Crestwood Equity Partners (CEQP+) 10-Q 8 May 14 2014 Q1 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	3 Months Ended
	Mar. 31, 2014
Document and Entity Information [Abstract]	'
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	31-Mar-14
Document Fiscal Year Focus	'2014
Document Fiscal Period Focus	'Q1
Amendment Flag	'false
Entity Common Stock, Shares Outstanding	0

CONSOLIDATED_BALANCE_SHEETS

CONSOLIDATED BALANCE SHEETS (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Current assets:	'	'
Cash and cash equivalents	$5	$2.70
Accounts receivable	237.3	205.1
Inventory	10.7	7
Prepaid expenses and other current assets	13.6	10.2
Total current assets	266.6	225
Property, plant and equipment (Note 3)	3,632.80	3,565.70
Less: accumulated depreciation and depletion	248.4	215.6
Property, plant and equipment, net	3,384.40	3,350.10
Intangible assets:	'	'
Intangible assets (Note 3)	1,029.80	1,025.10
Less: accumulated amortization	73.1	54.3
Intangible assets, net	956.7	970.8
Goodwill	1,689.30	1,682.80
Investment in unconsolidated affiliates (Note 5)	171.1	151.4
Other assets	23.3	21.7
Total assets	6,491.40	6,401.80
Current liabilities:	'	'
Accounts payable	153.7	154.5
Accounts payable - related party (Note 11)	37.5	8.7
Accrued expenses and other liabilities	151.8	148.4
Current portion of long-term debt (Note 7)	10.4	2.9
Total current liabilities	353.4	314.5
Long-term debt, less current portion (Note 7)	1,979.10	1,867.90
Other long-term liabilities	28	26.3
Commitments and contingencies (Note 10)	'	'
Partners’ capital (Note 8):	'	'
Partners’ capital (187,994,435 and 187,243,989 limited partner units issued and outstanding at March 31, 2014 and December 31, 2013)	4,014.50	4,092.10
Total Crestwood Midstream Partners LP partners’ capital	4,014.50	4,092.10
Interest of non-controlling partners in subsidiary	116.4	101
Total partners’ capital	4,130.90	4,193.10
Total liabilities and partners’ capital	$6,491.40	$6,401.80

CONSOLIDATED_BALANCE_SHEETS_Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical)	Mar. 31, 2014	Dec. 31, 2013
Statement of Financial Position [Abstract]	'	'
Common units, issued	187,994,435	187,243,989
Common units, outstanding	187,994,435	187,243,989

CONSOLIDATED_STATEMENTS_OF_OPE

CONSOLIDATED STATEMENTS OF OPERATIONS (USD $)	3 Months Ended
In Millions, except Share data in Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Revenues:	'	'
Gathering and processing	$78.60	$46.80
Storage and transportation	44.3	0
NGL and crude services	409.9	0
Related party (Note 11)	4.2	25.6
Revenues	537	72.4
Costs of product/services sold (excluding depreciation, amortization and accretion as shown below):	'	'
Gathering and processing	7.7	6.7
Storage and transportation	3.2	0
NGL and crude services	376.2	0
Related party (Note 11)	11	6.8
Cost of Revenue	398.1	13.5
Expenses:	'	'
Operations and maintenance	28	13
General and administrative	24.1	7.8
Depreciation, amortization and accretion	50.8	17.4
Costs and Expenses, Total	102.9	38.2
Other operating income (expense):	'	'
Gain on long-lived assets	0.5	0
Loss on contingent consideration (Note 10)	-2.1	0
Operating income	34.4	20.7
Loss from unconsolidated affiliates, net	-0.1	0
Interest and debt expense, net	-28.1	-11.4
Income before income taxes	6.2	9.3
Provision for income taxes	0.7	0.4
Net income	5.5	8.9
Net income attributable to non-controlling partners	-3.1	0
Net income attributable to Crestwood Midstream Partners LP	2.4	8.9
Partners’ interest information:	'	'
Non-managing general partner's interest in net income	7.5	5.2
Limited partners’ interest in net income (loss)	($5.10)	$3.70
Net income (loss) per limited partner unit:	'	'
Basic (usd per unit)	($0.03)	$0.06
Diluted (usd per unit)	($0.03)	$0.06
Weighted-average limited partners’ units outstanding (in thousands):	'	'
Basic (units)	187,840	64,656
Diluted (units)	187,840	64,656

CONSOLIDATED_STATEMENT_OF_PART

CONSOLIDATED STATEMENT OF PARTNERS' CAPITAL (USD $)	Total	Limited Partner	Non Controlling Partners	Partners' Capital
In Millions, unless otherwise specified
Beginning Balance at Dec. 31, 2013	$4,092.10	$4,092.10	$101	$4,193.10
Increase (Decrease) in Partners' Capital [Roll Forward]	'	'	'	'
Distributions to general partner	'	-10.5	0	-10.5
Distributions to limited partner	'	-74.1	0	-74.1
Unit-based compensation charges	'	4.6	0	4.6
Issuance of preferred equity of subsidiary	-12.3	0	12.3	12.3
Net income	5.5	2.4	3.1	5.5
Ending Balance at Mar. 31, 2014	$4,014.50	$4,014.50	$116.40	$4,130.90

CONSOLIDATED_STATEMENTS_OF_CAS

CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Operating activities	'	'
Net income	$5.50	$8.90
Adjustments to reconcile net income to net cash provided by operating activities:	'	'
Depreciation, amortization and accretion	50.8	17.4
Amortization of debt-related deferred costs and premiums	1.8	1.1
Unit-based compensation charges	4.6	0.6
Gain on long-lived assets	-0.5	0
Loss on contingent consideration	2.1	0
Loss from unconsolidated affiliates, net	0.1	0
Deferred income taxes	0.5	0
Other	0.2	0.1
Changes in operating assets and liabilities, net of effects from acquisitions	-7	6
Net cash provided by operating activities	58.1	34.1
Investing activities	'	'
Acquisitions, net of cash acquired (Note 4)	-12.1	0
Purchases of property, plant and equipment	-67.7	-24.3
Investment in unconsolidated affiliates	-19.8	0
Net cash used in investing activities	-99.6	-24.3
Financing activities	'	'
Proceeds from the issuance of long-term debt	306	199.5
Principal payments on long-term debt	-188.8	-157
Payments on capital leases	-1.1	-1
Payments for debt related deferred costs	0	-0.1
Distributions to limited partners	-74.1	-21
Distributions to general partner	-10.5	-4.1
Distributions for additional interest in Crestwood Marcellus Midstream LLC	0	-129
Net proceeds from issuance of limited partner units	0	103.5
Net proceeds from issuance of preferred equity of subsidiary	12.3	0
Taxes paid for unit-based compensation vesting	0	-0.7
Net cash provided by (used in) financing activities	43.8	-9.9
Net increase (decrease) in cash	2.3	-0.1
Cash at beginning of period	2.7	0.1
Cash at end of period	5	0
Supplemental schedule of non-cash investing and financing activities	'	'
Net change to property, plant and equipment through accounts payable and accrued expenses	($3.40)	$1.60

Business_Description

Business Description	3 Months Ended
	Mar. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
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 March 31, 2014, our general partner, Crestwood Equity Partners LP (CEQP), owns our non-economic general partnership interest, approximately 4% of our common units representing limited partnership interests 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 distributions 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 March 31, 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) and 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 gathering, storage 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 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,” “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	3 Months Ended
	Mar. 31, 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 as discussed above. 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 (Inergy, inclusive of Inergy Midstream) 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 Inergy Midstream 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, Inergy Midstream was the surviving entity for legal purposes, and consequently we changed our name from Inergy Midstream, L.P. to Crestwood Midstream Partners LP.
	The financial information as of March 31, 2014, and for the three-month periods ended March 31, 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 US 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. Beginning in the first quarter of 2014, we began recording our operating and administrative expenses as operations and maintenance expenses and general and administrative expenses. In addition, we also reclassified our income statement for the three months ended March 31, 2013 to reflect this change. This change had no 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 Securities and Exchange Commission (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 and no significant accounting pronouncements issued but not yet adopted as of March 31, 2014.

Certain_Balance_Sheet_Informat

Certain Balance Sheet Information	3 Months Ended
	Mar. 31, 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 March 31, 2014 and December 31, 2013 (in millions):
		March 31,		December 31,
		2014		2013
	Gathering systems and pipelines	1,225.40		1,231.10
	Facilities and equipment	1,289.40		1,041.00
	Buildings, land, rights-of-way, storage contracts and easements	769.5		766.2
	Vehicles	7.8		4.1
	Construction in process	179.7		360.5
	Base gas	36.3		36.3
	Salt deposits	120.5		120.5
	Office furniture and fixtures	4.2		6
		3,632.80		3,565.70
	Less: accumulated depreciation and depletion	248.4		215.6
	Total property, plant and equipment, net	$	3,384.40	$	3,350.10
	Capital Leases. We have a compressor station, treating facility and certain auto leases which are accounted for as capital leases. Our compressor station and treating facility leases are reflected in facilities and equipment in the above table. We had capital lease assets of $3.8 million and $5.0 million included in property, plant and equipment, net at March 31, 2014 and December 31, 2013.
	Intangible Assets
	Intangible assets consisted of the following at March 31, 2014 and December 31, 2013 (in millions):
		March 31,		December 31,
		2014		2013
	Customer accounts	$	480.3	$	476.4
	Covenants not to compete	3.8		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
		1,029.80		1,025.10
	Less: accumulated amortization	73.1		54.3
	Total intangible assets, net	$	956.7	$	970.8
	Accrued Expenses and Other Liabilities
	Accrued expenses and other liabilities consisted of the following at March 31, 2014 and December 31, 2013 (in millions):
		March 31, 2014		December 31, 2013
	Accrued expenses	$	14.5	$	20
	Accrued property taxes	3.5		7.6
	Accrued product purchases payable	1.8		1.6
	Tax payable	11.4		10.6
	Interest payable	27		14.9
	Accrued additions to property, plant and equipment	55.5		58.1
	Commitments and contingent liabilities (Note 10)	33.5		31.4
	Capital leases	2		2.6
	Deferred revenue	2.6		1.6
	Total accrued expenses and other liabilities	$	151.8	$	148.4

Acquisitions

Acquisitions	3 Months Ended
	Mar. 31, 2014
Business Combinations [Abstract]	'
Acquisitions	'
	Acquisitions
	2014 Acquisition
	Crude Transportation Acquisition (Bakken)
	On March 21, 2014, we purchased substantially all of the operating assets of Red Rock Transportation Inc. (Red Rock) for approximately $14.1 million, comprised of $12.1 million paid at closing plus deferred payments of $2.0 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 more than 25,000 barrels per day of crude hauling capacity. We allocated approximately $10.9 million of the purchase price to property, plant and equipment and intangible assets and approximately $3.2 million to goodwill. These assets are included in our NGL and crude services segment.
	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.
	The following table summarizes the preliminary fair values 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	1,537.70
	Net assets acquired	$	2,682.30
	Of the $1,537.7 million of goodwill, $809.1 million is reflected in our NGL and crude services segment and $728.6 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 Inergy and Legacy Crestwood.  The purchase price allocation has been prepared on a preliminary basis pending receipt of a final valuation report and is subject to material change.
	Arrow Acquisition
	On November 8, 2013, we acquired Arrow Midstream Holdings, LLC (Arrow) for approximately $750 million, subject to customary capital expenditure, working capital adjustments of approximately $12.8 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.
	The following table summarizes the preliminary fair values of the assets acquired and liabilities assumed at the acquisition date (in millions):
	Current assets	$	191.1
	Property, plant and equipment	400.2
	Intangible assets	323.4
	Other assets	19.5
	Total identifiable assets acquired	934.2
	Current liabilities	215.3
	Assets retirement obligations	1.2
	Other long-term liabilities	3.7
	Total liabilities assumed	220.2
	Net identifiable assets acquired	714
	Goodwill	48.8
	Net assets acquired	$	762.8
	The $48.8 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 months ended March 31, 2014, we also recognized approximately $4.6 million of transaction-related fees primarily related to services provided in 2013 related to this acquisition. The purchase price allocation has been prepared on a preliminary basis pending receipt of a final valuation report and is subject to material change.
	Unaudited Pro Forma Financial Information
	The following table represents the pro forma consolidated statement of operations as if the Legacy Inergy reverse merger and the Arrow Acquisition had been included in our consolidated results for the three months ended March 31, 2013 (in millions, except per unit information).
	Revenues	$	424.7
	Net income	$	13.1
	Net income per limited partner unit(a):
	Basic	$	0.09
	Diluted	$	0.09
	(a) Basic and diluted net income per limited partner unit for the three months ended March 31, 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 that would have been charged assuming the preliminary fair value adjustments to property, plant and equipment and intangible assets had been made at the beginning of the respective reporting period. The purchase price allocation for the reverse merger of Legacy Inergy and the Arrow Acquisition has been prepared on a preliminary basis pending final asset valuation and asset rationalization, and changes are expected when additional information becomes available. Accordingly, the purchase accounting adjustments made in connection with the development of the unaudited pro forma are preliminary and subject to change.

