the inputs and valuation techniques used to measure fair value, the types of instruments, or the levels in which they are classified.
	During the three months ended September 30, 2014, we began entering into daily and short-term forward crude purchase and sale agreements in our NGL and crude services segment related to available capacity on our crude contracts and facilities associated with our operations located in the Bakken and PRB Niobrara Shale plays.
	As of September 30, 2014 and December 31, 2013, the carrying amounts of cash and cash equivalents, accounts receivable and accounts payable represent fair value based on the short-term nature of these instruments. The fair value of the amount outstanding under our credit facility approximates its carrying amount as of September 30, 2014 and December 31, 2013 due primarily to the variable nature of the interest rate of the instrument, which is considered a Level 2 fair value measurement.
	We estimate the fair value of our senior notes primarily based on quoted market prices for the same or similar issuances (representing a Level 2 fair value measurement). The following table reflects the carrying value and fair value of our senior notes (in millions):
		September 30, 2014				December 31, 2013
		Carrying Amount		Fair		Carrying Amount		Fair
				Value				Value
	2019 Senior Notes	$	351	$	369.5	$	351.2	$	379.3
	2020 Senior Notes	$	504.1	$	507.9	$	504.7	$	513.8
	2022 Senior Notes	$	600	$	603	$	600	$	617.3
	Long-Term Debt
	Long-term debt consisted of the following at September 30, 2014 and December 31, 2013 (in millions):
		September 30,		December 31,
		2014		2013
	Credit Facility	$	435	$	414.9
	2019 Senior Notes	350		350
	Premium on 2019 Senior Notes	1		1.2
	2020 Senior Notes	500		500
	Fair value adjustment of 2020 Senior Notes	4.1		4.7
	2022 Senior Notes	600		600
	Other	3.5		—
	Total debt	1,893.60		1,870.80
	Less: current portion	0.6		2.9
	Total long-term debt	$	1,893.00	$	1,867.90
	Credit Facility
	We have a five-year $1 billion senior secured revolving credit facility due in October 2018 (the Credit Facility), which is available to fund acquisitions, working capital and internal growth projects and for general partnership purposes. The Credit Facility includes a sub-limit up to $25 million for same-day swing line advances and a sub-limit up to $250 million for letters of credit. Subject to limited exception, the Credit Facility is secured by substantially all of the equity interests and assets of our restricted domestic subsidiaries, and is joint and severally guaranteed by substantially all of our restricted domestic subsidiaries.
	On June 11, 2014, we amended our Credit Facility to clarify, among other things, (i) the methodology for calculating the value of our investment in certain joint ventures constituting unrestricted subsidiaries, and (ii) that redemptions, repurchases and retirements of equity interests are permitted to the extent made solely through the issuance of additional equity units. We did not pay any fees to our bank syndicate for this amendment.
	At September 30, 2014, the balance outstanding on our Credit Facility was $435.0 million and outstanding standby letters of credit were $84.1 million. We had $227.0 million of available capacity under the revolving credit facility at September 30, 2014 considering our most restrictive debt covenants under the facility. The interest rates on our Credit Facility are based on the prime rate and LIBOR plus the applicable spreads, resulting in interest rates which were between 2.91% and 5.00% at September 30, 2014. The weighted-average interest rate as of September 30, 2014 was 2.92%.
	We are required under our credit agreement to maintain a consolidated leverage ratio (as defined in our credit agreement) of not more than 5.00 to 1.0 and an interest coverage ratio (as defined in our credit agreement) of not less than 2.50 to 1.0. At September 30, 2014, our net debt to consolidated EBITDA (as defined in our credit agreement) was approximately 4.46 to 1.0 and consolidated EBITDA to consolidated interest expense was approximately 3.86 to 1.0.
	Senior Notes
	We have three series of senior unsecured notes outstanding, including (i) $350 million in aggregate principal amount of 7.75% Senior Notes due 2019 (the 2019 Senior Notes), (ii) $500 million in aggregate principal amount of 6.0% Senior Notes due 2020 (the 2020 Senior Notes), and (iii) $600 million in aggregate principal amount of 6.125% Senior Notes due 2022 (the 2022 Senior Notes, and together with the 2019 Senior Notes and 2020 Senior Notes, our Senior Notes). Our Senior Notes are guaranteed on a senior unsecured basis by all of our domestic restricted subsidiaries, subject to certain exceptions.
	Under the indenture governing our 2019 Senior Notes, we may not pay any dividend on our common units unless, among other things, at the time of and after giving effect to such dividend payment, no default under the indenture has occurred and is continuing or would occur as a consequence of such dividend payment.
	On July 17, 2014, we filed a registration statement with the SEC under which we offered to exchange $600 million in aggregate principal amount of registered 6.125% Senior Notes due 2022 for any and all outstanding 2022 Senior Notes, which were issued in a private offering in November 2013. We completed the exchange offer on August 29, 2014. The terms of the exchange notes are substantially identical to the terms of the 2022 Senior Notes, except that the exchange notes are freely tradable.
	At September 30, 2014, we were in compliance with all of our debt covenants applicable to our Credit Facility and our Senior Notes. For additional information regarding our debt covenants, see our 2013 Annual Report on Form 10-K as filed with the SEC.

Partners_Capital

Partners' Capital	9 Months Ended
	Sep. 30, 2014
Partners' Capital [Abstract]	'
Partners' Capital	'
	Partners’ Capital
	Equity Distribution Agreement
	On July 10, 2014, we entered into an equity distribution agreement with Morgan Stanley & Co. LLC, Merrill Lynch, Pierce, Fenner & Smith Incorporated, Citigroup Global Markets Inc., J.P. Morgan Securities LLC, RBC Capital Markets, LLC, SunTrust Robinson Humphrey, Inc. and Wells Fargo Securities, LLC (each, a Manager), under which we may offer and sell from time to time through one or more of the Managers, common units having an aggregate offering price of up to $300.0 million. Common units sold pursuant to this at-the-market (ATM) equity distribution program will be issued under a registration statement that became effective on May 27, 2014. We will pay the Managers an aggregate fee of up to 2.0% of the gross sales price per common unit sold under our ATM program. We have not issued any common units under this equity distribution program as of September 30, 2014 and through the date of this filing. Additional information on our ATM equity distribution program is available in our Form 8-K filed with the SEC on July 10, 2014.
	Distributions
	Our partnership agreement requires us to distribute, within 45 days after the end of each quarter, all available cash (as defined in our partnership agreement) to our common and preferred unitholders of record on the applicable record date. The general partner is not entitled to distributions on its non-economic general partner interest.
	Distributions to General Partner
	We paid cash distributions to our general partner (representing IDRs and distributions related to common units held by the general partner) of approximately $31.4 million and $17.1 million during the nine months ended September 30, 2014 and 2013.
	Distributions to Class A Preferred Unit Holders
	Our partnership agreement requires us to make quarterly distributions to our Class A Preferred Unit holders. The holders of our Class A Preferred Units (the Preferred Units) are entitled to receive fixed quarterly distributions of $0.5804 per unit. For the 12 quarters following the quarter ended June 30, 2014 (the Initial Distribution Period), distributions on our Preferred Units can be made in additional Preferred Units, cash, or a combination thereof, at our election. If we elect to pay the quarterly distribution through the issuance of additional Preferred Units, the number of units to be distributed will be calculated as the fixed quarterly distribution of $0.5804 per unit divided by the cash purchase price of $25.10 per unit. We accrue the fair value of such distribution at the end of the quarterly period and adjust the fair value of the distribution on the date the additional Preferred Units are distributed. Distributions on our Preferred Units following the Initial Distribution Period will be made in cash unless, subject to certain exceptions, (i) there is no distribution being paid on our common units and (ii) our available cash (as defined in our partnership agreement) is insufficient to make a cash distribution to our Preferred Unit holders. If we fail to pay the full amount payable to our Preferred Unit holders in cash following the Initial Distribution Period, then (x) the fixed quarterly distribution on the Preferred Units will increase to $0.7059 per unit, and (y) we will not be permitted to declare or make any distributions to our common unitholders until such time as all accrued and unpaid distributions on the Preferred Units have been paid in full in cash. In addition, if we fail to pay in full any Class A Preferred Distribution (as defined in our partnership agreement), the amount of such unpaid distribution will accrue and accumulate from the last day of the quarter for which such distribution is due until paid in full, and any accrued and unpaid distributions will be increased at a rate of 2.8125% per quarter. For additional information on our Preferred Units, see Class A Preferred Units section below.
	On July 23, 2014 and October 22, 2014, the board of directors of our general partner authorized the issuance of 42,523 and 345,471 Preferred Units to our Preferred Unit holders for the quarters ended June 30, 2014 and September 30, 2014 in lieu of paying a cash distribution. In accordance with our partnership agreement, the additional Preferred Units will be issued in November 2014.
	Distributions to Limited Partners
	The following table presents quarterly cash distributions paid to our limited partners (excluding distributions paid to our general partner on its common units held) during the nine months ended September 30, 2014:
	Nine Months Ended September 30, 2014
	Record Date	Payment Date	Per Unit Rate		Cash Distribution
					(in millions)
	February 7, 2014	February 14, 2014	$	0.41	$	74.1
	May 8, 2014	May 15, 2014	$	0.41	74.2
	August 7, 2014	August 14, 2014	$	0.41	74.1
					$	222.4
	The following table presents quarterly cash distributions associated with Legacy Crestwood and Legacy Inergy paid to the limited partners (excluding distributions paid to the general partner on its common units held) during the nine months ended ended September 30, 2013:
	Nine Months Ended September 30, 2013
	Record Date	Payment Date	Per Unit Rate		Cash Distribution
					(in millions)
	January 31, 2013	February 12, 2013	$	0.51	$	21
	April 30, 2013	May 10, 2013	$	0.51	27.4
	August 1, 2013	August 9, 2013	$	0.51	27.4
	August 7, 2013	August 14, 2013	$	0.4	34.3		(1)
					$	110.1
	(1) Represents distributions associated with Legacy Inergy limited partner units.
	On October 22, 2014, we declared a distribution of $0.41 per limited partner unit to be paid on November 14, 2014, to unitholders of record on November 7, 2014 with respect to the third quarter of 2014.
	Preferred Equity
	Class A Preferred Units
	On June 17, 2014, we entered into definitive agreements with a group of investors, including Magnetar Capital, affiliates of GSO Capital Partners LP and GE Energy Financial Services (the Class A Purchasers). Under these agreements, we have agreed to sell to the Class A Purchasers and the Class A Purchasers have agreed to purchase from us up to $500 million of Preferred Units at a fixed price of $25.10 per unit on or before September 30, 2015. Contemporaneously with the closing of this equity commitment, on June 17, 2014, the Class A Purchasers purchased 11,952,191 Preferred Units for a cash purchase price of $25.10 per unit resulting in gross proceeds to us of approximately $300 million (net proceeds of approximately $293.7 million after deducting transaction fees and offering expenses). On September 22, 2014, the Class A Purchasers purchased 2,988,047 Preferred Units for a cash purchase price of $25.10 per unit resulting in gross proceeds to us of approximately $75.0 million (net proceeds of approximately $73.1 million after deducting transaction fees and offering expenses).
	Subject to certain conditions, holders of the Preferred Units will have the right to convert Preferred Units into (i) common units on a one-for-one basis after June 17, 2017, or (ii) a number of common units determined pursuant to a conversion ratio set forth in our partnership agreement upon the occurrence of certain events, such as a change in control. Also, subject to certain conditions after the full $500 million purchase commitment has been satisfied, we may convert the Preferred Units into common units at a conversion ratio set forth in the partnership agreement, which is based in part on the aggregate principal amount of the Preferred Units outstanding and the weighted average trading price of our common units.
	The Preferred Units have voting rights that are identical to the voting rights of the common units and will vote with the common units as a single class, with each Preferred Unit entitled to one vote for each common unit into which such Preferred Unit is convertible, except that the Preferred Units are entitled to vote as a separate class on any matter on which all unitholders are entitled to vote that adversely affects the rights, powers, privileges or preferences of the Preferred Units in relation to our other securities outstanding.
	Additional information on the terms and conditions of the Preferred Units, including distribution, conversion, voting rights and liquidation preferences, is available on our Form 8-Ks filed with the SEC on June 19, 2014 and July 11, 2014, respectively.
	On July 9, 2014, we filed a shelf registration statement with the SEC under which holders of the Preferred Units may sell the common units into which the Preferred Units are convertible. The registration statement became effective on July 18, 2014. We registered 26,299,076 common units under the registration statement.
	Crestwood Niobrara Preferred Interest
	Crestwood Niobrara issued a preferred interest to a subsidiary of General Electric Capital Corporation and GE Structured Finance, Inc. (collectively, GE) in conjunction with the acquisition of its investment in Jackalope. The preferred interest is reflected as non-controlling interest in our consolidated financial statements. We allocated net income to the non-controlling interest based on the overall return attributable to the preferred security of approximately $4.5 million and $1.9 million during the three months ended September 30, 2014 and 2013, and $11.3 million and $1.9 million during the nine months ended September 30, 2014 and 2013.
	Pursuant to Crestwood Niobrara's agreement with GE, GE made capital contributions to Crestwood Niobrara in exchange for an equivalent number of preferred units. During the three months ended September 30, 2014 and 2013, GE made capital contributions of $20.3 million and $96.1 million to Crestwood Niobrara. During the nine months ended September 30, 2014 and 2013, GE made capital contributions of $53.9 million and $96.1 million to Crestwood Niobrara. As of September 30, 2014, GE has fulfilled its capital contribution commitment to Crestwood Niobrara of $150.0 million and is no longer required to make quarterly contributions to Crestwood Niobrara.
	Crestwood Niobrara has the option to pay distributions to GE with cash or by issuing additional preferred units through the January 2015 distribution. During the three and nine months ended September 30, 2014, Crestwood Niobrara issued 3,073,357 and 7,819,661 preferred units to GE in lieu of paying a cash distribution. We serve as the managing member of Crestwood Niobrara and, subject to certain restrictions, we have the ability to redeem GE’s preferred interest in either cash or our common units at an amount equal to the face amount of the preferred units plus an applicable return. On October 31, 2014, Crestwood Niobrara issued 3,599,580 preferred units to GE in lieu of paying a cash distribution.
	Other Partners’ Capital Transaction
	On January 8, 2013, Legacy Crestwood acquired Crestwood Holdings’ 65% membership interest in Crestwood Marcellus Midstream LLC (CMM) for approximately $258.0 million, of which approximately $129.0 million was funded through the issuance of 6,190,469 Class D units and the issuance of 133,060 general partner units to the Legacy Crestwood general partner. We reflected the issuances of the Class D and general partner units as distributions for additional interest in CMM in our consolidated statement of cash flows for the nine months ended September 30, 2013.

LongTerm_Incentive_Plan_Notes

Long-Term Incentive Plan (Notes)	9 Months Ended
	Sep. 30, 2014
Equity [Abstract]	'
Long-Term Incentive Plan	'
	Long-Term Incentive Plan
	Long-term incentive awards are granted under the Crestwood Midstream Partners LP Long Term Incentive Plan (Crestwood LTIP) (formerly the Inergy Midstream, L.P. Long Term Incentive Plan) in order to align the economic interests of key employees and directors with those of CMLP's common unitholders and to provide an incentive for continuous employment. Long-term incentive compensation consist solely of grants of restricted common units (which represent limited partner interests of CMLP) which vest based upon continued service.
	During 2014, we have issued restricted unit awards, which were approved by either CMLP's Board compensation committee or pursuant to the authority granted by the Chief Executive Officer, to certain key employees. These awards vest upon continued service with the Company.
	The following table summarizes information regarding restricted unit activity during the nine months ended September 30, 2014:
		Units		Weighted-Average Grant Date Fair Value
	Unvested - January 1, 2014	250,557		$	22.13
	Vested - restricted units	(190,818	)	$	22.16
	Granted - restricted units	838,036		$	23.31
	Forfeited	(57,208	)	$	23.49
	Unvested - September 30, 2014	840,567		$	23.21
	As of September 30, 2014 and December 31, 2013, we had total unamortized compensation expense of approximately $11.6 million and $1.8 million related to restricted units, which we expect will be amortized during the next three years (or sooner in certain cases, which generally represents the original vesting period of these instruments), except for grants to non-employee directors of our general partner, which vest over one year. We recognized compensation expense of approximately $2.5 million and $1.7 million during the three months ended September 30, 2014 and 2013 and $8.7 million and $3.2 million during the nine months ended September 30, 2014 and 2013, which is included in general and administrative expenses on our consolidated statements of operations. An additional $1.6 million and $5.2 million of net compensation expense was allocated from CEQP to us during the three and nine months ended September 30, 2014 and an additional $3.1 million and $3.3 million was allocated from CEQP to us during the three and nine months ended September 30, 2013 (see Note 11). We granted restricted units with a grant date fair value of approximately $19.5 million during the nine months ended September 30, 2014.  As of September 30, 2014, we had 6,430,021 units available for issuance under the Crestwood LTIP.
	Under the Crestwood LTIP, participants who have been granted restricted units may elect to have common units withheld to satisfy minimum statutory tax withholding obligations arising in connection with the vesting of non-vested common units. Any such common units withheld are returned to the Crestwood LTIP on the applicable vesting dates, which correspond to the times at which income is recognized by the employee. When we withhold these common units, we are required to remit to the appropriate taxing authorities the fair value of the units withheld as of the vesting date. The number of units withheld is determined based on the closing price per common unit as reported on the NYSE on such dates. During the three months ended September 30, 2013, we withheld 912 common units and during the nine months ended September 30, 2014 and 2013, we withheld 68,532 and 3,341 common units to satisfy employee tax withholding obligations. There were no common units withheld during the three months ended September 30, 2014.
	Employee Unit Purchase Plan
	Beginning in September 2014, the board of directors of our general partner made available an employee unit purchase plan under which employees of the general partner may purchase CMLP units through payroll deductions up to a maximum of 10 percent of the employees' eligible compensation. Under the plan, CMLP may purchase its units on the open market for the benefit of participating employees based on their payroll deductions.  In addition, CMLP may contribute an additional 10 percent of participating employees' payroll deductions to purchase additional CMLP units for participating employees. Unless increased by the board of directors of our general partner, the maximum number of units that may be purchased under the plan is 200,000.

