Crestwood Equity Partners (CEQP+) 10-K 2 Mar 15 2014 FY Annual report Financial data

Document_and_Entity_Informatio

Document and Entity Information (USD $)	12 Months Ended
In Billions, except Share data, unless otherwise specified	Dec. 31, 2014	Feb. 13, 2015	Jun. 30, 2014
Document and Entity Information [Abstract]
Entity Registrant Name	Crestwood Midstream Partners LP
Trading Symbol	CMLP
Entity Central Index Key	1304464
Current Fiscal Year End Date	-19
Entity Filer Category	Large Accelerated Filer
Document Type	10-K
Document Period End Date	31-Dec-14
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	FY
Amendment Flag	FALSE
Entity Common Stock, Shares Outstanding		188,356,692
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$3.30

CONSOLIDATED_BALANCE_SHEETS

CONSOLIDATED BALANCE SHEETS (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Current assets:
Cash	$4.60	$2.70
Accounts receivable	241.8	205.1
Inventory (Note 4)	8	7
Prepaid expenses and other current assets	18.7	10.2
Total current assets	273.1	225
Property, plant and equipment (Note 4)	3,883.50	3,565.70
Less: accumulated depreciation and depletion	365.4	215.6
Property, plant and equipment, net	3,518.10	3,350.10
Intangible assets (Note 4)	1,013.20	1,025.10
Less: accumulated amortization	137	54.3
Intangible assets, net	876.2	970.8
Goodwill	1,632.60	1,682.80
Investment in unconsolidated affiliates (Note 6)	295.1	151.4
Other assets	1.4	21.7
Total assets	6,596.50	6,401.80
Current liabilities:
Accounts payable	126.1	154.5
Accounts payable - related party (Note 13)	6.3	8.7
Accrued expenses and other liabilities (Note 4)	122	148.4
Current portion of long-term debt (Note 7)	0.7	2.9
Total current liabilities	255.1	314.5
Long-term debt, less current portion (Note 7)	2,012.80	1,867.90
Other long-term liabilities	31.2	26.3
Commitments and contingencies (Note 12)
Partners’ capital (Note 10):
Class A preferred units (17,917,870 issued and outstanding at December 31, 2014)	447.7	0
Common units (187,965,105 and 187,243,989 issued and outstanding at December 31, 2014 and December 31, 2013)	3,678	4,092.10
Total Crestwood Midstream Partners LP partners’ capital	4,125.70	4,092.10
Interest of non-controlling partners in subsidiary	171.7	101
Total partners’ capital	4,297.40	4,193.10
Total liabilities and partners’ capital	$6,596.50	$6,401.80

CONSOLIDATED_BALANCE_SHEETS_Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical)	Dec. 31, 2014	Dec. 31, 2013
Statement of Financial Position [Abstract]
Preferred Units, issued	17,917,870	0
Preferred Units, outstanding	17,917,870	0
Common units, issued	187,965,105	187,243,989
Common units, outstanding	187,965,105	187,243,989

CONSOLIDATED_STATEMENTS_OF_OPE

CONSOLIDATED STATEMENTS OF OPERATIONS (USD $)	12 Months Ended
In Millions, except Share data in Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenues:
Gathering and processing	$328.50	$216.30	$125.80
Storage and transportation	179.1	90.1	0
NGL and crude services	2,040.30	270.1	0
Related party (Note 13)	17.6	82.1	113.7
Revenues	2,565.50	658.6	239.5
Costs of product/services sold:
Gathering and processing	29.1	24.1	23.8
Storage and transportation	14.3	8.7	0
NGL and crude services	1,851.90	230.4	0
Related party (Note 13)	42.2	32.5	15.2
Cost of Revenue	1,937.50	295.7	39
Expenses:
Operations and maintenance	139	73.3	43.1
General and administrative (Note 13)	85.4	80.7	29.6
Depreciation, amortization and accretion	221.7	121.7	51.9
Operating Expenses	446.1	275.7	124.6
Costs and Expenses, Total	446.1	275.7
Gain (Loss) on Disposition of Assets and Impairments	-33.6	5.4	0
Other operating income (expense):
Goodwill impairment	-48.8	-4.1	0
Loss on contingent consideration (Note 12)	-8.6	-31.4	0
Operating income	90.9	57.1	75.9
Loss from unconsolidated affiliates, net	-0.7	-0.1	0
Interest and debt expense, net	-111.4	-71.4	-35.8
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest	-21.2	-14.4	40.1
Provision for income taxes	0.7	0.7	1.2
Net income (loss)	-21.9	-15.1	38.9
Net (income) loss attributable to non-controlling partners	-16.8	-4.9	0
Net income (loss) attributable to Crestwood Midstream Partners LP	-38.7	-20	38.9
Net income attributable to Class A preferred units	-17.2	0	0
Net Income (Loss), Partners Interest in Net Income	-55.9	-20	38.9
General partner's interest in net income	30.1	26.8	22.2
Payment to Legacy Crestwood unitholders	0	34.9	0
Limited partners’ interest in net income (loss) attributable to CMLP after incentive distributions	($86)	($81.70)	$16.70
Net income (loss) per limited partner unit:
Basic (usd per unit)	($0.46)	($0.82)	$0.26
Diluted (usd per unit)	($0.46)	($0.82)	$0.26
Weighted-average limited partners’ units outstanding (in thousands):
Basic (units)	187,942	99,183	64,656
Diluted (units)	187,942	99,183	64,656

CONSOLIDATED_STATEMENT_OF_PART

CONSOLIDATED STATEMENT OF PARTNERS' CAPITAL (USD $)	Total	Class A Preferred Units	Class A Preferred Units	Class A Preferred Units	Partners	Partners	Partners	Non-controlling Partners	Non-controlling Partners	Non-controlling Partners	Total Partners’ Capital	Total Partners’ Capital	Total Partners’ Capital
			Arrow Midstream Holdings, LLC	Tres Palacios Holdings LLC		Arrow Midstream Holdings, LLC	Tres Palacios Holdings LLC		Arrow Midstream Holdings, LLC	Tres Palacios Holdings LLC		Arrow Midstream Holdings, LLC	Tres Palacios Holdings LLC
Beginning Balance at Dec. 31, 2011		$0			$455,600,000			$0			$455,600,000
Increase (Decrease) in Partners' Capital [Roll Forward]
Proceeds from issuance of units		0			217,500,000			0			217,500,000
Contributions from general partner		0			249,700,000			0			249,700,000
Distributions to general partner	-25,800,000	0			-25,800,000						-25,800,000
Distributions to limited partner	-77,700,000	0			-77,700,000			0			-77,700,000
Unit-based compensation charges		0			1,900,000			0			1,900,000
Net proceeds from issuance of Class A preferred units	0
Adjustments Related to Tax Withholding for Share-based Compensation		0			-400,000			0			-400,000
Net income (loss)	38,900,000	0			38,900,000			0			38,900,000
Ending Balance at Dec. 31, 2012		0			859,700,000			0			859,700,000
Increase (Decrease) in Partners' Capital [Roll Forward]
Proceeds from issuance of units		0	0		714,000,000	200,000,000		0	0		714,000,000	200,000,000
Invested capital from Legacy Inergy, net of debt		0			2,682,300,000			0			2,682,300,000
Contributions from general partner		0			15,500,000			0			15,500,000
Distributions to general partner	-26,200,000	0			-26,200,000			0			-26,200,000
Distributions to limited partner	-24,900,000	0			-214,500,000			0			-214,500,000
Distributions for additional interest in Crestwood Marcellus Midstream LLC		0			-129,000,000			0			-129,000,000
Unit-based compensation charges		0			15,800,000			0			15,800,000
Net proceeds from issuance of preferred equity of subsidiary	-96,100,000	0			0			96,100,000			96,100,000
Net proceeds from issuance of Class A preferred units	0
Adjustments Related to Tax Withholding for Share-based Compensation		0			-5,500,000			0			-5,500,000
Net income (loss)	-15,100,000	0			-20,000,000			4,900,000			-15,100,000
Ending Balance at Dec. 31, 2013	4,092,100,000	0			4,092,100,000			101,000,000			4,193,100,000
Increase (Decrease) in Partners' Capital [Roll Forward]
Proceeds from issuance of units	17,529,879
Contributions from general partner		0			-5,000,000			0			-5,000,000
Distributions to general partner	-41,800,000	0		0	-41,800,000		-30,600,000	0		0	-41,800,000		-30,600,000
Distributions to limited partner		0			-296,500,000			0			-296,500,000
Unit-based compensation charges		0			18,100,000			0			18,100,000
Net proceeds from issuance of preferred equity of subsidiary	150,000,000	0			0			53,900,000			53,900,000
Net proceeds from issuance of Class A preferred units	-430,500,000	430,500,000			0			0			430,500,000
Adjustments Related to Tax Withholding for Share-based Compensation		0			-1,600,000			0			-1,600,000
Partners' Capital, Other		0			-800,000			0			-800,000
Net income (loss)	-21,900,000	17,200,000			-55,900,000			16,800,000			-21,900,000
Ending Balance at Dec. 31, 2014	$4,125,700,000	$447,700,000			$3,678,000,000			$171,700,000			$4,297,400,000

CONSOLIDATED_STATEMENTS_OF_CAS

CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Operating activities
Net income (loss)	($21.90)	($15.10)	$38.90
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion	221.7	121.7	51.9
Amortization of debt-related deferred costs, discounts and premiums	7.3	9.1	5.5
Unit-based compensation charges	18.1	15.8	1.9
Gain (Loss) on Disposition of Assets and Impairments	-33.6	5.4	0
Goodwill impairment	48.8	4.1	0
Loss on contingent consideration	8.6	31.4	0
Loss from unconsolidated affiliates, net	0.7	0.1	0
Deferred income taxes	0.6	0	0
Other	0	0.1	-0.2
Changes in operating assets and liabilities, net of effects from acquisitions:
Accounts receivable	15.1	70.3	-3.5
Inventories	-1.8	-0.1	0
Prepaid expenses and other current assets	-8.6	3.5	0.8
Accounts payable, accrued expenses and other liabilities	-20.8	-49	6.8
Reimbursements of property, plant and equipment	21.5	0	0
Net cash provided by operating activities	322.9	186.5	102.1
Investing activities
Acquisitions, net of cash acquired (Note 3)	-19.5	-561.5	-564
Purchases of property, plant and equipment	-407	-334.6	-52.6
Investment in unconsolidated affiliates	-144.4	-151.5	0
Proceeds from sale of assets	0	11.1	0
Net cash used in investing activities	-570.9	-1,036.50	-616.6
Financing activities
Proceeds from the issuance of long-term debt	2,089.90	2,072.80	706.7
Principal payments on long-term debt	-1,949.80	-1,634.30	-534
Payments on capital leases	-3.2	-4.3	-3
Payments for debt-related deferred costs	-0.1	-32	-11.4
Payments for deferred acquisition costs	0	0	-7.8
Distributions to limited partners	-296.5	-204.5	-77.7
Distributions to general partner	-41.8	-26.2	-25.8
Distribution for additional interest in Crestwood Marcellus Midstream LLC	0	-129	0
Contributions from general partner	0	5.5	249.7
Net proceeds from issuance of common units	0	714	217.5
Net proceeds from issuance of preferred equity of subsidiary	53.9	96.1	0
Net proceeds from issuance of Class A preferred units	430.5	0	0
Taxes paid for unit-based compensation vesting	-1.6	-5.5	-0.4
Other	-0.8	0	0
Net cash provided by financing activities	249.9	852.6	513.8
Net change in cash	1.9	2.6	-0.7
Cash at beginning of period	2.7	0.1	0.8
Cash at end of period	4.6	2.7	0.1
Supplemental disclosure of cash flow information
Cash paid during the period for interest	96.9	56.7	27.9
Cash paid during the period for income taxes	0.4	0	0
Supplemental schedule of noncash investing and financing activities
Net change to property, plant and equipment through accounts payable and accrued expenses	-40.6	-30.7	-1.7
Acquisitions, net of cash acquired:
Current assets	0.5	240	0
Property, plant and equipment	13.5	2,076.80	178
Intangible assets	9.4	519.4	384
Goodwill	3.6	1,583.20	4.1
Other assets	0	22.3	0
Current liabilities	-2.7	-243.9	-0.7
Debt	-3.5	-745	0
Invested capital of Crestwood Midstream Partners LP, net of debt (Note 3)	0	-2,882.30	0
Other liabilities	-1.3	-9	-1.4
Total acquisitions, net of cash acquired	19.5	561.5	564
Tres Palacios Holdings LLC
Financing activities
Distributions to general partner	($30.60)	$0	$0

Organization_and_Description_o

Organization and Description of Business	12 Months Ended
	Dec. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Description of Business	Organization and Description of Business
	Organization
	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, 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, the marketing of NGLs, and the gathering, storage and transportation of crude oil.
	Crestwood Equity Partners LP (CEQP) through its wholly-owned subsidiary, owns a non-economic general partnership interest in us 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. As of December 31, 2014, CEQP directly owns approximately 4% of our common limited partnership units. CEQP is indirectly owned by Crestwood Holdings LLC (Crestwood Holdings), which is substantially owned and controlled by First Reserve Management, L.P. (First Reserve), which owns approximately 11% of our common units as of December 31, 2014.
	On October 7, 2013, we changed our name from Inergy Midstream, L.P. to Crestwood Midstream Partners LP. Unless otherwise indicated, references in this report to “we,” “us,” “our,” “ours,” “our company,” the “partnership,” the “Company,” “CMLP,” “Crestwood” and similar terms refer to either Crestwood Midstream Partners LP itself or Crestwood Midstream Partners LP and its consolidated subsidiaries, as the context requires. Unless otherwise indicated, references to (i) the Crestwood Merger refers to the October 7, 2013 merger of the Company’s wholly-owned subsidiary with and into Legacy Crestwood, with Legacy Inergy continuing as the surviving legal entity; (ii) Legacy Crestwood refers to either Crestwood Midstream Partners LP itself or Crestwood Midstream Partners LP and its consolidated subsidiaries prior to the Crestwood Merger; and (iii) Legacy Inergy refers to either Inergy Midstream, L.P. itself or Inergy Midstream, L.P. and its consolidated subsidiaries prior to the Crestwood Merger. See Note 3 for additional information on the Crestwood Merger.
	Business Combination
	On May 5, 2013, CEQP and certain of its affiliates entered into a series of definitive agreements with Crestwood Holdings and certain of its affiliates under which, among other things, (i) CEQP agreed to distribute to its common unitholders all of the Legacy Inergy common units owned by CEQP; (ii) Crestwood Holdings agreed to acquire the owner of CEQP’s general partner; (iii) Crestwood Holdings agreed to contribute ownership of Legacy Crestwood’s general partner and IDRs to CEQP in exchange for common and subordinated units of CEQP; and (iv) Legacy Crestwood agreed to merge with and into a subsidiary of Legacy Inergy in a merger in which Legacy Crestwood unitholders received 1.07 Legacy Inergy common units for each Legacy Crestwood common unit they owned and, Legacy Crestwood unitholders (other than Crestwood Holdings) would receive a one-time $34.9 million cash payment at the closing of the Crestwood Merger, or $1.03 per unit.
	On June 5, 2013, Legacy Crestwood’s general partner distributed to a wholly-owned subsidiary of Crestwood Holdings approximately 137,105 common units and approximately 21,588 Class D units of Legacy Crestwood, representing all of the Legacy Crestwood common and Class D units held by Legacy Crestwood’s general partner.
	On June 18, 2013, CEQP distributed to its unitholders approximately 56.4 million Legacy Inergy common units, representing all of the Legacy Inergy common units held by CEQP.
	On June 19, 2013, Crestwood Holdings acquired the owner of CEQP’s general partner and contributed to CEQP ownership of Crestwood Gas Services GP, LLC, which owned 100% of the general partnership interest and IDRs of Legacy Crestwood. Crestwood Holdings and First Reserve acquired control of CEQP as a result of these transactions. As a result of Crestwood Holding’s acquisition of control of CEQP, Crestwood Holdings acquired control of our general partner and, consequently, the Company on June 19, 2013.
	On October 7, 2013, the merger of Legacy Inergy’s wholly-owned subsidiary with and into Legacy Crestwood (the Crestwood Merger) was completed, with Legacy Crestwood continuing as the surviving accounting entity. Immediately following the closing of the Crestwood Merger, on October 7, 2013, (i) Legacy Crestwood merged with and into Legacy Inergy, with Legacy Inergy continuing as the surviving legal entity, and (ii) Legacy Inergy changed its name to Crestwood Midstream Partners LP and changed its NYSE listing symbol to “CMLP”. Under the merger agreement, Legacy Crestwood unitholders received 1.07 units of Legacy Inergy units for each unit of Legacy Crestwood they owned and as a result, there were no Legacy Crestwood common or Class D units outstanding immediately following the merger. Additionally, Legacy Crestwood unitholders (other than Crestwood Holdings) received a one-time $34.9 million cash payment at the closing of the merger, or $1.03 per unit, $24.9 million of which was paid by Legacy Inergy and $10 million of which was paid by Crestwood Holdings.
	Following the closing of the Crestwood Merger on October 7, 2013, Crestwood Holdings exchanged 7,100,000 of our common units for 14,300,000 of CEQP common units pursuant to an option granted to Crestwood Holdings when it acquired our general partner.
	Description of Business
	We provide gathering, processing, storage and transportation solutions to customers in the crude oil, NGL and natural gas sectors of the energy industry. 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 our natural gas transmission facilities (the North-South Facilities, the MARC I Pipeline and the East Pipeline) in New York and Pennsylvania; and
	•	NGL and Crude Services: our NGL and crude services operations provide NGLs and crude oil gathering, storage, marketing and transportation services to producers, refiners, marketers and other customers in or near unconventional shale plays in North Dakota and New York. This segment primarily includes our integrated Bakken crude oil footprint in North Dakota, which consists of (i) the COLT Hub, a crude oil rail loading and storage terminal, (ii) the Arrow crude oil, natural gas and water gathering systems, and (iii) our fleet of over-the-road crude and produced water transportation assets. This segment also includes our Bath storage facility and US Salt, a solution-mining and salt production company in New York.