Investments_in_Unconsolidated_

Investments in Unconsolidated Affiliates (Notes)	3 Months Ended
	Mar. 31, 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. During the three months ended March 31, 2014, Crestwood Niobrara contributed $17.3 million to Jackalope to fund its construction projects.
	Our investment in Jackalope was $144.8 million and $127.2 million at March 31, 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 net earnings based on our ownership interest and other adjustments recorded by us as discussed below. During the three months ended March 31, 2014, our share of Jackalope’s net earnings was approximately $1.1 million. As of March 31, 2014, our investment balance in Jackalope exceeded our equity in the underlying net assets of Jackalope by approximately $56.0 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 reduction of our earnings from unconsolidated affiliates, and during the three months ended March 31, 2014, we recorded amortization expense of approximately $0.8 million.
	Jackalope is required to make quarterly distributions of its available cash to its members based on their respective ownership percentage. During the three months ended March 31, 2014, Jackalope did not make any distributions to its members.
	Our Jackalope investment is included in our gathering and processing segment.
	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. During the three months ended March 31, 2014, Crude Logistics invested approximately $2.5 million in PRBIC to fund its construction projects.
	Our investment in PRBIC was $26.3 million and $24.2 million at March 31, 2014 and December 31, 2013. During the three months ended March 31, 2014, our share of PRBIC’s loss was approximately $0.4 million. As of March 31, 2014, our investment balance in PRBIC approximated our equity in the underlying net assets of PRBIC.
	PRBIC is required to make quarterly distributions of its available cash to its members based on their respective ownership percentage. During the three months ended March 31, 2014, PRBIC did not make any distributions to its members.
	Our PRBIC investment is included in our NGL and crude services segment.

Earnings_Limited_Partner_Unit_

Earnings Limited Partner Unit Earnings Limited Partner Unit	3 Months Ended
	Mar. 31, 2014
Earnings Per Share [Abstract]	'
Earnings 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.
	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 limited partners 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-month periods ended March 31, 2014 and 2013 (in millions):
	Allocation of Net Income Attributable to CMLP to General Partner and Limited Partners
		Three Months Ended
		March 31,
		2014			2013
	Net income attributable to CMLP	$	2.4		$	8.9
	General partner’s incentive distributions	(7.5		)	(5.0		)
	Net income (loss) attributable to CMLP after incentive distributions	(5.1		)	3.9
	General partner’s interest in net income attributable to CMLP after incentive distributions	—			(0.2		)
	Limited partners’ interest in net income (loss) attributable to CMLP after incentive distributions	$	(5.1	)	$	3.7
	Earnings Per Limited Partner Unit
		Three Months Ended
		March 31,
		2014			2013
	Limited partners’ interest in net income (loss)	$	(5.1	)	$	3.7
	Weighted-average limited partner units - basic	187.8			64.7
	Effect of diluted units	—			—
	Weighted-average limited partner units - diluted	187.8			64.7
	Basic earnings per unit:
	Net income (loss) per limited partner	$	(0.03	)	$	0.06
	Diluted earnings per unit:
	Net income (loss) per limited partner	$	(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 months ended March 31, 2014, we excluded 4,922,372 common units, representing Crestwood Niobrara's preferred units if converted to common units, from our diluted earnings per unit. There were no units excluded from our dilutive earnings per share as we did not have any anti-dilutive units for the three months ended March 31, 2013. See Note 8 for additional information regarding the potential conversion of the preferred security units to common units.

Financial_Instruments

Financial Instruments	3 Months Ended
	Mar. 31, 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 March 31, 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.
	As of March 31, 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 our credit facilities approximated their carrying amounts as of March 31, 2014 and December 31, 2013 due primarily to the variable nature of the interest rate of the instruments, 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):
		March 31, 2014				December 31, 2013
		Carrying Amount		Fair		Carrying Amount		Fair
				Value				Value
	2022 Senior Notes	$	600	$	624	$	600	$	617.3
	2019 Senior Notes	$	351.2	$	381.5	$	351.2	$	379.3
	2020 Senior Notes	$	504.5	$	528.4	$	504.7	$	513.8
	Long-Term Debt
	Long-term debt consisted of the following at March 31, 2014 and December 31, 2013 (in millions):
		March 31,		December 31,
		2014		2013
	Credit Facility	$	532.1	$	414.9
	2019 Senior Notes	350		350
	Premium on 2019 Senior Notes	1.2		1.2
	2020 Senior Notes	500		500
	Fair value adjustment of 2020 Senior Notes	4.5		4.7
	2022 Senior Notes	600		600
	Other	1.7		—
	Total debt	1,989.50		1,870.80
	Less: current portion	10.4		2.9
	Total long-term debt	$	1,979.10	$	1,867.90
	Credit Facility
	We have a five-year $1 billion senior secured revolving credit facility (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.
	At March 31, 2014, the balance outstanding on the Credit Facility was $532.1 million and outstanding standby letters of credit amounted to $31.4 million. As a result, we had $436.5 million of remaining capacity under the revolving credit facility at March 31, 2014, subject to compliance with any applicable covenants under our credit agreement. The weighted-average interest rate as of March 31, 2014 was 5.71%.
	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 (subject to, at our election, a consolidated net leverage ratio of not more than 5.50 to 1.0 during certain periods following certain material acquisitions as further described in our credit agreement) to 1.0 and an interest coverage ratio (as defined in our credit agreement) of not less than 2.50 to 1.0.
	At March 31, 2014, we elected to use a consolidated net leverage ratio of 5.50 to 1.0. Our total funded debt to consolidated EBITDA was approximately 5.06 to 1.0 and consolidated EBITDA to consolidated interest expense was approximately 3.61 to 1.0 at March 31, 2014.
	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 2012 (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.
	At March 31, 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	3 Months Ended
	Mar. 31, 2014
Partners' Capital [Abstract]	'
Partners' Capital	'
	Partners’ Capital
	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 common 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
	During the three months ended March 31, 2014 and 2013, the general partner received cash distributions (representing IDRs and distributions related to general partner units held) of approximately $10.5 million and $4.1 million.
	Distributions to Limited Partners
	The following table presents our quarterly cash distribution for the three months ended March 31, 2014:
	Three Months Ended March 31, 2014
	Record Date	Payment Date	Per Unit Rate		Cash Distribution
					(in millions)
	February 7, 2014	February 14, 2014	$	0.41	$	74.1
	The following table presents Legacy Crestwood's quarterly cash distribution for the three months ended March 31, 2013:
	Three Months Ended March 31, 2013
	Record Date	Payment Date	Per Unit Rate		Cash Distribution
					(in millions)
	January 31, 2013	February 12, 2013	$	0.51	$	21
	On April 24, 2014, we declared a distribution of $0.41 per limited partner unit to be paid on May 15, 2014, to unitholders of record on May 8, 2014 with respect to the first quarter of 2014. On May 10, 2013, Legacy Crestwood paid a distribution of $0.51 per limited partner unit for a total of $27.4 million with respect to the first quarter of 2013.
	Other Partners’ Capital Transaction
	On January 8, 2013, Legacy Crestwood acquired Crestwood Holdings’ 65% membership interest in Crestwood Marcellus Midstream LLC 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 Crestwood Marcellus Midstream LLC in our consolidated statements of cash flows for the three months ended March 31, 2013.
	Preferred Equity of Subsidiary
	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. During the three months ended March 31, 2014, we allocated approximately $3.1 million of net income to the non-controlling interest, which was based on the overall return attributable to the preferred security.
	Crestwood Niobrara will fund 75% of future capital contributions to Jackalope through additional preferred interest issuances to GE (up to a maximum of an additional $41.6 million as of March 31, 2014), with the remainder to be funded through our capital contributions to Crestwood Niobrara. During the three months ended March 31, 2014, GE EFS made a capital contribution of $12.3 million to Crestwood Niobrara in exchange for an equivalent number of preferred units. Through March 31, 2014, GE has made capital contributions totaling $108.4 million.
	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 months ended March 31, 2014, Crestwood Niobrara issued 2,210,294 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 April 30, 2014, Crestwood Niobrara issued 2,536,010 preferred units to GE in lieu of paying a cash distribution.

LongTerm_Incentive_Plan_Notes

Long-Term Incentive Plan (Notes)	3 Months Ended
	Mar. 31, 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.
	On January 17, 2014, we issued restricted unit awards, which were approved by the CMLP Board's compensation committee, to certain key employees. The awards consisted of an annual award based on a percentage of each recipient's annual salary, and a one-time bridge award designed to provide an additional base award to certain key employees with no remaining unvested awards given that their previously accumulated equity ownership in Legacy Inergy and Legacy Crestwood vested as a result of the change of control with the Crestwood Merger. Both of these awards vest upon continued service.
	The following table summarizes information regarding restricted unit activity during the three months ended March 31, 2014:
		Units		Weighted-Average Grant Date Fair Value
	Unvested - January 1, 2014	250,557		$	22.13
	Vested - restricted units	(20,568	)	$	21.68
	Granted - restricted units	757,902		$	23.41
	Unvested - March 31, 2014	987,891		$	23.13
	As of March 31, 2014 and December 31, 2013, we had total unamortized compensation expense of approximately $16.4 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 $2.9 million and $0.6 million during the three months ended March 31, 2014 and 2013, which is included in general and administrative expenses on our consolidated statements of operations. An additional $1.7 million of net compensation expense was allocated from CEQP to CMLP during the three months ended March 31, 2014 (see Note 11). The compensation expense recognized during the three months ended March 31, 2013 was related to the Legacy Crestwood long-term incentive plan. We granted restricted units with a grant date fair value of approximately $17.7 million during the three months ended March 31, 2014.  As of March 31, 2014, we had 6,391,871 units available for issuance under the Crestwood LTIP.
	Under the Crestwood LTIP, participants who have been granted restricted units may elect to have us withhold common units 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 March 31, 2014 and 2013, we withheld 7,456 common units and 1,529 common units to satisfy employee tax withholding obligations.