Commitments_and_Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2014
Commitments and Contingencies Disclosure [Abstract]	'
Commitments and Contingencies	'
	Commitments and Contingencies
	Legal Proceedings
	Arrow Acquisition Class Action Lawsuit. Prior to the completion of the Arrow Acquisition on November 8, 2013, a train transporting over 50,000 barrels of crude oil produced in North Dakota derailed in Lac Megantic, Quebec, Canada on July 6, 2013. The derailment resulted in the death of 47 people, injured numerous others, and caused severe damage to property and the environment.  In October 2013, certain individuals suffering harm in the derailment filed a motion to certify a class action lawsuit in the Superior Court for the District of Megantic, Province of Quebec, Canada, on behalf of all persons suffering loss in the derailment.
	In March 2014, the plaintiffs filed their fourth amended motion to name Arrow and numerous other energy companies as additional defendants in the class action lawsuit. The plaintiffs have named at least 53 defendants purportedly involved in the events leading up to the derailment, including the producers and sellers of the crude being transported, the midstream companies that transported the crude from the well head to the rail system, the manufacturers of the rail cars used to transport the crude, the railroad companies involved, the insurers of these companies, and the Canadian Attorney General.  The plaintiffs allege, among other things, that Arrow (i) was a producer of the crude oil being transported on the derailed train, (ii) was negligent in failing to properly classify the crude delivered to the trucks that hauled the crude to the rail loading terminal, and (iii) owed a duty to the petitioners to ensure the safe transportation of the crude being transported.  The motion to authorize the class action and motions in opposition were heard by the Court in June 2014.  We anticipate a ruling from the Judge on Petitioners' motion to authorize the class action by the end of November 2014. We believe the claims against us are without merit and will vigorously defend ourselves.  Moreover, to the extent this action proceeds, we believe we have meritorious defenses to the claims.  Because this litigation is in the early stages of the proceeding, we are unable to estimate a reasonably possible loss or range of loss in this matter.  We believe this claim is an insurable event under our insurance policy and we have notified our insurance company of the claim.
	We are periodically involved in litigation proceedings. If we determine that a negative outcome is probable and the amount of loss is reasonably estimable, then we accrue the estimated amount. The results of litigation proceedings cannot be predicted with certainty. We could incur judgments, enter into settlements or revise our expectations regarding the outcome of certain matters, and such developments could have a material adverse effect on our results of operations or cash flows in the period in which the amounts are paid and/or accrued. As of September 30, 2014 and December 31, 2013, we had less than $0.1 million accrued for our outstanding legal matters. Based on currently available information, we believe it is remote that future costs related to known contingent liability exposures for which we can estimate will exceed current accruals by an amount that would have a material adverse impact on our consolidated financial statements. As we learn new facts concerning contingencies, we reassess our position both with respect to accrued liabilities and other potential exposures.
	Any loss estimates are inherently subjective, based on currently available information, and are subject to management's judgment and various assumptions. Due to the inherently subjective nature of these estimates and the uncertainty and unpredictability surrounding the outcome of legal proceedings, actual results may differ materially from any amounts that have been accrued.
	Regulatory Compliance
	In the ordinary course of our business, we are subject to various laws and regulations. In the opinion of our management, compliance with current laws and regulations will not have a material effect on our results of operations, cash flows or financial condition.
	Environmental Compliance
	During the three months ended September 30, 2014, we experienced two releases totaling approximately 28,000 barrels of produced water on our Arrow water gathering system located on the Fort Berthold Indian Reservation in North Dakota. We immediately notified the National Response Center, the Three Affiliated Tribes and numerous other regulatory authorities, and thereafter contained and cleaned up the releases completely and placed the impacted segments of these water lines back into service during the third quarter of 2014. During the three months ended September 30, 2014, we recognized $3.7 million of operations and maintenance expense related to these releases, of which $1.7 million was included in other current liabilities on our balance sheet as of September 30, 2014. We will continue our remediation efforts to ensure the impacted lands are restored to their prior state, and we may potentially be subject to fines and penalties. As of September 30, 2014, we had no amounts accrued for fines and penalties. We believe these releases are insurable events under our policies, and we have notified our carriers of these events; however, we have not recorded an insurance receivable as of September 30, 2014.
	Our operations are subject to stringent and complex laws and regulations pertaining to health, safety, and the environment. We are subject to laws and regulations at the federal, state and local levels that relate to air and water quality, hazardous and solid waste management and disposal and other environmental matters. The cost of planning, designing, constructing and operating our facilities must incorporate compliance with environmental laws and regulations and safety standards. Failure to comply with these laws and regulations may trigger a variety of administrative, civil and potentially criminal enforcement measures. At September 30, 2014, our accrual of approximately $1.7 million was primarily related to the Arrow water releases described above, which is based on our undiscounted estimate of amounts we will spend on compliance with environmental and other regulations. We estimate that our potential liability for reasonably possible outcomes related to our environmental exposures (including the Arrow water releases described above) could range from approximately $1.7 million to $2.1 million. Our accrual and potential exposure related to our environmental matters was immaterial at December 31, 2013.
	Contingent Consideration - Antero
	In connection with the acquisition of Antero Resources (Antero), we agreed to pay Antero conditional consideration in the form of potential additional cash payments of up to $40.0 million, depending on the achievement of certain defined average annual production levels achieved during 2012, 2013 and 2014. During 2012 and 2013, Antero did not meet the annual production level to earn additional payments. Based on our estimates of Antero’s 2014 production, we believe their production levels will exceed the annual production threshold in the earn-out provision and accordingly, we recognized a liability of $40.0 million and $31.4 million as of September 30, 2014 and December 31, 2013, which we anticipate paying in the first quarter of 2015.

Related_Party_Transactions

Related Party Transactions	9 Months Ended
	Sep. 30, 2014
Related Party Transactions [Abstract]	'
Related Party Transactions	'
	Related Party Transactions
	We do not have any employees. We share common management, operating and administrative and overhead costs with CEQP. We have an Omnibus Agreement with CEQP that requires us to reimburse CEQP for all shared costs incurred on our behalf, except for certain unit based compensation costs which are treated as capital transactions. CEQP allocated to us $14.0 million and $42.7 million of costs for the three and nine months ended September 30, 2014. Included in this amount was $1.6 million and $5.2 million of net unit-based compensation charges for the three and nine months ended September 30, 2014. During the three and nine months ended September 30, 2013, CEQP allocated to us $5.0 million and $5.5 million of costs, including $3.1 million and $3.3 million of net unit-based compensation charges. Due to the nature of these shared costs, it is not practicable to estimate what the costs would have been on a stand-alone basis. Accordingly, the accompanying financial statements may not necessarily be indicative of the conditions that would have existed, or the results of operations that would have occurred, if we operated as a stand-alone entity.
	The following table shows revenues, costs of goods sold and general and administrative expenses from our affiliates for the three and nine months ended September 30, 2014 and 2013 (in millions):
		Three Months Ended				Nine Months Ended
		September 30,				September 30,
		2014(1)		2013		2014(1)		2013
	Gathering and processing revenues	$	1.4	$	24.1	$	3	$	74.3
	NGL and crude services revenues	$	3.5	$	3.4	$	10.2	$	3.8
	Gathering and processing costs of product/services sold	$	11.3	$	7.6	$	32.1	$	22.2
	General and administrative expenses	$	4.5	$	5.9	$	12.8	$	16.5
	(1) Concurrent with the Crestwood Merger, Quicksilver Resources Inc. (Quicksilver) is no longer a related party, and as a result our transactions with
	Quicksilver subsequent to June 19, 2013, are now considered non-affiliated transactions.
	The following table shows accounts receivable and accounts payable from our affiliates as of September 30, 2014 and December 31, 2013 (in millions):
		September 30, 2014		December 31, 2013
	Accounts receivable	$	2.8	$	1.1
	Accounts payable	$	7.4	$	8.7
	For additional information regarding our related party transactions, see our 2013 Annual Report on Form 10-K as filed with the SEC.

Segments

Segments	9 Months Ended
	Sep. 30, 2014
Segment Reporting [Abstract]	'
Segments	'
	Segments
	Financial Information
	We have three operating and reportable segments; (i) gathering and processing operations; (ii) storage and transportation operations; and (iii) NGL and crude services operations. Our gathering and processing operations engage in the gathering, processing, treating, compression, transportation and sales of natural gas and the delivery of NGLs. Our storage and transportation operations provide regulated natural gas storage and transportations services to producers, utilities and other customers. Our NGL and crude services operations provide NGLs and crude oil gathering, storage, marketing and transportation services to producers, refiners, marketers and other customers that effectively provide flow assurances to our customers, as well as the production and sale of salt products. Our corporate operations include all general and administrative expenses that are not allocated to the reportable segments. We assess the performance of our operating segments based on EBITDA, which represents operating income plus depreciation, amortization and accretion expense.
	The following table is a reconciliation of net income to EBITDA (in millions):
		Three Months Ended					Nine Months Ended
		September 30,					September 30,
		2014			2013		2014			2013
	Net income	$	21.3		$	11.6	$	38.5		$	27.2
	Add:
	Interest and debt expense, net	27.7			19.5		84.8			43.4
	Provision for income taxes	—			0.3		0.8			1
	Depreciation, amortization and accretion	55.5			35.1		161.2			73.4
	EBITDA	$	104.5		$	66.5	$	285.3		$	145
	The following tables summarize the reportable segment data for the three and nine months ended September 30, 2014 and 2013 (in millions).
		Three Months Ended September 30, 2014
		Gathering and Processing			Storage and Transportation		NGL and Crude Services			Corporate			Total
	Revenues	$	85.3		$	44.2	$	608.9		$	—		$	738.4
	Costs of product/services sold	18.6			4.3		552.8			—			575.7
	Operations and maintenance expense	15.9			4.2		19.3			—			39.4
	General and administrative expense	—			—		—			18.2			18.2
	Loss on long-lived assets	(0.9		)	—		—			—			(0.9		)
	Earnings (loss) from unconsolidated affiliates, net	0.4			—		(0.1		)	—			0.3
	EBITDA	$	50.3		$	35.7	$	36.7		$	(18.2	)	$	104.5
	Goodwill	$	99.6		$	726.3	$	855.5		$	—		$	1,681.40
	Total assets	$	2,026.10		$	1,951.20	$	2,553.70		$	163.6		$	6,694.60
	Cash expenditures for property, plant and equipment	$	57.5		$	2.2	$	34.8		$	0.1		$	94.6
		Three Months Ended September 30, 2013
		Gathering and Processing			Storage and Transportation		NGL and Crude Services			Corporate			Total
	Revenues	$	71.1		$	42.1	$	26.9		$	—		$	140.1
	Costs of product/services sold	12.9			4		9.7			—			26.6
	Operations and maintenance expense	14.9			4.7		2.1			—			21.7
	General and administrative expense	—			—		—			25.2			25.2
	Goodwill impairment	(4.1		)	—		—			—			(4.1		)
	Gain on long-lived assets	4.4			—		—			—			4.4
	Loss from unconsolidated affiliates, net	(0.4		)	—		—			—			(0.4		)
	EBITDA	$	43.2		$	33.4	$	15.1		$	(25.2	)	$	66.5
	Goodwill	$	99.6		$	744.1	$	609.1		$	—		$	1,452.80
	Total assets	$	1,856.00		$	2,003.00	$	1,257.40		$	46.4		$	5,162.80
	Cash expenditures for property, plant and equipment	$	84.1		$	5.7	$	16		$	0.1		$	105.9
		Nine Months Ended September 30, 2014
		Gathering and Processing			Storage and Transportation		NGL and Crude Services			Corporate			Total
	Revenues	$	248.2		$	133.9	$	1,569.00		$	—		$	1,951.10
	Costs of product/services sold	54.9			11.3		1,426.70			—			1,492.90
	Operations and maintenance expense	44			12.9		43.2			—			100.1
	General and administrative expense	—			—		—			63.6			63.6
	Gain on long-lived assets	0.1			0.6		—			—			0.7
	Loss on contingent consideration	(8.6		)	—		—			—			(8.6		)
	Earnings (loss) from unconsolidated affiliates, net	0.1			—		(1.4		)	—			(1.3		)
	EBITDA	$	140.9		$	110.3	$	97.7		$	(63.6	)	$	285.3
	Goodwill	$	99.6		$	726.3	$	855.5		$	—		$	1,681.40
	Total assets	$	2,026.10		$	1,951.20	$	2,553.70		$	163.6		$	6,694.60
	Cash expenditures for property, plant and equipment	$	178.6		$	4.7	$	72.3		$	3.7		$	259.3
		Nine Months Ended September 30, 2013
		Gathering and Processing			Storage and Transportation		NGL and Crude Services			Corporate			Total
	Revenues	$	214.6		$	47.6	$	30.4		$	—		$	292.6
	Costs of product/services sold	40.4			4.4		10.6			—			55.4
	Operations and maintenance expense	40.5			5.3		2.3			—			48.1
	General and administrative expense	—			—		—			44			44
	Goodwill impairment	(4.1		)	—		—			—			(4.1		)
	Gain on long-lived assets	4.4			—		—			—			4.4
	Loss from unconsolidated affiliates, net	(0.4		)	—		—			—			(0.4		)
	EBITDA	$	133.6		$	37.9	$	17.5		$	(44.0	)	$	145
	Goodwill	$	99.6		$	744.1	$	609.1		$	—		$	1,452.80
Total assets	$	1,856.00		$	2,003.00	$	1,257.40		$	46.4		$	5,162.80
Cash expenditures for property, plant and equipment	$	164		$	7.9	$	17		$	0.5		$	189.4