Basis_of_Presentation_and_Summ

Basis of Presentation and Summary of Significant Accounting Policies	12 Months Ended
	Dec. 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. Crestwood Holdings' acquisition of control of CEQP’s general partner on June 19, 2013 was accounted for as a reverse acquisition under the purchase method of accounting in accordance with accounting standards for business combinations.  CEQP's accounting for this reverse acquisition resulted in the legal acquiree (Crestwood Gas Services GP LLC) being the acquirer for accounting purposes. CEQP’s
	accounting acquiree (inclusive of Legacy Inergy) was subject to the purchase method of accounting and its balance sheet was
	adjusted to fair market value as of June 19, 2013. Accordingly, the merger of Legacy Crestwood and Legacy Inergy on October
	7, 2013 was accounted for as a reverse merger amongst entities under common control with Legacy Crestwood continuing as the surviving entity for accounting purposes and Legacy Inergy continuing as the surviving entity for legal purposes. As the reverse merger was amongst entities under common control, the financial statements have been recasted to reflect the operations of Legacy Inergy as being acquired by Legacy Crestwood on June 19, 2013, the date in which Legacy Inergy and Legacy Crestwood came under common control.
	Our consolidated financial statements are prepared in accordance with GAAP and include the accounts of all consolidated subsidiaries after the elimination of all intercompany accounts and transactions. Our consolidated financial statements for prior periods include reclassifications that were made to conform to the current year presentation, none of which impacted our previously reported net income, earnings per unit or partners' capital. 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.
	Principles of Consolidation
	We consolidate entities when we have the ability to control or direct the operating and financial decisions of the entity or when we have a significant interest in the entity that gives us the ability to direct the activities that are significant to that entity. The determination to consolidate or apply the equity method of accounting to an entity can also require us to evaluate whether that entity is considered a variable interest entity. This evaluation, along with the determination of our ability to control, direct or exert significant influence over an entity involves the use of judgment. We apply the equity method of accounting where we can exert significant influence over, but do not control or direct the policies, decisions or activities of an entity. We use the cost method of accounting where we are unable to exert significant influence over the entity.
	Use of Estimates
	The preparation of our consolidated financial statements in conformity with GAAP requires the use of estimates and assumptions that affect the amounts we report as assets, liabilities, revenues and expenses and our disclosures in these consolidated financial statements. Actual results can differ from those estimates.
	Cash
	We consider all highly liquid investments with an original maturity of less than three months to be cash.
	Inventory
	Inventory for our NGL and crude services operations and our storage and transportation operations are stated at the lower of cost or market and are computed predominantly using the average cost method.
	Property, Plant and Equipment
	Property, plant and equipment is recorded at is original cost of construction or, upon acquisition, at the fair value of the assets acquired. For assets we construct, we capitalize direct costs, such as labor and materials, and indirect costs, such as overhead and interest. We capitalize major units of property replacements or improvement and expense minor items. Depreciation is computed by the straight-line method over the estimated useful lives of the assets, as follows:
		Years
	Gathering systems and pipelines	20
	Facilities and equipment	20-25
	Buildings, rights-of-way and easements	20-40
	Office furniture and fixtures	10-May
	Vehicles	5
	We deplete salt deposits included in our property, plant and equipment utilizing the unit of production method.
	When we retire property, plant and equipment, we charge accumulated depreciation for the original costs of the assets in addition to the cost to remove, sell or dispose of the assets, less their salvage value.
	We evaluate our long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. If such events or changes in circumstances are present, a loss is recognized if the carrying value of the asset is in excess of the sum of the undiscounted cash flows expected to result from the use of the asset and its eventual disposition. An impairment loss is measured as the amount by which the carrying amount of the asset exceeds the fair value of the asset, which is based on discounted cash flow projections, which is a Level 3 fair value measurement. Based on this evaluation, during the year ended December 31, 2014, we recorded a $13.2 million impairment in gain (loss) on long-lived assets in our consolidated statements of operations related to the property, plant and equipment of our gathering and processing assets located in the Granite Wash, which resulted from an announcement during the fourth quarter of 2014 by our major customer of those assets that they would cease any substantial drilling in the Granite Wash in the near future given current and future anticipated market conditions related to natural gas, which negatively impacted our future cash flows related to these operations. We had approximately $20.2 million of property, plant and equipment related to our gathering and processing operations located in the Granite Wash as of December 31, 2014, which represents the fair value of those assets based on its projected cash flows over the useful lives of the assets of 17 years and a discount rate of 9.0%, which are Level 3 fair value measurements. We did not record any impairments of our long-lived assets during the years ended December 31, 2013 and 2012 based on this evaluation.
	Identifiable Intangible Assets
	Our identifiable intangible assets consist of customer accounts, covenants not to compete, trademarks, certain revenue contracts and deferred financing costs. Customer accounts, covenants not to compete, trademarks and certain of our revenue contracts have arisen from acquisitions. We amortize certain of our revenue contracts based on the projected cash flows associated with these contracts if the projected cash flows are reliably determinable, otherwise we amortize our revenue contracts on a straight-line basis. Deferred financing costs represent financing costs incurred in obtaining financing and are being amortized over the term of the related debt using a method which approximates the effective interest method and has a weighted average life of six years. We recognize acquired intangible assets separately if the benefit of the intangible asset is obtained through contractual or other legal rights, or if the intangible asset can be sold, transferred, licensed, rented or exchanged, regardless of the acquirer's intent to do so. For the year ended December 31, 2014, we recorded a $21.3 million impairment of our intangible assets in gain (loss) on long-lived assets in our consolidated statements of operations. This impairment was based on the intangible assets’ fair value, estimated primarily by utilizing discounted cash flow projections, which is a Level 3 fair value measurement.  This impairment was primarily related to a full impairment of our intangible assets associated with our gathering and processing operations located in the Granite Wash. This impairment resulted from an announcement in the fourth quarter of 2014 by our major customer of those assets that they would cease any substantial drilling in the Granite Wash in the near future given current and future anticipated market conditions related to natural gas in the Granite Wash.
	Certain intangible assets are amortized on a straight-line basis over their estimated economic lives, as follows:
		Weighted-Average
		Life
		(years)
	Customer accounts	20
	Covenants not to compete	3
	Trademarks	5
	Goodwill
	Our goodwill represents consideration paid in excess of the fair value of the identifiable assets acquired in a business combination. We evaluate goodwill for impairment annually on December 31, and whenever events indicate that the fair value of a reporting unit could be less than its carrying amount. This evaluation requires us to compare the fair value of a reporting unit to its carrying value (including goodwill). If the fair value exceeds the carrying amount, goodwill of the reporting unit is not considered impaired. For a further discussion of the goodwill recorded during the year ended December 31, 2014, see Note 3.
	We estimate the fair value of our reporting units based on a number of factors, including the potential value we would receive if we sold the reporting unit, discount rates and projected cash flows, which are Level 3 fair value measurements. Estimating projected cash flows requires us to make certain assumptions as it relates to future operating performance. When considering operating performance, various factors are considered such as current and changing economic conditions and the commodity price environment, among others. Due to the imprecise nature of these projections and assumptions, actual results can and often do, differ from our estimates. If the growth assumptions utilized in the current year impairment analysis prove inaccurate, we could incur an impairment charge.
	For the year ended December 31, 2014, we recorded an impairment of goodwill of approximately $48.8 million related to four of our 10 reporting units including Granite Wash (G&P), Fayetteville (G&P), US Salt (NGL and Crude Services), and Watkins Glen (NGL and Crude Services).  The $14.2 million and $4.3 million impairments of our Granite Wash and Fayetteville goodwill, respectively, resulted from a decrease in anticipated revenues to be generated from those operations due to our primary customers in those operations announcing the cessation of any significant drilling in the near future given current and future anticipated market conditions in those areas.  The $2.2 million impairment ( of our US Salt goodwill resulted from a decrease in anticipated revenues to be generated from those operations due primarily to the loss of a significant customer in 2014.  The $28.1 million impairment of our Watkins Glen goodwill resulted from delays and related uncertainty in the permitting of our proposed NGL storage facility. We had approximately $72.5 million, $12.6 million and $66.2 million of goodwill remaining on the balance sheet as of December 31, 2014 related to our Fayetteville, US Salt and Watkins Glen reporting units, respectively, which represents the fair value of the goodwill related to those reporting units at December 31, 2014, which is a Level 3 fair value measurement.
	For the year ended December 31, 2013, we recorded an impairment of goodwill of approximately $4.1 million on our Haynesville/Bossier Shale system as a result of a decrease in anticipated revenues to be generated from those operations due primarily to our inability to renew and extend a significant revenue contract that expired in mid-2013.
	Investment in Unconsolidated Affiliates
	We evaluate our equity method investments for impairment when events or circumstances indicate that the carrying value of the equity method investment may be impaired. If an event occurs, we evaluate the recoverability of our carrying value based on the fair value of the investment. If an impairment is indicated, or if we decide to sell an investment in unconsolidated affiliate, we adjust the carrying values of the asset downward, if necessary, to their estimated fair values. Our fair value estimates are generally based on assumptions market participants would use, including marketing data obtained through the sales process.
	Asset Retirement Obligations
	An asset retirement obligation (ARO) is an estimated liability for the cost to retire a tangible asset. We record a liability for legal or contractual obligations to retire our long-lived assets associated with right-of-way contracts we hold and our facilities whether owned or leased. We record a liability in the period the obligation is incurred and estimable. An ARO is initially recorded at its estimated fair value with a corresponding increase to property, plant and equipment. This increase in property, plant and equipment is then depreciated over the useful life of the asset to which that liability relates. An ongoing expense is recognized for changes in the fair value of the liability as a result of the passage of time, which we record as depreciation, amortization and accretion expense on our consolidated statements of operations. The fair value of certain AROs could not be determined as the settlement dates (or range of dates) associated with these assets were not estimable. At December 31, 2014 and 2013, our AROs were reflected in other long-term liabilities on our consolidated balance sheets. See Note 5 for a discussion of our AROs.
	Revenue Recognition
	We gather, treat, compress, store, transport and sell various commodities (including crude oil, natural gas, NGLs and water) pursuant to fixed-fee and percent-of-proceeds contracts. We recognize revenues for these services and products when all of the following criteria are met:
	•	services have been rendered or products delivered or sold;
	•	persuasive evidence of an exchange arrangement exists;
	•	the price for services is fixed or determinable; and
	•	collectability is reasonably assured.
	For fixed-fee contracts, we recognize revenues based on the volume of crude oil, natural gas or produced water gathered, processed and treated or compressed, as applicable. For percent-of-proceeds contracts, we recognize revenues based on the value of products sold to third parties.
	Sales of crude oil, NGLs and salt are recognized at the time product is shipped or delivered to the customer depending on the sales terms. NGL processing fees are recognized upon delivery of the product. Revenues from the COLT Hub are recognized when the contractual services are provided, such as loading of customer rail cars. Revenues from storage and transportation contracts are recognized during the period in which the storage and transportation services are provided, such as providing storage and transportation services during the period a firm service contract is in place. We record deferred revenue when we receive amounts from our customers but have not met the criteria listed above. We recognize deferred revenue in our consolidated statements of operations when the criteria has been met and all services have been rendered. At December 31, 2014 and 2013, we had deferred revenue of approximately $11.6 million and $1.6 million, which is reflected in accrued expenses and other liabilities on our consolidated balance sheets.
	Credit Risk and Concentrations
	Inherent in our contractual portfolio are certain credit risks. Credit risk is the risk of loss from nonperformance by suppliers, customers or financial counterparties to a contract. We take an active role in managing credit risk and have established control procedures, which are reviewed on an ongoing basis. We attempt to minimize credit risk exposure through credit policies and periodic monitoring procedures as well as through customer deposits, letters of credit and entering into netting agreements that allow for offsetting counterparty receivable and payable balances for certain financial transactions, as deemed appropriate.
	Income Taxes
	We are a master limited partnership. Partnerships are generally not subject to federal income tax, although publicly-traded partnerships are treated as corporations for federal income tax purposes and therefore are subject to federal income tax, unless the partnership generates at least 90% of its gross income from qualifying sources. If the qualifying income requirement is satisfied, the publicly-traded partnership will be treated as a partnership for federal income tax purposes. We satisfy the qualifying income requirement and are treated as a partnership for federal and state income tax purposes. Our consolidated earnings are included in the federal and state income tax returns of our partners. However, legislation in certain states allows for taxation of partnerships, and as such, certain state taxes have been included in our accompanying financial statements as income taxes due to the nature of the tax in those particular states as discussed below. In addition, federal and state income taxes are provided on the earnings of the subsidiaries incorporated as taxable entities. We are required to recognize deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the financial statements or tax returns. Under this method, deferred tax assets and liabilities are determined based on the differences between the financial reporting and tax basis of assets and liabilities using expected rates in effect for the year in which the differences are expected to reverse.
	We are responsible for the Texas Margin tax computed on the Texas franchise tax returns. The margin tax qualifies as an income tax under GAAP, which requires us to recognize the impact of this tax on the temporary differences between the financial statement assets and liabilities and their tax basis attributable to such tax.
	Net earnings for financial statement purposes may differ significantly from taxable income reportable to unitholders as a result of differences between the tax basis and the financial reporting basis of assets and liabilities and the taxable income allocation requirements under our partnership agreement.
	Environmental Costs and Other Contingencies
	We recognize liabilities for environmental and other contingencies when there is an exposure that indicates it is both probable that a liability has been incurred and the amount of loss can be reasonably estimated. Where the most likely outcome of a contingency can be reasonably estimated, we accrue a liability for that amount. Where the most likely outcome cannot be estimated, a range of potential losses is established and if no one amount in that range is more likely than any other, the low end of range is accrued.
	We record liabilities for environmental contingencies at their undiscounted amounts on our consolidated balance sheets as accrued expenses and other liabilities when environmental assessments indicate that remediation efforts are probable and costs can be reasonably estimated. Estimates of our liabilities are based on currently available facts and presently enacted laws and regulations, taking into consideration the likely effects of other societal and economic factors. These estimates are subject to revision in future periods based on actual costs or new circumstances. We capitalize costs that benefit future periods and recognize a current period charge in operations and maintenance expenses when clean-up efforts do not benefit future periods.
	We evaluate potential recoveries of amounts from third parties, including insurance coverage, separately from our liability. Recovery is evaluated based on the solvency of the third party, among other factors. When recovery is assured, we record and report an asset separately from the associated liability on our consolidated balance sheet.
	Price Risk Management Activities
	In 2014, we began entering into daily and short-term forward crude purchase and sale agreements in our NGL and crude services segment. We utilize derivative financial instruments to (i) manage our exposure to commodity price risk, specifically, the related change in the fair value of inventory, as well as the variability of cash flows related to forecasted transactions; and (ii) ensure the availability of adequate physical supply of commodity. We record all derivative instruments on the balance sheet at their fair values as either assets or liabilities measured at fair value. Changes in the fair value of these derivative financial instruments are recorded through current earnings.
We did not have any derivatives identified as fair value hedges for accounting purposes or any derivatives designated as cash flow hedges for the year ended December 31, 2014. Our derivative instruments did not have a material impact on our financial statements during the year ended December 31, 2014.
Unit-Based Compensation
Long-term incentive awards are granted under our incentive plan. Unit-based compensation awards consist of restricted units that are valued at the closing market price of our common units on the date of grant, which reflects the fair value of such awards. For those awards that are settled in cash, the associated liability is remeasured at every balance sheet date through settlement, such that the vested portion of the liability is adjusted to reflect its revised fair value through compensation expense. We generally recognize the expense associated with the award over the vesting period.
Prior to the Crestwood Merger, Legacy Crestwood issued phantom units under its Fourth Amended and Restated 2007 Equity Plan (2007 Equity Plan). The 2007 Equity Plan was terminated in conjunction with the Crestwood Merger. See Note 11 for a further discussion of our long-term incentive plans.
New Accounting Pronouncements Issued But Not Yet Adopted
As of December 31, 2014, the following accounting standards had not yet been adopted by us.
In May 2014, the FASB issued Accounting Standards Update 2014-09, Revenue from Contracts with Customers, which outlines a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers and supersedes current revenue recognition guidance. We expect to adopt the provisions of this standard effective January 1, 2017 and are currently evaluating the impact that this standard will have on our financial statements.
In February 2015, the FASB issued Accounting Standards Update 2015-02, Consolidation (Topic 810): Amendments to the Consolidation Analysis, which provides additional guidance on the consolidation of limited partnerships and on the evaluation of variable interest entities. We expect to adopt the provisions of this standard effective January 1, 2016 and are currently evaluating the impact, if any, that this standard may have on our financial statements.