Commitments_and_Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2014
Commitments and Contingencies Disclosure [Abstract]	'
Commitments and Contingencies	'
	Commitments and Contingencies
	Legal Proceedings
	Class Action Lawsuits. Five putative class action lawsuits challenging the Crestwood Merger were filed, four in federal court in the United States District Court for the Southern District of Texas: (i) Abraham Knoll v. Robert G. Phillips, et al. (Case No. 4:13-cv-01528, filed May 23, 2013); (ii) Greg Podell v. Crestwood Midstream Partners, LP, et al. (Case No. 4:13-cv-01599, filed May 30, 2013); (iii) Johnny Cooper v. Crestwood Midstream Partners LP, et al. (Case No. 4:13-cv-01660, filed June 7, 2013), subsequently replaced as named plaintiff in this action by Linda Giaimo; and (iv) Steven Elliot LLC v. Robert G. Phillips, et al. (Case No. 4:13-cv-01763, June 17, 2013), and one in the Delaware Court of Chancery: Hawley v. Crestwood Midstream Partners LP, et al. (Case No. 8689-VCL, filed June 27, 2013). All the cases named Legacy Crestwood (since merged with the Company), Crestwood Gas Services GP LLC, Crestwood Holdings LLC, the current and former directors of Crestwood Gas Services GP LLC, CEQP, the Company, Crestwood Midstream GP LLC (formerly NRGM GP, LLC), and Intrepid Merger Sub, LLC as defendants. All of the suits were brought by purported holders of common units of Legacy Crestwood, both individually and on behalf of a putative class consisting of holders of common units of Legacy Crestwood. The lawsuits generally alleged, among other things, that the directors of Crestwood Gas Services GP LLC breached their fiduciary duties to holders of common units of Legacy Crestwood by agreeing to a transaction with inadequate consideration and unfair terms and pursuant to an inadequate process. The lawsuits further alleged that CEQP, the Company, Crestwood Midstream GP LLC, and Intrepid Merger Sub, LLC aided and abetted the Legacy Crestwood directors in the alleged breach of their fiduciary duties. The lawsuits sought, in general, (i) injunctive relief enjoining the merger, (ii) in the event the merger is consummated, rescission or an award of rescissory damages, (iii) an award of plaintiffs’ costs, including reasonable attorneys’ and experts’ fees, (iv) the accounting by the defendants to plaintiffs for all damages caused by the defendants, and (v) such further equitable relief as the court deems just and proper. The four federal actions also asserted claims of inadequate disclosure under Sections 14(a) and 20(a) of the Securities Exchange Act of 1934, and the Elliot case also named Citigroup Global Markets Inc. as an alleged aider and abettor. The plaintiff in the Hawley action in Delaware filed a motion for expedited proceedings but subsequently withdrew that motion and then filed a stipulation voluntarily dismissing the action without prejudice, which has been granted by the Court, such that the Hawley action has now been dismissed. The plaintiff in the Elliot action filed a motion for expedited discovery, which was denied by the Court. The plaintiffs in the Knoll, Podell, Cooper, and Elliot actions filed an unopposed motion to consolidate these four cases, which the Court granted and captioned the consolidated matter as In re Crestwood Midstream Partners Unitholder Litigation, Lead Case No. 4:13-cv-01528 (the “Consolidated Action”). The plaintiffs entered into a Memorandum of Understanding (MOU) on September 24, 2013 to settle the Consolidated Action whereby the defendants denied liability. The settlement contemplated by the MOU is subject to a number of conditions, including notice to the class and final court approval following completion of a settlement hearing, which is scheduled for May 16, 2014. The defendants expect the Court to approve the final settlement. The anticipated settlement of the MOU will not have a material impact to our consolidated financial statements.
	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 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 will be heard in June 2014.  We believe the claims against us are without merit and will vigorously defend ourselves and oppose the motion for class action.  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 have also 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 March 31, 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 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
	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. Our accruals and potential exposures related to our environmental matters were immaterial at March 31, 2014 and December 31, 2013.
	Contingent Consideration - Antero
	In connection with the Antero Acquisition, we agreed to pay Antero conditional consideration in the form of potential additional cash payments of up to $40 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 likely exceed the annual production threshold in the earn-out provision and accordingly, we recognized a liability of $33.5 million and $31.4 million as of March 31, 2014 and December 31, 2013 that represents the fair value of the potential payments that may be made under this earn-out provision. We estimated the liability based on the probability-weighted discounted cash flows using a 5.9% discount rate and our estimate of Antero’s production in 2014 (a Level 3 fair value measurement).

Related_Party_Transactions

Related Party Transactions	3 Months Ended
	Mar. 31, 2014
Related Party Transactions [Abstract]	'
Related Party Transactions	'
	Related Party Transactions
	CMLP does 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 its behalf, except for certain unit based compensation which are treated as capital transactions. CEQP allocated to us $15.8 million of costs for the three months ended March 31, 2014. Included in this amount was $1.7 million of net unit-based compensation charges. We have an omnibus agreement with CEQP that requires us to reimburse CEQP for all shared costs incurred on its behalf, except for certain unit based compensation costs which are treated as capital transactions. 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 operations and maintenance expenses from our affiliates for the three-month periods ended March 31, 2014 and 2013 (in millions):
		Three Months Ended
		March 31,
		2014(a)		2013
	Gathering and processing revenues	$	0.9	$	25.6
	NGL and crude services revenues	$	3.3	$	—
	Gathering and processing costs of goods sold	$	11	$	6.8
	General and administrative expenses	$	3.8	$	5.8
	(a)	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 March 31, 2014 and December 31, 2013 (in millions):
		March 31, 2014		December 31, 2013
	Accounts receivable	$	1.4	$	1.1
	Accounts payable	$	37.5	$	8.7
	For additional information regarding our related parties, see our 2013 Annual Report on Form 10-K as filed with the SEC.

Segments

Segments	3 Months Ended
	Mar. 31, 2014
Segment Reporting [Abstract]	'
Segments	'
	Segments
	Financial Information
	We have three operating and reporting 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 gathering, storage 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
		March 31,
		2014			2013
	Net income	$	5.5		$	8.9
	Add:
	Interest and debt expense, net	28.1			11.4
	Provision for income taxes	0.7			0.4
	Depreciation, amortization and accretion	50.8			17.4
	EBITDA	$	85.1		$	38.1
	The following tables summarize the reportable segment data for the three-month periods ended March 31, 2014 and 2013 (in millions).
		Three Months Ended March 31, 2014
		Gathering and Processing			Storage and Transportation		NGL and Crude Services			Corporate			Total
	Operating revenues	$	79.5		$	44.3	$	413.2		$	—		$	537
	Costs of product/services sold	18.7			3.2		376.2			—			398.1
	Operations and maintenance expense	13.4			4.3		10.3			—			28
	General and administrative expense	—			—		—			24.1			24.1
	Gain on long-lived assets	0.5			—		—			—			0.5
	Loss on contingent consideration	(2.1		)	—		—			—			(2.1		)
	Earnings (loss) from unconsolidated affiliates, net	0.3			—		(0.4		)	—			(0.1		)
	EBITDA	$	46.1		$	36.8	$	26.3		$	(24.1	)	$	85.1
	Goodwill	$	99.6		$	728.6	$	861.1		$	—		$	1,689.30
	Total assets	$	1,881.60		$	1,975.50	$	2,478.00		$	156.3		$	6,491.40
	Cash expenditures for property, plant and equipment	$	41.7		$	1.2	$	23.9		$	0.9		$	67.7
		Three Months Ended March 31, 2013
		Gathering and Processing			Storage and Transportation		NGL and Crude Services			Corporate			Total
	Operating revenues	$	72.4		$	—	$	—		$	—		$	72.4
	Costs of product/services sold	13.5			—		—			—			13.5
	Operations and maintenance expense	13			—		—			—			13
	General and administrative expense	—			—		—			7.8			7.8
	EBITDA	$	45.9		$	—	$	—		$	(7.8	)	$	38.1
	Goodwill	$	95		$	—	$	—		$	—		$	95
	Total assets	$	1,593.30		$	—	$	—		$	23.5		$	1,616.80
	Cash expenditures for property, plant and equipment	$	23.9		$	—	$	—		$	0.4		$	24.3
	Major Customers
	Three customers, Tesoro Refining & Marketing Company (Tesoro) (17%), QEP Energy Company (QEP) (12%) and WPX Energy Williston, LLC (WPX) (10%), accounted for 10% or more of our total consolidated revenues for the three months ended March 31, 2014. These customers' revenues are captured in the NGL and crude services segment. Two customers, Quicksilver (35%) and Antero Resources Appalachian Corporation (Antero) (20%), accounted for 10% or more of our total consolidated revenues for the three months ended March 31, 2013. These customers' revenues are captured in the gathering and processing segment.
	Four customers, QEP (17%), XTO Energy, Inc. (XTO) (13%), Halcon Resources Corp. (Halcon) (13%) and WPX (12%), accounted for 10% or more of our consolidated accounts receivable at March 31, 2014. These customers' accounts receivable are captured in the NGL and crude services segment. Three customers, Tesoro (19%), Eighty-Eight Oil LLC (10%) and QEP (10%), accounted for 10% or more of our consolidated accounts receivable at December 31, 2013. These customers' accounts receivable are captured in the NGL and crude services segment.

Condensed_Consolidating_Financ

Condensed Consolidating Financial Information (Notes)	3 Months Ended
	Mar. 31, 2014
Condensed Financial Information of Parent Company Only Disclosure [Abstract]	'
Condensed Consolidating Financial Information	'
	Condensed Consolidating Financial Information
	We are a holding company and own no operating assets and have no significant operations independent of our 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 (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 March 31, 2014 and December 31, 2013, and for the three months ended March 31, 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.  Accordingly, we have not reflected condensed consolidating financial information for the three months ended March 31, 2013 because our unrestricted subsidiaries were not formed or were not designated as unrestricted subsidiaries as of March 31, 2013.
	Condensed Consolidating Balance Sheet
	31-Mar-14
	(in millions)
		Parent			Guarantor			Non-			Eliminations			Consolidated
					Subsidiaries			Guarantor
								Subsidiaries
	Assets
	Current assets:
	Cash and cash equivalents	$	0.8		$	4.2		$	—		$	—		$	5
	Accounts receivable	544.2			227.3			0.2			(534.4		)	237.3
	Inventories	—			10.7			—			—			10.7
	Other current assets	—			13.6			—			—			13.6
	Total current assets	545			255.8			0.2			(534.4		)	266.6
	Property, plant and equipment, net	3.6			3,380.80			—			—			3,384.40
	Goodwill and intangible assets, net	—			2,646.00			—			—			2,646.00
	Investment in consolidated affiliates	6,371.30			—			—			(6,371.3		)	—
	Investment in unconsolidated affiliates	—			—			171.1			—			171.1
	Other assets	0.2			23.1			—			—			23.3
	Total assets	$	6,920.10		$	6,305.70		$	171.3		$	(6,905.7	)	$	6,491.40
	Liabilities and partners' capital
	Current liabilities:
	Accounts payable	$	797.5		$	(72.1	)	$	0.2		$	(534.4	)	$	191.2
	Other current liabilities	11.2			151			—			—			162.2
	Total current liabilities	808.7			78.9			0.2			(534.4		)	353.4
	Long-term liabilities:
	Long-term debt, less current portion	1,979.10			—			—			—			1,979.10
	Other long-term liabilities	1.4			26.6			—			—			28
	Total long-term liabilities	1,980.50			26.6			—			—			2,007.10
	Partners' capital	4,014.50			6,200.20			54.7			(6,254.9		)	4,014.50
	Interest of non-controlling partners in subsidiaries	116.4			—			116.4			(116.4		)	116.4
	Total partners' capital	4,130.90			6,200.20			171.1			(6,371.3		)	4,130.90
	Total liabilities and partners' capital	$	6,920.10		$	6,305.70		$	171.3		$	(6,905.7	)	$	6,491.40
	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 March 31, 2014
(in millions)
	Parent			Guarantor			Non-			Eliminations			Consolidated
				Subsidiaries			Guarantor
							Subsidiaries
Revenues:
Gathering and processing	$	—		$	78.6		$	—		$	—		$	78.6
Storage and transportation	—			44.3			—			—			44.3
NGL and crude services	—			409.9			—			—			409.9
Related party	—			4.2			—			—			4.2
	—			537			—			—			537
Costs of product/services sold (excluding depreciation, amortization and accretion as shown below):
Gathering and processing	—			7.7			—			—			7.7
Storage and transportation	—			3.2			—			—			3.2
NGL and crude services	—			376.2			—			—			376.2
Related party	—			11			—			—			11
	—			398.1			—			—			398.1
Expenses:
Operations and maintenance	—			28			—			—			28
General and administrative	(2.1		)	26.2			—			—			24.1
Depreciation, amortization and accretion	0.2			50.6			—			—			50.8
	(1.9		)	104.8			—			—			102.9
Other operating income (expense):
Loss on contingent consideration	—			(2.1		)	—			—			(2.1		)
Other	—			0.5			—			—			0.5
Operating income	1.9			32.5			—			—			34.4
Interest and debt expense, net	(28.1		)	—			—			—			(28.1		)
Equity in net income (loss) of subsidiary	31.7			—			—			(31.7		)	—
Other	—			—			(0.1		)	—			(0.1		)
Income (loss) before income taxes	5.5			32.5			(0.1		)	(31.7		)	6.2
Provision for income taxes	—			0.7			—			—			0.7
Net income (loss)	5.5			31.8			(0.1		)	(31.7		)	5.5
Net (income) attributable to non-controlling partners	—			—			(3.1		)	—			(3.1		)
Net income (loss) attributable to Crestwood Midstream Partners LP	5.5			31.8			(3.2		)	(31.7		)	2.4
Condensed Consolidating Statements of Cash Flows
Three Months Ended March 31, 2014
(in millions)
	Parent			Guarantor			Non-			Eliminations			Consolidated
				Subsidiaries			Guarantor
							Subsidiaries
Cash flows from operating activities:	$	5.8		$	52.3		$	—		$	—		$	58.1
Cash flows from investing activities:
Acquisitions, net of cash acquired	—			(12.1		)	—			—			(12.1		)
Purchases of property, plant and equipment	(0.9		)	(66.8		)	—			—			(67.7		)
Investment in unconsolidated affiliates, net	—			(2.5		)	(17.3		)	—			(19.8		)
Capital contribution from consolidated affiliates	(4.0		)	—			—			4			—
Other	(2.4		)	—			—			2.4			—
Net cash provided by (used in) investing activities	(7.3		)	(81.4		)	(17.3		)	6.4			(99.6		)
Cash flows from financing activities:
Proceeds from the issuance of long-term debt	2.5			303.5			—			—			306
Principal payments on long-term debt	—			(188.8		)	—			—			(188.8		)
Distributions paid	—			(84.6		)	—			—			(84.6		)
Contributions from parent	—			—			4			(4.0		)	—
Net proceeds from issuance of preferred equity	—			—			12.3			—			12.3
Payments on capital leases	(0.3		)	(0.8		)	—			—			(1.1		)
Net change in payables to affiliates	—			2.4			—			(2.4		)	—
Net cash provided by (used in) financing activities	2.2			31.7			16.3			(6.4		)	43.8
Net increase in cash	0.7			2.6			(1.0		)	—			2.3
Cash at beginning of period	0.1			1.6			1			—			2.7
Cash at end of period	$	0.8		$	4.2		$	—		$	—		$	5

Basis_of_Presentation_and_Summ1

Basis of Presentation and Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 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 and no significant accounting pronouncements issued but not yet adopted as of March 31, 2014.