Condensed_Consolidating_Financ

Condensed Consolidating Financial Information (Notes)	9 Months Ended
	Sep. 30, 2014
Condensed Financial Information of Parent Company Only Disclosure [Abstract]	'
Condensed Consolidating Financial Information	'
	Condensed Consolidating Financial Information
	Crestwood is a holding company and owns no operating assets and has no significant operations independent of its subsidiaries. Obligations under our Senior Notes and our Credit Facility are jointly and severally guaranteed by substantially all of our restricted domestic subsidiaries, except for Crestwood Niobrara and PRBIC and their subsidiaries (collectively, Non-Guarantor Subsidiaries). Crestwood Midstream Finance Corp., the co-issuer of our Senior Notes, is our 100% owned subsidiary and has no material assets, operations, revenues or cash flows other than those related to its service as co-issuer of our Senior Notes.
	The tables below present condensed consolidating financial statements for us (parent) on a stand-alone, unconsolidated basis, and our combined guarantor and combined non-guarantor subsidiaries as of September 30, 2014 and December 31, 2013, and for the three and nine months ended September 30, 2014.  As discussed in Note 2, the Crestwood Merger was accounted for as a reverse merger between entities under common control, and as such, changes in the composition of guarantors and non-guarantors should be reflected retrospectively based on the guarantor structure that existed as of the end of the most recent balance sheet.
	Condensed Consolidating Balance Sheet
	30-Sep-14
	(in millions)
		Parent			Guarantor			Non-			Eliminations			Consolidated
					Subsidiaries			Guarantor
								Subsidiaries
	Assets
	Current assets:
	Cash and cash equivalents	$	—		$	0.1		$	—		$	—		$	0.1
	Accounts receivable	579.1			295.4			0.1			(561.8		)	312.8
	Inventories	—			8.3			—			—			8.3
	Other current assets	—			20.3			—			—			20.3
	Total current assets	579.1			324.1			0.1			(561.8		)	341.5
	Property, plant and equipment, net	5.9			3,493.70			—			—			3,499.60
	Goodwill and intangible assets, net	—			2,602.20			—			—			2,602.20
	Investment in consolidated affiliates	6,571.50			—			—			(6,571.5		)	—
	Investment in unconsolidated affiliates	—			—			231.9			—			231.9
	Other assets	—			19.4			—			—			19.4
	Total assets	$	7,156.50		$	6,439.40		$	232		$	(7,133.3	)	$	6,694.60
	Liabilities and partners' capital
	Current liabilities:
	Accounts payable	$	855.5		$	(93.2	)	$	0.1		$	(561.8	)	$	200.6
	Other current liabilities	1			164.7			—			—			165.7
	Total current liabilities	856.5			71.5			0.1			(561.8		)	366.3
	Long-term liabilities:
	Long-term debt, less current portion	1,893.00			—			—			—			1,893.00
	Other long-term liabilities	1.7			28.3			—			—			30
	Total long-term liabilities	1,894.70			28.3			—			—			1,923.00
	Partners' capital	4,239.10			6,339.60			65.7			(6,405.3		)	4,239.10
	Interest of non-controlling partners in subsidiaries	166.2			—			166.2			(166.2		)	166.2
	Total partners' capital	4,405.30			6,339.60			231.9			(6,571.5		)	4,405.30
	Total liabilities and partners' capital	$	7,156.50		$	6,439.40		$	232		$	(7,133.3	)	$	6,694.60
	Condensed Consolidating Balance Sheet
	31-Dec-13
	(in millions)
		Parent			Guarantor			Non-			Eliminations			Consolidated
					Subsidiaries			Guarantor
								Subsidiaries
	Assets
	Current assets:
	Cash and cash equivalents	$	0.1		$	1.6		$	1		$	—		$	2.7
	Accounts receivable	466.8			197.8			0.2			(459.7		)	205.1
	Inventories	—			7			—			—			7
	Other current assets	—			10.2			—			—			10.2
	Total current assets	466.9			216.6			1.2			(459.7		)	225
	Property, plant and equipment, net	4.8			3,345.30			—			—			3,350.10
	Goodwill and intangible assets, net	—			2,653.60			—			—			2,653.60
	Investment in consolidated affiliates	6,385.20			—			—			(6,385.2		)	—
	Investment in unconsolidated affiliates	—			—			151.4			—			151.4
	Other assets	—			21.7			—			—			21.7
	Total assets	$	6,856.90		$	6,237.20		$	152.6		$	(6,844.9	)	$	6,401.80
	Liabilities and partners' capital
	Current liabilities:
	Accounts payable	$	782.7		$	(159.8	)	$	—		$	(459.7	)	$	163.2
	Other current liabilities	11.5			139.6			0.2			—			151.3
	Total current liabilities	794.2			(20.2		)	0.2			(459.7		)	314.5
	Long-term liabilities:
	Long-term debt, less current portion	1,867.90			—			—			—			1,867.90
	Other long-term liabilities	1.7			24.6			—			—			26.3
	Total long-term liabilities	1,869.60			24.6			—			—			1,894.20
Partners' capital	4,092.10			6,232.80			51.4			(6,284.2		)	4,092.10
Interest of non-controlling partners in subsidiaries	101			—			101			(101.0		)	101
Total partners' capital	4,193.10			6,232.80			152.4			(6,385.2		)	4,193.10
Total liabilities and partners' capital	$	6,856.90		$	6,237.20		$	152.6		$	(6,844.9	)	$	6,401.80
Condensed Consolidating Statements of Operations
Three Months Ended September 30, 2014
(in millions)
	Parent			Guarantor			Non-			Eliminations			Consolidated
				Subsidiaries			Guarantor
							Subsidiaries
Revenues:
Gathering and processing	$	—		$	83.9		$	—		$	—		$	83.9
Storage and transportation	—			44.2			—			—			44.2
NGL and crude services	—			605.4			—			—			605.4
Related party	—			4.9			—			—			4.9
	—			738.4			—			—			738.4
Costs of product/services sold (excluding depreciation, amortization and accretion as shown below):
Gathering and processing	—			7.3			—			—			7.3
Storage and transportation	—			4.3			—			—			4.3
NGL and crude services	—			552.8			—			—			552.8
Related party	—			11.3			—			—			11.3
	—			575.7			—			—			575.7
Expenses:
Operations and maintenance	—			39.4			—			—			39.4
General and administrative	(0.8		)	19			—			—			18.2
Depreciation, amortization and accretion	0.3			55.2			—			—			55.5
	(0.5		)	113.6			—			—			113.1
Other operating income (expense):
Other	—			(0.9		)	—			—			(0.9		)
Operating income	0.5			48.2			—			—			48.7
Interest and debt expense, net	(27.8		)	0.1			—			—			(27.7		)
Equity in net income (loss) of subsidiary	48.6			—			—			(48.6		)	—
Other	—			—			0.3			—			0.3
Income (loss) before income taxes	21.3			48.3			0.3			(48.6		)	21.3
Provision for income taxes	—			—			—			—			—
Net income (loss)	21.3			48.3			0.3			(48.6		)	21.3
Net income attributable to non-controlling partners	—			—			(4.5		)	—			(4.5		)
Net income (loss) attributable to Crestwood Midstream Partners LP	21.3			48.3			(4.2		)	(48.6		)	16.8
Net income attributable to Class A preferred units	(9.1		)	—			—			—			(9.1		)
Net income (loss) attributable to partners	$	12.2		$	48.3		$	(4.2	)	$	(48.6	)	$	7.7
Condensed Consolidating Statements of Operations
Three Months Ended September 30, 2013
(in millions)
	Parent			Guarantor			Non-			Eliminations			Consolidated
				Subsidiaries			Guarantor
							Subsidiaries
Revenues:
Gathering and processing	$	—		$	47		$	—		$	—		$	47
Storage and transportation	—			42.1			—			—			42.1
NGL and crude services	—			23.5			—			—			23.5
Related party	—			27.5			—			—			27.5
	—			140.1			—			—			140.1
Costs of product/services sold (excluding depreciation, amortization and accretion as shown below):
Gathering and processing	—			5.3			—			—			5.3
Storage and transportation	—			4			—			—			4
NGL and crude services	—			9.7			—			—			9.7
Related party	—			7.6			—			—			7.6
	—			26.6			—			—			26.6
Expenses:
Operations and maintenance	—			21.7			—			—			21.7
General and administrative	9.4			15.8			—			—			25.2
Depreciation, amortization and accretion	0.2			34.9			—			—			35.1
	9.6			72.4			—			—			82
Other operating income (expense):
Other	—			0.3			—			—			0.3
Operating income (loss)	(9.6		)	41.4			—			—			31.8
Interest and debt expense, net	(18.4		)	(1.1		)	—			—			(19.5		)
Equity in net income (loss) of subsidiary	39.6			—			—			(39.6		)	—
Other	—			—			(0.4		)	—			(0.4		)
Income (loss) before income taxes	11.6			40.3			(0.4		)	(39.6		)	11.9
Provision for income taxes	—			0.3			—			—			0.3
Net income (loss)	11.6			40			(0.4		)	(39.6		)	11.6
Net income attributable to non-controlling partners	—			—			(1.9		)	—			(1.9		)
Net income (loss) attributable to Crestwood Midstream Partners LP	$	11.6		$	40		$	(2.3	)	$	(39.6	)	$	9.7
Condensed Consolidating Statements of Operations
Nine Months Ended September 30, 2014
(in millions)
	Parent			Guarantor			Non-			Eliminations			Consolidated
				Subsidiaries			Guarantor
							Subsidiaries
Revenues:
Gathering and processing	$	—		$	245.2		$	—		$	—		$	245.2
Storage and transportation	—			133.9			—			—			133.9
NGL and crude services	—			1,558.80			—			—			1,558.80
Related party	—			13.2			—			—			13.2
	—			1,951.10			—			—			1,951.10
Costs of product/services sold (excluding depreciation, amortization and accretion as shown below):
Gathering and processing	—			22.8			—			—			22.8
Storage and transportation	—			11.3			—			—			11.3
NGL and crude services	—			1,426.70			—			—			1,426.70
Related party	—			32.1			—			—			32.1
	—			1,492.90			—			—			1,492.90
Expenses:
Operations and maintenance	—			100.1			—			—			100.1
General and administrative	(3.8		)	67.4			—			—			63.6
Depreciation, amortization and accretion	0.7			160.5			—			—			161.2
	(3.1		)	328			—			—			324.9
Other operating income (expense):
Loss on contingent consideration	—			(8.6		)	—			—			(8.6		)
Other	—			0.7			—			—			0.7
Operating income	3.1			122.3			—			—			125.4
Interest and debt expense, net	(85.1		)	0.3			—			—			(84.8		)
Equity in net income (loss) of subsidiary	120.5			—			—			(120.5		)	—
Other	—			—			(1.3		)	—			(1.3		)
Income (loss) before income taxes	38.5			122.6			(1.3		)	(120.5		)	39.3
Provision for income taxes	—			0.8			—			—			0.8
Net income (loss)	38.5			121.8			(1.3		)	(120.5		)	38.5
Net income attributable to non-controlling partners	—			—			(11.3		)	—			(11.3		)
Net income (loss) attributable to Crestwood Midstream Partners LP	38.5			121.8			(12.6		)	(120.5		)	27.2
Net income attributable to Class A preferred units	(10.2		)	—			—			—			(10.2		)
Net income (loss) attributable to partners	$	28.3		$	121.8		$	(12.6	)	$	(120.5	)	$	17
Condensed Consolidating Statements of Operations
Nine Months Ended September 30, 2013
(in millions)
	Parent			Guarantor			Non-			Eliminations			Consolidated
				Subsidiaries			Guarantor
							Subsidiaries
Revenues:
Gathering and processing	$	—		$	140.3		$	—		$	—		$	140.3
Storage and transportation	—			47.6			—			—			47.6
NGL and crude services	—			26.6			—			—			26.6
Related party	—			78.1			—			—			78.1
	—			292.6			—			—			292.6
Costs of product/services sold (excluding depreciation, amortization and accretion as shown below):
Gathering and processing	—			18.2			—			—			18.2
Storage and transportation	—			4.4			—			—			4.4
NGL and crude services	—			10.6			—			—			10.6
Related party	—			22.2			—			—			22.2
	—			55.4			—			—			55.4
Expenses:
Operations and maintenance	—			48.1			—			—			48.1
General and administrative	24			20			—			—			44
Depreciation, amortization and accretion	0.6			72.8			—			—			73.4
	24.6			140.9			—			—			165.5
Other operating income (expense):
Other	—			0.3			—			—			0.3
Operating income (loss)	(24.6		)	96.6			—			—			72
Interest and debt expense, net	(39.9		)	(3.5		)	—			—			(43.4		)
Equity in net income (loss) of subsidiary	91.7			—			—			(91.7		)	—
Other	—			—			(0.4		)	—			(0.4		)
Income (loss) before income taxes	27.2			93.1			(0.4		)	(91.7		)	28.2
Provision for income taxes	—			1			—			—			1
Net income (loss)	27.2			92.1			(0.4		)	(91.7		)	27.2
Net income attributable to non-controlling partners	—			—			(1.9		)	—			(1.9		)
Net income (loss) attributable to Crestwood Midstream Partners LP	$	27.2		$	92.1		$	(2.3	)	$	(91.7	)	$	25.3
Condensed Consolidating Statements of Cash Flows
Nine Months Ended September 30, 2014
(in millions)
	Parent			Guarantor			Non-			Eliminations			Consolidated
				Subsidiaries			Guarantor
							Subsidiaries
Cash flows from operating activities:	$	(27.6	)	$	203.4		$	—		$	—		$	175.8
Cash flows from investing activities:
Acquisitions, net of cash acquired	—			(19.5		)	—			—			(19.5		)
Purchases of property, plant and equipment	(3.7		)	(255.6		)	—			—			(259.3		)
Investment in unconsolidated affiliates	—			(3.5		)	(78.3		)	—			(81.8		)
Capital contribution from consolidated affiliates	(23.4		)	(3.5		)	—			26.9			—
Net change in receivables from affiliates	(313.7		)	—			—			313.7			—
Net cash provided by (used in) investing activities	(340.8		)	(282.1		)	(78.3		)	340.6			(360.6		)
Cash flows from financing activities:
Proceeds from the issuance of long-term debt	2.5			1,408.40			—			—			1,410.90
Principal payments on long-term debt	—			(1,390.8		)	—			—			(1,390.8		)
Distributions paid	—			(253.8		)	—			—			(253.8		)
Contributions from parent	—			3.5			23.4			(26.9		)	—
Net proceeds from issuance of preferred equity of subsidiary	—			—			53.9			—			53.9
Net proceeds from issuance of Class A preferred units	366.8			—			—			—			366.8
Payments on capital leases	(0.9		)	(1.7		)	—			—			(2.6		)
Taxes paid for unit-based compensation vesting	—			(1.5		)	—			—			(1.5		)
Payments for debt-related deferred costs	(0.1		)	—			—			—			(0.1		)
Net change in payables to affiliates	—			313.7			—			(313.7		)	—
Other	—			(0.6		)	—			—			(0.6		)
Net cash provided by (used in) financing activities	368.3			77.2			77.3			(340.6		)	182.2
Net change in cash	(0.1		)	(1.5		)	(1.0		)	—			(2.6		)
Cash at beginning of period	0.1			1.6			1			—			2.7
Cash at end of period	$	—		$	0.1		$	—		$	—		$	0.1
Condensed Consolidating Statements of Cash Flows
Nine Months Ended September 30, 2013
(in millions)
	Parent			Guarantor			Non-			Eliminations			Consolidated
				Subsidiaries			Guarantor
							Subsidiaries
Cash flows from operating activities:	$	(18.7	)	$	183		$	—		$	(33.8	)	$	130.5
Cash flows from investing activities:
Acquisitions, net of cash acquired	—			0.2			—			—			0.2
Purchases of property, plant and equipment	(0.5		)	(188.9		)	—			—			(189.4		)
Investment in unconsolidated affiliates	—			(24.4		)	(128.1		)	—			(152.5		)
Capital contribution from consolidated affiliates	(82.0		)	—			—			82			—
Proceeds from sale of assets	—			11			—			—			11
Net change in receivables from affiliates	57.4			—			—			(57.4		)	—
Net cash provided by (used in) investing activities	(25.1		)	(202.1		)	(128.1		)	24.6			(330.7		)
Cash flows from financing activities:
Proceeds from the issuance of long-term debt	343.5			233.7			—			—			577.2
Principal payments on long-term debt	(194.0		)	(374.5		)	—			—			(568.5		)
Distributions paid	(90.3		)	(70.7		)	—			33.8			(127.2		)
Distributions for additional interest in Crestwood Marcellus Midstream LLC	(129.0		)	—			—			—			(129.0		)
Contributions from parent	—			55.4			32			(82.0		)	5.4
Net proceeds from issuance of common units	118.5			238.2			—			—			356.7
Net proceeds from issuance of preferred equity of subsidiary	—			—			96.1			—			96.1
Payments on capital leases	(0.3		)	(2.7		)	—			—			(3.0		)
Taxes paid for unit-based compensation vesting	—			(0.7		)	—			—			(0.7		)
Payments for debt-related deferred costs	(0.1		)	—			—			—			(0.1		)
Net change in payables to affiliates	—			(57.4		)	—			57.4			—
Other	—			0.1			—			—			0.1
Net cash provided by financing activities	48.3			21.4			128.1			9.2			207
Net change in cash	4.5			2.3			—			—			6.8
Cash at beginning of period	—			0.1			—			—			0.1
Cash at end of period	$	4.5		$	2.4		$	—		$	—		$	6.9

Basis_of_Presentation_and_Summ1

Basis of Presentation and Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2014
Accounting Policies [Abstract]	'
Principals of Consolidation	'
	Significant Accounting Policies
	There were no material changes in our significant accounting policies from those described in our 2013 Annual Report on Form 10-K.

Basis_of_Presentation_and_Summ2

Basis of Presentation and Summary of Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2014
Accounting Policies [Abstract]	'
Schedule of Error Corrections and Prior Period Adjustments [Table Text Block]	'
	The following table summarizes the reclassification of the amounts previously reported in operating and administrative expenses for the periods presented (in millions):
		Year Ended December 31,
		2013		2012		2011
	Operating and administrative expenses as previously reported	$	154	$	72.7	$	60.4
	Operations and maintenance expenses	73.3		43.1		36.3
	General and administrative expenses	80.7		29.6		24.1

Certain_Balance_Sheet_Informat1

Certain Balance Sheet Information (Tables)	9 Months Ended
	Sep. 30, 2014
Balance Sheet Related Disclosures [Abstract]	'
Components of Property, Plant and Equipment	'
	Property, plant and equipment consisted of the following at September 30, 2014 and December 31, 2013 (in millions):
		September 30,		December 31,
		2014		2013
	Gathering systems and pipelines	1,251.90		1,231.10
	Facilities and equipment	1,378.50		1,041.00
	Buildings, land, rights-of-way, storage contracts and easements	783.4		766.2
	Vehicles	13.8		4.1
	Construction in process	221.3		360.5
	Base gas	37.3		36.3
	Salt deposits	120.5		120.5
	Office furniture and fixtures	6.2		6
		3,812.90		3,565.70
	Less: accumulated depreciation and depletion	313.3		215.6
	Total property, plant and equipment, net	$	3,499.60	$	3,350.10
Components of Intangible Assets	'
	Intangible assets consisted of the following at September 30, 2014 and December 31, 2013 (in millions):
		September 30,		December 31,
		2014		2013
	Customer accounts	$	483.2	$	476.4
	Covenants not to compete	5.5		3
	Gas gathering, compression and processing contracts	451.4		451.4
	Acquired storage contracts	29		29
	Trademarks	11		11
	Deferred financing and other costs	54.3		54.3
		1,034.40		1,025.10
	Less: accumulated amortization	113.6		54.3
	Total intangible assets, net	$	920.8	$	970.8
Components of Accrued Expenses and Other Liabilities	'
	Accrued expenses and other liabilities consisted of the following at September 30, 2014 and December 31, 2013 (in millions):
		September 30,		December 31, 2013
		2014
	Accrued expenses	$	31.9	$	20
	Accrued property taxes	5.6		7.6
	Accrued product purchases payable	1.4		1.6
	Tax payable	0.9		10.6
	Interest payable	27.4		14.9
	Accrued additions to property, plant and equipment	45.8		58.1
	Commitments and contingent liabilities (Note 10)	40		31.4
	Capital leases	1.5		2.6
	Deferred revenue	10.6		1.6
	Total accrued expenses and other liabilities	$	165.1	$	148.4