Acquisitions

Acquisitions	12 Months Ended
	Dec. 31, 2014
Business Combinations [Abstract]
Acquisitions	Acquisitions
	2014 Acquisitions
	Crude Transportation Acquisitions (Bakken)
	Red Rock. On March 21, 2014, we purchased substantially all of the operating assets of Red Rock Transportation Inc. (Red Rock) for approximately $13.8 million, comprised of $12.1 million paid at closing plus deferred payments of $1.8 million. Red Rock is a trucking operation located in Watford City, North Dakota which provides crude oil and produced water hauling services to the oilfields of western North Dakota and eastern Montana. The acquired assets include a fleet of approximately 56 trailer tanks, 22 double bottom body tanks and 44 tractors with 28,000 barrels per day of transportation capacity. We finalized the purchase price and allocated approximately $10.6 million of the purchase price to property, plant and equipment and intangible assets and approximately $3.2 million to goodwill. Goodwill recognized relates primarily to anticipated operating synergies between the assets acquired and our existing assets. These assets are included in our NGL and crude services segment.
	LT Enterprises. On May 9, 2014, we purchased substantially all of the operating assets of LT Enterprises, Inc. (LT Enterprises) for approximately $10.7 million, comprised of $9.0 million paid at closing plus deferred payments of $1.7 million. LT Enterprises is a trucking operation located in Watford City, North Dakota which provides crude oil and produced water hauling services primarily to the oilfields of western North Dakota. The acquired assets include a fleet of approximately 38 tractors, 51 crude trailers and 17 service vehicles with 20,000 barrels per day of transportation capacity. In addition, we acquired employee housing and 20 acres of greenfield real property located two miles south of Watford City. We finalized the purchase price and allocated all of the purchase price to property, plant and equipment and intangible assets. These assets are included in our NGL and crude services segment.
	The acquisitions of Red Rock and LT Enterprises were not material to our NGL and crude services segment's results of operations for the year ended December 31, 2014. In addition, transaction costs related to these acquisitions were not material for the year ended December 31, 2014.
	2013 Acquisitions
	Crestwood Merger
	As described in Note 2, the merger of Legacy Crestwood with and into Legacy Inergy was accounted for as a reverse merger amongst entities under common control. This accounting treatment requires the accounting acquiree (Legacy Inergy) to have its assets and liabilities stated at fair value as well as any other purchase accounting adjustments as of June 19, 2013, the date in which Legacy Crestwood and Legacy Inergy came under common control. The fair value of Legacy Inergy was calculated based on the consolidated enterprise fair value of Legacy Inergy as of June 19, 2013. This consolidated enterprise fair value considered Legacy Inergy's (i) discounted future cash flows based on its operations; (ii) the stock price of Legacy Inergy; (iii) the value of its outstanding senior notes based on quoted market prices for same or similar issuances; and (iv) the value of its outstanding floating rate debt.
	In June 2014, we finalized the Legacy Inergy purchase price allocation. The following table summarizes the final valuation of the assets acquired and liabilities assumed at the merger date (in millions):
	Current assets	$	49.1
	Property, plant and equipment	1,677.80
	Intangible assets	196
	Other assets	2.9
	Total identifiable assets acquired	1,925.80
	Current liabilities	30.9
	Long-term debt	745
	Other long-term liabilities	5.3
	Total liabilities assumed	781.2
	Net identifiable assets acquired	1,144.60
	Goodwill	1,532.70
	Net assets acquired	$	2,677.30
	Of the $1,532.7 million of goodwill, $806.4 million is reflected in our NGL and crude services segment and $726.3 million is reflected in our storage and transportation segment. Goodwill recognized relates primarily to synergies and new expansion opportunities expected to result from the combination of Legacy Crestwood and Legacy Inergy.  During 2014, we recorded impairments of goodwill for certain of our reporting units acquired in the Crestwood Merger. See Note 2 for a further discussion of our goodwill impairments.
	During the period ended from June 19, 2013 to December 31, 2013, we recognized $148.6 million of operating revenues and $29.8 million of operating income related to this reverse acquisition. Transaction costs related to the Crestwood Merger were $2.1 million and $24.7 million for the years ended December 31, 2014 and 2013. These costs are reflected in general and administrative expenses in our consolidated statements of operations.
	Arrow Acquisition
	On November 8, 2013, we acquired Arrow Midstream Holdings, LLC (Arrow), a privately-held midstream company, for approximately $750 million, subject to customary capital expenditure and working capital adjustments of approximately $11.3 million, representations, warranties and indemnifications.  The acquisition was consummated by merging one of our wholly-owned subsidiaries with and into Arrow (the Arrow Acquisition), with Arrow continuing as the surviving entity and , as a result, 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.
	Arrow, through its wholly-owned subsidiaries, owns and operates substantial crude oil, natural gas and water gathering systems located on the Fort Berthold Indian Reservation in the core of the Bakken Shale in McKenzie and Dunn Counties, North Dakota. Arrow also owns salt water disposal wells and a 23-acre central delivery point with multiple pipeline take-away outlets and a fully-automated truck loading facility.
	In June 2014, we finalized the Arrow Acquisition purchase price allocation. The following table summarizes the final valuation of the assets acquired and liabilities assumed at the acquisition date (in millions):
	Current assets	$	192.7
	Property, plant and equipment	400.5
	Intangible assets	323.4
	Other assets	19.5
	Total identifiable assets acquired	936.1
	Current liabilities	215.8
	Assets retirement obligations	1.2
	Other long-term liabilities	3.7
	Total liabilities assumed	220.7
	Net identifiable assets acquired	715.4
	Goodwill	45.9
	Net assets acquired	$	761.3
	The $45.9 million of goodwill is reflected in our NGL and crude services segment. Goodwill recognized relates primarily to anticipated operating synergies between the assets acquired and our existing assets. During the year ended December 31, 2013, we recognized $218.8 million of operating revenues and $1.7 million of operating income related to this acquisition. Transaction costs related to the Arrow Acquisition were approximately $5.4 million and $1.2 million, for the years ended December 31, 2014 and 2013. These costs are included in general and administrative expenses in our consolidated statements of operations.
	2012 Acquisitions
	Antero Acquisition
	On March 26, 2012, Crestwood Marcellus Midstream LLC (CMM) acquired from Antero gathering assets located in Harrison and Doddridge Counties, West Virginia (the Antero Acquisition) for approximately $376.8 million. The acquired assets consisted of a 33-mile low-pressure gathering system that delivers Antero’s Marcellus Shale production to various regional pipeline systems and MarkWest Energy Partners’ Sherwood Gas Processing Plant.
	In connection with the Antero Acquisition, Legacy Crestwood agreed to pay Antero conditional consideration in the form of potential additional cash payments of up to $40.0 million, depending on the achievement of certain defined average annual production levels achieved during 2012, 2013 and 2014. During 2012 and 2013, Antero did not meet the annual production level to earn additional payments. Based on our estimates of Antero’s 2014 production, we believed their production levels would exceed the annual production threshold in the earn-out provision and accordingly, we recognized a liability of $40.0 million and $31.4 million as of December 31, 2014 and 2013 that represented the fair value of the potential payments under the earn-out provision. We estimated the liability at December 31, 2013 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). In the first quarter of 2015, we expect to pay Antero $40.0 million under the earn-out provision.
	Upon the closing of the Antero Acquisition, CMM entered into a 20-year, fixed-fee Gas Gathering and Compression Agreement (GGA) with Antero. The GGA provided for an area of dedication of approximately 127,000 gross acres, or 104,000 net acres, largely located in the rich gas corridor of the southwestern core of the Marcellus Shale play. Under the GGA, Antero committed to deliver minimum annual throughput volumes to us for a seven year period from January 1, 2012 to January 1, 2019, ranging from an average of 300 MMcf/d in 2012 to an average of 450 MMcf/d in 2018. During the period ended December 31, 2012, Antero delivered less than the minimum annual throughput volumes and at December 31, 2012, we recorded a receivable and deferred revenue of approximately $2.6 million due to Antero’s potential ability to recover this amount if Antero’s 2013 throughput volumes exceeded the minimum annual throughput volumes included in the GGA for 2013. In 2013, Antero paid us approximately $2.4 million to satisfy their minimum volume commitment. For the year ended December 31, 2013, Antero's throughput volumes exceeded the 2013 minimum thresholds and was sufficient to recover their 2012 minimum volume shortfall that was previously paid. As a result of Antero's recovery of their 2012 shortfall, we reclassified approximately $2.4 million from deferred revenue to other accounts payable at December 31, 2013 to reflect the amount we owed to Antero, which was paid in 2014. We reflect deferred revenue and other accounts payable as accrued expenses and other liabilities on our consolidated balance sheets.
	Devon Acquisition
	On August 24, 2012, we acquired certain gathering and processing assets in the NGL rich gas region of the Barnett Shale (the Devon Acquisition) from Devon Energy Corporation (Devon). We paid approximately $87.3 million for these assets. During the year ended December 31, 2013, we finalized the purchase price allocation of the assets acquired and liabilities assumed, and as a result, we reduced our depreciation, amortization and accretion expense by approximately $2.2 million.
	The final purchase price allocation is as follows (in millions):
	Cash	$	87.9
	Total purchase price	$	87.9
	Purchase price allocation:
	Property, plant and equipment	$	88.6
	Total assets	88.6
	Asset retirement obligation	0.5
	Environmental liability	0.2
	Total liabilities	0.7
	Total	$	87.9
	Operating revenues, operating income and transaction costs related to the Devon Acquisition were immaterial to our results of operations for the year ended December 31, 2012. We believe that it is impracticable to present financial information for the acquired assets prior to the acquisition date due to the lack of availability of historical financial information related to the acquired assets, and because the 20-year fixed-fee gathering, processing and compression agreement with Devon has significantly different terms than the historical intercompany relationships between the acquired assets and Devon.
	EMAC Acquisition
	On December 28, 2012, CMM acquired all of the membership interest of E. Marcellus Asset Company, LLC (EMAC) from Enerven Compression, LLC (Enerven) for approximately $95.0 million. We financed this acquisition through CMM's credit facility. At the time of acquisition, EMAC’s assets consisted of four compression and dehydration stations located on our gathering systems in Harrison County, West Virginia. These assets provide compression and dehydration services to Antero under a compression services agreement through 2018. Antero has the option to renew the agreement for an additional five years upon expiration of the original agreement.
	During the year ended December 31, 2013, we finalized the purchase price allocation of the assets acquired and liabilities assumed, and as a result, we reduced our depreciation, amortization and accretion expense by approximately $0.7 million. In addition, we recognized goodwill of approximately $8.6 million, primarily related to anticipated operating synergies between the assets acquired and our existing assets.
	The final purchase price allocation is as follows (in millions):
	Cash	$	95
Total purchase price	$	95
Purchase price allocation:
Property, plant and equipment	$	53.4
Intangible assets	33.9
Goodwill	8.6
Total assets	95.9
Asset retirement obligation	0.8
Environmental liability	0.1
Total liabilities	0.9
Total	$	95
Our intangible assets recorded as a result of the EMAC acquisition relate to the compression services agreements with Antero. These intangibles will be amortized over the life of the contracts. The financial results of EMAC prior to the date of acquisition were not material to our results of operations, therefore, pro forma information has not been provided.
Unaudited Pro Forma Information
The following table presents unaudited pro forma consolidated revenues, net income and net income per limited partner unit as if the Legacy Inergy reverse acquisition and the Arrow Acquisition had been included in our consolidated results for the year ended December 31, 2012 and for the entire year ended December 31, 2013 (in millions, except per unit information). All other acquisitions were immaterial in consolidation.
	Year Ended December 31,
	2013			2012
Revenues	$	2,083.30		$	1,184.50
Net income (loss)	$	(21.0	)	$	50.1
Net income (loss) per limited partner unit(1):
Basic	$	(0.61	)	$	0.29
Diluted	$	(0.61	)	$	0.29
(1) Basic and diluted net income per limited partner unit for the year ended December 31, 2012 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 discussed in Note 1 and the number of units issued in conjunction with the Arrow acquisition.
These amounts have been calculated after applying our accounting policies and adjusting the results of the acquisitions to reflect the depreciation and amortization based on the estimated fair value adjustments to property, plant and equipment and intangible assets.

Certain_Balance_Sheet_Informat

Certain Balance Sheet Information	12 Months Ended
	Dec. 31, 2014
Balance Sheet Related Disclosures [Abstract]
Certain Balance Sheet Information	Certain Balance Sheet Information
	Inventory
	Inventory consisted of the following at December 31, 2014 and 2013 (in millions).
		December 31,
		2014		2013
	Parts and supplies	$	5.9	$	4.5
	Crude oil	0.9		1.4
	Raw materials	0.3		0.4
	Finished goods	0.9		0.7
	Total inventory	$	8	$	7
	Property, Plant and Equipment
	Property, plant and equipment consisted of the following at December 31, 2014 and 2013 (in millions):
		December 31,
		2014		2013
	Gathering systems and pipelines	1,276.60		1,231.10
	Facilities and equipment	1,468.80		1,041.00
	Buildings, land, rights-of-way, storage contracts and easements	806.4		766.2
	Vehicles	13.6		4.1
	Construction in process	153.7		360.5
	Base gas	37.5		36.3
	Salt deposits	120.5		120.5
	Office furniture and fixtures	6.4		6
		3,883.50		3,565.70
	Less: accumulated depreciation and depletion	365.4		215.6
	Total property, plant and equipment, net	$	3,518.10	$	3,350.10
	Depreciation. Depreciation expense totaled $148.3 million, $87.1 million and $40.8 million for the years ended December 31, 2014, 2013 and 2012. Depletion expense totaled $0.7 million and $0.4 million for the years ended December 31, 2014 and 2013. Legacy Crestwood did not have depletion expense.
	Capitalized Interest. During the year ended December 31, 2014, 2013 and 2012 we capitalized interest of $7.5 million. $3.4 million and $0.2 million related to certain expansion projects.
	Capital Leases. We have a treating facility and certain auto leases which are accounted for as capital leases. Our treating facility lease is reflected in facilities and equipment in the above table. We had capital lease assets of $2.8 million and $5.0 million included in property, plant and equipment, net at December 31, 2014 and 2013.
	Sale of Long-Lived Assets. In July 2013, we sold a cryogenic plant and associated equipment for approximately $11.0 million (net of fees) and recognized a gain of approximately $4.4 million for the year ended December 31, 2013.
	Intangible Assets
	Intangible assets consisted of the following at December 31, 2014 and 2013 (in millions):
		December 31,
		2014		2013
	Customer accounts	$	483.2	$	476.4
	Covenants not to compete	5.6		3
	Gas gathering, compression and processing contracts	431.4		451.4
	Acquired storage contracts	29		29
	Trademarks	9.7		11
	Deferred financing costs	54.3		54.3
		1,013.20		1,025.10
	Less: accumulated amortization	137		54.3
	Total intangible assets, net	$	876.2	$	970.8
	The following table summarizes the total of accumulated amortization of intangible assets by the type of intangible asset at December 31, 2014 and 2013:
		December 31,
		2014		2013
	Customer accounts	$	57	$	13.4
	Covenants not to compete	2.1		0.6
	Gas gathering, compression and processing contracts	47.9		27.9
	Acquired storage contracts	12.7		4
	Trademarks	0.9		0.3
	Deferred financing costs	16.4		8.1
	Total accumulated amortization	$	137	$	54.3
	Amortization and interest expense for the years ended December 31, 2014, 2013 and 2012, was approximately $81.0 million, $43.1 million and $15.9 million.
	Estimated amortization of our intangible assets for the next five years is as follows (in millions):
	Year Ending
	December 31,
	2015	$	89.6
	2016	76.4
	2017	63.5
	2018	51.5
	2019	44.6
	Accrued Expenses and Other Liabilities
	Accrued expenses and other liabilities consisted of the following at December 31, 2014 and 2013 (in millions):
		December 31,
	2014		2013
Accrued expenses	$	23.7	$	20
Accrued property taxes	2.1		7.6
Accrued product purchases payable	0.7		1.6
Tax payable	0.4		10.6
Interest payable	22		14.9
Accrued additions to property, plant and equipment	20		58.1
Commitments and contingent liabilities (Note 12)	40		31.4
Capital leases	1.3		2.6
Deferred revenue	11.6		1.6
Other	0.2		—
Total accrued expenses and other liabilities	$	122	$	148.4

Asset_Retirement_Obligations_N

Asset Retirement Obligations (Notes)	12 Months Ended
	Dec. 31, 2014
Asset Retirement Obligation Disclosure [Abstract]
Asset Retirement Obligation	Asset Retirement Obligations
	We have legal obligations associated with right-of-way contracts we hold and at our facilities whether owned or leased. Where we can reasonably estimate the asset retirement obligation, we accrue a liability based on an estimate of the timing and amount of settlement. We record changes in these estimates based on changes in the expected amount and timing of payments to settle our obligations.
	The following table presents the changes in the net asset retirement obligations for the years ended December 31, 2014 and 2013 (in millions):
		December 31,
		2014		2013
	Net asset retirement obligation at January 1	$	15.1	$	14
	Liabilities incurred	4.6		—
	Acquisitions	1.2		—
	Accretion expense	1.1		0.8
	Changes in estimate	—		0.3
	Net asset retirement obligation at December 31	$	22	$	15.1
	We did not have any material assets that were legally restricted for use in settling asset retirement obligations as of December 31, 2014 and 2013.

Investments_in_Unconsolidated_

Investments in Unconsolidated Affiliates (Notes)	12 Months Ended
	Dec. 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). Williams Partners LP operates and owns the remaining 50% interest in Jackalope. Crestwood Niobrara manages the commercial operations of the Jackalope system, and we account for our investment in Jackalope under the equity method of accounting. Our Jackalope investment is included in our gathering and processing segment.
	In July 2013, Crestwood Niobrara acquired its interest in Jackalope from RKI Exploration and Production, LLC (RKI), an affiliate of Crestwood Holdings, for approximately $107.5 million. During the years ended December 31, 2014 and 2013, Crestwood Niobrara contributed $105.2 million and $19.6 million to Jackalope to fund the construction of its gathering and processing system.
	Our investment in Jackalope was $232.9 million and $127.2 million at December 31, 2014 and 2013. We have reflected the earnings from our investment in Jackalope in our consolidated statements of operations, which includes our share of Jackalope's net earnings based on our ownership interest and other adjustments recorded by us as discussed below. Our share of Jackalope’s net earnings was approximately $3.6 million and $1.5 million for the years ended December 31, 2014 and 2013. As of December 31, 2014, our investment balance in Jackalope exceeded our equity in the underlying net assets of Jackalope by approximately $53.7 million. We amortize and generally assess the recoverability of this amount over 20 years, which represents the life of Jackalope’s gathering agreement with Chesapeake Energy Corporation (Chesapeake) and RKI. The amortization is reflected as reduction of our earnings from unconsolidated affiliates, and we recorded amortization expense of approximately $3.1 million and $1.4 million for the years ended December 31, 2014 and 2013.
	Jackalope is required to make quarterly distributions of its available cash to its members based on their respective ownership percentage. During the year ended December 31, 2014 and 2013, Jackalope did not make any distributions to its members.
	We entered into a construction agreement with Jackalope, pursuant to which we assumed the responsibility to construct a truck terminal and storage facility. Under this agreement, Jackalope reimburses us for all costs incurred on its behalf, therefore, no revenues are recognized under this agreement.
	Tres Palacios Holdings LLC
	In December 2014, CEQP sold its 100% interest in Tres Palacios Storage Company LLC (Tres Palacios) to Tres Palacios Holdings LLC (Tres Holdings), a newly formed joint venture between CMLP Tres Manager LLC, our consolidated subsidiary, and an affiliate of Brookfield Infrastructure Group (Brookfield), for total cash consideration of approximately $132.8 million, of which $66.4 million was paid by us to Crestwood Equity. As a result of this transaction, we own 50.01% of Tres Holdings and we are the operator of Tres Palacios and its assets. Brookfield owns the remaining 49.99% interest in Tres Holdings. We account for our investment in Tres Holdings under the equity method of accounting, and the investment is included in our storage and transportation segment.
	The acquisition of our 50.01% interest in Tres Palacios was considered a transaction between entities under common control and, as a result, we recorded our investment in Tres Palacios at approximately $35.8 million, which represented 50.01% of Crestwood Equity's historical basis in Tres Palacios. We reflected the difference between Crestwood Equity's historical basis and the cash paid by us in excess of Crestwood Equity's historical basis of approximately $30.6 million as a distribution to general partner.
	Tres Palacios is a 38.4 Bcf multi-cycle, salt dome storage facility. Its 60-mile, dual 24-inch diameter header system (including a 51-mile north pipeline lateral and an approximate 11-mile south pipeline lateral) interconnects with 10 pipeline systems and can receive residue gas from the tailgate of Kinder Morgan Inc.'s Houston central processing plant.
	Our investment in Tres Holdings was $36.0 million at December 31, 2014. We have reflected the earnings from our investment in Tres Holdings in our consolidated statements of operations, which includes our share of Tres Palacios' net earnings based on our ownership interest and other adjustments recorded by us as discussed below. Our share of Tres Holdings' net earnings was approximately $0.1 million for the year ended December 31, 2014. As of December 31, 2014, our equity in the underlying net assets of Tres Holdings exceeded our investment balance in Tres Holdings by approximately $30.6 million based on the transaction described above. We amortize and generally assess the recoverability of this amount over the life of the property, plant and equipment of Tres Palacios. The amortization is reflected as an increase in our earnings from unconsolidated affiliates, and we recorded amortization of approximately $0.1 million for the year ended December 31, 2014.
	Tres Holdings is required, within 30 days following the end of each quarter, to make quarterly distributions of its available cash (as defined in its limited liability company agreement) to its members based on their respective ownership percentage. Tres Holdings' distribution requirement to its members commences with the quarter ended March 31, 2015.
	We entered into an operating agreement with Tres Palacios, pursuant to which we assumed the responsibility of operating and maintaining the facilities as well as certain administrative and other general services identified in the agreement. Under this agreement, Tres Palacios reimburses us for all costs incurred on its behalf. We did not receive any reimbursements under this agreement during the year ended December 31, 2014.
	Powder River Basin Industrial Complex, LLC
	Crestwood Crude Logistics LLC (Crude Logistics), our consolidated subsidiary, owns a 50% ownership interest in Powder River Basin Industrial Complex, LLC (PRBIC) which we account for under the equity method of accounting. Our PRBIC investment is included in our NGL and crude services segment.
	In September 2013, Crude Logistics and Enserco Midstream, LLC formed PRBIC to construct, own and operate and early stage crude oil terminal located in Douglas County, Wyoming. The terminal was placed in manifest service in August 2013. Crude Logistics paid approximately $22.5 million to acquire its interest in PRBIC. During the years ended December 31, 2014 and 2013, Crude Logistics contributed approximately $3.4 million and $1.9 million to PRBIC to fund its construction projects.
	Our investment in PRBIC was $26.2 million and $24.2 million at December 31, 2014 and 2013. During the years ended December 31, 2014 and 2013, our share of PRBIC’s loss were approximately $1.4 million and $0.2 million. As of December 31, 2014 and 2013, 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 years ended December 31, 2014 and 2013, PRBIC did not make any distributions to its members. In February 2015, we received a cash distribution of approximately $0.3 million from PRBIC.