Certain_Balance_Sheet_Informat1

Certain Balance Sheet Information (Tables)	3 Months Ended
	Mar. 31, 2014
Balance Sheet Related Disclosures [Abstract]	'
Components of Property, Plant and Equipment	'
	Property, plant and equipment consisted of the following at March 31, 2014 and December 31, 2013 (in millions):
		March 31,		December 31,
		2014		2013
	Gathering systems and pipelines	1,225.40		1,231.10
	Facilities and equipment	1,289.40		1,041.00
	Buildings, land, rights-of-way, storage contracts and easements	769.5		766.2
	Vehicles	7.8		4.1
	Construction in process	179.7		360.5
	Base gas	36.3		36.3
	Salt deposits	120.5		120.5
	Office furniture and fixtures	4.2		6
		3,632.80		3,565.70
	Less: accumulated depreciation and depletion	248.4		215.6
	Total property, plant and equipment, net	$	3,384.40	$	3,350.10
Components of Intangible Assets	'
	Intangible assets consisted of the following at March 31, 2014 and December 31, 2013 (in millions):
		March 31,		December 31,
		2014		2013
	Customer accounts	$	480.3	$	476.4
	Covenants not to compete	3.8		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
		1,029.80		1,025.10
	Less: accumulated amortization	73.1		54.3
	Total intangible assets, net	$	956.7	$	970.8
Components of Accrued Expenses and Other Liabilities	'
	Accrued expenses and other liabilities consisted of the following at March 31, 2014 and December 31, 2013 (in millions):
		March 31, 2014		December 31, 2013
	Accrued expenses	$	14.5	$	20
	Accrued property taxes	3.5		7.6
	Accrued product purchases payable	1.8		1.6
	Tax payable	11.4		10.6
	Interest payable	27		14.9
	Accrued additions to property, plant and equipment	55.5		58.1
	Commitments and contingent liabilities (Note 10)	33.5		31.4
	Capital leases	2		2.6
	Deferred revenue	2.6		1.6
	Total accrued expenses and other liabilities	$	151.8	$	148.4

Acquisitions_Tables

Acquisitions (Tables)	3 Months Ended
	Mar. 31, 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 Legacy Inergy reverse merger and the Arrow Acquisition had been included in our consolidated results for the three months ended March 31, 2013 (in millions, except per unit information).
	Revenues	$	424.7
	Net income	$	13.1
	Net income per limited partner unit(a):
	Basic	$	0.09
	Diluted	$	0.09
Inergy Midstream	'
Business Acquisition [Line Items]	'
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block]	'
	The following table summarizes the preliminary fair values 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	1,537.70
	Net assets acquired	$	2,682.30
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 preliminary fair values of the assets acquired and liabilities assumed at the acquisition date (in millions):
	Current assets	$	191.1
	Property, plant and equipment	400.2
	Intangible assets	323.4
	Other assets	19.5
	Total identifiable assets acquired	934.2
	Current liabilities	215.3
	Assets retirement obligations	1.2
	Other long-term liabilities	3.7
	Total liabilities assumed	220.2
	Net identifiable assets acquired	714
	Goodwill	48.8
	Net assets acquired	$	762.8

Earnings_Limited_Partner_Unit_1

Earnings Limited Partner Unit (Tables)	3 Months Ended
	Mar. 31, 2014
Earnings Per Share [Abstract]	'
Schedule of Other Nonoperating Income (Expense)	'
	The tables below show the (i) allocation of net income attributable to limited partners 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-month periods ended March 31, 2014 and 2013 (in millions):
	Allocation of Net Income Attributable to CMLP to General Partner and Limited Partners
		Three Months Ended
		March 31,
		2014			2013
	Net income attributable to CMLP	$	2.4		$	8.9
	General partner’s incentive distributions	(7.5		)	(5.0		)
	Net income (loss) attributable to CMLP after incentive distributions	(5.1		)	3.9
	General partner’s interest in net income attributable to CMLP after incentive distributions	—			(0.2		)
	Limited partners’ interest in net income (loss) attributable to CMLP after incentive distributions	$	(5.1	)	$	3.7
Schedule of Earnings Per Share Reconciliation	'
	Earnings Per Limited Partner Unit
		Three Months Ended
		March 31,
		2014			2013
	Limited partners’ interest in net income (loss)	$	(5.1	)	$	3.7
	Weighted-average limited partner units - basic	187.8			64.7
	Effect of diluted units	—			—
	Weighted-average limited partner units - diluted	187.8			64.7
	Basic earnings per unit:
	Net income (loss) per limited partner	$	(0.03	)	$	0.06
	Diluted earnings per unit:
	Net income (loss) per limited partner	$	(0.03	)	$	0.06

Financial_Instruments_Tables

Financial Instruments (Tables)	3 Months Ended
	Mar. 31, 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):
		March 31, 2014				December 31, 2013
		Carrying Amount		Fair		Carrying Amount		Fair
				Value				Value
	2022 Senior Notes	$	600	$	624	$	600	$	617.3
	2019 Senior Notes	$	351.2	$	381.5	$	351.2	$	379.3
	2020 Senior Notes	$	504.5	$	528.4	$	504.7	$	513.8
Schedule of Debt	'
	Long-term debt consisted of the following at March 31, 2014 and December 31, 2013 (in millions):
		March 31,		December 31,
		2014		2013
	Credit Facility	$	532.1	$	414.9
	2019 Senior Notes	350		350
	Premium on 2019 Senior Notes	1.2		1.2
	2020 Senior Notes	500		500
	Fair value adjustment of 2020 Senior Notes	4.5		4.7
	2022 Senior Notes	600		600
	Other	1.7		—
	Total debt	1,989.50		1,870.80
	Less: current portion	10.4		2.9
	Total long-term debt	$	1,979.10	$	1,867.90

Partners_Capital_Tables

Partners' Capital (Tables)	3 Months Ended
	Mar. 31, 2014
Partners' Capital [Abstract]	'
Schedule of Distributions Made to Members or Limited Partners, by Distribution	'
	The following table presents our quarterly cash distribution for the three months ended March 31, 2014:
	Three Months Ended March 31, 2014
	Record Date	Payment Date	Per Unit Rate		Cash Distribution
					(in millions)
	February 7, 2014	February 14, 2014	$	0.41	$	74.1
	The following table presents Legacy Crestwood's quarterly cash distribution for the three months ended March 31, 2013:
	Three Months Ended March 31, 2013
	Record Date	Payment Date	Per Unit Rate		Cash Distribution
					(in millions)
	January 31, 2013	February 12, 2013	$	0.51	$	21

LongTerm_Incentive_Plan_Tables

Long-Term Incentive Plan (Tables)	3 Months Ended
	Mar. 31, 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 three months ended March 31, 2014:
		Units		Weighted-Average Grant Date Fair Value
	Unvested - January 1, 2014	250,557		$	22.13
	Vested - restricted units	(20,568	)	$	21.68
	Granted - restricted units	757,902		$	23.41
	Unvested - March 31, 2014	987,891		$	23.13

Related_Party_Transactions_Tab

Related Party Transactions (Tables)	3 Months Ended
	Mar. 31, 2014
Related Party Transactions [Abstract]	'
Schedule of Related Party Transactions	'
	The following table shows revenues, costs of goods sold and operations and maintenance expenses from our affiliates for the three-month periods ended March 31, 2014 and 2013 (in millions):
		Three Months Ended
		March 31,
		2014(a)		2013
	Gathering and processing revenues	$	0.9	$	25.6
	NGL and crude services revenues	$	3.3	$	—
	Gathering and processing costs of goods sold	$	11	$	6.8
	General and administrative expenses	$	3.8	$	5.8
	(a)	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 March 31, 2014 and December 31, 2013 (in millions):
		March 31, 2014		December 31, 2013
	Accounts receivable	$	1.4	$	1.1
	Accounts payable	$	37.5	$	8.7

Segments_Tables

Segments (Tables)	3 Months Ended
	Mar. 31, 2014
Segment Reporting [Abstract]	'
Reportable Segments	'
	The following table is a reconciliation of net income to EBITDA (in millions):
		Three Months Ended
		March 31,
		2014			2013
	Net income	$	5.5		$	8.9
	Add:
	Interest and debt expense, net	28.1			11.4
	Provision for income taxes	0.7			0.4
	Depreciation, amortization and accretion	50.8			17.4
	EBITDA	$	85.1		$	38.1
	The following tables summarize the reportable segment data for the three-month periods ended March 31, 2014 and 2013 (in millions).
		Three Months Ended March 31, 2014
		Gathering and Processing			Storage and Transportation		NGL and Crude Services			Corporate			Total
	Operating revenues	$	79.5		$	44.3	$	413.2		$	—		$	537
	Costs of product/services sold	18.7			3.2		376.2			—			398.1
	Operations and maintenance expense	13.4			4.3		10.3			—			28
	General and administrative expense	—			—		—			24.1			24.1
	Gain on long-lived assets	0.5			—		—			—			0.5
	Loss on contingent consideration	(2.1		)	—		—			—			(2.1		)
	Earnings (loss) from unconsolidated affiliates, net	0.3			—		(0.4		)	—			(0.1		)
	EBITDA	$	46.1		$	36.8	$	26.3		$	(24.1	)	$	85.1
	Goodwill	$	99.6		$	728.6	$	861.1		$	—		$	1,689.30
	Total assets	$	1,881.60		$	1,975.50	$	2,478.00		$	156.3		$	6,491.40
	Cash expenditures for property, plant and equipment	$	41.7		$	1.2	$	23.9		$	0.9		$	67.7
		Three Months Ended March 31, 2013
		Gathering and Processing			Storage and Transportation		NGL and Crude Services			Corporate			Total
	Operating revenues	$	72.4		$	—	$	—		$	—		$	72.4
	Costs of product/services sold	13.5			—		—			—			13.5
	Operations and maintenance expense	13			—		—			—			13
	General and administrative expense	—			—		—			7.8			7.8
	EBITDA	$	45.9		$	—	$	—		$	(7.8	)	$	38.1
	Goodwill	$	95		$	—	$	—		$	—		$	95
	Total assets	$	1,593.30		$	—	$	—		$	23.5		$	1,616.80
	Cash expenditures for property, plant and equipment	$	23.9		$	—	$	—		$	0.4		$	24.3