Acquisitions_and_Divestitures_

Acquisitions and Divestitures (Tables)	9 Months Ended
	Sep. 30, 2014
Business Acquisition [Line Items]	'
Pro Forma Consolidated Statements of Operations	'
	The following table represents the pro forma consolidated statement of operations as if the Arrow Acquisition had been included in our consolidated results for the full three and nine months ended September 30, 2013, and as if the results for Legacy Inergy reverse acquisition had been included for the entire nine months ended September 30, 2013 (in millions, except per unit information):
		Three Months Ended		Nine Months Ended
		30-Sep-13		30-Sep-13
	Revenues	$	601.2	$	1,526.80
	Net income	$	9.6	$	27.2
	Net income per limited partner unit(1):
	Basic	$	0.02	$	0.07
	Diluted	$	0.02	$	0.07
Inergy Midstream	'
Business Acquisition [Line Items]	'
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block]	'
	The following table summarizes the final valuation of the assets acquired and liabilities assumed at the merger date (in millions):
	Current assets	$	49.1
	Property, plant and equipment	1,677.80
	Intangible assets	196
	Other assets	2.9
	Total identifiable assets acquired	1,925.80
	Current liabilities	30.9
	Long-term debt	745
	Other long-term liabilities	5.3
	Total liabilities assumed	781.2
	Net identifiable assets acquired	1,144.60
	Goodwill	1,532.70
	Net assets acquired	$	2,677.30
Arrow Midstream Holdings, LLC	'
Business Acquisition [Line Items]	'
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block]	'
	The following table summarizes the final valuation of the assets acquired and liabilities assumed at the acquisition date (in millions):
	Current assets	$	192.7
	Property, plant and equipment	400.5
	Intangible assets	323.4
	Other assets	19.5
	Total identifiable assets acquired	936.1
	Current liabilities	215.8
	Assets retirement obligations	1.2
	Other long-term liabilities	3.7
	Total liabilities assumed	220.7
	Net identifiable assets acquired	715.4
	Goodwill	45.9
	Net assets acquired	$	761.3

Earnings_Per_Limited_Partner_U1

Earnings Per Limited Partner Unit (Tables)	9 Months Ended
	Sep. 30, 2014
Earnings Per Share [Abstract]	'
Schedule of Other Nonoperating Income (Expense)	'
	The tables below show the (i) allocation of net income attributable to CMLP and the (ii) net income attributable to CMLP per limited partner unit based on the number of basic and diluted limited partner units outstanding for the three and nine months ended September 30, 2014 and 2013 (in millions):
	Allocation of Net Income Attributable to CMLP
		Three Months Ended						Nine Months Ended
		September 30,						September 30,
		2014			2013			2014			2013
	Net income attributable to CMLP	$	16.8		$	9.7		$	27.2		$	25.3
	Class A preferred units interest in net income attributable to CMLP	(9.1		)	—			(10.2		)	—
	General partner’s incentive distributions	(7.5		)	(6.2		)	(22.5		)	(18.9		)
	General partner’s interest in net income attributable to CMLP	—			(0.1		)	—			(0.4		)
	Limited partners’ interest in net income (loss) attributable to CMLP	$	0.2		$	3.4		$	(5.5	)	$	6
Schedule of Earnings Per Share Reconciliation	'
	Earnings Per Limited Partner Unit
		Three Months Ended						Nine Months Ended
		September 30,						September 30,
		2014			2013			2014			2013
	Limited partners’ interest in net income (loss)	$	0.2		$	3.4		$	(5.5	)	$	6
	Weighted-average limited partner units - basic	188			161.6			187.9			101.1
	Effect of diluted units	—			—			—			—
	Weighted-average limited partner units - diluted	188			161.6			187.9			101.1
	Basic earnings per unit:
	Net income (loss) per limited partner	$	—		$	0.02		$	(0.03	)	$	0.06
	Diluted earnings per unit:
	Net income (loss) per limited partner	$	—		$	0.02		$	(0.03	)	$	0.06

Financial_Instruments_Tables

Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2014
Debt Disclosure [Abstract]	'
Schedule of Carrying Values and Estimated Fair Values of Debt Instruments	'
	The following table reflects the carrying value and fair value of our senior notes (in millions):
		September 30, 2014				December 31, 2013
		Carrying Amount		Fair		Carrying Amount		Fair
				Value				Value
	2019 Senior Notes	$	351	$	369.5	$	351.2	$	379.3
	2020 Senior Notes	$	504.1	$	507.9	$	504.7	$	513.8
	2022 Senior Notes	$	600	$	603	$	600	$	617.3
Schedule of Debt	'
	Long-term debt consisted of the following at September 30, 2014 and December 31, 2013 (in millions):
		September 30,		December 31,
		2014		2013
	Credit Facility	$	435	$	414.9
	2019 Senior Notes	350		350
	Premium on 2019 Senior Notes	1		1.2
	2020 Senior Notes	500		500
	Fair value adjustment of 2020 Senior Notes	4.1		4.7
	2022 Senior Notes	600		600
	Other	3.5		—
	Total debt	1,893.60		1,870.80
	Less: current portion	0.6		2.9
	Total long-term debt	$	1,893.00	$	1,867.90

Partners_Capital_Tables

Partners' Capital (Tables)	9 Months Ended
	Sep. 30, 2014
Partners' Capital [Abstract]	'
Schedule of Distributions Made to Members or Limited Partners, by Distribution	'
	The following table presents quarterly cash distributions paid to our limited partners (excluding distributions paid to our general partner on its common units held) during the nine months ended September 30, 2014:
	Nine Months Ended September 30, 2014
	Record Date	Payment Date	Per Unit Rate		Cash Distribution
					(in millions)
	February 7, 2014	February 14, 2014	$	0.41	$	74.1
	May 8, 2014	May 15, 2014	$	0.41	74.2
	August 7, 2014	August 14, 2014	$	0.41	74.1
					$	222.4
	The following table presents quarterly cash distributions associated with Legacy Crestwood and Legacy Inergy paid to the limited partners (excluding distributions paid to the general partner on its common units held) during the nine months ended ended September 30, 2013:
	Nine Months Ended September 30, 2013
	Record Date	Payment Date	Per Unit Rate		Cash Distribution
					(in millions)
	January 31, 2013	February 12, 2013	$	0.51	$	21
	April 30, 2013	May 10, 2013	$	0.51	27.4
	August 1, 2013	August 9, 2013	$	0.51	27.4
	August 7, 2013	August 14, 2013	$	0.4	34.3		(1)
					$	110.1

LongTerm_Incentive_Plan_Tables

Long-Term Incentive Plan (Tables)	9 Months Ended
	Sep. 30, 2014
Equity [Abstract]	'
Disclosure of Share-based Compensation Arrangements by Share-based Payment Award	'
	The following table summarizes information regarding restricted unit activity during the nine months ended September 30, 2014:
		Units		Weighted-Average Grant Date Fair Value
	Unvested - January 1, 2014	250,557		$	22.13
	Vested - restricted units	(190,818	)	$	22.16
	Granted - restricted units	838,036		$	23.31
	Forfeited	(57,208	)	$	23.49
	Unvested - September 30, 2014	840,567		$	23.21

Related_Party_Transactions_Tab

Related Party Transactions (Tables)	9 Months Ended
	Sep. 30, 2014
Related Party Transactions [Abstract]	'
Schedule of Related Party Transactions	'
	The following table shows revenues, costs of goods sold and general and administrative expenses from our affiliates for the three and nine months ended September 30, 2014 and 2013 (in millions):
		Three Months Ended				Nine Months Ended
		September 30,				September 30,
		2014(1)		2013		2014(1)		2013
	Gathering and processing revenues	$	1.4	$	24.1	$	3	$	74.3
	NGL and crude services revenues	$	3.5	$	3.4	$	10.2	$	3.8
	Gathering and processing costs of product/services sold	$	11.3	$	7.6	$	32.1	$	22.2
	General and administrative expenses	$	4.5	$	5.9	$	12.8	$	16.5
	(1) Concurrent with the Crestwood Merger, Quicksilver Resources Inc. (Quicksilver) is no longer a related party, and as a result our transactions with
	Quicksilver subsequent to June 19, 2013, are now considered non-affiliated transactions.
Schedule of Related Party Receivables and Payables	'
	The following table shows accounts receivable and accounts payable from our affiliates as of September 30, 2014 and December 31, 2013 (in millions):
		September 30, 2014		December 31, 2013
	Accounts receivable	$	2.8	$	1.1
	Accounts payable	$	7.4	$	8.7

Segments_Tables

Segments (Tables)	9 Months Ended
	Sep. 30, 2014
Segment Reporting [Abstract]	'
Reportable Segments	'
	The following table is a reconciliation of net income to EBITDA (in millions):
		Three Months Ended					Nine Months Ended
		September 30,					September 30,
		2014			2013		2014			2013
	Net income	$	21.3		$	11.6	$	38.5		$	27.2
	Add:
	Interest and debt expense, net	27.7			19.5		84.8			43.4
	Provision for income taxes	—			0.3		0.8			1
	Depreciation, amortization and accretion	55.5			35.1		161.2			73.4
	EBITDA	$	104.5		$	66.5	$	285.3		$	145
	The following tables summarize the reportable segment data for the three and nine months ended September 30, 2014 and 2013 (in millions).
		Three Months Ended September 30, 2014
		Gathering and Processing			Storage and Transportation		NGL and Crude Services			Corporate			Total
	Revenues	$	85.3		$	44.2	$	608.9		$	—		$	738.4
	Costs of product/services sold	18.6			4.3		552.8			—			575.7
	Operations and maintenance expense	15.9			4.2		19.3			—			39.4
	General and administrative expense	—			—		—			18.2			18.2
	Loss on long-lived assets	(0.9		)	—		—			—			(0.9		)
	Earnings (loss) from unconsolidated affiliates, net	0.4			—		(0.1		)	—			0.3
	EBITDA	$	50.3		$	35.7	$	36.7		$	(18.2	)	$	104.5
	Goodwill	$	99.6		$	726.3	$	855.5		$	—		$	1,681.40
	Total assets	$	2,026.10		$	1,951.20	$	2,553.70		$	163.6		$	6,694.60
	Cash expenditures for property, plant and equipment	$	57.5		$	2.2	$	34.8		$	0.1		$	94.6
		Three Months Ended September 30, 2013
		Gathering and Processing			Storage and Transportation		NGL and Crude Services			Corporate			Total
	Revenues	$	71.1		$	42.1	$	26.9		$	—		$	140.1
	Costs of product/services sold	12.9			4		9.7			—			26.6
	Operations and maintenance expense	14.9			4.7		2.1			—			21.7
	General and administrative expense	—			—		—			25.2			25.2
	Goodwill impairment	(4.1		)	—		—			—			(4.1		)
	Gain on long-lived assets	4.4			—		—			—			4.4
	Loss from unconsolidated affiliates, net	(0.4		)	—		—			—			(0.4		)
	EBITDA	$	43.2		$	33.4	$	15.1		$	(25.2	)	$	66.5
	Goodwill	$	99.6		$	744.1	$	609.1		$	—		$	1,452.80
	Total assets	$	1,856.00		$	2,003.00	$	1,257.40		$	46.4		$	5,162.80
	Cash expenditures for property, plant and equipment	$	84.1		$	5.7	$	16		$	0.1		$	105.9
		Nine Months Ended September 30, 2014
		Gathering and Processing			Storage and Transportation		NGL and Crude Services			Corporate			Total
	Revenues	$	248.2		$	133.9	$	1,569.00		$	—		$	1,951.10
	Costs of product/services sold	54.9			11.3		1,426.70			—			1,492.90
	Operations and maintenance expense	44			12.9		43.2			—			100.1
	General and administrative expense	—			—		—			63.6			63.6
	Gain on long-lived assets	0.1			0.6		—			—			0.7
	Loss on contingent consideration	(8.6		)	—		—			—			(8.6		)
	Earnings (loss) from unconsolidated affiliates, net	0.1			—		(1.4		)	—			(1.3		)
	EBITDA	$	140.9		$	110.3	$	97.7		$	(63.6	)	$	285.3
	Goodwill	$	99.6		$	726.3	$	855.5		$	—		$	1,681.40
	Total assets	$	2,026.10		$	1,951.20	$	2,553.70		$	163.6		$	6,694.60
	Cash expenditures for property, plant and equipment	$	178.6		$	4.7	$	72.3		$	3.7		$	259.3
		Nine Months Ended September 30, 2013
		Gathering and Processing			Storage and Transportation		NGL and Crude Services			Corporate			Total
	Revenues	$	214.6		$	47.6	$	30.4		$	—		$	292.6
	Costs of product/services sold	40.4			4.4		10.6			—			55.4
	Operations and maintenance expense	40.5			5.3		2.3			—			48.1
	General and administrative expense	—			—		—			44			44
	Goodwill impairment	(4.1		)	—		—			—			(4.1		)
	Gain on long-lived assets	4.4			—		—			—			4.4
	Loss from unconsolidated affiliates, net	(0.4		)	—		—			—			(0.4		)
	EBITDA	$	133.6		$	37.9	$	17.5		$	(44.0	)	$	145
	Goodwill	$	99.6		$	744.1	$	609.1		$	—		$	1,452.80
	Total assets	$	1,856.00		$	2,003.00	$	1,257.40		$	46.4		$	5,162.80
	Cash expenditures for property, plant and equipment	$	164		$	7.9	$	17		$	0.5		$	189.4