Financial_Instruments

Financial Instruments	12 Months Ended
	Dec. 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 December 31, 2014 and 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.
	In September 2014, we began entering into daily and short-term forward crude purchase and sale agreements in our NGL and crude services segment related to available capacity on our crude contracts and facilities for our operations located in the Bakken and PRB Niobrara Shale plays. As of December 31, 2014, our outstanding positions and the related impact to our consolidated statement of operations associated with our risk management activities were not material.
	As of December 31, 2014 and 2013, the carrying amounts of cash, accounts receivable and accounts payable represent fair value based on the short-term nature of these instruments. The fair value of the amount outstanding under our credit facility approximates its carrying amount as of December 31, 2014 and 2013 due primarily to the variable nature of the interest rate of the instrument, which is considered a Level 2 fair value measurement. As discussed below, contemporaneously with the closing of the Crestwood Merger on October 7, 2013, we repaid and retired the credit facilities of Legacy Crestwood and CMM with borrowings under the Crestwood Midstream Revolver.
	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):
		December 31, 2014				December 31, 2013
		Carrying Amount		Fair		Carrying Amount		Fair
				Value				Value
	2019 Senior Notes	$	351	$	360.5	$	351.2	$	379.3
	2020 Senior Notes	$	504	$	481.6	$	504.7	$	513.8
	2022 Senior Notes	$	600	$	568.5	$	600	$	617.3
	Debt
	Long-term debt consisted of the following at December 31, 2014 and 2013 (in millions):
		December 31,
		2014		2013
	Credit Facility	$	555	$	414.9
	2019 Senior Notes	350		350
	Premium on 2019 Senior Notes	1		1.2
	2020 Senior Notes	500		500
	Fair value adjustment of 2020 Senior Notes	4		4.7
	2022 Senior Notes	600		600
	Other	3.5		—
	Total debt	2,013.50		1,870.80
	Less: current portion	0.7		2.9
	Total long-term debt	$	2,012.80	$	1,867.90
	Credit Facility
	Description of Facility. We have a five-year $1.0 billion senior secured revolving credit facility due in October 2018 (the Credit Facility), which is available to fund acquisitions, working capital and internal growth projects and for general partnership purposes. The Credit Facility includes a sub-limit up to $25 million for same-day swing line advances and a sub-limit up to $250 million for letters of credit. Subject to limited exception, the Credit Facility is secured by substantially all of the equity interests and assets of our restricted domestic subsidiaries, and is joint and severally guaranteed by substantially all of our restricted domestic subsidiaries, except for Crestwood Niobrara LLC, Crestwood Crude Logistics LLC and CMLP Tres Manager LLC.
	In June 2014, we amended the Credit Facility to clarify, among other things, (i) the methodology for calculating the value of our investment in certain joint ventures constituting unrestricted subsidiaries; and (ii) that redemptions, repurchases and retirements of equity interests are permitted to the extent made solely through the issuance of additional equity units. We did not pay any fees to our bank syndicate for this amendment.
	At December 31, 2014 and 2013, the balance outstanding on the Credit Facility was $555.0 million and $414.9 million and outstanding standby letters of credit were $15.1 million and $30.7 million. We had $429.9 million of available capacity under the revolving credit facility at December 31, 2014 considering our most restrictive debt covenants under the facility. The interest rates on the Credit Facility are based on the prime rate and LIBOR plus the applicable spreads, resulting in interest rates which were between 2.66% and 4.75% at December 31, 2014 and 2.67% and 4.75% at December 31, 2013. The weighted-average interest rate as of December 31, 2014 and 2013 was 2.86% and 2.75%.
	Borrowings under our Credit Facility (other than swing line loans) bear interest at its option at either:
	•	the Alternate Base Rate, which is defined as the highest of (i) the federal funds rate plus 0.50%; (ii) JP Morgan's prime rate; or (iii) Adjusted LIBOR plus 1%; plus a margin varying from 0.75% to 1.75% depending on our most recent total leverage ratio; or
	•	Adjusted LIBOR, which is defined as LIBOR plus a margin varying from 1.75% to 2.75% depending on our most recent total leverage ratio.
	Swingline loans bear interest at the Alternate Base Rate plus a margin varying from 0.75% to 1.75%. The unused portion of the Credit Facility is subject to a commitment fee ranging from 0.30% to 0.50% per annum according to our most recent total leverage ratio. Interest on Alternative Base Rate loans is payable quarterly or, if Adjusted LIBOR applies, it may be paid at more frequent intervals.
	Restrictive Covenants. The Credit Facility contains various covenants and restrictive provisions that limit our ability to, among other things, (i) incur additional debt; (ii) make distributions on or redeem or repurchase units; (iii) make certain investments and acquisitions; (iv) incur or permit certain liens to exist; (v) enter into certain types of transactions with affiliates; (vi) merger, consolidate or amalgamate with another company; and (vii) transfer or otherwise dispose of assets.
	The Credit Facility requires maintenance of a consolidated leverage ratio (as defined in our credit agreement) of not more than 5.00 to 1.0 (and, if applicable, 5.50 to 1.0 during certain periods immediately following a material acquisition by us) and an interest coverage ratio (as defined in its credit agreement) of not less than 2.50 to 1.0. At December 31, 2014, the net debt to consolidated EBITDA was approximately 4.50 to 1.0 and consolidated EBITDA to consolidated interest expense was approximately 3.99 to 1.0.
	In December 2014, we notified the administrative agent of our election to commence an Acquisition Period (as defined in our credit agreement) effective as of December 3, 2014. We made this election following our acquisition of a 50.01% indirect interest in Tres Palacios. Our consolidation leverage ratio (as defined in our credit agreement) increases to 5.50 to 1.0 during the 270-day Acquisition Period as a result of this election.
	If we fail to perform our obligations under these and other covenants, the lenders' credit commitment could be terminated and any outstanding borrowings, together with accrued interest, under the Credit Facility could be declared immediately due and payable. The Credit Facility also has cross default provisions that apply to any other material indebtedness of ours.
	Senior Notes
	2019 Senior Notes. In April 2011, Legacy Crestwood and Crestwood Midstream Finance Corporation (Legacy Crestwood Finance, and together with Legacy Crestwood, the Legacy Crestwood Issuers) issued $200 million of 7.75% Senior Notes due 2019 (the Initial 2019 Senior Notes) in a private offering. On November 14, 2012, the Legacy Crestwood Issuers issued and sold an additional $150 million of these notes (the Additional 2019 Senior Notes, and together with the Initial 2019 Senior Notes, the 2019 Senior Notes). The 2019 Senior Notes will mature on April 1, 2019, and interest is payable semi-annually in arrears on April 1 and October 1 of each year.
	Following the close of the Crestwood Merger on October 7, 2013, (i) the Company and Crestwood Midstream Finance Corp. (Finance Corp) assumed the obligations of Legacy Crestwood and Legacy Crestwood Finance under their 2019 Senior Notes; (ii) certain Legacy Crestwood subsidiary guarantors of the 2019 Senior Notes guaranteed the obligations of the Company and Finance Corp. under the 2020 Senior Notes described below; (iii) the Company’s subsidiary guarantors of the 2020 Senior Notes guaranteed obligations of Legacy Crestwood Issuers under the 2019 Senior Notes; and (iv) Legacy Crestwood Finance merged with and into NRGM Finance Corp., with NRGM Finance Corp. continuing as the surviving entity and immediately thereafter changing its name to Crestwood Midstream Finance Corp.
	2020 Senior Notes. At December 31, 2014, the balance outstanding on our 6.0% Senior Notes due 2020 (the 2020 Senior Notes) was $500 million. We recorded an adjustment in conjunction with Legacy Crestwood GP's reverse acquisition of us to adjust the debt to fair value. At the December 31, 2014 and 2013, the unamortized balance of the adjustment was $4.0 million and $4.7 million. The adjustment is being amortized over the remaining life of the 2020 Senior Notes. The senior notes will mature on December 15, 2020, and interest is payable semi-annually in arrears on June 15 and December 15 of each year.
	2022 Senior Notes. In November 2013, Crestwood Midstream and Finance Corp, completed an offering of $600 million in aggregate principal amount of 6.125% Senior Notes due 2022 (the 2022 Senior Notes) in a private offering exempt from registration requirements of the Securities Act of 1933. Crestwood Midstream used the net proceeds from the offering to fund a portion of the consideration paid in the Arrow Acquisition and related fees and expenses, and to repay borrowings under the Crestwood Midstream Revolver.
	On July 17, 2014, we filed a registration statement with the SEC under which we offered to exchange the 2022 Senior Notes for any and all outstanding 2022 Senior Notes, which were issued in the private offering in November 2013.  We completed the exchange offer on August 29, 2014. The terms of the exchange notes are substantially identical to the terms of the 2022 Senior Notes, except that the exchange notes are freely tradable. At December 31, 2014, the balance outstanding on the 2022 Senior Notes was $600 million.
	In general, each series of our senior notes are fully and unconditionally guaranteed, joint and severally, on a senior unsecured basis by our domestic restricted subsidiaries (other than Finance Corp.). The indentures contain customary release provisions, such as (i) disposition of all or substantially all of the assets of, or the capital stock of, a guarantor subsidiary to a third person if the disposition complies with the indentures; (ii) designation of a guarantor subsidiary as an unrestricted subsidiary in accordance with its indentures; and (iii) legal or covenant defeasance of a series of senior notes, or satisfaction and discharge of the related indenture; and (iv) guarantor subsidiary ceases to guarantee any other indebtedness of us or any other guarantor subsidiary, provided it no longer guarantees indebtedness under the Credit Facility.
	The indentures restricts our ability and the ability of our restricted subsidiaries to, among other things, sell assets; redeem or repurchase subordinated debt; make investments; incur or guarantee additional indebtedness or issue preferred units; create or incur certain liens; enter into agreements that restrict distributions or other payments to us from our restricted subsidiaries; consolidate, merge or transfer all of substantially all of our assets; engage in affiliate transactions; and create unrestricted subsidiaries. These restrictions are subject to a number of important exceptions and qualifications, and many of these restrictions will terminate when the senior notes are rated investment grade by either Moody's Investors Service, Inc. or Standard & Poor's Rating Services and no default or event of default (each as defined in the respective indentures) under the indentures has occurred and is continuing. In addition, under the indenture governing our 2019 Senior Notes, we may not pay any dividend on our common units unless, among other things, at the time of and after giving effect to such dividend payment, no default under the indenture has occurred and is continuing or would occur as a consequence of such dividend payment.
	At December 31, 2014, we were in compliance with the debt covenants and restrictions in each of its credit agreements discussed above.
	Other Obligations
	Non-interest bearing obligations due under noncompetition agreements consisted of agreement between Crestwood Midstream and sellers of certain companies acquired in 2014 with payments due through 2019 and imputed interest of 5.02%. Non-interest bearing obligations consisted of $4.0 million in total payments due under agreements, less unamortized discount based on imputed interest of $0.5 million at December 31, 2014.
	Maturities
	The aggregate maturities of principal amounts on our outstanding long-term debt and other notes payable as of December 31, 2014 for the next five years and in total thereafter are as follows (in millions):
	2015	$	0.7
	2016	0.7
	2017	0.7
	2018	555.8
	2019	350.6
	Thereafter	1,100.00
	Total debt	$	2,008.50

Earnings_Per_Limited_Partner_U

Earnings Per Limited Partner Unit	12 Months Ended
	Dec. 31, 2014
Earnings Per Share [Abstract]
Earnings Per Limited Partner Unit	Earnings Per Limited Partner Unit
	Prior to the Crestwood Merger, net income attributable to Legacy Crestwood was allocated to the general partner and the limited partners in accordance with their respective ownership percentages, after giving effect to incentive distributions earned by the general partner. To the extent cash distributions exceeded net income attributable to Legacy Crestwood, the excess distributions were allocated proportionately to all participating units outstanding based on their respective ownership percentages. As a result of the Crestwood Merger, CEQP, which owns our general partner, owns a non-economic general partner interest in us and 100% of our IDRs. We allocate net income attributable to CMLP to our limited partners after giving effect to the IDRs earned by CEQP and net income attributable to the Class A preferred units.
	Basic earnings per unit are calculated using the two-class method. Diluted earnings per unit are computed using the treasury stock method, which considers the impact to net income attributable to CMLP and limited partner units from the potential issuance of limited partner units as discussed below. The weighted average number of units outstanding is calculated based on the presumption that the number of common units issued by Legacy Inergy to Legacy Crestwood unitholders as part of the Crestwood Merger were outstanding for the entire period prior to Crestwood Merger.
	The tables below show the (i) allocation of net income attributable to CMLP and the (ii) net income attributable to CMLP per limited partner unit based on the number of basic and diluted limited partner units outstanding for the years ended December 31, 2014, 2013 and 2012 (in millions):
	Allocation of Net Income Attributable to CMLP
		Year Ended December 31,
		2014			2013			2012
	Net income (loss) attributable to CMLP	$	(38.7	)	$	(20.0	)	$	38.9
	Class A preferred units interest in net income attributable to CMLP	(17.2		)	—			—
	General partner’s incentive distributions	(30.1		)	(26.4		)	(14.8		)
	General partner’s interest in net income attributable to CMLP after incentive distributions	—			(0.4		)	(7.4		)
	Payment to Legacy Crestwood unitholders	—			(34.9		)	—
	Limited partners’ interest in net income (loss) attributable to CMLP after incentive distributions	$	(86.0	)	$	(81.7	)	$	16.7
	Earnings Per Limited Partner Unit
		Year Ended December 31,
		2014			2013			2012
	Limited partners’ interest in net income (loss)	$	(86.0	)	$	(81.7	)	$	16.7
	Weighted-average limited partner units - basic	187.9			99.2			64.7
	Effect of diluted units	—			—			—
	Weighted-average limited partner units - diluted	187.9			99.2			64.7
	Basic earnings per unit:
	Net income (loss) per limited partner	$	(0.46	)	$	(0.82	)	$	0.26
	Diluted earnings per unit:
	Net income (loss) per limited partner	$	(0.46	)	$	(0.82	)	$	0.26
	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 years ended December 31, 2014 and 2013, we excluded a weighted-average of 9,089,196 common units and 1,891,326 common units, representing Crestwood Niobrara's preferred units if converted to common units, from our diluted earnings per unit. During the year ended December 31, 2014, we also excluded a weighted-average of 7,441,255 common units, representing Class A 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 year ended December 31, 2012.
	General Partner Interest and Incentive Distribution Rights
	Prior to the Crestwood Merger, Legacy Crestwood’s general partner was entitled to quarterly distributions equal to its general partner interest. In addition, Legacy Crestwood’s general partner held IDRs in accordance with the Legacy Crestwood Partnership Agreement. These rights paid an increasing percentage, up to a maximum of 50% of the cash they distributed from operating surplus in excess of $0.45 per unit per quarter. The maximum distribution of 50% included distributions paid to the general partner based on its general partner interest and assumed that Legacy Crestwood’s general partner maintained its general partner interest. The maximum distribution of 50% did not include any distributions that the general partner may have received on limited partner units that it owned.
	Following the Crestwood Merger, our general partner is not entitled to distributions on its non-economic general partner interest. IDRs are entitled to receive 50% of the cash distributed from operating surplus (as defined in our partnership agreement) in excess of the initial quarterly distribution of $0.37.
	CEQP, as the owner of our IDRs, has the right under our partnership agreement to elect to relinquish the right to receive incentive distribution payments based on the initial quarterly distribution and to reset, at a higher level, the quarterly distribution amount (upon which the incentive distribution payments to CEQP would be set). If CEQP elects to reset the quarterly distribution, it will be entitled to receive a number of newly issued Company common units. The number of common units to be issued to CEQP will equal the number of common units that would have entitled the holder to the quarterly cash distribution in the prior quarter equal to the distribution to CEQP on the IDRs in such prior quarter. As the reset election has not been made, no additional units have been issued. For accounting purposes, diluted earnings per unit can be impacted, (even if the reset election has not been made), if the combined impact of issuing the additional units and resetting the cash target distribution is dilutive. Currently, diluted earnings per unit has not been impacted because the combined impact is anti-dilutive.
	See Note 10 for a further discussion of the distributions and IDRs paid to the general partner during the three years ended December 31, 2014.

Income_Taxes_Notes

Income Taxes (Notes)	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes
	The provision for income taxes for the years ended December 31, 2014, 2013, and 2012 consisted of current state taxes of approximately $0.7 million, $0.7 million and $1.2 million.  The effective rate differs from the statutory rate for the years ended December 31, 2014 and 2013 and 2012 primarily due to the Partnership not being treated as a corporation for federal income tax purposes as discussed in Note 2.
	Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. We are responsible for the Texas Margin tax computed on the Texas franchise tax return. The margin tax qualifies as an income tax under GAAP, which requires us to recognize the impact of this tax on the temporary differences between the financial statement assets and liabilities and their tax basis attributable to such tax. For the year ended December 31, 2014, we had a deferred tax liability of approximately $0.6 million associated with the Texas Margin Tax. For the years ended December 31, 2013, there were no deferred tax liability recognized on our consolidated balance sheet.
	Uncertain Tax Positions. We evaluate the uncertainty in tax positions taken or expected to be taken in the course of preparing our consolidated financial statements to determine whether the tax positions are more likely than not of being sustained by the applicable tax authority. Tax positions with respect to tax at the partnership level deemed not to meet the more likely than not threshold would be recorded as a tax benefit or expense in the current year. We believe that there were no uncertain tax positions that would impact our operations for the years ended December 31, 2014, 2013 and 2012 and that no provision for income tax was required for these consolidated financial statements. However, our conclusions regarding the evaluation are subject to review and may change based on factors including, but not limited to, ongoing analyses of tax laws, regulations and interpretations thereof.