Condensed_Consolidating_Financ1

Condensed Consolidating Financial Information (Tables)	3 Months Ended
	Mar. 31, 2014
Condensed Financial Information of Parent Company Only Disclosure [Abstract]	'
Consolidating Balance Sheet	'
	Condensed Consolidating Balance Sheet
	31-Mar-14
	(in millions)
		Parent			Guarantor			Non-			Eliminations			Consolidated
					Subsidiaries			Guarantor
								Subsidiaries
	Assets
	Current assets:
	Cash and cash equivalents	$	0.8		$	4.2		$	—		$	—		$	5
	Accounts receivable	544.2			227.3			0.2			(534.4		)	237.3
	Inventories	—			10.7			—			—			10.7
	Other current assets	—			13.6			—			—			13.6
	Total current assets	545			255.8			0.2			(534.4		)	266.6
	Property, plant and equipment, net	3.6			3,380.80			—			—			3,384.40
	Goodwill and intangible assets, net	—			2,646.00			—			—			2,646.00
	Investment in consolidated affiliates	6,371.30			—			—			(6,371.3		)	—
	Investment in unconsolidated affiliates	—			—			171.1			—			171.1
	Other assets	0.2			23.1			—			—			23.3
	Total assets	$	6,920.10		$	6,305.70		$	171.3		$	(6,905.7	)	$	6,491.40
	Liabilities and partners' capital
	Current liabilities:
	Accounts payable	$	797.5		$	(72.1	)	$	0.2		$	(534.4	)	$	191.2
	Other current liabilities	11.2			151			—			—			162.2
	Total current liabilities	808.7			78.9			0.2			(534.4		)	353.4
	Long-term liabilities:
	Long-term debt, less current portion	1,979.10			—			—			—			1,979.10
	Other long-term liabilities	1.4			26.6			—			—			28
	Total long-term liabilities	1,980.50			26.6			—			—			2,007.10
	Partners' capital	4,014.50			6,200.20			54.7			(6,254.9		)	4,014.50
	Interest of non-controlling partners in subsidiaries	116.4			—			116.4			(116.4		)	116.4
	Total partners' capital	4,130.90			6,200.20			171.1			(6,371.3		)	4,130.90
	Total liabilities and partners' capital	$	6,920.10		$	6,305.70		$	171.3		$	(6,905.7	)	$	6,491.40
	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 March 31, 2014
	(in millions)
		Parent			Guarantor			Non-			Eliminations			Consolidated
					Subsidiaries			Guarantor
								Subsidiaries
	Revenues:
	Gathering and processing	$	—		$	78.6		$	—		$	—		$	78.6
	Storage and transportation	—			44.3			—			—			44.3
	NGL and crude services	—			409.9			—			—			409.9
	Related party	—			4.2			—			—			4.2
		—			537			—			—			537
	Costs of product/services sold (excluding depreciation, amortization and accretion as shown below):
	Gathering and processing	—			7.7			—			—			7.7
	Storage and transportation	—			3.2			—			—			3.2
	NGL and crude services	—			376.2			—			—			376.2
	Related party	—			11			—			—			11
		—			398.1			—			—			398.1
	Expenses:
	Operations and maintenance	—			28			—			—			28
	General and administrative	(2.1		)	26.2			—			—			24.1
	Depreciation, amortization and accretion	0.2			50.6			—			—			50.8
		(1.9		)	104.8			—			—			102.9
	Other operating income (expense):
	Loss on contingent consideration	—			(2.1		)	—			—			(2.1		)
	Other	—			0.5			—			—			0.5
	Operating income	1.9			32.5			—			—			34.4
	Interest and debt expense, net	(28.1		)	—			—			—			(28.1		)
	Equity in net income (loss) of subsidiary	31.7			—			—			(31.7		)	—
	Other	—			—			(0.1		)	—			(0.1		)
	Income (loss) before income taxes	5.5			32.5			(0.1		)	(31.7		)	6.2
	Provision for income taxes	—			0.7			—			—			0.7
	Net income (loss)	5.5			31.8			(0.1		)	(31.7		)	5.5
	Net (income) attributable to non-controlling partners	—			—			(3.1		)	—			(3.1		)
	Net income (loss) attributable to Crestwood Midstream Partners LP	5.5			31.8			(3.2		)	(31.7		)	2.4
Consolidating Statement of Cash Flows	'
	Condensed Consolidating Statements of Cash Flows
	Three Months Ended March 31, 2014
	(in millions)
		Parent			Guarantor			Non-			Eliminations			Consolidated
					Subsidiaries			Guarantor
								Subsidiaries
	Cash flows from operating activities:	$	5.8		$	52.3		$	—		$	—		$	58.1
	Cash flows from investing activities:
	Acquisitions, net of cash acquired	—			(12.1		)	—			—			(12.1		)
	Purchases of property, plant and equipment	(0.9		)	(66.8		)	—			—			(67.7		)
	Investment in unconsolidated affiliates, net	—			(2.5		)	(17.3		)	—			(19.8		)
	Capital contribution from consolidated affiliates	(4.0		)	—			—			4			—
	Other	(2.4		)	—			—			2.4			—
	Net cash provided by (used in) investing activities	(7.3		)	(81.4		)	(17.3		)	6.4			(99.6		)
	Cash flows from financing activities:
	Proceeds from the issuance of long-term debt	2.5			303.5			—			—			306
	Principal payments on long-term debt	—			(188.8		)	—			—			(188.8		)
	Distributions paid	—			(84.6		)	—			—			(84.6		)
	Contributions from parent	—			—			4			(4.0		)	—
	Net proceeds from issuance of preferred equity	—			—			12.3			—			12.3
	Payments on capital leases	(0.3		)	(0.8		)	—			—			(1.1		)
	Net change in payables to affiliates	—			2.4			—			(2.4		)	—
	Net cash provided by (used in) financing activities	2.2			31.7			16.3			(6.4		)	43.8
	Net increase in cash	0.7			2.6			(1.0		)	—			2.3
	Cash at beginning of period	0.1			1.6			1			—			2.7
	Cash at end of period	$	0.8		$	4.2		$	—		$	—		$	5

Business_Description_Details

Business Description (Details) (USD $)	3 Months Ended		9 Months Ended			3 Months Ended
	Mar. 31, 2014	Mar. 31, 2014	Jun. 30, 2013	Jun. 30, 2013	Jun. 30, 2013	Mar. 31, 2014
	segment	CEQP	Parent	First Reserve	Distribution Rights	Distribution Rights
						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%	'	'	'	'
Percentage of distribution entitled to receive	'	'	50.00%	11.00%	'	100.00%
Distribution declared per limited partner unit	'	'	'	'	$0.37	'
Number of operating segments	3	'	'	'	'	'

Certain_Balance_Sheet_Informat2

Certain Balance Sheet Information (Property Plant and Equipment) (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Property, Plant and Equipment [Line Items]	'	'
Property, plant and equipment (Note 3)	$3,632.80	$3,565.70
Less: accumulated depreciation and depletion	248.4	215.6
Property, plant and equipment, net	3,384.40	3,350.10
Capital Leased Assets, Gross	3.8	5
Gathering systems and pipelines	'	'
Property, Plant and Equipment [Line Items]	'	'
Property, plant and equipment (Note 3)	1,225.40	1,231.10
Facilities and equipment	'	'
Property, Plant and Equipment [Line Items]	'	'
Property, plant and equipment (Note 3)	1,289.40	1,041
Buildings, land, rights-of-way, storage contracts and easements	'	'
Property, Plant and Equipment [Line Items]	'	'
Property, plant and equipment (Note 3)	769.5	766.2
Vehicles	'	'
Property, Plant and Equipment [Line Items]	'	'
Property, plant and equipment (Note 3)	7.8	4.1
Construction in process	'	'
Property, Plant and Equipment [Line Items]	'	'
Property, plant and equipment (Note 3)	179.7	360.5
Base gas	'	'
Property, Plant and Equipment [Line Items]	'	'
Property, plant and equipment (Note 3)	36.3	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)	$4.20	$6

Certain_Balance_Sheet_Informat3

Certain Balance Sheet Information (Intangible Assets) (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Finite-Lived Intangible Assets [Line Items]	'	'
Intangible assets, Gross	$1,029.80	$1,025.10
Less: accumulated amortization	73.1	54.3
Total intangible assets, net	956.7	970.8
Customer accounts	'	'
Finite-Lived Intangible Assets [Line Items]	'	'
Intangible assets, Gross	480.3	476.4
Covenants not to compete	'	'
Finite-Lived Intangible Assets [Line Items]	'	'
Intangible assets, Gross	3.8	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 $)	Mar. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Payables and Accruals [Abstract]	'	'
Accrued expenses	$14.50	$20
Accrued property taxes	3.5	7.6
Accrued product purchases payable	1.8	1.6
Tax payable	11.4	10.6
Interest payable	27	14.9
Accrued additions to property, plant and equipment	55.5	58.1
Commitments and contingent liabilities (Note 12)	33.5	31.4
Capital leases	2	2.6
Deferred revenue	2.6	1.6
Total accrued expenses and other liabilities	$151.80	$148.40

Acquisitions_Details

Acquisitions (Details) (USD $)

3 Months Ended

0 Months Ended

3 Months Ended

Mar. 31, 2014

Mar. 31, 2013

Dec. 31, 2013

Jan. 08, 2013

Mar. 21, 2014

Oct. 08, 2013

Jun. 19, 2013

Nov. 08, 2013

Mar. 31, 2014

Oct. 08, 2013

Mar. 31, 2014

Mar. 31, 2013

Jun. 19, 2013

Mar. 31, 2014

Mar. 31, 2013

Mar. 31, 2014

Red Rock Transportation, Inc

Red Rock Transportation, Inc

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

Storage and Transportation

Storage and Transportation

Storage and Transportation

trailer_tanks

Inergy Midstream

Inergy Midstream

bbl

tractor

double_bottom_body_tanks

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

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Consideration Transferred

'

'

'

$258,000,000

$14,100,000

'

'

$750,000,000

'

'

'

'

'

'

'

'

Cost of Acquired Entity, Cash Paid

'

'

'

'

'

12,100,000

'

'

'

'

'

'

'

'

'

'

Cost of Acquired Entity, Liabilities Incurred

'

'

'

'

'

2,000,000

'

'

'

'

'

'

'

'

'

'

Trailer Tanks, Number

'

'

'

'

'

56

'

'

'

'

'

'

'

'

'

'

Double Bottom Body Tanks

'

'

'

'

'

22

'

'

'

'

'

'

'

'

'

'

Tractors

'

'

'

'

'

44

'

'

'

'

'

'

'

'

'

'

Crude Hauling Capacity

'

'

'

'

'

25,000

'

'

'

'

'

'

'

'

'

'

Business Acquisition, Purchase Price Allocation, Assets Acquired (Liabilities Assumed), Net [Abstract]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Current assets

'

'

'

'

'

'

49,100,000

191,100,000

'

'

'

'

'

'

'

'

Property, plant and equipment

'

'

'

'

'

10,900,000

1,677,800,000

400,200,000

'

'

'

'

'

'

'

'

Intangible assets

'

'

'

'

'

'

196,000,000

323,400,000

'

'

'

'

'

'

'

'

Other assets

'

'

'

'

'

'

2,900,000

19,500,000

'

'

'

'

'

'

'

'

Total identifiable assets acquired

'

'

'

'

'

'

1,925,800,000

934,200,000

'

'

'

'

'

'

'

'

Current liabilities

'

'

'

'

'

'

30,900,000

215,300,000

'

'

'

'

'

'

'

'

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

220,200,000

'

'

'

'

'

'

'

'

Net identifiable assets acquired

'

'

'

'

'

'

1,144,600,000

714,000,000

'

'

'

'

'

'

'

'

Goodwill

1,689,300,000

95,000,000

1,682,800,000

'

'

3,200,000

1,537,700,000

48,800,000

'

'

861,100,000

0

809,100,000

728,600,000

0

728,600,000

Net assets acquired

'

'

'

'

'

'

2,682,300,000

762,800,000

'

'

'

'

'

'

'

'

Business Combination, Consideration Transferred, Other

'

'

'

'

'

'

'

'

'

12,800,000

'

'

'

'

'

'

Payments to Acquire Businesses

'

'

'

'

'

'

'

550,000,000

'

'

'

'

'

'

'

'

Incentive Distribution, Distribution

7,500,000

5,000,000

'

'

'

'

'

8,826,125

'

'

'

'

'

'

'

'

Business Acquisition, Pro Forma Information [Abstract]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Revenue

'

424,700,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Net income

'

13,100,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Basic (usd per unit)

'

$0.09

[1]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Diluted (usd per unit)

'

$0.09

[1]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Business Combination, Acquisition Related Costs

'

'

'

'

'

'

'

'

$4,600,000

'

'

'

'

'

'

'

[1]

Basic and diluted net income per limited partner unit for the three months ended March 31, 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

3 Months Ended

3 Months Ended

In Millions, unless otherwise specified

Mar. 31, 2014

Mar. 31, 2013

Dec. 31, 2013

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Jul. 19, 2013

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Jackalope Gas Gathering Services, LLC

Jackalope Gas Gathering Services, LLC

PRBIC

PRBIC

Crestwood Niobrara LLC

Crestwood Niobrara LLC

Crude Logistics LLC

RKI Exploration and Production, LLC's [Member]

Majority Shareholder

Jackalope Gas Gathering Services, LLC

Jackalope Gas Gathering Services, LLC

PRBIC

Jackalope Gas Gathering Services, LLC

PRBIC

Schedule of Equity Method Investments [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

Equity method ownership percentage

'

'

'

'

'

50.01%

'

'

50.00%

'

'

'

Investment in Unconsolidated Affiliate

'

'

'

'

'

'

'

$17.30

'

'

'