Condensed_Consolidating_Financ1

Condensed Consolidating Financial Information (Tables)	9 Months Ended
	Sep. 30, 2014
Condensed Financial Information of Parent Company Only Disclosure [Abstract]	'
Consolidating Balance Sheet	'
	Condensed Consolidating Balance Sheet
	30-Sep-14
	(in millions)
		Parent			Guarantor			Non-			Eliminations			Consolidated
					Subsidiaries			Guarantor
								Subsidiaries
	Assets
	Current assets:
	Cash and cash equivalents	$	—		$	0.1		$	—		$	—		$	0.1
	Accounts receivable	579.1			295.4			0.1			(561.8		)	312.8
	Inventories	—			8.3			—			—			8.3
	Other current assets	—			20.3			—			—			20.3
	Total current assets	579.1			324.1			0.1			(561.8		)	341.5
	Property, plant and equipment, net	5.9			3,493.70			—			—			3,499.60
	Goodwill and intangible assets, net	—			2,602.20			—			—			2,602.20
	Investment in consolidated affiliates	6,571.50			—			—			(6,571.5		)	—
	Investment in unconsolidated affiliates	—			—			231.9			—			231.9
	Other assets	—			19.4			—			—			19.4
	Total assets	$	7,156.50		$	6,439.40		$	232		$	(7,133.3	)	$	6,694.60
	Liabilities and partners' capital
	Current liabilities:
	Accounts payable	$	855.5		$	(93.2	)	$	0.1		$	(561.8	)	$	200.6
	Other current liabilities	1			164.7			—			—			165.7
	Total current liabilities	856.5			71.5			0.1			(561.8		)	366.3
	Long-term liabilities:
	Long-term debt, less current portion	1,893.00			—			—			—			1,893.00
	Other long-term liabilities	1.7			28.3			—			—			30
	Total long-term liabilities	1,894.70			28.3			—			—			1,923.00
	Partners' capital	4,239.10			6,339.60			65.7			(6,405.3		)	4,239.10
	Interest of non-controlling partners in subsidiaries	166.2			—			166.2			(166.2		)	166.2
	Total partners' capital	4,405.30			6,339.60			231.9			(6,571.5		)	4,405.30
	Total liabilities and partners' capital	$	7,156.50		$	6,439.40		$	232		$	(7,133.3	)	$	6,694.60
	Condensed Consolidating Balance Sheet
	31-Dec-13
	(in millions)
		Parent			Guarantor			Non-			Eliminations			Consolidated
					Subsidiaries			Guarantor
								Subsidiaries
	Assets
	Current assets:
	Cash and cash equivalents	$	0.1		$	1.6		$	1		$	—		$	2.7
	Accounts receivable	466.8			197.8			0.2			(459.7		)	205.1
	Inventories	—			7			—			—			7
	Other current assets	—			10.2			—			—			10.2
	Total current assets	466.9			216.6			1.2			(459.7		)	225
	Property, plant and equipment, net	4.8			3,345.30			—			—			3,350.10
	Goodwill and intangible assets, net	—			2,653.60			—			—			2,653.60
	Investment in consolidated affiliates	6,385.20			—			—			(6,385.2		)	—
	Investment in unconsolidated affiliates	—			—			151.4			—			151.4
	Other assets	—			21.7			—			—			21.7
	Total assets	$	6,856.90		$	6,237.20		$	152.6		$	(6,844.9	)	$	6,401.80
	Liabilities and partners' capital
	Current liabilities:
	Accounts payable	$	782.7		$	(159.8	)	$	—		$	(459.7	)	$	163.2
	Other current liabilities	11.5			139.6			0.2			—			151.3
	Total current liabilities	794.2			(20.2		)	0.2			(459.7		)	314.5
	Long-term liabilities:
	Long-term debt, less current portion	1,867.90			—			—			—			1,867.90
	Other long-term liabilities	1.7			24.6			—			—			26.3
	Total long-term liabilities	1,869.60			24.6			—			—			1,894.20
	Partners' capital	4,092.10			6,232.80			51.4			(6,284.2		)	4,092.10
	Interest of non-controlling partners in subsidiaries	101			—			101			(101.0		)	101
	Total partners' capital	4,193.10			6,232.80			152.4			(6,385.2		)	4,193.10
Total liabilities and partners' capital	$	6,856.90		$	6,237.20		$	152.6		$	(6,844.9	)	$	6,401.80
Consolidating Statements of Operations	'
	Condensed Consolidating Statements of Operations
	Three Months Ended September 30, 2014
	(in millions)
		Parent			Guarantor			Non-			Eliminations			Consolidated
					Subsidiaries			Guarantor
								Subsidiaries
	Revenues:
	Gathering and processing	$	—		$	83.9		$	—		$	—		$	83.9
	Storage and transportation	—			44.2			—			—			44.2
	NGL and crude services	—			605.4			—			—			605.4
	Related party	—			4.9			—			—			4.9
		—			738.4			—			—			738.4
	Costs of product/services sold (excluding depreciation, amortization and accretion as shown below):
	Gathering and processing	—			7.3			—			—			7.3
	Storage and transportation	—			4.3			—			—			4.3
	NGL and crude services	—			552.8			—			—			552.8
	Related party	—			11.3			—			—			11.3
		—			575.7			—			—			575.7
	Expenses:
	Operations and maintenance	—			39.4			—			—			39.4
	General and administrative	(0.8		)	19			—			—			18.2
	Depreciation, amortization and accretion	0.3			55.2			—			—			55.5
		(0.5		)	113.6			—			—			113.1
	Other operating income (expense):
	Other	—			(0.9		)	—			—			(0.9		)
	Operating income	0.5			48.2			—			—			48.7
	Interest and debt expense, net	(27.8		)	0.1			—			—			(27.7		)
	Equity in net income (loss) of subsidiary	48.6			—			—			(48.6		)	—
	Other	—			—			0.3			—			0.3
	Income (loss) before income taxes	21.3			48.3			0.3			(48.6		)	21.3
	Provision for income taxes	—			—			—			—			—
	Net income (loss)	21.3			48.3			0.3			(48.6		)	21.3
	Net income attributable to non-controlling partners	—			—			(4.5		)	—			(4.5		)
	Net income (loss) attributable to Crestwood Midstream Partners LP	21.3			48.3			(4.2		)	(48.6		)	16.8
	Net income attributable to Class A preferred units	(9.1		)	—			—			—			(9.1		)
	Net income (loss) attributable to partners	$	12.2		$	48.3		$	(4.2	)	$	(48.6	)	$	7.7
	Condensed Consolidating Statements of Operations
	Three Months Ended September 30, 2013
	(in millions)
		Parent			Guarantor			Non-			Eliminations			Consolidated
					Subsidiaries			Guarantor
								Subsidiaries
	Revenues:
	Gathering and processing	$	—		$	47		$	—		$	—		$	47
	Storage and transportation	—			42.1			—			—			42.1
	NGL and crude services	—			23.5			—			—			23.5
	Related party	—			27.5			—			—			27.5
		—			140.1			—			—			140.1
	Costs of product/services sold (excluding depreciation, amortization and accretion as shown below):
	Gathering and processing	—			5.3			—			—			5.3
	Storage and transportation	—			4			—			—			4
	NGL and crude services	—			9.7			—			—			9.7
	Related party	—			7.6			—			—			7.6
		—			26.6			—			—			26.6
	Expenses:
	Operations and maintenance	—			21.7			—			—			21.7
	General and administrative	9.4			15.8			—			—			25.2
	Depreciation, amortization and accretion	0.2			34.9			—			—			35.1
		9.6			72.4			—			—			82
	Other operating income (expense):
	Other	—			0.3			—			—			0.3
	Operating income (loss)	(9.6		)	41.4			—			—			31.8
	Interest and debt expense, net	(18.4		)	(1.1		)	—			—			(19.5		)
Equity in net income (loss) of subsidiary	39.6			—			—			(39.6		)	—
Other	—			—			(0.4		)	—			(0.4		)
Income (loss) before income taxes	11.6			40.3			(0.4		)	(39.6		)	11.9
Provision for income taxes	—			0.3			—			—			0.3
Net income (loss)	11.6			40			(0.4		)	(39.6		)	11.6
Net income attributable to non-controlling partners	—			—			(1.9		)	—			(1.9		)
Net income (loss) attributable to Crestwood Midstream Partners LP	$	11.6		$	40		$	(2.3	)	$	(39.6	)	$	9.7
Condensed Consolidating Statements of Operations
Nine Months Ended September 30, 2014
(in millions)
	Parent			Guarantor			Non-			Eliminations			Consolidated
				Subsidiaries			Guarantor
							Subsidiaries
Revenues:
Gathering and processing	$	—		$	245.2		$	—		$	—		$	245.2
Storage and transportation	—			133.9			—			—			133.9
NGL and crude services	—			1,558.80			—			—			1,558.80
Related party	—			13.2			—			—			13.2
	—			1,951.10			—			—			1,951.10
Costs of product/services sold (excluding depreciation, amortization and accretion as shown below):
Gathering and processing	—			22.8			—			—			22.8
Storage and transportation	—			11.3			—			—			11.3
NGL and crude services	—			1,426.70			—			—			1,426.70
Related party	—			32.1			—			—			32.1
	—			1,492.90			—			—			1,492.90
Expenses:
Operations and maintenance	—			100.1			—			—			100.1
General and administrative	(3.8		)	67.4			—			—			63.6
Depreciation, amortization and accretion	0.7			160.5			—			—			161.2
	(3.1		)	328			—			—			324.9
Other operating income (expense):
Loss on contingent consideration	—			(8.6		)	—			—			(8.6		)
Other	—			0.7			—			—			0.7
Operating income	3.1			122.3			—			—			125.4
Interest and debt expense, net	(85.1		)	0.3			—			—			(84.8		)
Equity in net income (loss) of subsidiary	120.5			—			—			(120.5		)	—
Other	—			—			(1.3		)	—			(1.3		)
Income (loss) before income taxes	38.5			122.6			(1.3		)	(120.5		)	39.3
Provision for income taxes	—			0.8			—			—			0.8
Net income (loss)	38.5			121.8			(1.3		)	(120.5		)	38.5
Net income attributable to non-controlling partners	—			—			(11.3		)	—			(11.3		)
Net income (loss) attributable to Crestwood Midstream Partners LP	38.5			121.8			(12.6		)	(120.5		)	27.2
Net income attributable to Class A preferred units	(10.2		)	—			—			—			(10.2		)
Net income (loss) attributable to partners	$	28.3		$	121.8		$	(12.6	)	$	(120.5	)	$	17
Consolidating Statement of Cash Flows	'
	Condensed Consolidating Statements of Cash Flows
	Nine Months Ended September 30, 2014
	(in millions)
		Parent			Guarantor			Non-			Eliminations			Consolidated
					Subsidiaries			Guarantor
								Subsidiaries
	Cash flows from operating activities:	$	(27.6	)	$	203.4		$	—		$	—		$	175.8
	Cash flows from investing activities:
	Acquisitions, net of cash acquired	—			(19.5		)	—			—			(19.5		)
	Purchases of property, plant and equipment	(3.7		)	(255.6		)	—			—			(259.3		)
	Investment in unconsolidated affiliates	—			(3.5		)	(78.3		)	—			(81.8		)
	Capital contribution from consolidated affiliates	(23.4		)	(3.5		)	—			26.9			—
	Net change in receivables from affiliates	(313.7		)	—			—			313.7			—
	Net cash provided by (used in) investing activities	(340.8		)	(282.1		)	(78.3		)	340.6			(360.6		)
	Cash flows from financing activities:
	Proceeds from the issuance of long-term debt	2.5			1,408.40			—			—			1,410.90
	Principal payments on long-term debt	—			(1,390.8		)	—			—			(1,390.8		)
	Distributions paid	—			(253.8		)	—			—			(253.8		)
	Contributions from parent	—			3.5			23.4			(26.9		)	—
	Net proceeds from issuance of preferred equity of subsidiary	—			—			53.9			—			53.9
	Net proceeds from issuance of Class A preferred units	366.8			—			—			—			366.8
	Payments on capital leases	(0.9		)	(1.7		)	—			—			(2.6		)
	Taxes paid for unit-based compensation vesting	—			(1.5		)	—			—			(1.5		)
	Payments for debt-related deferred costs	(0.1		)	—			—			—			(0.1		)
	Net change in payables to affiliates	—			313.7			—			(313.7		)	—
	Other	—			(0.6		)	—			—			(0.6		)
	Net cash provided by (used in) financing activities	368.3			77.2			77.3			(340.6		)	182.2
	Net change in cash	(0.1		)	(1.5		)	(1.0		)	—			(2.6		)
	Cash at beginning of period	0.1			1.6			1			—			2.7
	Cash at end of period	$	—		$	0.1		$	—		$	—		$	0.1

Business_Description_Details

Business Description (Details) (USD $)	9 Months Ended
	Sep. 30, 2014
	segment
Partnership Organization And Basis Of Presentation [Line Items]	'
Number of operating segments	3
CEQP	'
Partnership Organization And Basis Of Presentation [Line Items]	'
Limited Liability Company (LLC) or Limited Partnership (LP), Managing Member or General Partner, Ownership Interest	4.00%
Parent	'
Partnership Organization And Basis Of Presentation [Line Items]	'
Percentage of distribution entitled to receive	50.00%
First Reserve	'
Partnership Organization And Basis Of Presentation [Line Items]	'
Limited Liability Company (LLC) or Limited Partnership (LP), Managing Member or General Partner, Ownership Interest	11.00%
Distribution Rights	'
Partnership Organization And Basis Of Presentation [Line Items]	'
Distribution declared per limited partner unit	0.37
Distribution Rights | CEQP	'
Partnership Organization And Basis Of Presentation [Line Items]	'
Percentage of distribution entitled to receive	100.00%

Basis_of_Presentation_and_Summ3

Basis of Presentation and Summary of Significant Accounting Policies (Details) (USD $)	3 Months Ended		9 Months Ended		12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Operating and administrative expenses as previously reported	$39.40	$21.70	$100.10	$48.10	'	'	'
Operations and maintenance expenses	39.4	21.7	100.1	48.1	73.3	43.1	36.3
General and administrative expense	18.2	25.2	63.6	44	80.7	29.6	24.1
Scenario, Previously Reported [Member]	'	'	'	'	'	'	'
Operating and administrative expenses as previously reported	'	'	'	'	$154	$72.70	$60.40

Certain_Balance_Sheet_Informat2

Certain Balance Sheet Information (Property Plant and Equipment) (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Property, Plant and Equipment [Line Items]	'	'
Property, plant and equipment (Note 3)	$3,812.90	$3,565.70
Less: accumulated depreciation and depletion	313.3	215.6
Property, plant and equipment, net	3,499.60	3,350.10
Capital Leased Assets, Gross	3	5
Gathering systems and pipelines	'	'
Property, Plant and Equipment [Line Items]	'	'
Property, plant and equipment (Note 3)	1,251.90	1,231.10
Facilities and equipment	'	'
Property, Plant and Equipment [Line Items]	'	'
Property, plant and equipment (Note 3)	1,378.50	1,041
Buildings, land, rights-of-way, storage contracts and easements	'	'
Property, Plant and Equipment [Line Items]	'	'
Property, plant and equipment (Note 3)	783.4	766.2
Vehicles	'	'
Property, Plant and Equipment [Line Items]	'	'
Property, plant and equipment (Note 3)	13.8	4.1
Construction in process	'	'
Property, Plant and Equipment [Line Items]	'	'
Property, plant and equipment (Note 3)	221.3	360.5
Base gas	'	'
Property, Plant and Equipment [Line Items]	'	'
Property, plant and equipment (Note 3)	37.3	36.3
Salt deposits	'	'
Property, Plant and Equipment [Line Items]	'	'
Property, plant and equipment (Note 3)	120.5	120.5
Office furniture and fixtures	'	'
Property, Plant and Equipment [Line Items]	'	'
Property, plant and equipment (Note 3)	$6.20	$6

Certain_Balance_Sheet_Informat3

Certain Balance Sheet Information (Intangible Assets) (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Finite-Lived Intangible Assets [Line Items]	'	'
Intangible assets, Gross	$1,034.40	$1,025.10
Less: accumulated amortization	113.6	54.3
Total intangible assets, net	920.8	970.8
Customer accounts	'	'
Finite-Lived Intangible Assets [Line Items]	'	'
Intangible assets, Gross	483.2	476.4
Covenants not to compete	'	'
Finite-Lived Intangible Assets [Line Items]	'	'
Intangible assets, Gross	5.5	3
Gas gathering, compression and processing contracts	'	'
Finite-Lived Intangible Assets [Line Items]	'	'
Intangible assets, Gross	451.4	451.4
Acquired storage contracts	'	'
Finite-Lived Intangible Assets [Line Items]	'	'
Intangible assets, Gross	29	29
Trademarks	'	'
Finite-Lived Intangible Assets [Line Items]	'	'
Intangible assets, Gross	11	11
Deferred financing and other costs	'	'
Finite-Lived Intangible Assets [Line Items]	'	'
Intangible assets, Gross	$54.30	$54.30

Certain_Balance_Sheet_Informat4

Certain Balance Sheet Information (Accrued Expenses and Other Liabilities) (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Payables and Accruals [Abstract]	'	'
Accrued expenses	$31.90	$20
Accrued property taxes	5.6	7.6
Accrued product purchases payable	1.4	1.6
Tax payable	0.9	10.6
Interest payable	27.4	14.9
Accrued additions to property, plant and equipment	45.8	58.1
Commitments and contingent liabilities (Note 10)	40	31.4
Capital leases	1.5	2.6
Deferred revenue	10.6	1.6
Total accrued expenses and other liabilities	$165.10	$148.40

Acquisitions_and_Divestitures_1

Acquisitions and Divestitures (Details) (USD $)

0 Months Ended

3 Months Ended

9 Months Ended

3 Months Ended

9 Months Ended

0 Months Ended

0 Months Ended

0 Months Ended

3 Months Ended

9 Months Ended

3 Months Ended

9 Months Ended

3 Months Ended

9 Months Ended

Jul. 25, 2014

Jan. 08, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Dec. 31, 2013

Sep. 30, 2013

Sep. 30, 2013

Mar. 21, 2014

9-May-14

9-May-14

9-May-14

9-May-14

Jun. 30, 2013

Jun. 19, 2013

Nov. 08, 2013

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Jun. 30, 2014

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Jun. 30, 2014

Arrow Midstream Holdings, LLC and Inergy Midstream

Arrow Midstream Holdings, LLC and Inergy Midstream

Red Rock Transportation, Inc

LT Enterprises

LT Enterprises

LT Enterprises

LT Enterprises

Inergy Midstream

Inergy Midstream

Arrow Midstream Holdings, LLC

Arrow Midstream Holdings, LLC

Arrow Midstream Holdings, LLC

NGL and Crude Services Operations

NGL and Crude Services Operations

NGL and Crude Services Operations

NGL and Crude Services Operations

NGL and Crude Services Operations

Storage and Transportation

Storage and Transportation

Storage and Transportation

Storage and Transportation

Storage and Transportation

tractor

tractor

crude_trailer

service_vehicles

Inergy Midstream

Inergy Midstream

trailer_tanks

acre

bbl

bbl

double_bottom_body_tanks

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Consideration Transferred

'

$258,000,000

'

'

'

'

'

'

'

$13,800,000

$10,700,000

'

'

'

'

'

$750,000,000

'

'

'

'

'

'

'

'

'

'

'

'

Cost of Acquired Entity, Cash Paid

'

'

'

'

'

'

'

'

'

12,100,000

9,000,000

'

'

'

'

'

550,000,000

'

'

'

'

'

'

'

'

'

'

'

'

Cost of Acquired Entity, Liabilities Incurred

'

'

'

'

'

'

'

'

'

1,700,000

1,700,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Trailer Tanks, Number

'

'

'

'

'

'

'

'

'

22

'

38

51

17

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Crude Hauling Capacity

'

'

'

'

'

'

'

'

'

28,000

'

20,000

20,000

20,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets [Abstract]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Current assets

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

49,100,000

192,700,000

'

'

'

'

'

'

'

'

'

'

'

'

Property, plant and equipment

'

'

'

'

'

'

'

'

'

10,600,000

'

'

'

'

'

1,677,800,000

400,500,000

'

'

'

'

'

'

'

'

'

'

'

'

Intangible assets

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

196,000,000

323,400,000

'

'

'

'

'

'

'

'

'

'

'

'

Other assets

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2,900,000

19,500,000

'

'

'

'

'

'

'

'

'

'

'

'

Total identifiable assets acquired

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1,925,800,000

936,100,000

'

'

'

'

'

'

'

'

'

'

'

'

Current liabilities

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

30,900,000

215,800,000

'

'

'

'

'

'

'

'

'

'

'

'

Long-term debt

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

745,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

Asset Retirement Obligation

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1,200,000

'

'

'

'

'

'

'

'

'

'

'

'

Other long-term liabilities

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

5,300,000

3,700,000

'

'

'

'

'

'

'

'

'

'

'

'

Total liabilities assumed

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

781,200,000

220,700,000

'

'

'

'

'

'

'

'

'

'

'

'

Net identifiable assets acquired

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1,144,600,000

715,400,000

'

'

'

'

'

'

'

'

'

'

'

'

Goodwill

'

'

1,681,400,000

1,452,800,000

1,681,400,000

1,452,800,000

1,682,800,000

'

'

3,200,000

'

'

'

'

'

1,532,700,000

45,900,000

'

'

855,500,000

609,100,000

855,500,000

609,100,000

806,400,000

726,300,000

744,100,000

726,300,000

744,100,000

726,300,000

Net assets acquired

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2,677,300,000

761,300,000

'

'

'

'

'

'

'

'

'

'

'

'

Business Combination, Consideration Transferred, Other

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

11,300,000

'

'

'

'

'

'

'

'

'

'

'

'

Cost of Acquired Entity, Cash Paid

'

'

'

'

'

'

'

'

'

12,100,000

9,000,000

'

'

'

'

'

550,000,000

'

'

'

'

'

'

'

'

'

'

'

'

Incentive Distribution, Distribution

'

'

7,500,000

6,200,000

22,500,000

18,900,000

'

'

'

'

'

'

'

'

'

'

8,826,125

'

'

'

'

'

'

'

'

'

'

'

'

Business Acquisition, Pro Forma Information [Abstract]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Revenue

'

'

'

'

'

'

'

601,200,000

1,526,800,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Net income

'

'

'

'

'

'

'

9,600,000

27,200,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Basic (usd per unit)

'

'

'

'

'

'

'

$0.02

[1]

$0.07

[1]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Diluted (usd per unit)

'

'

'

'

'

'

'

$0.02

[1]

$0.07

[1]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Business Combination, Acquisition Related Costs

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

200,000

5,400,000

'

'

'

'

'

'

'

'

'

'

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Land, Area

'

'

'

'

'

'

'

'

'

'

'

20

20

20

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Revenues

'

'

738,400,000

140,100,000

1,951,100,000

292,600,000

'

'

'

'

'

'

'

'

78,000,000

'

'

'

'

608,900,000

26,900,000

1,569,000,000

30,400,000

'

44,200,000

42,100,000

133,900,000

47,600,000

'

Net income

'

'

21,300,000

11,600,000

38,500,000

27,200,000

'

'

'

'

'

'

'

'

7,100,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Divestitures [Abstract]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Proceeds from Sale of Property, Plant, and Equipment

11,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Gain (Loss) on Disposition of Property Plant Equipment

'

'

$4,400,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

[1]

Basic and diluted net income per limited partner unit for the three and nine months ended SeptemberB 30, 2013 were computed based on the number of Legacy Inergy common units outstanding plus the number of common units issued by Legacy Inergy to Legacy Crestwood unitholders as part of the Crestwood Merger and the number of units issued in conjunction with the Arrow Acquisition.