Partners_Capital

Partners' Capital	12 Months Ended
	Dec. 31, 2014
Partners' Capital [Abstract]
Partners' Capital	Partners’ Capital
	Class A Preferred Units
	On June 17, 2014, we entered into definitive agreements with a group of investors, including Magnetar Financial, affiliates of GSO Capital Partners LP and GE Energy Financial Services (the Class A Purchasers). Under these agreements, we have agreed to sell to the Class A Purchasers and the Class A Purchasers have agreed to purchase from us up to $500 million of Preferred Units at a fixed price of $25.10 per unit on or before September 30, 2015. During the year ended December 31, 2014, the Class A Purchasers purchased 17,529,879 Preferred Units for a cash purchase price of $25.10 per unit resulting in gross proceeds to us of approximately $440.0 million (net proceeds of approximately $430.5 million after deducting transaction fees and offering expenses). Subject to certain conditions, holders of the Preferred Units will have the right to convert Preferred Units into (i) common units on a one-for-one basis after June 17, 2017, or (ii) a number of common units determined pursuant to a conversion ratio set forth in our partnership agreement upon the occurrence of certain events, such as a change in control. Also, subject to certain conditions after the full $500 million purchase commitment has been satisfied, we may convert the Preferred Units into common units at a conversion ratio set forth in the partnership agreement, which is based in part on the aggregate principal amount of the Preferred Units outstanding and the weighted average trading price of our common units.
	The Preferred Units have voting rights that are identical to the voting rights of the common units and will vote with the common units as a single class, with each Preferred Unit entitled to one vote for each common unit into which such Preferred Unit is convertible, except that the Preferred Units are entitled to vote as a separate class on any matter on which all unitholders are entitled to vote that adversely affects the rights, powers, privileges or preferences of the Preferred Units in relation to our other securities outstanding.
	On July 9, 2014, we filed a shelf registration statement with the SEC under which holders of the Preferred Units may sell the common units into which the Preferred Units are convertible. The registration statement became effective on July 18, 2014. We registered 26,299,076 common units under the registration statement.
	Common Units
	Common Unit Issuances. We periodically sell common units in public offerings to generate funds to reduce our indebtedness under our credit facilities and to fund acquisitions. The table below presents limited partner unit issuances by Legacy Crestwood, Legacy Inergy and Crestwood Midstream.
	Issuer		Issuance Date	Units			Per Unit			Per Unit		Net
							Gross Price			Net Price (1)		Proceeds
	Legacy Crestwood		13-Jan-12	3,500,000			$	30.73		$	29.5	$	103.1
	Legacy Crestwood		25-Jul-12	4,600,000		(2)	26			24.97		114.4
	Legacy Crestwood		22-Mar-13	5,175,000		(3)	23.9			23		118.5
	Legacy Inergy		13-Sep-13	11,773,191		(4)	22.5			21.69		255.2
	Crestwood Midstream		23-Oct-13	16,100,000		(5)	N/A			21.19		340.3
	(1)	Price is net of underwriting discounts.
	(2)	Includes 600,000 units that were issued in August 2012.
	(3)	Includes 675,000 units that were issued in April 2013.
	(4)	Includes 773,191 units that were issued on October 7, 2013.
	(5)	Includes 2,100,000 units that were issued on October 30, 2013.
	During 2011 and 2013, Legacy Crestwood issued Class C and Class D units, respectively, representing limited partner units. Legacy Crestwood had the option to pay distributions to its Class C and Class D unitholders with cash or by issuing additional paid-in-kind units based upon the volume common unit weighted-average price for 10 trading days immediately preceding the date the distribution was declared. On April 1, 2013, the outstanding Legacy Crestwood Class C units converted to common units on a one-for-one basis. In conjunction with the Crestwood Merger, Legacy Crestwood unitholders received 1.07 units of Legacy Inergy units for each unit of Legacy Crestwood they owned and as a result, there were no common or Class D units outstanding immediately following the Crestwood Merger. During 2013, Legacy Crestwood issued 183,995 and 292,660 additional Class C and Class D units in lieu of paying a quarterly cash distribution. For the year ended December 31, 2012, Legacy Crestwood issued 633,084 additional Class C units in lieu of paying quarterly cash distributions.
	Equity Distribution Agreement. On July 10, 2014, we entered into an equity distribution agreement with certain financial institutions (each, a Manager), under which we may offer and sell from time to time through one or more of the Managers, common units having an aggregate offering price of up to $300.0 million. Common units sold pursuant to this at-the-market (ATM) equity distribution program will be issued under a registration statement that became effective on May 27, 2014. We will pay the Managers an aggregate fee of up to 2.0% of the gross sales price per common unit sold under our ATM program. We have not issued any common units under this equity distribution program as of December 31, 2014 and through the date of this filing.
	Distributions
	Prior to the Crestwood Merger, Legacy Crestwood’s Second Amended and Restated Agreement of Limited Partnership, dated February 19, 2008, as amended (Legacy Crestwood Partnership Agreement), required that, within 45 days after the end of each quarter, they distribute all of their available cash (as defined therein) to unitholders of record on the applicable record date, as determined by its general partner. Legacy Crestwood’s minimum quarterly distribution was $0.30 per unit, to the extent they had sufficient cash flows from operations after the establishment of cash reserve and payment of fees and expenses, including payments to its general partner.
	Following the Crestwood Merger, 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 unitholders of record on the applicable record date. The general partner is not be entitled to distributions on its non-economic general partner interest.
	Distributions to General Partner
	During the years ended December 31, 2014, 2013 and 2012, we paid cash distributions to our general partner (representing IDRs and distributions related to common units held by the general partner) of approximately $41.8 million, $26.2 million and $25.8 million.
	As discussed in Note 6, in December 2014, we paid approximately $66.4 million to acquire a 50.01% in Tres Palacios from Crestwood Equity. We reflected the difference between the cash paid by us in excess of Crestwood Equity's basis of approximately $30.6 million as a distribution to our general partner on our consolidated statement of partners' capital and our consolidated statement of cash flows for the year ended December 31, 2014.
	Distributions to Class A Preferred Unit Holders
	Our partnership agreement requires us to make quarterly distributions to our Class A Preferred Unit holders. The holders of our Class A Preferred Units (the Preferred Units) are entitled to receive fixed quarterly distributions of $0.5804 per unit. For the 12 quarters following the quarter ended June 30, 2014 (the Initial Distribution Period), distributions on our Preferred Units can be made in additional Preferred Units, cash, or a combination thereof, at our election. If we elect to pay the quarterly distribution through the issuance of additional Preferred Units, the number of units to be distributed will be calculated as the fixed quarterly distribution of $0.5804 per unit divided by the cash purchase price of $25.10 per unit. We accrue the fair value of such distribution at the end of the quarterly period and adjust the fair value of the distribution on the date the additional Preferred Units are distributed. Distributions on our Preferred Units following the Initial Distribution Period will be made in cash unless, subject to certain exceptions, (i) there is no distribution being paid on our common units and (ii) our available cash (as defined in our partnership agreement) is insufficient to make a cash distribution to our Preferred Unit holders. If we fail to pay the full amount payable to our Preferred Unit holders in cash following the Initial Distribution Period, then (x) the fixed quarterly distribution on the Preferred Units will increase to $0.7059 per unit, and (y) we will not be permitted to declare or make any distributions to our common unitholders until such time as all accrued and unpaid distributions on the Preferred Units have been paid in full in cash. In addition, if we fail to pay in full any Class A Preferred Distribution (as defined in our partnership agreement), the amount of such unpaid distribution will accrue and accumulate from the last day of the quarter for which such distribution is due until paid in full, and any accrued and unpaid distributions will be increased at a rate of 2.8125% per quarter.
	During the year ended December 31, 2014, we issued 387,991 Class A Preferred Units to our preferred unitholders in lieu of paying quarterly cash distributions. On February 13, 2015 we issued 414,325 Class A Preferred Units to our preferred unitholders for the quarter ended December 31, 2014 in lieu of paying a cash distribution.
	Distributions to Limited Partners
	The following table presents quarterly cash distributions paid to our limited partners (excluding distributions paid to our general partner on its common units held) during the years ended December 31, 2014 and 2013. In addition, during the year ended December 31, 2013, we paid cash distributions of approximately $24.9 million as a result of the Crestwood Merger discussed below. During the year ended December 31, 2012, Legacy Crestwood paid cash distributions of $77.7 million to its limited partners.
	Record Date		Payment Date	Per Unit Rate				Cash Distributions
								(in millions)
	2014
	February 7, 2014		February 14, 2014	$	0.41			$	74.1
	May 8, 2014		May 15, 2014	$	0.41			74.2
	August 7, 2014		August 14, 2014	$	0.41			74.1
	November 7, 2014		November 14, 2014	$	0.41			74.1
								$	296.5
	2013
	January 31, 2013		February 12, 2013	$	0.51			$	21
	April 30, 2013		May 10, 2013	$	0.51			27.4
	August 1, 2013		August 9, 2013	$	0.51			27.4
	August 7, 2013		August 14, 2013	$	0.4			34.3		(1)
	November 7, 2013		November 14, 2013	$	0.405			69.5		(1)
								$	179.6
	-1	Represents distributions associated with Legacy Inergy limited partner units.
	On February 13, 2015, we paid a distribution of $0.41 per limited partner unit to unitholders of record on February 6, 2015 with respect to the fourth quarter of 2014.
	Non-Controlling Partners
	Crestwood Niobrara Preferred Interest. Crestwood Niobrara issued a preferred interest to a subsidiary of General Electric Capital Corporation and GE Structured Finance, Inc. (collectively, GE) in conjunction with the acquisition of its investment in Jackalope. The preferred interest is reflected as non-controlling interest in our consolidated financial statements. We allocated net income to the non-controlling interest based on the overall return attributable to the preferred security of approximately $16.8 million and $4.9 million during the years ended December 31, 2014 and 2013.
	Pursuant to Crestwood Niobrara's agreement with GE, GE made capital contributions to Crestwood Niobrara in exchange for an equivalent number of preferred units. During the years ended December 31, 2014 and 2013, GE made capital contributions of $53.9 million and $96.1 million to Crestwood Niobrara. As of December 31, 2014, GE has fulfilled its capital contribution commitment to Crestwood Niobrara of $150.0 million and is no longer required to make quarterly contributions to Crestwood Niobrara.
	Distributions to Non-Controlling Partners. Crestwood Midstream serves as the managing member of Crestwood Niobrara and, subject to certain restrictions, it has the ability to redeem GE’s preferred interest in either cash or Crestwood Midstream common units at an amount equal to the face amount of the preferred units plus an applicable return. During the years ended December 31, 2014 and 2013, Crestwood Niobrara issued 11,419,241 and 2,161,657 preferred units to GE in lieu of paying a cash distribution. On January 30, 2015, Crestwood Niobrara issued 3,680,570 preferred units to GE in lieu of paying a cash distribution. Beginning with the first quarter of 2015, Crestwood Niobrara no longer has the option to pay distributions to GE by issuing additional preferred units in lieu of paying a cash distribution.
	Contributions
	During 2012, Legacy Crestwood's general partner made additional capital contributions of approximately $5.9 million in exchange for the issuance of an additional 215,722 general partner units.
	Other Partners' Capital Transactions
	Crestwood Merger
	As discussed in Note 1, in conjunction with the Crestwood Merger, Legacy Crestwood unitholders received 1.07 units of Legacy Inergy units for each Legacy Crestwood unit they owned and as a result, there were no Legacy Crestwood common or Class D units outstanding immediately following the merger. In addition, Legacy Crestwood unitholders also received a $34.9 million distribution, $10 million of which was funded as a non-cash contribution from Crestwood Holdings and is reflected on our consolidated statements of partners’ capital as contributions from general partner for the year ended December 31, 2013. We reflected the distribution of $34.9 million as distributions to partners on our consolidated statements of partners’ capital for the year ended December 31, 2013.
	Acquisitions and Other
	CMM. In February 2012, Legacy Crestwood and Crestwood Holdings formed the CMM joint venture. Legacy Crestwood contributed approximately $131.3 million for a 35% membership interest and Crestwood Holdings contributed approximately $243.8 million for a 65% membership interest. On January 8, 2013, Legacy Crestwood acquired Crestwood Holdings’ 65% membership interest in CMM for approximately $258.0 million, which was funded through $129.0 million of borrowings under the Legacy Crestwood credit facility, the issuance of 6,190,469 Class D units and the issuance of 133,060 general partner units to the Legacy Crestwood general partner. As a result of the acquisition of the additional membership interest, Legacy Crestwood had the ability to control CMM’s operating and financial decisions and policies. The transaction was accounted for as a reorganization of entities under common control and accordingly, the historical results of Legacy Crestwood were retrospectively adjusted to reflect the change in reporting entity as of and for the year ended December 31, 2012. We reflected the $243.8 million contribution by Crestwood Holdings as a contribution from partners in our consolidated statements of cash flows and statements of partners’ capital for the year ended December 31, 2012. The issuances of the Class D and general partner units in conjunction with the acquisition of the additional interest in CMM were reflected as distributions for additional interest in Crestwood Marcellus Midstream LLC in our consolidated statements of cash flows and statements of partners’ capital for the year ended December 31, 2013.
	Arrow. On November 7, 2013, we issued 8,826,125 common units as partial consideration of the Arrow Acquisition. See Note 3 for additional information regarding the Arrow Acquisition.
	Other. During the year ended December 31, 2013, we received a contribution of approximately $5.5 million related to reimbursements of costs pursuant to our omnibus agreement with CEQP.

Equity_Plans_Notes

Equity Plans (Notes)	12 Months Ended
	Dec. 31, 2014
Equity [Abstract]
Equity Plan	Equity Plans
	Crestwood Midstream
	Long-term incentive awards are granted under the Crestwood Midstream Partners LP Long Term Incentive Plan (Crestwood LTIP) in order to align the economic interests of key employees and directors with those of Crestwood'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 the Company) which vest based upon continued service.
	During 2014, we have issued restricted unit awards, which were approved by either our Board compensation committee or pursuant to the authority granted by the Chief Executive Officer, to certain key employees. These awards vest upon continued service with the Company.
	Crestwood LTIP. The following table summarizes information regarding restricted unit activity during the year ended December 31, 2014:
			Units			Weighted-Average Grant Date Fair Value
	Unvested - January 1, 2014		250,557			$	22.13
	Vested - restricted units		(208,361	)		$	22.15
	Granted - restricted units		871,078			$	23.25
	Forfeited		(78,478	)		$	23.33
	Unvested - December 31, 2014		834,796			$	23.18
	As of December 31, 2014 and 2013, we had total unamortized compensation expense of approximately $9.5 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 $11.2 million and $11.4 million (including $6.5 million recognized by Legacy Crestwood in 2013 as discussed below) during the years ended December 31, 2014 and 2013, which is included in general and administrative expenses on our consolidated statements of operations. An additional $6.9 million and $4.4 million of net compensation expense was allocated from CEQP to us during the years ended December 31, 2014 and 2013 (see Note 13). We granted restricted units with a grant date fair value of approximately $20.3 million during the year ended December 31, 2014.  As of December 31, 2014, we had 17,629,657 units available for issuance under the Crestwood LTIP.
	Under the Crestwood LTIP, participants who have been granted restricted units may elect to have common units withheld to satisfy minimum statutory tax withholding obligations arising in connection with the vesting of non-vested common units. Any such common units withheld are returned to the Crestwood LTIP on the applicable vesting dates, which correspond to the times at which income is recognized by the employee. When we withhold these common units, we are required to remit to the appropriate taxing authorities the fair value of the units withheld as of the vesting date. The number of units withheld is determined based on the closing price per common unit as reported on the NYSE on such dates. During the year ended December 31, 2014, we withheld 71,484 common units to satisfy employee tax withholding obligations.
	Employee Unit Purchase Plan. Beginning in September 2014, the board of directors of our general partner made available an employee unit purchase plan under which employees of the general partner may purchase our common units through payroll deductions up to a maximum of 10% of the employees' eligible compensation. Under the plan, we may purchase our common units on the open market for the benefit of participating employees based on their payroll deductions.  In addition, we may contribute an additional 10% of participating employees' payroll deductions to purchase additional Crestwood common units for participating employees. Unless increased by the board of directors of our general partner, the maximum number of common units that may be purchased under the plan is 200,000. In January 2015, there were 2,011 common units purchased through the unit purchase plan for the year ended December 31, 2014.
	Legacy Crestwood
	Prior to the Crestwood Merger, awards of phantom and restricted units were granted under the Legacy Crestwood Fourth Amended and Restated 2007 Equity Plan (the 2007 Equity Plan). The 2007 Equity Plan was terminated in conjunction with the Crestwood Merger. All of the unvested phantom and restricted units became vested upon consummation of the Crestwood Merger and all unamortized compensation expense related to those units was recognized on that date. The following table summarizes information regarding phantom and restricted unit activity:
		Payable In Cash						Payable In Units
		Units			Weighted-			Units		Weighted-
					Average Grant					Average Grant
					Date Fair					Date Fair
					Value					Value
	Unvested - December 31, 2012	8,312			$	26.45		221,992		$	28.35
	Vested - phantom units	(7,958	)		$	26.48		(329,825	)	$	26.69
	Vested - restricted units	—			$	—		(74,760	)	$	25.6
	Granted - phantom units	—			$	—		161,807		$	24.33
	Granted - restricted units	—			$	—		27,900		$	24.86
	Canceled - phantom units	(354	)		$	25.81		(7,114	)	$	27.96
	Unvested - December 31, 2013	—			$	—		—		$	—
	As discussed above, the vesting period of our phantom and restricted units were accelerated upon consummation of the Crestwood Merger.  We recognized compensation expense under the 2007 Equity Plan of approximately $6.5 million and $1.9 million for the years ended December 31, 2013 and 2012, included in operating expenses on our consolidated statements of income. We granted phantom and restricted units under the 2007 Equity Plan with a grant date fair value of approximately $4.6 million and $4.7 million for the years ended December 31, 2013 and 2012. During the year ended December 31, 2013, we withheld 21,014 common units to satisfy employee tax withholding obligations.

Commitments_and_Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies
	Legal Proceedings
	Arrow Acquisition Class Action Lawsuit. Prior to the completion of the Arrow Acquisition on November 8, 2013, a train transporting over 50,000 barrels of crude oil produced in North Dakota derailed in Lac Megantic, Quebec, Canada on July 6, 2013. The derailment resulted in the death of 47 people, injured numerous others, and caused severe damage to property and the environment.  In October 2013, certain individuals suffering harm in the derailment filed a motion to certify a class action lawsuit in the Superior Court for the District of Megantic, Province of Quebec, Canada, on behalf of all persons suffering loss in the derailment (the Class Action Suit).
	In March 2014, the plaintiffs filed their fourth amended motion to name Arrow and numerous other energy companies as additional defendants in the class action lawsuit. The plaintiffs have named at least 53 defendants purportedly involved in the events leading up to the derailment, including the producers and sellers of the crude being transported, the midstream companies that transported the crude from the well head to the rail system, the manufacturers of the rail cars used to transport the crude, the railroad companies involved, the insurers of these companies, and the Canadian Attorney General.  The plaintiffs allege, among other things, that Arrow (i) was a producer of the crude oil being transported on the derailed train, (ii) was negligent in failing to properly classify the crude delivered to the trucks that hauled the crude to the rail loading terminal, and (iii) owed a duty to the petitioners to ensure the safe transportation of the crude being transported.  The motion to authorize the class action and motions in opposition were heard by the Court in June 2014.  We anticipate a ruling from the Judge on the Petitioners' motion to authorize the class action in the first quarter of 2015.
	There are three other lawsuits related to the Class Action Suit. Montreal Main & Atlantic Railway filed bankruptcy actions in both the U.S. Bankruptcy Court for the District of Maine and in the Canadian Bankruptcy Court. In addition, a lawsuit was filed in Cook County, Illinois on behalf of the deceased claimants, which is currently stayed due to the bankruptcy proceeding. We are not currently named as a defendant in these additional lawsuits; however, we have been notified by the bankruptcy trustees of a proposal to contribute to a settlement in exchange for a release from all claims related to the Class Action Suit. We are currently evaluating this proposal and negotiating with the Bankruptcy Trustee.
	We will vigorously defend ourselves and, to the extent these actions proceed, we believe we have meritorious defenses to the claims.  Because these related actions are in the early stages of the proceeding, we are unable to estimate a reasonably possible loss or range of loss in this matter.  We also believe these claims are insurable under our insurance policy and we have notified our insurance company of them.
	When we were served with the Class Action Suit, we notified the former owners of the Arrow system that the claims alleged in the Class Action Suit would, if true, result in breaches of certain representations and warranties made by the former sellers in the agreement under which we acquired Arrow. As part of the acquisition, we deposited 3,309,797 of our common units into an escrow account to cover potential indemnification claims made by us on or before December 31, 2014. Subject to indemnification claims paid out with escrowed units and any outstanding claims outstanding at year end, all common units remaining in the escrow account on January 1, 2015 were to be released to the former owners. In December 2014, we notified the escrow agent of our indemnification notices delivered to the former owners and instructed the escrow agent not to release any escrowed units to the former owners. On February 19, 2015, we received a summons for an action filed against us in the Supreme Court of the State of New York (County of New York), under which the former owners have asserted our indemnification notices regarding the Class Action Suit and our notice to the escrow agent breach the terms of the merger and escrow agreements and the implied covenant of good faith and fair dealing.  The former owners have requested declaratory and injunctive relief, as well as monetary damages. Although our insurance policies would not cover this action, we believe we have meritorious defenses to this lawsuit and will aggressively defend ourselves. We are unable to estimate a reasonably possible loss or range of loss in this matter due to the recent filing of this lawsuit.
	General. 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 December 31, 2014 and 2013, we had less than $0.1 million accrued for our outstanding legal matters. Based on currently available information, we believe it is remote that future costs related to known contingent liability exposures for which we can estimate will exceed current accruals by an amount that would have a material adverse impact on our consolidated financial statements. As we learn new facts concerning contingencies, we reassess our position both with respect to accrued liabilities and other potential exposures.
	Any loss estimates are inherently subjective, based on currently available information, and are subject to management's judgment and various assumptions. Due to the inherently subjective nature of these estimates and the uncertainty and unpredictability surrounding the outcome of legal proceedings, actual results may differ materially from any amounts that have been accrued.
	Regulatory Compliance
	In the ordinary course of our business, we are subject to various laws and regulations. In the opinion of our management, compliance with current laws and regulations will not have a material effect on our results of operations, cash flows or financial condition.
	Environmental Compliance
	During the year ended December 31, 2014, we experienced three releases totaling approximately 28,000 barrels of produced water on our Arrow water gathering system located on the Fort Berthold Indian Reservation in North Dakota. We immediately notified the National Response Center, the Three Affiliated Tribes and numerous other regulatory authorities, and thereafter contained and cleaned up the releases completely and placed the impacted segments of these water lines back into service during the third quarter of 2014. During the year ended December 31, 2014, we recognized $4.6 million of operations and maintenance expense related to these releases, of which $1.1 million was included in other current liabilities on our balance sheet as of December 31, 2014. We will continue our remediation efforts to ensure the impacted lands are restored to their prior state, and we may potentially be subject to fines and penalties. We believe these releases are insurable events under our policies, and we have notified our insurance companies of these events. As of December 31, 2014, we had no amounts accrued for fines and penalties. We have not recorded an insurance receivable as of December 31, 2014.
	Our operations are subject to stringent and complex laws and regulations pertaining to health, safety, and the environment. We are subject to laws and regulations at the federal, state and local levels that relate to air and water quality, hazardous and solid waste management and disposal and other environmental matters. The cost of planning, designing, constructing and operating our facilities must incorporate compliance with environmental laws and regulations and safety standards. Failure to comply with these laws and regulations may trigger a variety of administrative, civil and potentially criminal enforcement measures. At December 31, 2014, our accrual of approximately $1.1 million was primarily related to the Arrow water releases described above, which is based on our undiscounted estimate of amounts we will spend on compliance with environmental and other regulations. We estimate that our potential liability for reasonably possible outcomes related to our environmental exposures (including the Arrow water releases described above) could range from approximately $1.1 million to $1.5 million. Our accrual and potential exposure related to our environmental matters was immaterial at December 31, 2013.
	Commitments and Purchase Obligations
	Operating Leases. We maintain operating leases in the ordinary course of our business activities. These leases include those for office buildings, crude oil railroad cars and other operating facilities and equipment. The terms of the agreements vary from 2015 until 2032.
	Future minimum lease payments under noncancelable operating leases for the next five years ending December 31 and in total thereafter consist of the following (in millions):
	Year Ending
	December 31,
	2015	$	6.6
	2016	5.9
	2017	5.3
	2018	4.8
	2019	4.6
	Thereafter	16.3
	Total minimum lease payments	$	43.5
	Rent expense for operating leases for the years ended December 31, 2014, 2013 and 2012, totaled $8.7 million, $7.6 million and $7.4 million.
	Capital Leases. We have a treating facility and certain auto leases which are accounted for as capital leases. The terms of the agreements vary from 2015 until 2018. We recorded amortization of expense of approximately $2.9 million, $3.6 million and $3.1 million for the years ended December 31, 2014, 2013 and 2012.
	Future minimum lease payments related to our capital leases at December 31, 2014 are as follows (in millions):
	Year Ending
	December 31,
	2015	$	1.4
	2016	0.8
	2017	0.5
	2018	0.2
	Total payments	2.9
	Imputed interest	(0.1		)
	Present value of future payments	$	2.8
	Our capital lease liabilities were $2.8 million and $4.7 million at December 31, 2014 and 2013 and are included in accrued expenses and other liabilities and other long-term liabilities on our consolidated balance sheets.
	Purchase Commitments. We have entered into certain purchase commitments in connection with the identified growth projects primarily related to the Arrow development project in the Bakken Shale, certain upgrades to the US Salt facility and growth and maintenance obligations related to our G&P segment. At December 31, 2014, the total of our storage and transportation and NGL and crude services operations' firm purchase commitments was approximately $20.0 million and our gathering and processing segment purchase commitments totaled approximately $9.8 million. The majority of the purchases associated with these commitments are expected to occur over the next twelve months.