'

Investment in unconsolidated affiliates in period

19.8

0

'

'

'

'

'

'

'

2.5

'

'

Earnings (loss) from unconsolidated affiliates, net

-0.1

0

'

'

'

'

'

'

'

'

'

-0.4

Difference between carrying amount and underlying equity

'

'

'

'

'

'

'

'

'

'

56

'

Amortization

'

'

'

'

'

'

'

'

'

'

0.8

'

Investment in unconsolidated affiliates (Note 5)

171.1

'

151.4

144.8

127.2

26.3

24.2

'

'

'

'

'

Share of Net Earnings In Unconsolidated Affiliate

'

'

'

'

'

'

'

'

'

'

$1.10

'

Earnings_Limited_Partner_Unit_2

Earnings Limited Partner Unit (Allocation of Net Income to General and Limited Partners) (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Earnings Per Share [Abstract]	'	'
Net income (loss) attributable to CMLP	$2.40	$8.90
General partner’s incentive distributions	-7.5	-5
Net income (loss) attributable to CMLP after incentive distributions	-5.1	3.9
General partner’s interest in net income attributable to CMLP after incentive distributions	0	-0.2
Limited partners’ interest in net income (loss) attributable to CMLP after incentive distributions	($5.10)	$3.70

Earnings_Limited_Partner_Unit_3

Earnings Limited Partner Unit (Schedule of Reconciliation of Earnings Per Share) (Details) (USD $)	3 Months Ended
In Millions, except Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Earnings Per Share [Abstract]	'	'
Limited partners’ interest in net income (loss) attributable to CMLP after incentive distributions	($5.10)	$3.70
Basic (units)	187,840,000	64,656,000
Incremental Common Shares Attributable to Share-based Payment Arrangements	0	0
Diluted (units)	187,840,000	64,656,000
Basic, in dollars per unit	-0.03	0.06
Diluted, in dollars per unit	-0.03	0.06

Earnings_Limited_Partner_Unit_4

Earnings Limited Partner Unit (Narrative) (Details)	3 Months Ended
	Mar. 31, 2014
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0
Crestwood Niobrara LLC	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	4,922,372

Financial_Instruments_Schedule

Financial Instruments (Schedule of Carrying Values and Estimated Fair Values of Senior Notes) (Details) (Unsecured Debt, USD $)	Mar. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Carrying Amount | 2022 senior unsecured notes	'	'
Debt Instrument [Line Items]	'	'
Fair value of senior notes	$600	$600
Carrying Amount | 2019 senior unsecured notes	'	'
Debt Instrument [Line Items]	'	'
Fair value of senior notes	351.2	351.2
Carrying Amount | 2020 senior unsecured notes	'	'
Debt Instrument [Line Items]	'	'
Fair value of senior notes	504.5	504.7
Fair Value | 2022 senior unsecured notes	'	'
Debt Instrument [Line Items]	'	'
Fair value of senior notes	624	617.3
Fair Value | 2019 senior unsecured notes	'	'
Debt Instrument [Line Items]	'	'
Fair value of senior notes	381.5	379.3
Fair Value | 2020 senior unsecured notes	'	'
Debt Instrument [Line Items]	'	'
Fair value of senior notes	$528.40	$513.80

Financial_Instruments_Debt_Det

Financial Instruments (Debt) (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Debt Instrument [Line Items]	'	'
Total debt	$1,989.50	$1,870.80
Less: current portion	10.4	2.9
Total long-term debt	1,979.10	1,867.90
Other	'	'
Debt Instrument [Line Items]	'	'
Senior notes	1.7	0
Senior Notes | 2019 Senior Notes	'	'
Debt Instrument [Line Items]	'	'
Senior notes	350	350
Premium on senior notes	1.2	1.2
Senior Notes | 2020 Senior Notes	'	'
Debt Instrument [Line Items]	'	'
Senior notes	500	500
Fair value adjustment of senior notes	4.5	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	$532.10	$414.90

Financial_Instruments_Narrativ

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

3 Months Ended

0 Months Ended

3 Months Ended

Mar. 31, 2014

Oct. 07, 2013

Mar. 31, 2014

Dec. 31, 2013

Oct. 07, 2013

Oct. 07, 2013

Mar. 31, 2014

Dec. 31, 2013

Apr. 30, 2011

Mar. 31, 2014

Dec. 31, 2013

Dec. 07, 2012

Mar. 31, 2014

Dec. 31, 2013

Oct. 22, 2013

Crestwood Midstream Revolver

Crestwood Midstream Revolver

Crestwood Midstream Revolver

Crestwood Midstream Revolver

Crestwood Midstream Revolver

Crestwood Midstream Revolver

2019 Senior Notes

2019 Senior Notes

2019 Senior Notes

2020 Senior Notes

2020 Senior Notes

2020 Senior Notes

2022 Senior Notes

2022 Senior Notes

2022 Senior Notes

Revolver

Revolver

Revolver

Standby Letters of Credit

Swing Line Loans

Senior Notes

Senior Notes

Senior Notes

Senior Notes

Senior Notes

Senior Notes

Senior Notes

Senior Notes

Senior Notes

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

'

'

532,100,000

414,900,000

'

'

'

'

'

'

'

'

'

'

'

Letters of credit outstanding

'

'

31,400,000

'

'

'

'

'

'

'

'

'

'

'

'

Remaining borrowing capacity

'

'

436,500,000

'

'

'

'

'

'

'

'

'

'

'

'

Weighted average interest rate

'

'

5.71%

'

'

'

'

'

'

'

'

'

'

'

'

Maximum leverage ratio

'

'

5

'

'

'

'

'

'

'

'

'

'

'

'

Maximum leverage ratio, certain periods post acquisition

'

'

5.5

'

'

'

'

'

'

'

'

'

'

'

'

Minimum interest coverage ratio

'

'

2.5

'

'

'

'

'

'

'

'

'

'

'

'

Current debt to EBITDA ratio

5.06

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Consolidated EBITDA to interest expense ratio

3.61

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Face amount of debt

'

'

'

'

'

'

'

'

350,000,000

'

'

500,000,000

'

'

600,000,000

Interest rate on debt

'

'

'

'

'

'

'

'

7.75%

'

'

6.00%

'

'

6.13%

Debt Instrument, Fair Value Adjustment

'

'

'

'

'

'

'

'

'

4,500,000

4,700,000

'

'

'

'

Senior notes

'

'

'

'

'

'

$350,000,000

$350,000,000

'

$500,000,000

$500,000,000

'

$600,000,000

$600,000,000

'

Partners_Capital_Narrative_Det

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

3 Months Ended

0 Months Ended

3 Months Ended

0 Months Ended

3 Months Ended

0 Months Ended

3 Months Ended

Mar. 31, 2014

Mar. 31, 2013

Mar. 31, 2012

Jan. 08, 2013

Jan. 08, 2013

10-May-13

Jan. 08, 2013

Jan. 08, 2013

Mar. 31, 2014

Mar. 31, 2013

Mar. 31, 2014

Apr. 30, 2014

Mar. 31, 2014

Mar. 31, 2014

Jul. 19, 2013

Mar. 31, 2014

Legacy Crestwood Credit Facility

Cash distribution

Preferred Units

General Partner

Legacy Crestwood

Legacy Crestwood

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

Preferred Units

Subsequent event

Preferred Units

Crestwood Niobrara LLC

Crestwood Niobrara LLC

Preferred Units

Preferred Units

Distribution Made to Member or Limited Partner [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Maximum Period For Distribution Of Available Cash

'45 days

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Per unit rate, in dollars per unit

'

'

$0.51

'

'

$0.51

'

'

'

$0.41

'

'

'

'

'

'

Incentive Distribution, Distribution

$7,500,000

$5,000,000

'

'

'

'

'

'

$10,500,000

'

'

'

'

'

'

'

Contribution from issuance of units

'

'

'

'

'

'

'

'

'

'

'

'

'

108,400,000

'

12,300,000

Net Income (Loss) Attributable to Noncontrolling Interest

3,100,000

0

'

'

'

'

'

'

'

'

'

'

3,100,000

'

'

'

Percent of Contributions to be Funded by Units

'

'

'

'

'

'

'

'

'

'

'

'

'

'

75.00%

'

Funds from Capital Contributions, Maximum

'

'

'

'

'

'

'

'

'

'

'

'

'

'

41,600,000

'

Distribution Made to Member or Limited Partner, Cash Distributions Paid

74,100,000

21,000,000

21,000,000

'

'

27,400,000

'

'

'

74,100,000

'

'

'

'

'

'

Business Acquisition, Percentage of Voting Interests Acquired

'

'

'

65.00%

'

'

'

'

'

'

'

'

'

'

'

'

Consideration Transferred

'

'

'

258,000,000

129,000,000

'

'

'

'

'

'

'

'

'

'

'

Distribution Made to Non-Controlling Partners, Share Distribution

'

'

'

'

'

'

6,190,469

133,060

'

'

2,210,294

2,536,010

'

'

'

'

Distribution Made to General Partner, Cash Distributions Paid

$10,500,000

$4,100,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Partners_Capital_Schedule_of_P

Partners' Capital (Schedule of Partnership Distributions) (Details) (USD $)	3 Months Ended			0 Months Ended		3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2012	10-May-13	Apr. 17, 2014	Mar. 31, 2014	Mar. 31, 2013
				Cash distribution	Dividend Paid	Legacy Crestwood	Legacy Crestwood
					Cash distribution
					Subsequent event
Disclosure Partners Capital Summary Of Quarterly Distributions Of Available Cash [Abstract]	'	'	'	'	'	'	'
Incentive Distribution, Distribution	$7,500,000	$5,000,000	'	'	'	$10,500,000	'
Distribution to limited partner, record date	'	'	31-Jan-13	'	'	'	7-Feb-14
Distribution to limited partner, distribution date	'	'	12-Feb-13	'	'	'	14-Feb-14
Per unit rate	'	'	$0.51	$0.51	'	'	$0.41
Distribution amount	$74,100,000	$21,000,000	$21,000,000	$27,400,000	'	'	$74,100,000
Distribution declared per limited partner unit	'	'	'	'	$0.41	'	'

LongTerm_Incentive_Plan_Narrat

Long-Term Incentive Plan (Narrative) (Details) (USD $)	3 Months Ended
In Millions, except Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014	Mar. 31, 2014	Dec. 31, 2013
			Crestwood LTIP	Crestwood LTIP	Crestwood LTIP	Crestwood LTIP	Crestwood LTIP
					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	'	'	'	'	'	$16.40	$1.80
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition	'	'	'3 years	'	'	'	'
Unit-based compensation charges	4.6	0.6	2.9	0.6	'	'	'
Unit-based compensation charges	'	'	'	'	1.7	'	'
Share-based Compensation Arrangement, Equity Instruments Other than Options, Grants in Period, Fair Value	'	'	'	'	'	$17.70	'
Common Stock, Capital Shares Reserved for Future Issuance	'	'	'	'	'	6,391,871	'
Shares Paid for Tax Withholding for Share Based Compensation	'	'	7,456	1,529	'	'	'

LongTerm_Incentive_Plan_Restri

Long-Term Incentive Plan (Restricted Unit Activity) (Details) (Crestwood LTIP, Restricted units, USD $)	3 Months Ended
	Mar. 31, 2014
Crestwood LTIP | Restricted units	'
Units	'
Unvested - January 1, 2014	250,557
Vested - restricted units	-20,568
Granted - restricted units	757,902
Unvested - March 31, 2014	987,891
Weighted-Average Grant Date Fair Value	'
Unvested - January 1, 2014	$22.13
Vested - restricted units	$21.68
Granted - restricted units	$23.41
Unvested - March 31, 2014	$23.13

Commitments_and_Contingencies_

Commitments and Contingencies (Details) (USD $)	3 Months Ended					1 Months Ended
In Millions, except Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Sep. 30, 2013	Mar. 31, 2014	Nov. 08, 2013
		Antero	Antero	Class Action Challenging Crestwood Merger	Class Action Challenging Crestwood Merger - Federal	Arrow Acquisition Class Action Lawsuit	Arrow Acquisition Class Action Lawsuit
				Lawsuit	Lawsuit	defendant	people
							bbl
Schedule Of Commitments And Contingencies [Line Items]	'	'	'	'	'	'	'
Loss Contingency, Pending Claims, Number	'	'	'	5	4	'	'
Loss contingency accrual, less than	$0.10	'	'	'	'	'	'
Shares Paid for Tax Withholding for Share Based Compensation	'	40,000,000	'	'	'	'	'
Business Acquisition, Contingent Consideration, at Fair Value	'	$33.50	$31.40	'	'	'	'
Barrels of Oil Equivalents Spilled	'	'	'	'	'	'	50,000
Loss Contingency, Loss of Life, Number	'	'	'	'	'	'	47
Loss Contingency, Number of Defendants	'	'	'	'	'	53	'
Fair Value Inputs, Discount Rate	5.90%	'	'	'	'	'	'