Investments_in_Unconsolidated_1

Investments in Unconsolidated Affiliates (Details) (USD $)

3 Months Ended

9 Months Ended

3 Months Ended

9 Months Ended

3 Months Ended

1 Months Ended

9 Months Ended

1 Months Ended

9 Months Ended

In Millions, unless otherwise specified

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Dec. 31, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

Jul. 31, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Jackalope Gas Gathering Services, LLC

Jackalope Gas Gathering Services, LLC

Jackalope Gas Gathering Services, LLC

Jackalope Gas Gathering Services, LLC

Jackalope Gas Gathering Services, LLC

PRBIC

PRBIC

Crestwood Niobrara LLC

Crestwood Niobrara LLC

Crestwood Niobrara LLC

Crude Logistics LLC

Crude Logistics LLC

Crude Logistics LLC

Jackalope Gas Gathering Services, LLC

Jackalope Gas Gathering Services, LLC

Jackalope Gas Gathering Services, LLC

PRBIC

PRBIC

Schedule of Equity Method Investments [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Equity method ownership percentage

'

'

'

'

'

'

'

'

'

'

50.00%

'

'

50.00%

'

'

'

'

Investment in unconsolidated affiliates (Note 5)

$231.90

'

$231.90

'

$151.40

$205.60

'

$205.60

'

$127.20

$26.30

$24.20

'

'

'

'

'

'

Share of Net Earnings In Unconsolidated Affiliate

'

'

'

'

'

1.2

0.2

2.4

0.2

'

'

'

'

'

'

'

'

'

Difference between carrying amount and underlying equity

'

'

'

'

'

54.5

'

54.5

'

'

'

'

'

'

'

'

'

'

Amortization

'

'

'

'

'

0.8

0.6

2.3

0.6

'

'

'

'

'

'

'

'

'

Investment in unconsolidated affiliates in period

'

'

81.8

152.5

'

'

'

'

'

'

'

'

107.5

78.3

20.6

22.5

3.5

1.9

Earnings (loss) from unconsolidated affiliates, net

$0.30

($0.40)

($1.30)

($0.40)

'

'

'

'

'

'

($0.10)

'

'

'

'

'

'

'

Earnings_Per_Limited_Partner_U2

Earnings Per Limited Partner Unit (Allocation of Net Income to General and Limited Partners) (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Earnings Per Share [Abstract]	'	'	'	'
Net income attributable to CMLP	$16.80	$9.70	$27.20	$25.30
Class A preferred units interest in net income attributable to CMLP	-9.1	0	-10.2	0
General partnerbs incentive distributions	-7.5	-6.2	-22.5	-18.9
General partnerbs interest in net income attributable to CMLP	0	-0.1	0	-0.4
Limited partnersb interest in net income (loss) attributable to CMLP	$0.20	$3.40	($5.50)	$6

Earnings_Per_Limited_Partner_U3

Earnings Per Limited Partner Unit (Schedule of Reconciliation of Earnings Per Share) (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, except Share data, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Earnings Per Share [Abstract]	'	'	'	'
Limited partnersb interest in net income (loss) attributable to CMLP after incentive distributions	$0.20	$3.40	($5.50)	$6
Basic (units)	187,955,000	161,575,000	187,931,000	101,094,000
Incremental Common Shares Attributable to Share-based Payment Arrangements	0	0	0	0
Diluted (units)	187,955,000	161,575,000	187,931,000	101,094,000
Basic, in dollars per unit	$0	$0.02	($0.03)	$0.06
Diluted, in dollars per unit	$0	$0.02	($0.03)	$0.06

Earnings_Per_Limited_Partner_U4

Earnings Per Limited Partner Unit (Narrative) (Details)	3 Months Ended	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2014
Crestwood Niobrara LLC	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	7,191,463	5,984,792
Preferred Units	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	12,244,500	4,739,285
Preferred Units | Crestwood Niobrara LLC	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	3,262,275	1,099,375
Distribution Rights | CEQP	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'
Percentage of distribution entitled to receive	'	100.00%

Financial_Instruments_Schedule

Financial Instruments (Schedule of Carrying Values and Estimated Fair Values of Senior Notes) (Details) (Unsecured Debt, USD $)	Sep. 30, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Carrying Amount | 2019 senior unsecured notes	'	'
Debt Instrument [Line Items]	'	'
Fair value of senior notes	$351	$351.20
Carrying Amount | 2020 senior unsecured notes	'	'
Debt Instrument [Line Items]	'	'
Fair value of senior notes	504.1	504.7
Carrying Amount | 2022 senior unsecured notes	'	'
Debt Instrument [Line Items]	'	'
Fair value of senior notes	600	600
Fair Value | 2019 senior unsecured notes	'	'
Debt Instrument [Line Items]	'	'
Fair value of senior notes	369.5	379.3
Fair Value | 2020 senior unsecured notes	'	'
Debt Instrument [Line Items]	'	'
Fair value of senior notes	507.9	513.8
Fair Value | 2022 senior unsecured notes	'	'
Debt Instrument [Line Items]	'	'
Fair value of senior notes	$603	$617.30

Financial_Instruments_Debt_Det

Financial Instruments (Debt) (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Debt Instrument [Line Items]	'	'
Total debt	$1,893.60	$1,870.80
Less: current portion	0.6	2.9
Total long-term debt	1,893	1,867.90
Other	'	'
Debt Instrument [Line Items]	'	'
Senior notes	3.5	0
Senior Notes | 2019 Senior Notes	'	'
Debt Instrument [Line Items]	'	'
Senior notes	350	350
Premium on senior notes	1	1.2
Senior Notes | 2020 Senior Notes	'	'
Debt Instrument [Line Items]	'	'
Senior notes	500	500
Fair value adjustment of senior notes	4.1	4.7
Senior Notes | 2022 Senior Notes	'	'
Debt Instrument [Line Items]	'	'
Senior notes	600	600
Revolver | Crestwood Midstream Revolver	'	'
Debt Instrument [Line Items]	'	'
Outstanding balance on the credit facility	$435	$414.90

Financial_Instruments_Narrativ

Financial Instruments (Narrative) (Details) (USD $)

9 Months Ended

0 Months Ended

9 Months Ended

Sep. 30, 2014

Oct. 07, 2013

Sep. 30, 2014

Dec. 31, 2013

Oct. 07, 2013

Oct. 07, 2013

Apr. 30, 2011

Dec. 07, 2012

Jul. 17, 2014

Oct. 22, 2013

Sep. 30, 2014

Sep. 30, 2014

Crestwood Midstream Revolver

Crestwood Midstream Revolver

Crestwood Midstream Revolver

Crestwood Midstream Revolver

Crestwood Midstream Revolver

Crestwood Midstream Revolver

2019 Senior Notes

2020 Senior Notes

2022 Senior Notes

2022 Senior Notes

Minimum

Maximum

Revolver

Revolver

Revolver

Standby Letters of Credit

Swing Line Loans

Senior Notes

Senior Notes

Senior Notes

Senior Notes

Crestwood Midstream Revolver

Crestwood Midstream Revolver

Revolver

Revolver

Debt Instrument [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

Term of debt instrument

'

'5 years

'

'

'

'

'

'

'

'

'

'

Line of credit, maximum capacity

'

$1,000,000,000

'

'

$250,000,000

$25,000,000

'

'

'

'

'

'

Outstanding balance on the credit facility

'

'

435,000,000

414,900,000

'

'

'

'

'

'

'

'

Letters of credit outstanding

'

'

84,100,000

'

'

'

'

'

'

'

'

'

Remaining borrowing capacity

'

'

227,000,000

'

'

'

'

'

'

'

'

'

Line of Credit Facility, Interest Rate at Period End

'

'

'

'

'

'

'

'

'

'

2.91%

5.00%

Weighted average interest rate

'

'

2.92%

'

'

'

'

'

'

'

'

'

Maximum leverage ratio

'

'

5

'

'

'

'

'

'

'

'

'

Minimum interest coverage ratio

'

'

2.5

'

'

'

'

'

'

'

'

'

Current debt to EBITDA ratio

4.46

'

'

'

'

'

'

'

'

'

'

'

Consolidated EBITDA to interest expense ratio

3.86

'

'

'

'

'

'

'

'

'

'

'

Face amount of debt

'

'

'

'

'

'

$350,000,000

$500,000,000

$600,000,000

$600,000,000

'

'

Interest rate on debt

'

'

'

'

'

'

7.75%

6.00%

6.13%

6.13%

'

'

Partners_Capital_Narrative_Det

Partners' Capital (Narrative) (Details) (USD $)

0 Months Ended

3 Months Ended

9 Months Ended

0 Months Ended

3 Months Ended

9 Months Ended

3 Months Ended

9 Months Ended

3 Months Ended

9 Months Ended

0 Months Ended

9 Months Ended

0 Months Ended

9 Months Ended

0 Months Ended

Aug. 14, 2014

Aug. 07, 2014

Jul. 10, 2014

15-May-14

8-May-14

Feb. 14, 2014

Feb. 07, 2014

Aug. 14, 2013

Aug. 09, 2013

Aug. 07, 2013

Aug. 01, 2013

10-May-13

Apr. 30, 2013

Feb. 12, 2013

Jan. 31, 2013

Jan. 08, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Jul. 10, 2014

Jan. 08, 2013

Jan. 08, 2013

Jun. 17, 2014

Jul. 18, 2014

Jan. 08, 2013

Jan. 08, 2013

Jul. 23, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2014

Jun. 17, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 22, 2014

Jun. 17, 2014

Sep. 30, 2014

Oct. 31, 2014

Oct. 22, 2014

Legacy Crestwood Credit Facility

Preferred Units, Class A

Common Unit

Preferred Units, Class D

General Partner

Preferred Units

Crestwood Niobrara LLC

Crestwood Niobrara LLC

Jackalope Gas Gathering Services, LLC

Jackalope Gas Gathering Services, LLC

Jackalope Gas Gathering Services, LLC

Jackalope Gas Gathering Services, LLC

Jackalope Gas Gathering Services, LLC

Jackalope Gas Gathering Services, LLC

Jackalope Gas Gathering Services, LLC

Jackalope Gas Gathering Services, LLC

Jackalope Gas Gathering Services, LLC

Preferred Partner

Preferred Partner

Preferred Partner

Class A Purchasers

Class A Purchasers

Limited Partner

Subsequent event

Subsequent event

Preferred Units, Class D

Preferred Units, Class D

Preferred Units

Crestwood Niobrara LLC

Crestwood Niobrara LLC

Crestwood Niobrara LLC

Crestwood Niobrara LLC

Preferred Units, Class A

Preferred Units, Class A

Maximum

Crestwood Niobrara LLC

Scenario, Forecast

Preferred Units

Preferred Units, Class A

Preferred Units

Preferred Units

Distribution Made to Limited Partner [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Partners' Capital Account, Units, Sale of Units

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

11,952,191

26,299,076

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Issuance of Class A preferred units

'

'

$300,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$2,988,047

$500,000,000

'

'

'

Offering Costs, Partnership Interests

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

0.02

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Maximum Period For Distribution Of Available Cash

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'45 days

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Distributions to general partner

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

31,400,000

17,100,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

31,400,000

'

'

Distribution Made to Limited Partner, Date of Record

'

7-Aug-14

'

'

8-May-14

'

7-Feb-14

'

'

7-Aug-13

[1]

1-Aug-13

'

30-Apr-13

'

31-Jan-13

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Per unit rate, in dollars per unit

$0.41

'

'

$0.41

'

$0.41

'

$0.40

[1]

$0.51

'

'

$0.51

'

$0.51

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Contribution from issuance of units

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

150,000,000

'

'

'

53,900,000

'

'

'

'

'

'

'

'

Net Income (Loss) Attributable to Noncontrolling Interest

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

4,500,000

1,900,000

11,300,000

1,900,000

'

'

'

'

'

'

'

'

'

'

4,500,000

1,900,000

11,300,000

1,900,000

'

'

'

'

'

'

'

'

'

'

'

'

'

Funds from Capital Contributions, Maximum

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

20,300,000

96,100,000

96,100,000

'

'

'

'

'

'

'

'

'

Distribution Made to Member or Limited Partner, Cash Distributions Paid

74,100,000

'

'

74,200,000

'

74,100,000

'

34,300,000

[1]

27,400,000

'

'

27,400,000

'

21,000,000

'

'

'

'

222,400,000

110,100,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Business Acquisition, Percentage of Voting Interests Acquired

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

65.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Consideration Transferred

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

258,000,000

'

'

'

'

'

'

129,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Distribution Made to Limited Partner, Unit Distribution

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

6,190,469

133,060

42,523

3,073,357

7,819,661

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

3,599,580

345,471

Distribution Made to Limited Partner, Distribution Date

14-Aug-14

'

'

15-May-14

'

14-Feb-14

'

14-Aug-13

[1]

9-Aug-13

'

'

10-May-13

'

12-Feb-13

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Partners' Capital, Distribution Amount Per Share

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$0.58

'

'

'

'

'

'

Partners' Capital Account, Term to Convert Cash Distributions to Stock Distributions

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'36 months

'

'

'

'

'

Partners' Capital Account, Private Placement of Units

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$25.10

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$25.10

'

'

$25.10

'

'

'

'

Proceeds from Issuance of Preferred Limited Partners Units, Gross

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

300,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

75,000,000

'

'

'

'

Net proceeds from the issuance of Class A preferred units

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$366,800,000

'

'

'

'

$293,700,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$73,100,000

'

'

'

'

Partners' Capital, Contingent Distribution Amount Per Share

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$0.71

'

'

'

'

'

'

Partner's Capital, Unpaid Distribution, Accrual Percentage

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2.81%

'

'

'

'

'

'

'

[1]

Represents distributions associated with Legacy Inergy limited partner units.

Partners_Capital_Schedule_of_P

Partners' Capital (Schedule of Partnership Distributions) (Details) (USD $)

0 Months Ended

9 Months Ended

0 Months Ended

Aug. 14, 2014

Aug. 07, 2014

15-May-14

8-May-14

Feb. 14, 2014

Feb. 07, 2014

Aug. 14, 2013

Aug. 09, 2013

Aug. 07, 2013

Aug. 01, 2013

10-May-13

Apr. 30, 2013

Feb. 12, 2013

Jan. 31, 2013

Sep. 30, 2014

Sep. 30, 2013

Oct. 22, 2014

Dividend Paid

Cash distribution

Subsequent event

Limited Partners' Capital Account [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Distribution Made to Limited Partner, Date of Record

'

7-Aug-14

'

8-May-14

'

7-Feb-14

'

'

7-Aug-13

[1]

1-Aug-13

'

30-Apr-13

'

31-Jan-13

'

'

'

Distribution Made to Limited Partner, Distribution Date

14-Aug-14

'

15-May-14

'

14-Feb-14

'

14-Aug-13

[1]

9-Aug-13

'

'

10-May-13

'

12-Feb-13

'

'

'

'

Distribution Made to Limited Partner, Distributions Paid, Per Unit

$0.41

'

$0.41

'

$0.41

'

$0.40

[1]

$0.51

'

'

$0.51

'

$0.51

'

'

'

'

Distribution Made to Member or Limited Partner, Cash Distributions Paid

$74,100,000

'

$74,200,000

'

$74,100,000

'

$34,300,000

[1]

$27,400,000

'

'

$27,400,000

'

$21,000,000

'

$222,400,000

$110,100,000

'

Distributions to limited partners

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$222,400,000

$110,100,000

'

Disclosure Partners Capital Summary Of Quarterly Distributions Of Available Cash [Abstract]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Distribution declared per limited partner unit

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$0.41

[1]

Represents distributions associated with Legacy Inergy limited partner units.