Related_Party_Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2014
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions
	Our general partner is indirectly owned by Crestwood Holdings. The affiliates of Crestwood Holdings and its owners are considered our related parties, including Sabine Oil and Gas LLC and Mountaineer Keystone LLC.
	We enter into transactions with our affiliates within the ordinary course of business and the services are based on the same terms as non-affiliates, including gas gathering and processing services under long-term contracts, firm storage services, product purchases and various operating agreements. See Notes 6 and 10 for additional information on our related party transactions.
	We do not have any employees. We share common management, general and administrative and overhead costs with CEQP. We have an omnibus agreement with CEQP that requires us to reimburse CEQP for all shared costs incurred on our behalf, except for certain unit based compensation costs which are treated as capital transactions. Prior to the Crestwood Merger, we were managed and operated by the directors and officers of Legacy Crestwood’s general partner. We had an omnibus agreement with Crestwood Holdings and the Legacy Crestwood general partner under which Legacy Crestwood reimbursed Crestwood Holdings for the provision of various general and administrative services for its benefit and for direct expenses incurred by Crestwood Holdings on its behalf. Crestwood Holdings billed Legacy Crestwood directly for certain general and administrative costs and allocated a portion of its general and administrative costs to Legacy Crestwood. Due to the nature of these shared costs, it is not practicable to estimate what the costs would have been on a stand-alone basis. Accordingly, the accompanying financial statements may not necessarily be indicative of the conditions that would have existed, or the results of operations that would have occurred, if we operated as a stand-alone entity.
	The following table shows revenues, costs of goods sold and general and administrative expenses from our affiliates for the years December 31, 2014, 2013 and 2012 (in millions):
		Year Ended December 31,
		2014 (1)		2013		2012
	Gathering and processing revenues	$	4	$	74.9	$	113.7
	NGL and crude services revenues	$	13.6	$	7.2	$	—
	Gathering and processing costs of product/services sold(2)	$	42.2	$	32.5	$	15.2
	General and administrative expenses(3)	$	63.6	$	34.7	$	19.5
	-1	Concurrent with the Crestwood Merger, Quicksilver Resources Inc. (Quicksilver) is no longer a related party, and as a result our transactions with Quicksilver subsequent to June 19, 2013, are now considered non-affiliated transactions.
	-2	Represents natural gas purchases from Sabine Oil and Gas.
	-3	Included in general and administrative expenses is approximately $6.9 million and $4.4 million of net unit-based compensation charges allocated to us from CEQP for the years ended December 31, 2014 and 2013.
	The following table shows accounts receivable and accounts payable from our affiliates as of December 31, 2014 and 2013 (in millions):
		December 31,
		2014		2013
	Accounts receivable	$	0.3	$	1.1
	Accounts payable	$	6.3	$	8.7
	Following the closing of the Crestwood Merger on October 7, 2013, Crestwood Holdings exchanged 7,100,000 of our common units for 14,300,000 of CEQP common units pursuant to an option granted to Crestwood Holdings when it acquired our general partner.

Segments

Segments	12 Months Ended
	Dec. 31, 2014
Segment Reporting [Abstract]
Segments	Segments
	Financial Information
	We have three operating and reportable segments; (i) gathering and processing operations; (ii) storage and transportation operations; and (iii) NGL and crude services operations. Our gathering and processing operations engage in the gathering, processing, treating, compression, transportation and sales of natural gas and the delivery of NGLs. Our storage and transportation operations provide regulated natural gas storage and transportations services to producers, utilities and other customers. Our NGL and crude services operations provide NGLs and crude oil gathering, storage, marketing and transportation services to producers, refiners, marketers and other customers that effectively provide flow assurances to our customers, as well as the production and sale of salt products. Our corporate operations include all general and administrative expenses that are not allocated to the reportable segments. We assess the performance of our operating segments based on EBITDA, which represents operating income plus depreciation, amortization and accretion expense.
	Below is a reconciliation of our net income to EBITDA (in millions):
		Year Ended December 31,
		2014			2013			2012
	Net income (loss)	$	(21.9	)	$	(15.1	)	$	38.9
	Add:
	Interest and debt expense, net	111.4			71.4			35.8
	Provision for income taxes	0.7			0.7			1.2
	Depreciation, amortization and accretion	221.7			121.7			51.9
	EBITDA	$	311.9		$	178.7		$	127.8
	The following tables summarize the reportable segment data for the years ended December 31, 2014, 2013 and 2012 (in millions).
		Year Ended December 31, 2014
		Gathering and Processing			Storage and Transportation			NGL and Crude Services			Corporate			Total
	Revenues	$	332.5		$	179.1		$	2,053.90		$	—		$	2,565.50
	Costs of product/services sold	71.3			14.3			1,851.90			—			1,937.50
	Operations and maintenance expense	62.9			16.6			59.5			—			139
	General and administrative expense	—			—			—			85.4			85.4
	Gain (loss) on long-lived assets, net	(32.7		)	0.6			(1.5		)	—			(33.6		)
	Goodwill impairment	(18.5		)	—			(30.3		)	—			(48.8		)
	Loss on contingent consideration	(8.6		)	—			—			—			(8.6		)
	Earnings (loss) from unconsolidated affiliates, net	0.5			0.2			(1.4		)	—			(0.7		)
	EBITDA	$	139		$	149		$	109.3		$	(85.4	)	$	311.9
	Goodwill	$	81.1		$	726.3		$	825.2		$	—		$	1,632.60
	Total assets	$	1,993.00		$	1,981.20		$	2,455.50		$	166.8		$	6,596.50
	Purchases of property, plant and equipment	$	245.7		$	9.1		$	147.8		$	4.4		$	407
		Year Ended December 31, 2013
		Gathering and Processing			Storage and Transportation			NGL and Crude Services			Corporate			Total
	Revenues	$	291.2		$	90.1		$	277.3		$	—		$	658.6
	Costs of product/services sold	56.6			8.7			230.4			—			295.7
	Operations and maintenance expense	54.9			9.9			8.5			—			73.3
	General and administrative expense	—			—			—			80.7			80.7
	Gain on long-lived assets	5.4			—			—			—			5.4
	Goodwill impairment	(4.1		)	—			—			—			(4.1		)
	Loss on contingent consideration	(31.4		)	—			—			—			(31.4		)
	Earnings (loss) from unconsolidated affiliates, net	0.1			—			(0.2		)	—			(0.1		)
	EBITDA	$	149.7		$	71.5		$	38.2		$	(80.7	)	$	178.7
	Goodwill	$	99.6		$	936.5		$	646.7		$	—		$	1,682.80
	Total assets	$	1,836.40		$	2,190.50		$	2,217.30		$	157.6		$	6,401.80
	Purchases of property, plant and equipment	$	271.2		$	10.3		$	52.1		$	1		$	334.6
		Year Ended December 31, 2012
		Gathering and Processing			Storage and Transportation			NGL and Crude Services			Corporate			Total
	Revenues	$	239.5		$	—		$	—		$	—		$	239.5
	Costs of product/services sold	39			—			—			—			39
	Operation and maintenance expense	43.1			—			—			—			43.1
	General and administrative expense	—			—			—			29.6			29.6
	EBITDA	$	157.4		$	—		$	—		$	(29.6	)	$	127.8
	Goodwill	$	95		$	—		$	—		$	—		$	95
	Total assets	$	1,587.90		$	—		$	—		$	22.7		$	1,610.60
	Purchases of property, plant and equipment	$	51.5		$	—		$	—		$	1.1		$	52.6
	Major Customers
	For the year ended December 31, 2014, revenues from Tesoro, QEP Midstream Partners (QEP) and Eighty-Eight Oil LLC were approximately $401.1 million, $285.1 million and $286.9 million, which exceeded 10% of our total consolidated revenues. Revenues from Tesoro, QEP and Eighty-Eight Oil LLC are reflected in our NGL and crude services segment. For the year ended December 31, 2013, revenues from Quicksilver were approximately $96.3 million which exceeded 10% of our total consolidated revenues. For the year ended December 31, 2012, revenues from Quicksilver and Antero were approximately $112.6 million and $25.5 million, which exceeded 10% of our total consolidated revenues. Revenues from Quicksilver and Antero are reflected in our gathering and processing segment.

Condensed_Consolidating_Financ

Condensed Consolidating Financial Information (Notes)	12 Months Ended
	Dec. 31, 2014
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Condensed Consolidating Financial Information	Condensed Consolidating Financial Information
	Crestwood is a holding company and own no operating assets and has 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, PRBIC and CMLP Tres Manager LLC and their subsidiaries (collectively, Non-Guarantor Subsidiaries). Crestwood Midstream Finance Corp., the co-issuer of our Senior Notes, is our 100% owned subsidiary and has no material assets, operations, revenues or cash flows other than those related to its service as co-issuer of our Senior Notes.
	As summarized in the table below, the condensed consolidating financial statements for the year ended December 31, 2013 have been corrected for certain errors in presentation. There was no impact to our consolidated balance sheet or our consolidated statement of cash flows.
		Parent						Guarantor						Eliminations
								Subsidiaries
		As Adjusted			As Previously Reported			As Adjusted			As Previously Reported			As Adjusted			As Previously Reported
		(in millions)
	Assets
	Accounts receivable	$	4.4		$	466.8		$	199.4		$	197.8		$	—		$	(459.7	)
	Accounts receivable - related party	1.1			—			—			—			—			—
	Total accounts receivable	5.5			466.8			199.4			197.8			—			(459.7		)
	Total current assets	5.6			466.9			218.2			216.6			—			(459.7		)
	Goodwill and intangible assets, net	46.2			—			2,607.40			2,653.60			—			—
	Investment in consolidated affiliates	6,053.00			6,385.20			—			—			(6,053.0		)	(6,385.2		)
	Total assets	6,109.60			6,856.90			6,192.60			6,237.20			(6,053.0		)	(6,844.9		)
	Liabilities and partners' capital
	Accounts payable	$	15.1		$	782.7		$	139.4		$	(165.2	)	$	—		$	(459.7	)
	Accounts payable - related party	5.4			—			3.3			—			—			—
	Total accounts payable	20.5			782.7			142.7			(165.2		)	—			(459.7		)
	Other current liabilities	26.4			11.5			124.7			145			—			—
	Total current liabilities	46.9			794.2			267.4			(20.2		)	—			(459.7		)
	Partners' capital	4,092.10			4,092.10			5,900.60			6,232.80			(5,952.0		)	(6,284.2		)
	Total partners' capital	4,193.10			4,193.10			5,900.60			6,232.80			(6,053.0		)	(6,385.2		)
	Total liabilities and partners' capital	6,109.60			6,856.90			6,192.60			6,237.20			(6,053.0		)	(6,844.9		)
		Parent						Guarantor						Non-Guarantor						Eliminations
								Subsidiaries						Subsidiaries
		As Adjusted			As Previously Reported			As Adjusted			As Previously Reported			As Adjusted			As Previously Reported			As Adjusted			As Previously Reported
	Cash flows from operating activities:	$	(46.1	)	$	3.9		$	266.4		$	216.4		$	—		$	—		$	(33.8	)	$	(33.8	)
	Cash flows from investing activities:
	Investment in unconsolidated affiliates, net	—			—			—			(24.4		)	(151.5		)	(127.1		)	—			—
	Capital contributions from consolidated affiliates	(106.4		)	(82.0		)	—			—			—			—			106.4			82
	Other	—			(0.4		)	11.1			11.1			—			—			—			0.4
	Net cash provided by (used in) investing activities	(107.4		)	(83.4		)	(884.0		)	(908.4		)	(151.5		)	(127.1		)	106.4			82.4
	Cash flows from financing activities:
	Proceeds from the issuance of long-term debt	1,930.90			382.9			141.9			1,689.90			—			—			—			—
	Principal payments on long-term debt	(1,559.3		)	(202.0		)	(75.0		)	(1,432.3		)	—			—			—			—
	Payments for debt-related deferred costs	(32.0		)	(0.1		)	—			(31.9		)	—			—			—			—
	Distributions paid	(359.7		)	(219.3		)	(33.8		)	(174.2		)	—			—			33.8			33.8
	Contributions from parent	—			—			55.5			55.5			56.4			32			(106.4		)	(82.0		)
	Net proceeds from the issuance of common units	714			118.5			—			595.5			—			—			—			—
	Change in intercompany balances	(539.9		)	—			539.9			0.4			—			—			—			(0.4		)
	Net cash provided by (used in) financing activities	153.6			79.6			619.1			693.5			152.5			128.1			(72.6		)	(48.6		)
	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 and for the years ended December 31, 2014 and 2013.  The financial information may not necessarily be indicative of the results of operations, cash flows or financial position has the subsidiaries operated as independent entities. 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 as of and for the years ended December 31, 2012 because our unrestricted subsidiaries were not formed or were not designated as unrestricted subsidiaries as of December 31, 2012.
	Condensed Consolidating Balance Sheet
	31-Dec-14
	(in millions)
		Parent			Guarantor			Non-			Eliminations			Consolidated
					Subsidiaries			Guarantor
								Subsidiaries
	Assets
	Current assets:
	Cash	$	—		$	4.6		$	—		$	—		$	4.6
	Accounts receivable	1.2			240.3			—			—			241.5
	Accounts receivable - related party	—			—			0.3			—			0.3
	Total accounts receivable	1.2			240.3			0.3			—			241.8
	Inventories	—			8			—			—			8
	Other current assets	—			18.7			—			—			18.7
	Total current assets	1.2			271.6			0.3			—			273.1
	Property, plant and equipment, net	7.9			3,510.20			—			—			3,518.10
	Goodwill and intangible assets, net	38			2,470.80			—			—			2,508.80
	Investment in consolidated affiliates	6,296.70			—			—			(6,296.7		)	—
	Investment in unconsolidated affiliates	—			—			295.1			—			295.1
	Other assets	—			1.4			—			—			1.4
	Total assets	$	6,343.80		$	6,254.00		$	295.4		$	(6,296.7	)	$	6,596.50
Liabilities and partners' capital
Current liabilities:
Accounts payable	$	4.8		$	121.3		$	—		$	—		$	126.1
Accounts payable - related party	4.2			1.9			0.2			—			6.3
Total accounts payable	9			123.2			0.2			—			132.4
Other current liabilities	23			99.7			—			—			122.7
Total current liabilities	32			222.9			0.2			—			255.1
Long-term liabilities:
Long-term debt, less current portion	2,012.80			—			—			—			2,012.80
Other long-term liabilities	1.6			29.6			—			—			31.2
Total long-term liabilities	2,014.40			29.6			—			—			2,044.00
Partners' capital	4,125.70			6,001.50			123.5			(6,125.0		)	4,125.70
Interest of non-controlling partners in subsidiaries	171.7			—			171.7			(171.7		)	171.7
Total partners' capital	4,297.40			6,001.50			295.2			(6,296.7		)	4,297.40
Total liabilities and partners' capital	$	6,343.80		$	6,254.00		$	295.4		$	(6,296.7	)	$	6,596.50
Condensed Consolidating Balance Sheet
31-Dec-13
(in millions)
	Parent			Guarantor			Non-			Eliminations			Consolidated
				Subsidiaries			Guarantor
							Subsidiaries
Assets
Current assets:
Cash	$	0.1		$	1.6		$	1		$	—		$	2.7
Accounts receivable	4.4			199.4			0.2			—			204
Accounts receivable - related party	1.1			—			—			—			1.1
Total accounts receivable	5.5			199.4			0.2			—			205.1
Inventories	—			7			—			—			7
Other current assets	—			10.2			—			—			10.2
Total current assets	5.6			218.2			1.2			—			225
Property, plant and equipment, net	4.8			3,345.30			—			—			3,350.10
Goodwill and intangible assets, net	46.2			2,607.40			—			—			2,653.60
Investment in consolidated affiliates	6,053.00			—			—			(6,053.0		)	—
Investment in unconsolidated affiliates	—			—			151.4			—			151.4
Other assets	—			21.7			—			—			21.7
Total assets	$	6,109.60		$	6,192.60		$	152.6		$	(6,053.0	)	$	6,401.80
Liabilities and partners' capital
Current liabilities:
Accounts payable	$	15.1		$	139.4		$	—		$	—		$	154.5
Accounts payable - related party	5.4			3.3			—			—			8.7
Total accounts payable	20.5			142.7			—			—			163.2
Other current liabilities	26.4			124.7			0.2			—			151.3
Total current liabilities	46.9			267.4			0.2			—			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			5,900.60			51.4			(5,952.0		)	4,092.10
Interest of non-controlling partners in subsidiaries	101			—			101			(101.0		)	101
Total partners' capital	4,193.10			5,900.60			152.4			(6,053.0		)	4,193.10
Total liabilities and partners' capital	$	6,109.60		$	6,192.60		$	152.6		$	(6,053.0	)	$	6,401.80
Condensed Consolidating Statements of Operations
Year Ended December 31, 2014
(in millions)
	Parent			Guarantor			Non-			Eliminations			Consolidated
				Subsidiaries			Guarantor
							Subsidiaries
Revenues:
Gathering and processing	$	—		$	328.5		$	—		$	—		$	328.5
Storage and transportation	—			179.1			—			—			179.1
NGL and crude services	—			2,040.30			—			—			2,040.30
Related party	—			17.6			—			—			17.6
	—			2,565.50			—			—			2,565.50
Costs of product/services sold:
Gathering and processing	—			29.1			—			—			29.1
Storage and transportation	—			14.3			—			—			14.3
NGL and crude services	—			1,851.90			—			—			1,851.90
Related party	—			42.2			—			—			42.2
	—			1,937.50			—			—			1,937.50
Expenses:
Operations and maintenance	—			139			—			—			139
General and administrative	49.4			36			—			—			85.4
Depreciation, amortization and accretion	0.9			220.8			—			—			221.7
	50.3			395.8			—			—			446.1
Other operating income (expense):
Loss on long-lived assets, net	—			(33.6		)	—			—			(33.6		)
Goodwill impairment	—			(48.8		)	—			—			(48.8		)
Loss on contingent consideration	—			(8.6		)	—			—			(8.6		)
Operating income (loss)	(50.3		)	141.2			—			—			90.9
Loss from unconsolidated affiliates, net	—			—			(0.7		)	—			(0.7		)
Interest and debt expense, net	(111.4		)	—			—			—			(111.4		)
Equity in net income (loss) of subsidiary	139.8			—			—			(139.8		)	—
Income (loss) before income taxes	(21.9		)	141.2			(0.7		)	(139.8		)	(21.2		)
Provision for income taxes	—			0.7			—			—			0.7
Net income (loss)	(21.9		)	140.5			(0.7		)	(139.8		)	(21.9		)
Net (income) loss attributable to non-controlling partners	—			—			(16.8		)	—			(16.8		)
Net income (loss) attributable to Crestwood Midstream Partners LP	(21.9		)	140.5			(17.5		)	(139.8		)	(38.7		)
Net income attributable to Class A preferred units	(17.2		)	—			—			—			(17.2		)
Net income (loss) attributable to partners	$	(39.1	)	$	140.5		$	(17.5	)	$	(139.8	)	$	(55.9	)
Condensed Consolidating Statements of Operations
Year Ended December 31, 2013
(in millions)
	Parent			Guarantor			Non-			Eliminations			Consolidated
				Subsidiaries			Guarantor
							Subsidiaries
Revenues:
Gathering and processing	$	—		$	216.3		$	—		$	—		$	216.3
Storage and transportation	—			90.1			—			—			90.1
NGL and crude services	—			270.1			—			—			270.1
Related party	—			82.1			—			—			82.1
	—			658.6			—			—			658.6
Costs of product/services sold:
Gathering and processing	—			24.1			—			—			24.1
Storage and transportation	—			8.7			—			—			8.7
NGL and crude services	—			230.4			—			—			230.4
Related party	—			32.5			—			—			32.5
	—			295.7			—			—			295.7
Expenses:
Operations and maintenance	—			73.3			—			—			73.3
General and administrative	46.5			34.2			—			—			80.7
Depreciation, amortization and accretion	1			120.7			—			—			121.7
	47.5			228.2			—			—			275.7
Other operating income (expense):
Gain on long-lived assets, net	—			5.4			—			—			5.4
Goodwill impairment	—			(4.1		)	—			—			(4.1		)
Loss on contingent consideration	—			(31.4		)	—			—			(31.4		)
Operating income (loss)	(47.5		)	104.6			—			—			57.1
Loss from unconsolidated affiliates, net	—			—			(0.1		)	—			(0.1		)
Interest and debt expense, net	(68.7		)	(2.7		)	—			—			(71.4		)
Equity in net income (loss) of subsidiary	101.1			—			—			(101.1		)	—
Income (loss) before income taxes	(15.1		)	101.9			(0.1		)	(101.1		)	(14.4		)
Provision for income taxes	—			0.7			—			—			0.7
Net income (loss)	(15.1		)	101.2			(0.1		)	(101.1		)	(15.1		)
Net (income) loss attributable to non-controlling partners	—			—			(4.9		)	—			(4.9		)
Net income (loss) attributable to Crestwood Midstream Partners LP	$	(15.1	)	$	101.2		$	(5.0	)	$	(101.1	)	$	(20.0	)
Condensed Consolidating Statements of Cash Flows
Year Ended December 31, 2014
(in millions)
	Parent			Guarantor			Non-			Eliminations			Consolidated
				Subsidiaries			Guarantor
							Subsidiaries
Cash flows from operating activities:	$	(165.6	)	$	488.5		$	—		$	—		$	322.9
Cash flows from investing activities:
Acquisitions, net of cash acquired	—			(19.5		)	—			—			(19.5		)
Purchases of property, plant and equipment	(4.3		)	(402.7		)	—			—			(407.0		)
Investment in unconsolidated affiliates	—			—			(144.4		)	—			(144.4		)
Capital contribution from consolidated affiliates	(89.5		)	—			—			89.5			—
Net cash provided by (used in) investing activities	(93.8		)	(422.2		)	(144.4		)	89.5			(570.9		)
Cash flows from financing activities:
Proceeds from the issuance of long-term debt	2,089.90			—			—			—			2,089.90
Principal payments on long-term debt	(1,949.8		)	—			—			—			(1,949.8		)
Payments on capital leases	(1.3		)	(1.9		)	—			—			(3.2		)
Payments for debt-related deferred costs	(0.1		)	—			—			—			(0.1		)
Distributions paid	(368.9		)	—			—			—			(368.9		)
Contributions from parent	—			—			89.5			(89.5		)	—
Net proceeds from issuance of preferred equity of subsidiary	—			—			53.9			—			53.9
Net proceeds from issuance of Class A preferred units	430.5			—			—			—			430.5
Taxes paid for unit-based compensation vesting	—			(1.6		)	—			—			(1.6		)
Change in intercompany balances	59.8			(59.8		)	—			—			—
Other	(0.8		)	—			—			—			(0.8		)
Net cash provided by (used in) financing activities	259.3			(63.3		)	143.4			(89.5		)	249.9
Net change in cash	(0.1		)	3			(1.0		)	—			1.9
Cash at beginning of period	0.1			1.6			1			—			2.7
Cash at end of period	$	—		$	4.6		$	—		$	—		$	4.6
Condensed Consolidating Statements of Cash Flows
Year Ended December 31, 2013
(in millions)
	Parent			Guarantor			Non-			Eliminations			Consolidated
				Subsidiaries			Guarantor
							Subsidiaries
Cash flows from operating activities:	$	(46.1	)	$	266.4		$	—		$	(33.8	)	$	186.5
Cash flows from investing activities:
Acquisitions, net of cash acquired	—			(561.5		)	—			—			(561.5		)
Purchases of property, plant and equipment	(1.0		)	(333.6		)	—			—			(334.6		)
Investment in unconsolidated affiliates	—			—			(151.5		)	—			(151.5		)
Capital contribution from consolidated affiliates	(106.4		)	—			—			106.4			—
Other	—			11.1			—			—			11.1
Net cash provided by (used in) investing activities	(107.4		)	(884.0		)	(151.5		)	106.4			(1,036.5		)
Cash flows from financing activities:
Proceeds from the issuance of long-term debt	1,930.90			141.9			—			—			2,072.80
Principal payments on long-term debt	(1,559.3		)	(75.0		)	—			—			(1,634.3		)
Payments on capital leases	(0.4		)	(3.9		)	—			—			(4.3		)
Payments for debt-related deferred costs	(32.0		)	—			—			—			(32.0		)
Distributions paid	(359.7		)	(33.8		)	—			33.8			(359.7		)
Contributions from parent	—			55.5			56.4			(106.4		)	5.5
Net proceeds from issuance of common units	714			—			—			—			714
Net proceeds from issuance of preferred equity of subsidiary	—			—			96.1			—			96.1
Taxes paid for unit-based compensation vesting	—			(5.5		)	—			—			(5.5		)
Change in intercompany balances	(539.9		)	539.9			—			—			—
Net cash provided by (used in) financing activities	153.6			619.1			152.5			(72.6		)	852.6
Net change in cash	0.1			1.5			1			—			2.6
Cash at beginning of period	—			0.1			—			—			0.1
Cash at end of period	$	0.1		$	1.6		$	1		$	—		$	2.7