Related_Party_Transactions_Det

Related Party Transactions (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014		Mar. 31, 2013	Dec. 31, 2013
Related Party Transaction [Line Items]	'		'	'
Operating, administrative and overhead cost	$15.80		'	'
Disclosure Related Party Transaction Additional Information [Abstract]	'		'	'
Gathering and processing revenues	4.2		25.6	'
NGL and crude services	409.9		'	'
Related Party Transaction, Due from (to) Related Party [Abstract]	'		'	'
Accounts payable	37.5		'	8.7
CEQP	'		'	'
Disclosure Related Party Transaction Additional Information [Abstract]	'		'	'
Gathering and processing revenues	0.9	[1]	25.6	'
NGL and crude services	3.3	[1]	0	'
Gathering and processing costs of goods sold	11	[1]	6.8	'
General and administrative expenses	3.8	[1]	5.8	'
Affiliates	'		'	'
Related Party Transaction, Due from (to) Related Party [Abstract]	'		'	'
Accounts receivable	1.4		'	1.1
Accounts payable	37.5		'	8.7
Crestwood LTIP | CMLP	'		'	'
Related Party Transaction [Line Items]	'		'	'
Unit-based compensation charges	$1.70		'	'
[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)	3 Months Ended		12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
	customer	customer	customer
	segment
Segment Reporting Information [Line Items]	'	'	'
Number Of Customers Representing Ten Percent Or More Of Consolidated Revenues	3	2	'
Number Of Customers Representing Ten Percent Or More Of Consolidated Accounts Receivable	4	'	3
Number of operating segments	3	'	'
Tesoro Refining and Marketing Company [Member] | Sales Revenue, Net [Member] | Customer Concentration Risk [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Concentration Risk, Percentage	17.00%	'	'
Tesoro Refining and Marketing Company [Member] | Accounts Receivable | Customer Concentration Risk [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Concentration Risk, Percentage	'	'	19.00%
Eighty-Eight Oil LLC [Member] | Accounts Receivable | Customer Concentration Risk [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Concentration Risk, Percentage	'	'	10.00%
QEP Energy Company [Member] | Sales Revenue, Net [Member] | Customer Concentration Risk [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Concentration Risk, Percentage	12.00%	'	'
QEP Energy Company [Member] | Accounts Receivable | Customer Concentration Risk [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Concentration Risk, Percentage	17.00%	'	10.00%
WPX Williston, LLC [Member] | Sales Revenue, Net [Member] | Customer Concentration Risk [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Concentration Risk, Percentage	10.00%	'	'
WPX Williston, LLC [Member] | Accounts Receivable | Customer Concentration Risk [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Concentration Risk, Percentage	12.00%	'	'
Quicksilver | Revenue	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Concentration Risk, Percentage	'	35.00%	'
Antero | Revenue	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Concentration Risk, Percentage	'	20.00%	'
XTO Energy, Inc [Member] | Accounts Receivable | Customer Concentration Risk [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Concentration Risk, Percentage	13.00%	'	'
Halcon Resources Corp [Member] | Accounts Receivable | Customer Concentration Risk [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Concentration Risk, Percentage	13.00%	'	'

Segments_Reconciliation_of_Net

Segments (Reconciliation of Net Income to EBITDA) (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Segment Reporting [Abstract]	'	'
Net income	$5.50	$8.90
Interest Income (Expense), Net	28.1	11.4
Provision for income taxes	0.7	0.4
Depreciation, Amortization and Accretion, Net	50.8	17.4
EBITDA	$85.10	$38.10

Segments_Schedule_of_Reportabl

Segments (Schedule of Reportable Segment Data) (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Segment Reporting Information [Line Items]	'	'	'
Operating revenues	$537	$72.40	'
Costs of product/services sold	398.1	13.5	'
Storage and transportation	3.2	0	'
NGL and crude services	376.2	0	'
Operations and maintenance	28	13	'
Operations and maintenance expense	24.1	7.8	'
Gain on long-lived assets	0.5	0	'
Loss on contingent consideration	-2.1	0	'
Earnings (loss) from unconsolidated affiliates, net	-0.1	0	'
EBITDA	85.1	38.1	'
Goodwill	1,689.30	95	1,682.80
Total assets	6,491.40	1,616.80	6,401.80
Cash expenditures for property, plant and equipment	67.7	24.3	'
Gathering and Processing	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Operating revenues	79.5	72.4	'
Costs of product/services sold	18.7	13.5	'
Operations and maintenance	13.4	13	'
Operations and maintenance expense	0	0	'
Gain on long-lived assets	0.5	'	'
Loss on contingent consideration	-2.1	'	'
Earnings (loss) from unconsolidated affiliates, net	0.3	'	'
EBITDA	46.1	45.9	'
Goodwill	99.6	95	'
Total assets	1,881.60	1,593.30	'
Cash expenditures for property, plant and equipment	41.7	23.9	'
NGL and Crude Services	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Operating revenues	413.2	0	'
Costs of product/services sold	'	0	'
Operations and maintenance	10.3	0	'
Operations and maintenance expense	0	0	'
Gain on long-lived assets	0	'	'
Loss on contingent consideration	0	'	'
Earnings (loss) from unconsolidated affiliates, net	-0.4	'	'
EBITDA	26.3	0	'
Goodwill	861.1	0	'
Total assets	2,478	0	'
Cash expenditures for property, plant and equipment	23.9	0	'
Storage and Transportation	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Operating revenues	44.3	0	'
Costs of product/services sold	'	0	'
Operations and maintenance	4.3	0	'
Operations and maintenance expense	0	0	'
Gain on long-lived assets	0	'	'
Loss on contingent consideration	0	'	'
Earnings (loss) from unconsolidated affiliates, net	0	'	'
EBITDA	36.8	0	'
Goodwill	728.6	0	'
Total assets	1,975.50	0	'
Cash expenditures for property, plant and equipment	1.2	0	'
Corporate	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Operating revenues	0	0	'
Costs of product/services sold	0	0	'
Operations and maintenance	0	0	'
Operations and maintenance expense	24.1	7.8	'
Gain on long-lived assets	0	'	'
Loss on contingent consideration	0	'	'
Earnings (loss) from unconsolidated affiliates, net	0	'	'
EBITDA	-24.1	-7.8	'
Goodwill	0	0	'
Total assets	156.3	23.5	'
Cash expenditures for property, plant and equipment	$0.90	$0.40	'

Condensed_Consolidating_Financ2

Condensed Consolidating Financial Information (Condensed Consolidating Balance Sheet) (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Cash and cash equivalents	$5	$2.70	$0	$0.10
Accounts receivable	237.3	205.1	'	'
Inventory	10.7	7	'	'
Prepaid expenses and other current assets	13.6	10.2	'	'
Total current assets	266.6	225	'	'
Property, plant and equipment, net	3,384.40	3,350.10	'	'
Goodwill and intangible assets, net	2,646	'	'	'
Investment in consolidated affiliates	0	'	'	'
Investment in unconsolidated affiliates (Note 5)	171.1	151.4	'	'
Other assets	23.3	21.7	'	'
Total assets	6,491.40	6,401.80	1,616.80	'
Accounts payable	191.2	'	'	'
Other current liabilities	162.2	'	'	'
Total current liabilities	353.4	314.5	'	'
Long-term debt, less current portion	1,979.10	1,867.90	'	'
Other long-term liabilities	28	26.3	'	'
Total long-term liabilities	2,007.10	'	'	'
Partners' capital	4,014.50	4,092.10	'	'
Interest of non-controlling partners in subsidiary	116.4	101	'	'
Total partners’ capital	4,130.90	4,193.10	'	'
Total liabilities and partners’ capital	6,491.40	6,401.80	'	'
Parent	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Cash and cash equivalents	0.8	0.1	'	'
Accounts receivable	544.2	466.8	'	'
Inventory	0	'	'	'
Prepaid expenses and other current assets	0	'	'	'
Total current assets	545	466.9	'	'
Property, plant and equipment, net	3.6	4.8	'	'
Goodwill and intangible assets, net	0	0	'	'
Investment in Unconsolidated Subsidiary	'	0	'	'
Investment in consolidated affiliates	6,371.30	'	'	'
Investment in unconsolidated affiliates (Note 5)	0	'	'	'
Other assets	0.2	0	'	'
Total assets	6,920.10	6,856.90	'	'
Accounts payable	797.5	782.7	'	'
Other current liabilities	11.2	11.5	'	'
Total current liabilities	808.7	794.2	'	'
Long-term debt, less current portion	1,979.10	1,867.90	'	'
Other long-term liabilities	1.4	1.7	'	'
Total long-term liabilities	1,980.50	1,869.60	'	'
Partners' capital	4,014.50	'	'	'
Interest of non-controlling partners in subsidiary	116.4	'	'	'
Total partners’ capital	4,130.90	4,193.10	'	'
Total liabilities and partners’ capital	6,920.10	6,856.90	'	'
Inventory	'	0	'	'
Other Assets, Current	'	0	'	'
Equity Investment In Subsidiary	'	6,385.20	'	'
Stockholders' Equity Attributable to Parent	'	4,092.10	'	'
Stockholders' Equity Attributable to Noncontrolling Interest	'	101	'	'
Guarantor Subsidiaries	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Cash and cash equivalents	4.2	1.6	'	'
Accounts receivable	227.3	197.8	'	'
Inventory	10.7	'	'	'
Prepaid expenses and other current assets	13.6	'	'	'
Total current assets	255.8	216.6	'	'
Property, plant and equipment, net	3,380.80	3,345.30	'	'
Goodwill and intangible assets, net	2,646	2,653.60	'	'
Investment in Unconsolidated Subsidiary	'	0	'	'
Investment in consolidated affiliates	0	'	'	'
Investment in unconsolidated affiliates (Note 5)	0	'	'	'
Other assets	23.1	21.7	'	'
Total assets	6,305.70	6,237.20	'	'
Accounts payable	-72.1	-159.8	'	'
Other current liabilities	151	139.6	'	'
Total current liabilities	78.9	-20.2	'	'
Long-term debt, less current portion	0	0	'	'
Other long-term liabilities	26.6	24.6	'	'
Total long-term liabilities	26.6	24.6	'	'
Partners' capital	6,200.20	'	'	'
Interest of non-controlling partners in subsidiary	0	'	'	'
Total partners’ capital	6,200.20	6,232.80	'	'
Total liabilities and partners’ capital	6,305.70	6,237.20	'	'
Inventory	'	7	'	'
Other Assets, Current	'	10.2	'	'
Equity Investment In Subsidiary	'	0	'	'
Stockholders' Equity Attributable to Parent	'	6,232.80	'	'
Stockholders' Equity Attributable to Noncontrolling Interest	'	0	'	'
Non-Guarantor Subsidiaries	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Cash and cash equivalents	0	1	'	'
Accounts receivable	0.2	0.2	'	'
Inventory	0	'	'	'
Prepaid expenses and other current assets	0	'	'	'
Total current assets	0.2	1.2	'	'
Property, plant and equipment, net	0	0	'	'
Goodwill and intangible assets, net	0	0	'	'
Investment in Unconsolidated Subsidiary	'	151.4	'	'
Investment in consolidated affiliates	0	'	'	'
Investment in unconsolidated affiliates (Note 5)	171.1	'	'	'
Other assets	0	0	'	'
Total assets	171.3	152.6	'	'
Accounts payable	0.2	0	'	'
Other current liabilities	0	0.2	'	'
Total current liabilities	0.2	0.2	'	'
Long-term debt, less current portion	0	0	'	'
Other long-term liabilities	0	0	'	'
Total long-term liabilities	0	0	'	'
Partners' capital	54.7	'	'	'
Interest of non-controlling partners in subsidiary	116.4	'	'	'
Total partners’ capital	171.1	152.4	'	'
Total liabilities and partners’ capital	171.3	152.6	'	'
Inventory	'	0	'	'
Other Assets, Current	'	0	'	'
Equity Investment In Subsidiary	'	0	'	'
Stockholders' Equity Attributable to Parent	'	51.4	'	'
Stockholders' Equity Attributable to Noncontrolling Interest	'	101	'	'
Consolidation, Eliminations	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Cash and cash equivalents	0	0	'	'
Accounts receivable	-534.4	-459.7	'	'
Inventory	0	'	'	'
Prepaid expenses and other current assets	0	'	'	'
Total current assets	-534.4	-459.7	'	'
Property, plant and equipment, net	0	0	'	'
Goodwill and intangible assets, net	0	0	'	'
Investment in Unconsolidated Subsidiary	'	0	'	'
Investment in consolidated affiliates	-6,371.30	'	'	'
Investment in unconsolidated affiliates (Note 5)	0	'	'	'
Other assets	0	0	'	'
Total assets	-6,905.70	-6,844.90	'	'
Accounts payable	-534.4	-459.7	'	'
Other current liabilities	0	0	'	'
Total current liabilities	-534.4	-459.7	'	'
Long-term debt, less current portion	0	0	'	'
Other long-term liabilities	0	0	'	'
Total long-term liabilities	0	0	'	'
Partners' capital	-6,254.90	'	'	'
Interest of non-controlling partners in subsidiary	-116.4	'	'	'
Total partners’ capital	-6,371.30	-6,385.20	'	'
Total liabilities and partners’ capital	-6,905.70	-6,844.90	'	'
Inventory	'	0	'	'
Other Assets, Current	'	0	'	'
Equity Investment In Subsidiary	'	-6,385.20	'	'
Stockholders' Equity Attributable to Parent	'	-6,284.20	'	'
Stockholders' Equity Attributable to Noncontrolling Interest	'	-101	'	'
Consolidated Entities [Member]	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Cash and cash equivalents	'	2.7	'	'
Accounts receivable	'	205.1	'	'
Total current assets	'	225	'	'
Property, plant and equipment, net	'	3,350.10	'	'
Goodwill and intangible assets, net	'	2,653.60	'	'
Investment in Unconsolidated Subsidiary	'	151.4	'	'
Other assets	'	21.7	'	'
Total assets	'	6,401.80	'	'
Accounts payable	'	163.2	'	'
Other current liabilities	'	151.3	'	'
Total current liabilities	'	314.5	'	'
Long-term debt, less current portion	'	1,867.90	'	'
Other long-term liabilities	'	26.3	'	'
Total long-term liabilities	'	1,894.20	'	'
Total partners’ capital	'	4,193.10	'	'
Total liabilities and partners’ capital	'	6,401.80	'	'
Inventory	'	7	'	'
Other Assets, Current	'	10.2	'	'
Equity Investment In Subsidiary	'	0	'	'
Stockholders' Equity Attributable to Parent	'	4,092.10	'	'
Stockholders' Equity Attributable to Noncontrolling Interest	'	$101	'	'