LongTerm_Incentive_Plan_Narrat

Long-Term Incentive Plan (Narrative) (Details) (USD $)

1 Months Ended

9 Months Ended

3 Months Ended

9 Months Ended

3 Months Ended

9 Months Ended

In Millions, except Share data, unless otherwise specified

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Dec. 31, 2013

Crestwood LTIP

Crestwood LTIP

Crestwood LTIP

Crestwood LTIP

Crestwood LTIP

Crestwood LTIP

Crestwood LTIP

Crestwood LTIP

Crestwood LTIP

Crestwood LTIP

CMLP

CMLP

CMLP

CMLP

Restricted units

Restricted units

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized

'

'

'

'

'

'

'

'

'

'

'

$11.60

$1.80

Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition

'

'

'

'

'

'3 years

'

'

'

'

'

'

'

Unit-based compensation charges

'

13.9

6.5

2.5

1.7

8.7

3.2

'

'

'

'

'

'

Allocated Share-based Compensation Expense

'

'

'

'

'

'

'

1.6

3.1

5.2

3.3

'

'

Share-based Compensation Arrangement, Equity Instruments Other than Options, Grants in Period, Fair Value

'

'

'

'

'

'

'

'

'

'

'

$19.50

'

Common Stock, Capital Shares Reserved for Future Issuance

'

'

'

'

'

'

'

'

'

'

'

6,430,021

'

Shares Paid for Tax Withholding for Share Based Compensation

'

'

'

0

912

68,532

3,341

'

'

'

'

'

'

Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent

10.00%

'

'

'

'

'

'

'

'

'

'

'

'

Defined Contribution Plan, Employer Matching Contribution, Percent of Match

10.00%

'

'

'

'

'

'

'

'

'

'

'

'

Defined Contribution Plan, Maximum Purchasable Units

200,000

200,000

'

'

'

'

'

'

'

'

'

'

'

LongTerm_Incentive_Plan_Restri

Long-Term Incentive Plan (Restricted Unit Activity) (Details) (Crestwood LTIP, Restricted units, USD $)	9 Months Ended
	Sep. 30, 2014
Crestwood LTIP | Restricted units	'
Units	'
Unvested - January 1, 2014	250,557
Vested - restricted units	-190,818
Granted - restricted units	838,036
Forfeited	-57,208
Unvested - September 30, 2014	840,567
Weighted-Average Grant Date Fair Value	'
Unvested - January 1, 2014	$22.13
Vested - restricted units	$22.16
Granted - restricted units	$23.31
Forfeited	$23.49
Unvested - September 30, 2014	$23.21

Commitments_and_Contingencies_

Commitments and Contingencies (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014	Dec. 31, 2013	Mar. 31, 2014	Nov. 08, 2013
In Millions, unless otherwise specified			Antero	Antero	Arrow Acquisition Class Action Lawsuit	Arrow Acquisition Class Action Lawsuit
					defendant	bbl
						people
Schedule Of Commitments And Contingencies [Line Items]	'	'	'	'	'	'
Barrels of Oil Equivalents Spilled	'	'	'	'	'	50,000
Loss Contingency, Loss of Life, Number	'	'	'	'	'	47
Loss Contingency, Number of Defendants	'	'	'	'	53	'
Loss contingency accrual, less than	$0.10	$0.10	'	'	'	'
Business Combination, Contingent Consideration, Liability, Current	'	'	40	'	'	'
Contingent Consideration Classified as Equity, Fair Value Disclosure	'	'	$40	$31.40	'	'

Commitments_and_Contingencies_1

Commitments and Contingencies Environmental Compliance (Details) (Fort Berthold Indian Reservation, USD $)	3 Months Ended	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2014
	Release	bbl
	bbl
Fort Berthold Indian Reservation	'	'
Site Contingency [Line Items]	'	'
Number of releases of produced water	2	'
Number of barrels of produced water	28,000	28,000
Environmental remediation expense	$3.70	'
Accrual for environmental loss contingencies	1.7	1.7
Low estimate of environmental liability	'	1.7
High estimate of environmental liability	'	$2.10

Related_Party_Transactions_Det

Related Party Transactions (Details) (USD $)	3 Months Ended			9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014		Sep. 30, 2013	Sep. 30, 2014		Sep. 30, 2013	Dec. 31, 2013
Disclosure Related Party Transaction Additional Information [Abstract]	'		'	'		'	'
Gathering and processing revenues	$4.90		$27.50	$13.20		$78.10	'
Related Party Transaction, Due from (to) Related Party [Abstract]	'		'	'		'	'
Accounts payable	7.4		'	7.4		'	8.7
CEQP	'		'	'		'	'
Disclosure Related Party Transaction Additional Information [Abstract]	'		'	'		'	'
Gathering and processing revenues	1.4	[1]	24.1	3	[1]	74.3	'
NGL and crude services revenues	3.5	[1]	3.4	10.2	[1]	3.8	'
Gathering and processing costs of product/services sold	11.3	[1]	7.6	32.1	[1]	22.2	'
General and administrative expenses	4.5	[1]	5.9	12.8	[1]	16.5	'
Affiliates	'		'	'		'	'
Related Party Transaction, Due from (to) Related Party [Abstract]	'		'	'		'	'
Accounts receivable	2.8		'	2.8		'	1.1
Accounts payable	7.4		'	7.4		'	8.7
Crestwood LTIP | CMLP	'		'	'		'	'
Related Party Transaction [Line Items]	'		'	'		'	'
Operating, administrative and overhead cost	14		5	42.7		5.5	'
Allocated Share-based Compensation Expense	$1.60		$3.10	$5.20		$3.30	'
[1]	Concurrent with the Crestwood Merger, Quicksilver Resources Inc. (Quicksilver) is no longer a related party, and as a result our transactions with Quicksilver subsequent to June 19, 2013, are now considered non-affiliated transactions.

Segments_Narrative_Details

Segments (Narrative) (Details)	9 Months Ended
	Sep. 30, 2014
	segment
Segment Reporting Information [Line Items]	'
Number of operating segments	3

Segments_Reconciliation_of_Net

Segments (Reconciliation of Net Income to EBITDA) (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Segment Reporting [Abstract]	'	'	'	'
Net income	$21.30	$11.60	$38.50	$27.20
Interest and debt expense, net	27.7	19.5	84.8	43.4
Provision for income taxes	0	0.3	0.8	1
Depreciation, amortization and accretion	55.5	35.1	161.2	73.4
EBITDA	$104.50	$66.50	$285.30	$145

Segments_Schedule_of_Reportabl

Segments (Schedule of Reportable Segment Data) (Details) (USD $)	3 Months Ended		9 Months Ended		12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Segment Reporting Information [Line Items]	'	'	'	'	'	'	'
Revenues	$738.40	$140.10	$1,951.10	$292.60	'	'	'
Costs of product/services sold	575.7	26.6	1,492.90	55.4	'	'	'
Operations and maintenance expense	39.4	21.7	100.1	48.1	'	'	'
General and administrative expense	18.2	25.2	63.6	44	80.7	29.6	24.1
Goodwill impairment	0	-4.1	0	-4.1	'	'	'
Gain (loss) on long-lived assets, net	-0.9	4.4	0.7	4.4	'	'	'
Loss on contingent consideration	'	'	-8.6	0	'	'	'
Earnings (loss) from unconsolidated affiliates, net	0.3	-0.4	-1.3	-0.4	'	'	'
EBITDA	104.5	66.5	285.3	145	'	'	'
Goodwill	1,681.40	1,452.80	1,681.40	1,452.80	1,682.80	'	'
Total assets	6,694.60	5,162.80	6,694.60	5,162.80	6,401.80	'	'
Cash expenditures for property, plant and equipment	94.6	105.9	259.3	189.4	'	'	'
Gathering and Processing	'	'	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'	'	'
Revenues	85.3	71.1	248.2	214.6	'	'	'
Costs of product/services sold	18.6	12.9	54.9	40.4	'	'	'
Operations and maintenance expense	15.9	14.9	44	40.5	'	'	'
General and administrative expense	0	0	0	0	'	'	'
Goodwill impairment	'	-4.1	'	-4.1	'	'	'
Gain (loss) on long-lived assets, net	-0.9	4.4	0.1	4.4	'	'	'
Loss on contingent consideration	'	'	-8.6	'	'	'	'
Earnings (loss) from unconsolidated affiliates, net	0.4	-0.4	0.1	-0.4	'	'	'
EBITDA	50.3	43.2	140.9	133.6	'	'	'
Goodwill	99.6	99.6	99.6	99.6	'	'	'
Total assets	2,026.10	1,856	2,026.10	1,856	'	'	'
Cash expenditures for property, plant and equipment	57.5	84.1	178.6	164	'	'	'
Storage and Transportation	'	'	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'	'	'
Revenues	44.2	42.1	133.9	47.6	'	'	'
Costs of product/services sold	4.3	4	11.3	4.4	'	'	'
Operations and maintenance expense	4.2	4.7	12.9	5.3	'	'	'
General and administrative expense	0	0	0	0	'	'	'
Goodwill impairment	'	0	'	0	'	'	'
Gain (loss) on long-lived assets, net	0	0	0.6	0	'	'	'
Loss on contingent consideration	'	'	0	'	'	'	'
Earnings (loss) from unconsolidated affiliates, net	0	0	0	0	'	'	'
EBITDA	35.7	33.4	110.3	37.9	'	'	'
Goodwill	726.3	744.1	726.3	744.1	'	'	'
Total assets	1,951.20	2,003	1,951.20	2,003	'	'	'
Cash expenditures for property, plant and equipment	2.2	5.7	4.7	7.9	'	'	'
NGL and Crude Services	'	'	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'	'	'
Revenues	608.9	26.9	1,569	30.4	'	'	'
Costs of product/services sold	552.8	9.7	1,426.70	10.6	'	'	'
Operations and maintenance expense	19.3	2.1	43.2	2.3	'	'	'
General and administrative expense	0	0	0	0	'	'	'
Goodwill impairment	'	0	'	0	'	'	'
Gain (loss) on long-lived assets, net	0	0	0	0	'	'	'
Loss on contingent consideration	'	'	0	'	'	'	'
Earnings (loss) from unconsolidated affiliates, net	-0.1	0	-1.4	0	'	'	'
EBITDA	36.7	15.1	97.7	17.5	'	'	'
Goodwill	855.5	609.1	855.5	609.1	'	'	'
Total assets	2,553.70	1,257.40	2,553.70	1,257.40	'	'	'
Cash expenditures for property, plant and equipment	34.8	16	72.3	17	'	'	'
Corporate	'	'	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'	'	'
Revenues	0	0	0	0	'	'	'
Costs of product/services sold	0	0	0	0	'	'	'
Operations and maintenance expense	0	0	0	0	'	'	'
General and administrative expense	18.2	25.2	63.6	44	'	'	'
Goodwill impairment	'	0	'	0	'	'	'
Gain (loss) on long-lived assets, net	0	0	0	0	'	'	'
Loss on contingent consideration	'	'	0	'	'	'	'
Earnings (loss) from unconsolidated affiliates, net	0	0	0	0	'	'	'
EBITDA	-18.2	-25.2	-63.6	-44	'	'	'
Goodwill	0	0	0	0	'	'	'
Total assets	163.6	46.4	163.6	46.4	'	'	'
Cash expenditures for property, plant and equipment	$0.10	$0.10	$3.70	$0.50	'	'	'

Condensed_Consolidating_Financ2

Condensed Consolidating Financial Information (Condensed Consolidating Balance Sheet) (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Cash and cash equivalents	$0.10	$2.70	$6.90	$0.10
Accounts receivable	312.8	205.1	'	'
Inventory	8.3	7	'	'
Prepaid expenses and other current assets	20.3	10.2	'	'
Total current assets	341.5	225	'	'
Property, plant and equipment, net	3,499.60	3,350.10	'	'
Goodwill and intangible assets, net	2,602.20	2,653.60	'	'
Investment in Consolidated Subsidiaries	0	0	'	'
Investment in unconsolidated affiliates (Note 5)	231.9	151.4	'	'
Other assets	19.4	21.7	'	'
Total assets	6,694.60	6,401.80	5,162.80	'
Accounts payable	200.6	163.2	'	'
Other current liabilities	165.7	151.3	'	'
Total current liabilities	366.3	314.5	'	'
Long-term debt, less current portion	1,893	1,867.90	'	'
Other long-term liabilities	30	26.3	'	'
Total long-term liabilities	1,923	1,894.20	'	'
Partners' Capital	4,239.10	4,092.10	'	'
Interest of non-controlling partners in subsidiary	166.2	101	'	'
Total partnersb capital	4,405.30	4,193.10	'	'
Total liabilities and partnersb capital	6,694.60	6,401.80	'	'
Parent	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Cash and cash equivalents	0	0.1	4.5	0
Accounts receivable	579.1	466.8	'	'
Inventory	0	0	'	'
Prepaid expenses and other current assets	0	0	'	'
Total current assets	579.1	466.9	'	'
Property, plant and equipment, net	5.9	4.8	'	'
Goodwill and intangible assets, net	0	0	'	'
Investment in Consolidated Subsidiaries	6,571.50	6,385.20	'	'
Investment in unconsolidated affiliates (Note 5)	0	0	'	'
Other assets	0	0	'	'
Total assets	7,156.50	6,856.90	'	'
Accounts payable	855.5	782.7	'	'
Other current liabilities	1	11.5	'	'
Total current liabilities	856.5	794.2	'	'
Long-term debt, less current portion	1,893	1,867.90	'	'
Other long-term liabilities	1.7	1.7	'	'
Total long-term liabilities	1,894.70	1,869.60	'	'
Partners' Capital	4,239.10	4,092.10	'	'
Interest of non-controlling partners in subsidiary	166.2	101	'	'
Total partnersb capital	4,405.30	4,193.10	'	'
Total liabilities and partnersb capital	7,156.50	6,856.90	'	'
Guarantor Subsidiaries	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Cash and cash equivalents	0.1	1.6	2.4	0.1
Accounts receivable	295.4	197.8	'	'
Inventory	8.3	7	'	'
Prepaid expenses and other current assets	20.3	10.2	'	'
Total current assets	324.1	216.6	'	'
Property, plant and equipment, net	3,493.70	3,345.30	'	'
Goodwill and intangible assets, net	2,602.20	2,653.60	'	'
Investment in Consolidated Subsidiaries	0	0	'	'
Investment in unconsolidated affiliates (Note 5)	0	0	'	'
Other assets	19.4	21.7	'	'
Total assets	6,439.40	6,237.20	'	'
Accounts payable	-93.2	-159.8	'	'
Other current liabilities	164.7	139.6	'	'
Total current liabilities	71.5	-20.2	'	'
Long-term debt, less current portion	0	0	'	'
Other long-term liabilities	28.3	24.6	'	'
Total long-term liabilities	28.3	24.6	'	'
Partners' Capital	6,339.60	6,232.80	'	'
Interest of non-controlling partners in subsidiary	0	0	'	'
Total partnersb capital	6,339.60	6,232.80	'	'
Total liabilities and partnersb capital	6,439.40	6,237.20	'	'
Non-Guarantor Subsidiaries	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Cash and cash equivalents	0	1	0	0
Accounts receivable	0.1	0.2	'	'
Inventory	0	0	'	'
Prepaid expenses and other current assets	0	0	'	'
Total current assets	0.1	1.2	'	'
Property, plant and equipment, net	0	0	'	'
Goodwill and intangible assets, net	0	0	'	'
Investment in Consolidated Subsidiaries	0	0	'	'
Investment in unconsolidated affiliates (Note 5)	231.9	151.4	'	'
Other assets	0	0	'	'
Total assets	232	152.6	'	'
Accounts payable	0.1	0	'	'
Other current liabilities	0	0.2	'	'
Total current liabilities	0.1	0.2	'	'
Long-term debt, less current portion	0	0	'	'
Other long-term liabilities	0	0	'	'
Total long-term liabilities	0	0	'	'
Partners' Capital	65.7	51.4	'	'
Interest of non-controlling partners in subsidiary	166.2	101	'	'
Total partnersb capital	231.9	152.4	'	'
Total liabilities and partnersb capital	232	152.6	'	'
Consolidation, Eliminations	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Cash and cash equivalents	0	0	0	0
Accounts receivable	-561.8	-459.7	'	'
Inventory	0	0	'	'
Prepaid expenses and other current assets	0	0	'	'
Total current assets	-561.8	-459.7	'	'
Property, plant and equipment, net	0	0	'	'
Goodwill and intangible assets, net	0	0	'	'
Investment in Consolidated Subsidiaries	-6,571.50	-6,385.20	'	'
Investment in unconsolidated affiliates (Note 5)	0	0	'	'
Other assets	0	0	'	'
Total assets	-7,133.30	-6,844.90	'	'
Accounts payable	-561.8	-459.7	'	'
Other current liabilities	0	0	'	'
Total current liabilities	-561.8	-459.7	'	'
Long-term debt, less current portion	0	0	'	'
Other long-term liabilities	0	0	'	'
Total long-term liabilities	0	0	'	'
Partners' Capital	-6,405.30	-6,284.20	'	'
Interest of non-controlling partners in subsidiary	-166.2	-101	'	'
Total partnersb capital	-6,571.50	-6,385.20	'	'
Total liabilities and partnersb capital	-7,133.30	-6,844.90	'	'
Consolidated Entities [Member]	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Total liabilities and partnersb capital	'	$6,401.80	'	'