Quarterly_Financial_Data_Unaud

Quarterly Financial Data (Unaudited)	12 Months Ended
	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Data (Unaudited)	Quarterly Financial Data (Unaudited)
	Summarized unaudited quarterly financial data is presented below (in millions, except per unit information):
		Quarter Ended
		March 31				June 30			September 30			31-Dec
	2014
	Revenues	$	537			$	675.7		$	738.4		$	614.4
	Operating income (loss)	34.4				42.3			48.7			(34.5		)	(1)
	Earnings (loss) from unconsolidated affiliates, net	(0.1		)		(1.5		)	0.3			0.6
	Net income (loss)	5.5				11.7			21.3			(60.4		)
	Net income (loss) attributable to partners	2.4				6.9			7.7			(72.9		)
	Net income (loss) per limited partner unit:
	Basic	$	(0.03	)		$	—		$	—		$	(0.43	)
	Diluted	$	(0.03	)		$	—		$	—		$	(0.43	)
	2013
	Revenues	$	72.4			$	80.1		$	140.1		$	366
	Operating income (loss)	20.7				19.5			31.8			(14.9		)	(2)
	Earnings (loss) from unconsolidated affiliates, net	—				—			(0.4		)	0.3
	Net income (loss)	8.9				6.7			11.6			(42.3		)
	Net income (loss) attributable to partners	8.9				6.7			9.7			(45.3		)
	Net income (loss) per limited partner unit:
	Basic(4)	$	0.06		(3)	$	(0.01	)	$	0.02		$	(0.50	)
	Diluted(4)	$	0.06		(3)	$	(0.01	)	$	0.02		$	(0.50	)
	-1	Includes goodwill, property, plant and equipment and intangible impairments of approximately $48.8 million, $13.2 million and $21.3 million, respectively. See Note 2 for a further discussion of our impairments recorded during 2014.
	-2	Includes a $31.4 million loss on contingent consideration which reflects the fair value of an earn-out premium associated with the original acquisition of our Antero assets. See Note 3 for a further discussion of this non-cash charge.
	-3	Basic and diluted net income for each of the quarters ended September 30, 2013, were computed based on the number of common units issued by Legacy Inergy to Legacy Crestwood unitholders as part of the Crestwood Merger.
	-4	The accumulation of basic and diluted net income (loss) per limited partner unit does not total the amount for the year due to changes in ownership percentages throughout the year.

Basis_of_Presentation_and_Summ1

Basis of Presentation and Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Principals of Consolidation	Principles of Consolidation
	We consolidate entities when we have the ability to control or direct the operating and financial decisions of the entity or when we have a significant interest in the entity that gives us the ability to direct the activities that are significant to that entity. The determination to consolidate or apply the equity method of accounting to an entity can also require us to evaluate whether that entity is considered a variable interest entity. This evaluation, along with the determination of our ability to control, direct or exert significant influence over an entity involves the use of judgment. We apply the equity method of accounting where we can exert significant influence over, but do not control or direct the policies, decisions or activities of an entity. We use the cost method of accounting where we are unable to exert significant influence over the entity.
Use of Estimates	Use of Estimates
	The preparation of our consolidated financial statements in conformity with GAAP requires the use of estimates and assumptions that affect the amounts we report as assets, liabilities, revenues and expenses and our disclosures in these consolidated financial statements. Actual results can differ from those estimates.
Cash	Cash
	We consider all highly liquid investments with an original maturity of less than three months to be cash.
Inventory	Inventory
	Inventory for our NGL and crude services operations and our storage and transportation operations are stated at the lower of cost or market and are computed predominantly using the average cost method.
Property, Plant and Equipment	Property, Plant and Equipment
	Property, plant and equipment is recorded at is original cost of construction or, upon acquisition, at the fair value of the assets acquired. For assets we construct, we capitalize direct costs, such as labor and materials, and indirect costs, such as overhead and interest. We capitalize major units of property replacements or improvement and expense minor items. Depreciation is computed by the straight-line method over the estimated useful lives of the assets, as follows:
		Years
	Gathering systems and pipelines	20
	Facilities and equipment	20-25
	Buildings, rights-of-way and easements	20-40
	Office furniture and fixtures	10-May
	Vehicles	5
	We deplete salt deposits included in our property, plant and equipment utilizing the unit of production method.
	When we retire property, plant and equipment, we charge accumulated depreciation for the original costs of the assets in addition to the cost to remove, sell or dispose of the assets, less their salvage value.
	We evaluate our long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. If such events or changes in circumstances are present, a loss is recognized if the carrying value of the asset is in excess of the sum of the undiscounted cash flows expected to result from the use of the asset and its eventual disposition. An impairment loss is measured as the amount by which the carrying amount of the asset exceeds the fair value of the asset, which is based on discounted cash flow projections, which is a Level 3 fair value measurement. Based on this evaluation, during the year ended December 31, 2014, we recorded a $13.2 million impairment in gain (loss) on long-lived assets in our consolidated statements of operations related to the property, plant and equipment of our gathering and processing assets located in the Granite Wash, which resulted from an announcement during the fourth quarter of 2014 by our major customer of those assets that they would cease any substantial drilling in the Granite Wash in the near future given current and future anticipated market conditions related to natural gas, which negatively impacted our future cash flows related to these operations. We had approximately $20.2 million of property, plant and equipment related to our gathering and processing operations located in the Granite Wash as of December 31, 2014, which represents the fair value of those assets based on its projected cash flows over the useful lives of the assets of 17 years and a discount rate of 9.0%, which are Level 3 fair value measurements. We did not record any impairments of our long-lived assets during the years ended December 31, 2013 and 2012 based on this evaluation.
Identifiable Intangible Assets and Goodwill	Identifiable Intangible Assets
	Our identifiable intangible assets consist of customer accounts, covenants not to compete, trademarks, certain revenue contracts and deferred financing costs. Customer accounts, covenants not to compete, trademarks and certain of our revenue contracts have arisen from acquisitions. We amortize certain of our revenue contracts based on the projected cash flows associated with these contracts if the projected cash flows are reliably determinable, otherwise we amortize our revenue contracts on a straight-line basis. Deferred financing costs represent financing costs incurred in obtaining financing and are being amortized over the term of the related debt using a method which approximates the effective interest method and has a weighted average life of six years. We recognize acquired intangible assets separately if the benefit of the intangible asset is obtained through contractual or other legal rights, or if the intangible asset can be sold, transferred, licensed, rented or exchanged, regardless of the acquirer's intent to do so. For the year ended December 31, 2014, we recorded a $21.3 million impairment of our intangible assets in gain (loss) on long-lived assets in our consolidated statements of operations. This impairment was based on the intangible assets’ fair value, estimated primarily by utilizing discounted cash flow projections, which is a Level 3 fair value measurement.  This impairment was primarily related to a full impairment of our intangible assets associated with our gathering and processing operations located in the Granite Wash. This impairment resulted from an announcement in the fourth quarter of 2014 by our major customer of those assets that they would cease any substantial drilling in the Granite Wash in the near future given current and future anticipated market conditions related to natural gas in the Granite Wash.
	Certain intangible assets are amortized on a straight-line basis over their estimated economic lives, as follows:
		Weighted-Average
		Life
		(years)
	Customer accounts	20
	Covenants not to compete	3
	Trademarks	5
	Goodwill
	Our goodwill represents consideration paid in excess of the fair value of the identifiable assets acquired in a business combination. We evaluate goodwill for impairment annually on December 31, and whenever events indicate that the fair value of a reporting unit could be less than its carrying amount. This evaluation requires us to compare the fair value of a reporting unit to its carrying value (including goodwill). If the fair value exceeds the carrying amount, goodwill of the reporting unit is not considered impaired. For a further discussion of the goodwill recorded during the year ended December 31, 2014, see Note 3.
	We estimate the fair value of our reporting units based on a number of factors, including the potential value we would receive if we sold the reporting unit, discount rates and projected cash flows, which are Level 3 fair value measurements. Estimating projected cash flows requires us to make certain assumptions as it relates to future operating performance. When considering operating performance, various factors are considered such as current and changing economic conditions and the commodity price environment, among others. Due to the imprecise nature of these projections and assumptions, actual results can and often do, differ from our estimates. If the growth assumptions utilized in the current year impairment analysis prove inaccurate, we could incur an impairment charge.
	For the year ended December 31, 2014, we recorded an impairment of goodwill of approximately $48.8 million related to four of our 10 reporting units including Granite Wash (G&P), Fayetteville (G&P), US Salt (NGL and Crude Services), and Watkins Glen (NGL and Crude Services).  The $14.2 million and $4.3 million impairments of our Granite Wash and Fayetteville goodwill, respectively, resulted from a decrease in anticipated revenues to be generated from those operations due to our primary customers in those operations announcing the cessation of any significant drilling in the near future given current and future anticipated market conditions in those areas.  The $2.2 million impairment ( of our US Salt goodwill resulted from a decrease in anticipated revenues to be generated from those operations due primarily to the loss of a significant customer in 2014.  The $28.1 million impairment of our Watkins Glen goodwill resulted from delays and related uncertainty in the permitting of our proposed NGL storage facility. We had approximately $72.5 million, $12.6 million and $66.2 million of goodwill remaining on the balance sheet as of December 31, 2014 related to our Fayetteville, US Salt and Watkins Glen reporting units, respectively, which represents the fair value of the goodwill related to those reporting units at December 31, 2014, which is a Level 3 fair value measurement.
	For the year ended December 31, 2013, we recorded an impairment of goodwill of approximately $4.1 million on our Haynesville/Bossier Shale system as a result of a decrease in anticipated revenues to be generated from those operations due primarily to our inability to renew and extend a significant revenue contract that expired in mid-2013.
Investment in Unconsolidated Affiliates	Investment in Unconsolidated Affiliates
	We evaluate our equity method investments for impairment when events or circumstances indicate that the carrying value of the equity method investment may be impaired. If an event occurs, we evaluate the recoverability of our carrying value based on the fair value of the investment. If an impairment is indicated, or if we decide to sell an investment in unconsolidated affiliate, we adjust the carrying values of the asset downward, if necessary, to their estimated fair values. Our fair value estimates are generally based on assumptions market participants would use, including marketing data obtained through the sales process.
Asset Retirement Obligations	Asset Retirement Obligations
	An asset retirement obligation (ARO) is an estimated liability for the cost to retire a tangible asset. We record a liability for legal or contractual obligations to retire our long-lived assets associated with right-of-way contracts we hold and our facilities whether owned or leased. We record a liability in the period the obligation is incurred and estimable. An ARO is initially recorded at its estimated fair value with a corresponding increase to property, plant and equipment. This increase in property, plant and equipment is then depreciated over the useful life of the asset to which that liability relates. An ongoing expense is recognized for changes in the fair value of the liability as a result of the passage of time, which we record as depreciation, amortization and accretion expense on our consolidated statements of operations. The fair value of certain AROs could not be determined as the settlement dates (or range of dates) associated with these assets were not estimable. At December 31, 2014 and 2013, our AROs were reflected in other long-term liabilities on our consolidated balance sheets. See Note 5 for a discussion of our AROs.
Revenue Recognition	Revenue Recognition
	We gather, treat, compress, store, transport and sell various commodities (including crude oil, natural gas, NGLs and water) pursuant to fixed-fee and percent-of-proceeds contracts. We recognize revenues for these services and products when all of the following criteria are met:
	•	services have been rendered or products delivered or sold;
	•	persuasive evidence of an exchange arrangement exists;
	•	the price for services is fixed or determinable; and
	•	collectability is reasonably assured.
	For fixed-fee contracts, we recognize revenues based on the volume of crude oil, natural gas or produced water gathered, processed and treated or compressed, as applicable. For percent-of-proceeds contracts, we recognize revenues based on the value of products sold to third parties.
	Sales of crude oil, NGLs and salt are recognized at the time product is shipped or delivered to the customer depending on the sales terms. NGL processing fees are recognized upon delivery of the product. Revenues from the COLT Hub are recognized when the contractual services are provided, such as loading of customer rail cars. Revenues from storage and transportation contracts are recognized during the period in which the storage and transportation services are provided, such as providing storage and transportation services during the period a firm service contract is in place. We record deferred revenue when we receive amounts from our customers but have not met the criteria listed above. We recognize deferred revenue in our consolidated statements of operations when the criteria has been met and all services have been rendered. At December 31, 2014 and 2013, we had deferred revenue of approximately $11.6 million and $1.6 million, which is reflected in accrued expenses and other liabilities on our consolidated balance sheets.
Credit Risk and Concentrations	Credit Risk and Concentrations
	Inherent in our contractual portfolio are certain credit risks. Credit risk is the risk of loss from nonperformance by suppliers, customers or financial counterparties to a contract. We take an active role in managing credit risk and have established control procedures, which are reviewed on an ongoing basis. We attempt to minimize credit risk exposure through credit policies and periodic monitoring procedures as well as through customer deposits, letters of credit and entering into netting agreements that allow for offsetting counterparty receivable and payable balances for certain financial transactions, as deemed appropriate.
Income Taxes	Income Taxes
	We are a master limited partnership. Partnerships are generally not subject to federal income tax, although publicly-traded partnerships are treated as corporations for federal income tax purposes and therefore are subject to federal income tax, unless the partnership generates at least 90% of its gross income from qualifying sources. If the qualifying income requirement is satisfied, the publicly-traded partnership will be treated as a partnership for federal income tax purposes. We satisfy the qualifying income requirement and are treated as a partnership for federal and state income tax purposes. Our consolidated earnings are included in the federal and state income tax returns of our partners. However, legislation in certain states allows for taxation of partnerships, and as such, certain state taxes have been included in our accompanying financial statements as income taxes due to the nature of the tax in those particular states as discussed below. In addition, federal and state income taxes are provided on the earnings of the subsidiaries incorporated as taxable entities. We are required to recognize deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the financial statements or tax returns. Under this method, deferred tax assets and liabilities are determined based on the differences between the financial reporting and tax basis of assets and liabilities using expected rates in effect for the year in which the differences are expected to reverse.
	We are responsible for the Texas Margin tax computed on the Texas franchise tax returns. The margin tax qualifies as an income tax under GAAP, which requires us to recognize the impact of this tax on the temporary differences between the financial statement assets and liabilities and their tax basis attributable to such tax.
	Net earnings for financial statement purposes may differ significantly from taxable income reportable to unitholders as a result of differences between the tax basis and the financial reporting basis of assets and liabilities and the taxable income allocation requirements under our partnership agreement.
Environmental Costs and Other Contingencies	Environmental Costs and Other Contingencies
	We recognize liabilities for environmental and other contingencies when there is an exposure that indicates it is both probable that a liability has been incurred and the amount of loss can be reasonably estimated. Where the most likely outcome of a contingency can be reasonably estimated, we accrue a liability for that amount. Where the most likely outcome cannot be estimated, a range of potential losses is established and if no one amount in that range is more likely than any other, the low end of range is accrued.
	We record liabilities for environmental contingencies at their undiscounted amounts on our consolidated balance sheets as accrued expenses and other liabilities when environmental assessments indicate that remediation efforts are probable and costs can be reasonably estimated. Estimates of our liabilities are based on currently available facts and presently enacted laws and regulations, taking into consideration the likely effects of other societal and economic factors. These estimates are subject to revision in future periods based on actual costs or new circumstances. We capitalize costs that benefit future periods and recognize a current period charge in operations and maintenance expenses when clean-up efforts do not benefit future periods.
	We evaluate potential recoveries of amounts from third parties, including insurance coverage, separately from our liability. Recovery is evaluated based on the solvency of the third party, among other factors. When recovery is assured, we record and report an asset separately from the associated liability on our consolidated balance sheet.
Price Risk Management Activities	Price Risk Management Activities
	In 2014, we began entering into daily and short-term forward crude purchase and sale agreements in our NGL and crude services segment. We utilize derivative financial instruments to (i) manage our exposure to commodity price risk, specifically, the related change in the fair value of inventory, as well as the variability of cash flows related to forecasted transactions; and (ii) ensure the availability of adequate physical supply of commodity. We record all derivative instruments on the balance sheet at their fair values as either assets or liabilities measured at fair value. Changes in the fair value of these derivative financial instruments are recorded through current earnings.
	We did not have any derivatives identified as fair value hedges for accounting purposes or any derivatives designated as cash flow hedges for the year ended December 31, 2014. Our derivative instruments did not have a material impact on our financial statements during the year ended December 31, 2014.
Unit-Based Compensation	Unit-Based Compensation
	Long-term incentive awards are granted under our incentive plan. Unit-based compensation awards consist of restricted units that are valued at the closing market price of our common units on the date of grant, which reflects the fair value of such awards. For those awards that are settled in cash, the associated liability is remeasured at every balance sheet date through settlement, such that the vested portion of the liability is adjusted to reflect its revised fair value through compensation expense. We generally recognize the expense associated with the award over the vesting period.
	Prior to the Crestwood Merger, Legacy Crestwood issued phantom units under its Fourth Amended and Restated 2007 Equity Plan (2007 Equity Plan). The 2007 Equity Plan was terminated in conjunction with the Crestwood Merger. See Note 11 for a further discussion of our long-term incentive plans.
New Accounting Pronouncements Issued But Not Yet Adopted	New Accounting Pronouncements Issued But Not Yet Adopted
	As of December 31, 2014, the following accounting standards had not yet been adopted by us.
	In May 2014, the FASB issued Accounting Standards Update 2014-09, Revenue from Contracts with Customers, which outlines a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers and supersedes current revenue recognition guidance. We expect to adopt the provisions of this standard effective January 1, 2017 and are currently evaluating the impact that this standard will have on our financial statements.