Condensed_Consolidating_Financ3

Condensed Consolidating Financial Information (Condensed Consolidating Statement of Operations) (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Condensed Financial Statements, Captions [Line Items]	'	'
Gathering and processing	$78.60	'
Storage and transportation	44.3	'
NGL and crude services	409.9	'
Related party (Note 11)	4.2	25.6
Revenues	537	72.4
Gathering and processing	7.7	'
Storage and transportation	3.2	'
NGL and crude services	376.2	'
Related party	11	'
Cost of Goods and Services Sold	398.1	13.5
Operations and maintenance	28	13
Operations and maintenance expense	24.1	7.8
Depreciation, amortization and accretion	50.8	17.4
Costs and Expenses, Total	102.9	38.2
Loss on contingent consideration	-2.1	0
Other	0.5	'
Operating income	34.4	20.7
Interest and debt expense, net	-28.1	-11.4
Equity in net income (loss) of subsidiary	0	'
Loss from unconsolidated affiliates, net	-0.1	0
Income before income taxes	6.2	9.3
Provision for income taxes	0.7	0.4
Net income	5.5	8.9
Net income attributable to non-controlling partners	-3.1	0
Net income attributable to Crestwood Midstream Partners LP	2.4	8.9
Parent	'	'
Condensed Financial Statements, Captions [Line Items]	'	'
Gathering and processing	0	'
Storage and transportation	0	'
NGL and crude services	0	'
Related party (Note 11)	0	'
Revenues	0	'
Gathering and processing	0	'
Storage and transportation	0	'
NGL and crude services	0	'
Related party	0	'
Cost of Goods and Services Sold	0	'
Operations and maintenance	0	'
Operations and maintenance expense	-2.1	'
Depreciation, amortization and accretion	0.2	'
Costs and Expenses, Total	-1.9	'
Loss on contingent consideration	0	'
Other	0	'
Operating income	1.9	'
Interest and debt expense, net	-28.1	'
Equity in net income (loss) of subsidiary	31.7	'
Loss from unconsolidated affiliates, net	0	'
Income before income taxes	5.5	'
Provision for income taxes	0	'
Net income	5.5	'
Net income attributable to non-controlling partners	0	'
Net income attributable to Crestwood Midstream Partners LP	5.5	'
Guarantor Subsidiaries	'	'
Condensed Financial Statements, Captions [Line Items]	'	'
Gathering and processing	78.6	'
Storage and transportation	44.3	'
NGL and crude services	409.9	'
Related party (Note 11)	4.2	'
Revenues	537	'
Gathering and processing	7.7	'
Storage and transportation	3.2	'
NGL and crude services	376.2	'
Related party	11	'
Cost of Goods and Services Sold	398.1	'
Operations and maintenance	28	'
Operations and maintenance expense	26.2	'
Depreciation, amortization and accretion	50.6	'
Costs and Expenses, Total	104.8	'
Loss on contingent consideration	-2.1	'
Other	0.5	'
Operating income	32.5	'
Interest and debt expense, net	0	'
Equity in net income (loss) of subsidiary	0	'
Loss from unconsolidated affiliates, net	0	'
Income before income taxes	32.5	'
Provision for income taxes	0.7	'
Net income	31.8	'
Net income attributable to non-controlling partners	0	'
Net income attributable to Crestwood Midstream Partners LP	31.8	'
Non-Guarantor Subsidiaries	'	'
Condensed Financial Statements, Captions [Line Items]	'	'
Gathering and processing	0	'
Storage and transportation	0	'
NGL and crude services	0	'
Related party (Note 11)	0	'
Revenues	0	'
Gathering and processing	0	'
Storage and transportation	0	'
NGL and crude services	0	'
Related party	0	'
Cost of Goods and Services Sold	0	'
Operations and maintenance	0	'
Operations and maintenance expense	0	'
Depreciation, amortization and accretion	0	'
Costs and Expenses, Total	0	'
Loss on contingent consideration	0	'
Other	0	'
Operating income	0	'
Interest and debt expense, net	0	'
Equity in net income (loss) of subsidiary	0	'
Loss from unconsolidated affiliates, net	-0.1	'
Income before income taxes	-0.1	'
Provision for income taxes	0	'
Net income	-0.1	'
Net income attributable to non-controlling partners	-3.1	'
Net income attributable to Crestwood Midstream Partners LP	-3.2	'
Consolidation, Eliminations	'	'
Condensed Financial Statements, Captions [Line Items]	'	'
Gathering and processing	0	'
Storage and transportation	0	'
NGL and crude services	0	'
Related party (Note 11)	0	'
Revenues	0	'
Gathering and processing	0	'
Storage and transportation	0	'
NGL and crude services	0	'
Related party	0	'
Cost of Goods and Services Sold	0	'
Operations and maintenance	0	'
Operations and maintenance expense	0	'
Depreciation, amortization and accretion	0	'
Costs and Expenses, Total	0	'
Loss on contingent consideration	0	'
Other	0	'
Operating income	0	'
Interest and debt expense, net	0	'
Equity in net income (loss) of subsidiary	-31.7	'
Loss from unconsolidated affiliates, net	0	'
Income before income taxes	-31.7	'
Provision for income taxes	0	'
Net income	-31.7	'
Net income attributable to non-controlling partners	0	'
Net income attributable to Crestwood Midstream Partners LP	($31.70)	'

Condensed_Consolidating_Financ4

Condensed Consolidating Financial Information (Condensed Consolidating Statements of Cash Flows) (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Condensed Financial Statements, Captions [Line Items]	'	'
Net cash provided by operating activities	$58.10	$34.10
Acquisitions, net of cash acquired	-12.1	0
Purchases of property, plant and equipment	-67.7	-24.3
Investment in unconsolidated affiliates	-19.8	0
Capital contribution from consolidated affiliate	0	'
Proceeds from sale of assets	0	'
Net cash used in investing activities	-99.6	-24.3
Proceeds from the issuance of long-term debt	306	199.5
Repayments of Long-term Debt	-188.8	-157
Payments of Capital Distribution	-84.6	'
Contributions from general partner	0	'
Net proceeds from issuance of preferred equity of subsidiary	12.3	0
Payments on capital leases	-1.1	-1
Net change in payables to affiliate	0	'
Net cash provided by (used in) financing activities	43.8	-9.9
Net increase (decrease) in cash	2.3	-0.1
Cash at beginning of period	2.7	0.1
Cash at end of period	5	0
Parent	'	'
Condensed Financial Statements, Captions [Line Items]	'	'
Net cash provided by operating activities	5.8	'
Acquisitions, net of cash acquired	0	'
Purchases of property, plant and equipment	-0.9	'
Investment in unconsolidated affiliates	0	'
Capital contribution from consolidated affiliate	-4	'
Proceeds from sale of assets	-2.4	'
Net cash used in investing activities	-7.3	'
Proceeds from the issuance of long-term debt	2.5	'
Repayments of Long-term Debt	0	'
Payments of Capital Distribution	0	'
Contributions from general partner	0	'
Net proceeds from issuance of preferred equity of subsidiary	0	'
Payments on capital leases	-0.3	'
Net change in payables to affiliate	0	'
Net cash provided by (used in) financing activities	2.2	'
Net increase (decrease) in cash	0.7	'
Cash at beginning of period	0.1	'
Cash at end of period	0.8	'
Guarantor Subsidiaries	'	'
Condensed Financial Statements, Captions [Line Items]	'	'
Net cash provided by operating activities	52.3	'
Acquisitions, net of cash acquired	-12.1	'
Purchases of property, plant and equipment	-66.8	'
Investment in unconsolidated affiliates	-2.5	'
Capital contribution from consolidated affiliate	0	'
Proceeds from sale of assets	0	'
Net cash used in investing activities	-81.4	'
Proceeds from the issuance of long-term debt	303.5	'
Repayments of Long-term Debt	-188.8	'
Payments of Capital Distribution	-84.6	'
Contributions from general partner	0	'
Net proceeds from issuance of preferred equity of subsidiary	0	'
Payments on capital leases	-0.8	'
Net change in payables to affiliate	2.4	'
Net cash provided by (used in) financing activities	31.7	'
Net increase (decrease) in cash	2.6	'
Cash at beginning of period	1.6	'
Cash at end of period	4.2	'
Non-Guarantor Subsidiaries	'	'
Condensed Financial Statements, Captions [Line Items]	'	'
Net cash provided by operating activities	0	'
Acquisitions, net of cash acquired	0	'
Purchases of property, plant and equipment	0	'
Investment in unconsolidated affiliates	-17.3	'
Capital contribution from consolidated affiliate	0	'
Proceeds from sale of assets	0	'
Net cash used in investing activities	-17.3	'
Proceeds from the issuance of long-term debt	0	'
Repayments of Long-term Debt	0	'
Payments of Capital Distribution	0	'
Contributions from general partner	4	'
Net proceeds from issuance of preferred equity of subsidiary	12.3	'
Payments on capital leases	0	'
Net change in payables to affiliate	0	'
Net cash provided by (used in) financing activities	16.3	'
Net increase (decrease) in cash	-1	'
Cash at beginning of period	1	'
Cash at end of period	0	'
Consolidation, Eliminations	'	'
Condensed Financial Statements, Captions [Line Items]	'	'
Net cash provided by operating activities	0	'
Acquisitions, net of cash acquired	0	'
Purchases of property, plant and equipment	0	'
Investment in unconsolidated affiliates	0	'
Capital contribution from consolidated affiliate	4	'
Proceeds from sale of assets	2.4	'
Net cash used in investing activities	6.4	'
Proceeds from the issuance of long-term debt	0	'
Repayments of Long-term Debt	0	'
Payments of Capital Distribution	0	'
Contributions from general partner	-4	'
Net proceeds from issuance of preferred equity of subsidiary	0	'
Payments on capital leases	0	'
Net change in payables to affiliate	-2.4	'
Net cash provided by (used in) financing activities	-6.4	'
Net increase (decrease) in cash	0	'
Cash at beginning of period	0	'
Cash at end of period	$0	'