Condensed_Consolidating_Financ3

Condensed Consolidating Financial Information (Condensed Consolidating Statement of Operations) (Details) (USD $)	3 Months Ended		9 Months Ended		12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Condensed Financial Statements, Captions [Line Items]	'	'	'	'	'	'	'
Gathering and processing	$83.90	$47	$245.20	$140.30	'	'	'
Storage and transportation	44.2	42.1	133.9	47.6	'	'	'
NGL and crude services	605.4	23.5	1,558.80	26.6	'	'	'
Related party (Note 11)	4.9	27.5	13.2	78.1	'	'	'
Revenues	738.4	140.1	1,951.10	292.6	'	'	'
Gathering and processing	7.3	5.3	22.8	18.2	'	'	'
Storage and transportation	4.3	4	11.3	4.4	'	'	'
NGL and crude services	552.8	9.7	1,426.70	10.6	'	'	'
Related party	-11.3	-7.6	-32.1	-22.2	'	'	'
Cost of Revenue	575.7	26.6	1,492.90	55.4	'	'	'
Operations and maintenance	39.4	21.7	100.1	48.1	73.3	43.1	36.3
Operations and maintenance expense	39.4	21.7	100.1	48.1	'	'	'
General and administrative expense	18.2	25.2	63.6	44	80.7	29.6	24.1
Depreciation, amortization and accretion	55.5	35.1	161.2	73.4	'	'	'
Costs and Expenses, Total	113.1	82	324.9	165.5	'	'	'
Loss on contingent consideration (Note 10)	0	0	-8.6	0	'	'	'
Other	-0.9	0.3	0.7	0.3	'	'	'
Operating income	48.7	31.8	125.4	72	'	'	'
Interest and debt expense, net	-27.7	-19.5	-84.8	-43.4	'	'	'
Equity in net income (loss) of subsidiary	0	0	0	0	'	'	'
Other	0.3	-0.4	-1.3	-0.4	'	'	'
Income before income taxes	21.3	11.9	39.3	28.2	'	'	'
Provision for income taxes	0	0.3	0.8	1	'	'	'
Net income	21.3	11.6	38.5	27.2	'	'	'
Net income attributable to non-controlling partners	-4.5	-1.9	-11.3	-1.9	'	'	'
Net income attributable to Crestwood Midstream Partners LP	16.8	9.7	27.2	25.3	'	'	'
Net income attributable to Class A preferred units	-9.1	0	-10.2	0	'	'	'
Net Income (Loss), Partners Interest in Net Income	7.7	9.7	17	25.3	'	'	'
Parent	'	'	'	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'	'	'	'
Gathering and processing	0	0	0	0	'	'	'
Storage and transportation	0	0	0	0	'	'	'
NGL and crude services	0	0	0	0	'	'	'
Related party (Note 11)	0	0	0	0	'	'	'
Revenues	0	0	0	0	'	'	'
Gathering and processing	0	0	0	0	'	'	'
Storage and transportation	0	0	0	0	'	'	'
NGL and crude services	0	0	0	0	'	'	'
Related party	0	0	0	0	'	'	'
Cost of Revenue	0	0	0	0	'	'	'
Operations and maintenance	0	0	0	0	'	'	'
General and administrative expense	-0.8	9.4	-3.8	24	'	'	'
Depreciation, amortization and accretion	0.3	0.2	0.7	0.6	'	'	'
Costs and Expenses, Total	-0.5	9.6	-3.1	24.6	'	'	'
Loss on contingent consideration (Note 10)	'	'	0	'	'	'	'
Other	0	0	0	0	'	'	'
Operating income	0.5	-9.6	3.1	-24.6	'	'	'
Interest and debt expense, net	-27.8	-18.4	-85.1	-39.9	'	'	'
Equity in net income (loss) of subsidiary	48.6	39.6	120.5	91.7	'	'	'
Other	0	0	0	0	'	'	'
Income before income taxes	21.3	11.6	38.5	27.2	'	'	'
Provision for income taxes	0	0	0	0	'	'	'
Net income	21.3	11.6	38.5	27.2	'	'	'
Net income attributable to non-controlling partners	0	0	0	0	'	'	'
Net income attributable to Crestwood Midstream Partners LP	21.3	11.6	38.5	27.2	'	'	'
Net income attributable to Class A preferred units	-9.1	'	-10.2	'	'	'	'
Net Income (Loss), Partners Interest in Net Income	12.2	'	28.3	'	'	'	'
Guarantor Subsidiaries	'	'	'	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'	'	'	'
Gathering and processing	83.9	47	245.2	140.3	'	'	'
Storage and transportation	44.2	42.1	133.9	47.6	'	'	'
NGL and crude services	605.4	23.5	1,558.80	26.6	'	'	'
Related party (Note 11)	4.9	27.5	13.2	78.1	'	'	'
Revenues	738.4	140.1	1,951.10	292.6	'	'	'
Gathering and processing	7.3	5.3	22.8	18.2	'	'	'
Storage and transportation	4.3	4	11.3	4.4	'	'	'
NGL and crude services	552.8	9.7	1,426.70	10.6	'	'	'
Related party	-11.3	-7.6	-32.1	-22.2	'	'	'
Cost of Revenue	575.7	26.6	1,492.90	55.4	'	'	'
Operations and maintenance	39.4	21.7	100.1	48.1	'	'	'
General and administrative expense	19	15.8	67.4	20	'	'	'
Depreciation, amortization and accretion	55.2	34.9	160.5	72.8	'	'	'
Costs and Expenses, Total	113.6	72.4	328	140.9	'	'	'
Loss on contingent consideration (Note 10)	'	'	-8.6	'	'	'	'
Other	-0.9	0.3	0.7	0.3	'	'	'
Operating income	48.2	41.4	122.3	96.6	'	'	'
Interest and debt expense, net	0.1	-1.1	0.3	-3.5	'	'	'
Equity in net income (loss) of subsidiary	0	0	0	0	'	'	'
Other	0	0	0	0	'	'	'
Income before income taxes	48.3	40.3	122.6	93.1	'	'	'
Provision for income taxes	0	0.3	0.8	1	'	'	'
Net income	48.3	40	121.8	92.1	'	'	'
Net income attributable to non-controlling partners	0	0	0	0	'	'	'
Net income attributable to Crestwood Midstream Partners LP	48.3	40	121.8	92.1	'	'	'
Net income attributable to Class A preferred units	0	'	0	'	'	'	'
Net Income (Loss), Partners Interest in Net Income	48.3	'	121.8	'	'	'	'
Non-Guarantor Subsidiaries	'	'	'	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'	'	'	'
Gathering and processing	0	0	0	0	'	'	'
Storage and transportation	0	0	0	0	'	'	'
NGL and crude services	0	0	0	0	'	'	'
Related party (Note 11)	0	0	0	0	'	'	'
Revenues	0	0	0	0	'	'	'
Gathering and processing	0	0	0	0	'	'	'
Storage and transportation	0	0	0	0	'	'	'
NGL and crude services	0	0	0	0	'	'	'
Related party	0	0	0	0	'	'	'
Cost of Revenue	0	0	0	0	'	'	'
Operations and maintenance	0	0	0	0	'	'	'
General and administrative expense	0	0	0	0	'	'	'
Depreciation, amortization and accretion	0	0	0	0	'	'	'
Costs and Expenses, Total	0	0	0	0	'	'	'
Loss on contingent consideration (Note 10)	'	'	0	'	'	'	'
Other	0	0	0	0	'	'	'
Operating income	0	0	0	0	'	'	'
Interest and debt expense, net	0	0	0	0	'	'	'
Equity in net income (loss) of subsidiary	0	0	0	0	'	'	'
Other	0.3	-0.4	-1.3	-0.4	'	'	'
Income before income taxes	0.3	-0.4	-1.3	-0.4	'	'	'
Provision for income taxes	0	0	0	0	'	'	'
Net income	0.3	-0.4	-1.3	-0.4	'	'	'
Net income attributable to non-controlling partners	-4.5	-1.9	-11.3	-1.9	'	'	'
Net income attributable to Crestwood Midstream Partners LP	-4.2	-2.3	-12.6	-2.3	'	'	'
Net income attributable to Class A preferred units	0	'	0	'	'	'	'
Net Income (Loss), Partners Interest in Net Income	-4.2	'	-12.6	'	'	'	'
Consolidation, Eliminations	'	'	'	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'	'	'	'
Gathering and processing	0	0	0	0	'	'	'
Storage and transportation	0	0	0	0	'	'	'
NGL and crude services	0	0	0	0	'	'	'
Related party (Note 11)	0	0	0	0	'	'	'
Revenues	0	0	0	0	'	'	'
Gathering and processing	0	0	0	0	'	'	'
Storage and transportation	0	0	0	0	'	'	'
NGL and crude services	0	0	0	0	'	'	'
Related party	0	0	0	0	'	'	'
Cost of Revenue	0	0	0	0	'	'	'
Operations and maintenance	0	0	0	0	'	'	'
General and administrative expense	0	0	0	0	'	'	'
Depreciation, amortization and accretion	0	0	0	0	'	'	'
Costs and Expenses, Total	0	0	0	0	'	'	'
Loss on contingent consideration (Note 10)	'	'	0	'	'	'	'
Other	0	0	0	0	'	'	'
Operating income	0	0	0	0	'	'	'
Interest and debt expense, net	0	0	0	0	'	'	'
Equity in net income (loss) of subsidiary	-48.6	-39.6	-120.5	-91.7	'	'	'
Other	0	0	0	0	'	'	'
Income before income taxes	-48.6	-39.6	-120.5	-91.7	'	'	'
Provision for income taxes	0	0	0	0	'	'	'
Net income	-48.6	-39.6	-120.5	-91.7	'	'	'
Net income attributable to non-controlling partners	0	0	0	0	'	'	'
Net income attributable to Crestwood Midstream Partners LP	-48.6	-39.6	-120.5	-91.7	'	'	'
Net income attributable to Class A preferred units	0	'	0	'	'	'	'
Net Income (Loss), Partners Interest in Net Income	($48.60)	'	($120.50)	'	'	'	'

Condensed_Consolidating_Financ4

Condensed Consolidating Financial Information (Condensed Consolidating Statements of Cash Flows) (Details) (USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Condensed Financial Statements, Captions [Line Items]	'	'
Net cash provided by operating activities	$175.80	$130.50
Acquisitions, net of cash acquired	-19.5	0.2
Purchases of property, plant and equipment	-259.3	-189.4
Investment in unconsolidated affiliates	-81.8	-152.5
Capital contribution from consolidated affiliate	0	0
Proceeds from sale of assets	0	11
Net change in receivables from affiliates	0	0
Net cash used in investing activities	-360.6	-330.7
Proceeds from the issuance of long-term debt	1,410.90	577.2
Principal payments on long-term debt	-1,390.80	-568.5
Distributions paid	-253.8	-127.2
Contributions from parent	0	5.4
Net proceeds from issuance of common units	'	356.7
Net proceeds from issuance of preferred equity of subsidiary	53.9	96.1
Net proceeds from the issuance of Class A preferred units	366.8	'
Payments on capital leases	-2.6	-3
Taxes paid for unit-based compensation vesting	-1.5	-0.7
Payments of Debt Issuance Costs	0.1	0.1
Payments of Financing Costs	'	-0.1
Net change in payables to affiliate	0	0
Other	-0.6	0.1
Net cash provided by financing activities	182.2	207
Net change in cash	-2.6	6.8
Cash at beginning of period	2.7	0.1
Cash at end of period	0.1	6.9
Distributions for additional interest in Crestwood Marcellus Midstream LLC	0	-129
Parent	'	'
Condensed Financial Statements, Captions [Line Items]	'	'
Net cash provided by operating activities	-27.6	-18.7
Acquisitions, net of cash acquired	0	0
Purchases of property, plant and equipment	-3.7	-0.5
Investment in unconsolidated affiliates	0	0
Capital contribution from consolidated affiliate	-23.4	-82
Proceeds from sale of assets	'	0
Net change in receivables from affiliates	-313.7	57.4
Net cash used in investing activities	-340.8	-25.1
Proceeds from the issuance of long-term debt	2.5	343.5
Principal payments on long-term debt	0	-194
Distributions paid	0	-90.3
Contributions from parent	0	0
Net proceeds from issuance of common units	'	118.5
Net proceeds from issuance of preferred equity of subsidiary	0	0
Net proceeds from the issuance of Class A preferred units	366.8	'
Payments on capital leases	-0.9	-0.3
Taxes paid for unit-based compensation vesting	0	0
Payments of Debt Issuance Costs	0.1	'
Payments of Financing Costs	'	-0.1
Net change in payables to affiliate	0	0
Other	0	0
Net cash provided by financing activities	368.3	48.3
Net change in cash	-0.1	4.5
Cash at beginning of period	0.1	0
Cash at end of period	0	4.5
Distributions for additional interest in Crestwood Marcellus Midstream LLC	'	-129
Guarantor Subsidiaries	'	'
Condensed Financial Statements, Captions [Line Items]	'	'
Net cash provided by operating activities	203.4	183
Acquisitions, net of cash acquired	-19.5	0.2
Purchases of property, plant and equipment	-255.6	-188.9
Investment in unconsolidated affiliates	-3.5	-24.4
Capital contribution from consolidated affiliate	-3.5	0
Proceeds from sale of assets	'	11
Net change in receivables from affiliates	0	0
Net cash used in investing activities	-282.1	-202.1
Proceeds from the issuance of long-term debt	1,408.40	233.7
Principal payments on long-term debt	-1,390.80	-374.5
Distributions paid	-253.8	-70.7
Contributions from parent	3.5	55.4
Net proceeds from issuance of common units	'	238.2
Net proceeds from issuance of preferred equity of subsidiary	0	0
Net proceeds from the issuance of Class A preferred units	0	'
Payments on capital leases	-1.7	-2.7
Taxes paid for unit-based compensation vesting	-1.5	-0.7
Payments of Debt Issuance Costs	0	'
Payments of Financing Costs	'	0
Net change in payables to affiliate	313.7	-57.4
Other	-0.6	0.1
Net cash provided by financing activities	77.2	21.4
Net change in cash	-1.5	2.3
Cash at beginning of period	1.6	0.1
Cash at end of period	0.1	2.4
Distributions for additional interest in Crestwood Marcellus Midstream LLC	'	0
Non-Guarantor Subsidiaries	'	'
Condensed Financial Statements, Captions [Line Items]	'	'
Net cash provided by operating activities	0	0
Acquisitions, net of cash acquired	0	0
Purchases of property, plant and equipment	0	0
Investment in unconsolidated affiliates	-78.3	-128.1
Capital contribution from consolidated affiliate	0	0
Proceeds from sale of assets	'	0
Net change in receivables from affiliates	0	0
Net cash used in investing activities	-78.3	-128.1
Proceeds from the issuance of long-term debt	0	0
Principal payments on long-term debt	0	0
Distributions paid	0	0
Contributions from parent	23.4	32
Net proceeds from issuance of common units	'	0
Net proceeds from issuance of preferred equity of subsidiary	53.9	96.1
Net proceeds from the issuance of Class A preferred units	0	'
Payments on capital leases	0	0
Taxes paid for unit-based compensation vesting	0	0
Payments of Debt Issuance Costs	0	'
Payments of Financing Costs	'	0
Net change in payables to affiliate	0	0
Other	0	0
Net cash provided by financing activities	77.3	128.1
Net change in cash	-1	0
Cash at beginning of period	1	0
Cash at end of period	0	0
Distributions for additional interest in Crestwood Marcellus Midstream LLC	'	0
Consolidation, Eliminations	'	'
Condensed Financial Statements, Captions [Line Items]	'	'
Net cash provided by operating activities	0	-33.8
Acquisitions, net of cash acquired	0	0
Purchases of property, plant and equipment	0	0
Investment in unconsolidated affiliates	0	0
Capital contribution from consolidated affiliate	26.9	82
Proceeds from sale of assets	'	0
Net change in receivables from affiliates	313.7	-57.4
Net cash used in investing activities	340.6	24.6
Proceeds from the issuance of long-term debt	0	0
Principal payments on long-term debt	0	0
Distributions paid	0	33.8
Contributions from parent	-26.9	-82
Net proceeds from issuance of common units	'	0
Net proceeds from issuance of preferred equity of subsidiary	0	0
Net proceeds from the issuance of Class A preferred units	0	'
Payments on capital leases	0	0
Taxes paid for unit-based compensation vesting	0	0
Payments of Debt Issuance Costs	0	'
Payments of Financing Costs	'	0
Net change in payables to affiliate	-313.7	57.4
Other	0	0
Net cash provided by financing activities	-340.6	9.2
Net change in cash	0	0
Cash at beginning of period	0	0
Cash at end of period	0	0
Distributions for additional interest in Crestwood Marcellus Midstream LLC	'	$0