Basis_of_Presentation_and_Summ2

Basis of Presentation and Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Estimated Useful Lives of Assets	Depreciation is computed by the straight-line method over the estimated useful lives of the assets, as follows:
		Years
	Gathering systems and pipelines	20
	Facilities and equipment	20-25
	Buildings, rights-of-way and easements	20-40
	Office furniture and fixtures	10-May
	Vehicles	5
Components of Intangible Assets	Certain intangible assets are amortized on a straight-line basis over their estimated economic lives, as follows:
		Weighted-Average
		Life
		(years)
	Customer accounts	20
	Covenants not to compete	3
	Trademarks	5
	Intangible assets consisted of the following at December 31, 2014 and 2013 (in millions):
		December 31,
		2014		2013
	Customer accounts	$	483.2	$	476.4
	Covenants not to compete	5.6		3
	Gas gathering, compression and processing contracts	431.4		451.4
	Acquired storage contracts	29		29
	Trademarks	9.7		11
	Deferred financing costs	54.3		54.3
		1,013.20		1,025.10
	Less: accumulated amortization	137		54.3
	Total intangible assets, net	$	876.2	$	970.8
	The following table summarizes the total of accumulated amortization of intangible assets by the type of intangible asset at December 31, 2014 and 2013:
		December 31,
		2014		2013
	Customer accounts	$	57	$	13.4
	Covenants not to compete	2.1		0.6
	Gas gathering, compression and processing contracts	47.9		27.9
	Acquired storage contracts	12.7		4
	Trademarks	0.9		0.3
	Deferred financing costs	16.4		8.1
	Total accumulated amortization	$	137	$	54.3
Estimated Economic Lives of Identifiable Intangible Assets	Certain intangible assets are amortized on a straight-line basis over their estimated economic lives, as follows:
		Weighted-Average
		Life
		(years)
	Customer accounts	20
	Covenants not to compete	3
	Trademarks	5

Acquisitions_Tables

Acquisitions (Tables)	12 Months Ended
	Dec. 31, 2014
Business Acquisition [Line Items]
Pro Forma Consolidated Statements of Operations	The following table presents unaudited pro forma consolidated revenues, net income and net income per limited partner unit as if the Legacy Inergy reverse acquisition and the Arrow Acquisition had been included in our consolidated results for the year ended December 31, 2012 and for the entire year ended December 31, 2013 (in millions, except per unit information). All other acquisitions were immaterial in consolidation.
		Year Ended December 31,
		2013			2012
	Revenues	$	2,083.30		$	1,184.50
	Net income (loss)	$	(21.0	)	$	50.1
	Net income (loss) per limited partner unit(1):
	Basic	$	(0.61	)	$	0.29
	Diluted	$	(0.61	)	$	0.29
Inergy Midstream
Business Acquisition [Line Items]
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block]	The following table summarizes the final valuation of the assets acquired and liabilities assumed at the merger date (in millions):
	Current assets	$	49.1
	Property, plant and equipment	1,677.80
	Intangible assets	196
	Other assets	2.9
	Total identifiable assets acquired	1,925.80
	Current liabilities	30.9
	Long-term debt	745
	Other long-term liabilities	5.3
	Total liabilities assumed	781.2
	Net identifiable assets acquired	1,144.60
	Goodwill	1,532.70
	Net assets acquired	$	2,677.30
Arrow Midstream Holdings, LLC
Business Acquisition [Line Items]
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block]	The following table summarizes the final valuation of the assets acquired and liabilities assumed at the acquisition date (in millions):
	Current assets	$	192.7
	Property, plant and equipment	400.5
	Intangible assets	323.4
	Other assets	19.5
	Total identifiable assets acquired	936.1
	Current liabilities	215.8
	Assets retirement obligations	1.2
	Other long-term liabilities	3.7
	Total liabilities assumed	220.7
	Net identifiable assets acquired	715.4
	Goodwill	45.9
	Net assets acquired	$	761.3
Devon
Business Acquisition [Line Items]
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block]	The final purchase price allocation is as follows (in millions):
	Cash	$	87.9
	Total purchase price	$	87.9
	Purchase price allocation:
	Property, plant and equipment	$	88.6
	Total assets	88.6
	Asset retirement obligation	0.5
	Environmental liability	0.2
	Total liabilities	0.7
	Total	$	87.9
EMAC
Business Acquisition [Line Items]
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block]	The final purchase price allocation is as follows (in millions):
	Cash	$	95
	Total purchase price	$	95
	Purchase price allocation:
	Property, plant and equipment	$	53.4
	Intangible assets	33.9
	Goodwill	8.6
	Total assets	95.9
	Asset retirement obligation	0.8
	Environmental liability	0.1
	Total liabilities	0.9
	Total	$	95

Certain_Balance_Sheet_Informat1

Certain Balance Sheet Information (Tables)	12 Months Ended
	Dec. 31, 2014
Balance Sheet Related Disclosures [Abstract]
Components of Inventories	Inventory consisted of the following at December 31, 2014 and 2013 (in millions).
		December 31,
		2014		2013
	Parts and supplies	$	5.9	$	4.5
	Crude oil	0.9		1.4
	Raw materials	0.3		0.4
	Finished goods	0.9		0.7
	Total inventory	$	8	$	7
Components of Property, Plant and Equipment	Property, plant and equipment consisted of the following at December 31, 2014 and 2013 (in millions):
		December 31,
		2014		2013
	Gathering systems and pipelines	1,276.60		1,231.10
	Facilities and equipment	1,468.80		1,041.00
	Buildings, land, rights-of-way, storage contracts and easements	806.4		766.2
	Vehicles	13.6		4.1
	Construction in process	153.7		360.5
	Base gas	37.5		36.3
	Salt deposits	120.5		120.5
	Office furniture and fixtures	6.4		6
		3,883.50		3,565.70
	Less: accumulated depreciation and depletion	365.4		215.6
	Total property, plant and equipment, net	$	3,518.10	$	3,350.10
Components of Intangible Assets	Certain intangible assets are amortized on a straight-line basis over their estimated economic lives, as follows:
		Weighted-Average
		Life
		(years)
	Customer accounts	20
	Covenants not to compete	3
	Trademarks	5
	Intangible assets consisted of the following at December 31, 2014 and 2013 (in millions):
		December 31,
		2014		2013
	Customer accounts	$	483.2	$	476.4
	Covenants not to compete	5.6		3
	Gas gathering, compression and processing contracts	431.4		451.4
	Acquired storage contracts	29		29
	Trademarks	9.7		11
	Deferred financing costs	54.3		54.3
		1,013.20		1,025.10
	Less: accumulated amortization	137		54.3
	Total intangible assets, net	$	876.2	$	970.8
	The following table summarizes the total of accumulated amortization of intangible assets by the type of intangible asset at December 31, 2014 and 2013:
		December 31,
		2014		2013
	Customer accounts	$	57	$	13.4
	Covenants not to compete	2.1		0.6
	Gas gathering, compression and processing contracts	47.9		27.9
	Acquired storage contracts	12.7		4
	Trademarks	0.9		0.3
	Deferred financing costs	16.4		8.1
	Total accumulated amortization	$	137	$	54.3
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense	Estimated amortization of our intangible assets for the next five years is as follows (in millions):
	Year Ending
	December 31,
	2015	$	89.6
	2016	76.4
	2017	63.5
	2018	51.5
	2019	44.6
Schedule of Accrued Liabilities	Accrued expenses and other liabilities consisted of the following at December 31, 2014 and 2013 (in millions):
		December 31,
		2014		2013
	Accrued expenses	$	23.7	$	20
	Accrued property taxes	2.1		7.6
	Accrued product purchases payable	0.7		1.6
	Tax payable	0.4		10.6
	Interest payable	22		14.9
	Accrued additions to property, plant and equipment	20		58.1
	Commitments and contingent liabilities (Note 12)	40		31.4
	Capital leases	1.3		2.6
	Deferred revenue	11.6		1.6
	Other	0.2		—
	Total accrued expenses and other liabilities	$	122	$	148.4

Asset_Retirement_Obligations_T

Asset Retirement Obligations (Tables)	12 Months Ended
	Dec. 31, 2014
Asset Retirement Obligation Disclosure [Abstract]
Schedule of Asset Retirement Obligations	The following table presents the changes in the net asset retirement obligations for the years ended December 31, 2014 and 2013 (in millions):
		December 31,
		2014		2013
	Net asset retirement obligation at January 1	$	15.1	$	14
	Liabilities incurred	4.6		—
	Acquisitions	1.2		—
	Accretion expense	1.1		0.8
	Changes in estimate	—		0.3
	Net asset retirement obligation at December 31	$	22	$	15.1

Financial_Instruments_Tables

Financial Instruments (Tables)	12 Months Ended
	Dec. 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):
		December 31, 2014				December 31, 2013
		Carrying Amount		Fair		Carrying Amount		Fair
				Value				Value
	2019 Senior Notes	$	351	$	360.5	$	351.2	$	379.3
	2020 Senior Notes	$	504	$	481.6	$	504.7	$	513.8
	2022 Senior Notes	$	600	$	568.5	$	600	$	617.3
Schedule of Debt	Long-term debt consisted of the following at December 31, 2014 and 2013 (in millions):
		December 31,
		2014		2013
	Credit Facility	$	555	$	414.9
	2019 Senior Notes	350		350
	Premium on 2019 Senior Notes	1		1.2
	2020 Senior Notes	500		500
	Fair value adjustment of 2020 Senior Notes	4		4.7
	2022 Senior Notes	600		600
	Other	3.5		—
	Total debt	2,013.50		1,870.80
	Less: current portion	0.7		2.9
	Total long-term debt	$	2,012.80	$	1,867.90
Schedule of Maturities of Long-term Debt	The aggregate maturities of principal amounts on our outstanding long-term debt and other notes payable as of December 31, 2014 for the next five years and in total thereafter are as follows (in millions):
	2015	$	0.7
	2016	0.7
	2017	0.7
	2018	555.8
	2019	350.6
	Thereafter	1,100.00
	Total debt	$	2,008.50

Earnings_Per_Limited_Partner_U1

Earnings Per Limited Partner Unit (Tables)	12 Months Ended
	Dec. 31, 2014
Earnings Per Share [Abstract]
Schedule of Other Nonoperating Income (Expense)	The tables below show the (i) allocation of net income attributable to CMLP and the (ii) net income attributable to CMLP per limited partner unit based on the number of basic and diluted limited partner units outstanding for the years ended December 31, 2014, 2013 and 2012 (in millions):
	Allocation of Net Income Attributable to CMLP
		Year Ended December 31,
		2014			2013			2012
	Net income (loss) attributable to CMLP	$	(38.7	)	$	(20.0	)	$	38.9
	Class A preferred units interest in net income attributable to CMLP	(17.2		)	—			—
	General partner’s incentive distributions	(30.1		)	(26.4		)	(14.8		)
	General partner’s interest in net income attributable to CMLP after incentive distributions	—			(0.4		)	(7.4		)
	Payment to Legacy Crestwood unitholders	—			(34.9		)	—
	Limited partners’ interest in net income (loss) attributable to CMLP after incentive distributions	$	(86.0	)	$	(81.7	)	$	16.7
Schedule of Earnings Per Share Reconciliation
	Earnings Per Limited Partner Unit
		Year Ended December 31,
		2014			2013			2012
	Limited partners’ interest in net income (loss)	$	(86.0	)	$	(81.7	)	$	16.7
	Weighted-average limited partner units - basic	187.9			99.2			64.7
	Effect of diluted units	—			—			—
	Weighted-average limited partner units - diluted	187.9			99.2			64.7
	Basic earnings per unit:
	Net income (loss) per limited partner	$	(0.46	)	$	(0.82	)	$	0.26
	Diluted earnings per unit:
	Net income (loss) per limited partner	$	(0.46	)	$	(0.82	)	$	0.26

Partners_Capital_Tables

Partners' Capital (Tables)	12 Months Ended
	Dec. 31, 2014
Partners' Capital [Abstract]
Schedule of Limited Partners' Capital Account by Class	The table below presents limited partner unit issuances by Legacy Crestwood, Legacy Inergy and Crestwood Midstream.
	Issuer		Issuance Date	Units			Per Unit			Per Unit		Net
							Gross Price			Net Price (1)		Proceeds
	Legacy Crestwood		13-Jan-12	3,500,000			$	30.73		$	29.5	$	103.1
	Legacy Crestwood		25-Jul-12	4,600,000		(2)	26			24.97		114.4
	Legacy Crestwood		22-Mar-13	5,175,000		(3)	23.9			23		118.5
	Legacy Inergy		13-Sep-13	11,773,191		(4)	22.5			21.69		255.2
	Crestwood Midstream		23-Oct-13	16,100,000		(5)	N/A			21.19		340.3
	(1)	Price is net of underwriting discounts.
	(2)	Includes 600,000 units that were issued in August 2012.
	(3)	Includes 675,000 units that were issued in April 2013.
	(4)	Includes 773,191 units that were issued on October 7, 2013.
	(5)	Includes 2,100,000 units that were issued on October 30, 2013.
Schedule of Distributions Made to Members or Limited Partners, by Distribution	The following table presents quarterly cash distributions paid to our limited partners (excluding distributions paid to our general partner on its common units held) during the years ended December 31, 2014 and 2013. In addition, during the year ended December 31, 2013, we paid cash distributions of approximately $24.9 million as a result of the Crestwood Merger discussed below. During the year ended December 31, 2012, Legacy Crestwood paid cash distributions of $77.7 million to its limited partners.
	Record Date		Payment Date	Per Unit Rate				Cash Distributions
								(in millions)
	2014
	February 7, 2014		February 14, 2014	$	0.41			$	74.1
	May 8, 2014		May 15, 2014	$	0.41			74.2
	August 7, 2014		August 14, 2014	$	0.41			74.1
	November 7, 2014		November 14, 2014	$	0.41			74.1
								$	296.5
	2013
	January 31, 2013		February 12, 2013	$	0.51			$	21
	April 30, 2013		May 10, 2013	$	0.51			27.4
	August 1, 2013		August 9, 2013	$	0.51			27.4
	August 7, 2013		August 14, 2013	$	0.4			34.3		(1)
	November 7, 2013		November 14, 2013	$	0.405			69.5		(1)
								$	179.6
	-1	Represents distributions associated with Legacy Inergy limited partner units.

Equity_Plans_Tables

Equity Plans (Tables)	12 Months Ended
	Dec. 31, 2014					Dec. 31, 2013
Equity [Abstract]
Disclosure of Share-based Compensation Arrangements by Share-based Payment Award	The following table summarizes information regarding restricted unit activity during the year ended December 31, 2014:					The following table summarizes information regarding phantom and restricted unit activity:
		Units		Weighted-Average Grant Date Fair Value			Payable In Cash				Payable In Units
	Unvested - January 1, 2014	250,557		$	22.13		Units		Weighted-		Units		Weighted-
									Average Grant				Average Grant
	Vested - restricted units	(208,361	)	$	22.15				Date Fair				Date Fair
									Value				Value
	Granted - restricted units	871,078		$	23.25	Unvested - December 31, 2012	8,312		$	26.45	221,992		$	28.35
	Forfeited	(78,478	)	$	23.33	Vested - phantom units	(7,958	)	$	26.48	(329,825	)	$	26.69
	Unvested - December 31, 2014	834,796		$	23.18	Vested - restricted units	—		$	—	(74,760	)	$	25.6
						Granted - phantom units	—		$	—	161,807		$	24.33
						Granted - restricted units	—		$	—	27,900		$	24.86
						Canceled - phantom units	(354	)	$	25.81	(7,114	)	$	27.96
						Unvested - December 31, 2013	—		$	—	—		$	—

Commitments_and_Contingencies_

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Schedule of Future Minimum Rental Payments for Operating Leases	Future minimum lease payments under noncancelable operating leases for the next five years ending December 31 and in total thereafter consist of the following (in millions):
	Year Ending
	December 31,
	2015	$	6.6
	2016	5.9
	2017	5.3
	2018	4.8
	2019	4.6
	Thereafter	16.3
	Total minimum lease payments	$	43.5
Schedule of Future Minimum Lease Payments for Capital Leases	Future minimum lease payments related to our capital leases at December 31, 2014 are as follows (in millions):
	Year Ending
	December 31,
	2015	$	1.4
	2016	0.8
	2017	0.5
	2018	0.2
	Total payments	2.9
	Imputed interest	(0.1		)
	Present value of future payments	$	2.8

Related_Party_Transactions_Tab

Related Party Transactions (Tables)	12 Months Ended
	Dec. 31, 2014
Related Party Transactions [Abstract]
Schedule of Related Party Transactions	The following table shows revenues, costs of goods sold and general and administrative expenses from our affiliates for the years December 31, 2014, 2013 and 2012 (in millions):
		Year Ended December 31,
		2014 (1)		2013		2012
	Gathering and processing revenues	$	4	$	74.9	$	113.7
	NGL and crude services revenues	$	13.6	$	7.2	$	—
	Gathering and processing costs of product/services sold(2)	$	42.2	$	32.5	$	15.2
	General and administrative expenses(3)	$	63.6	$	34.7	$	19.5
	-1	Concurrent with the Crestwood Merger, Quicksilver Resources Inc. (Quicksilver) is no longer a related party, and as a result our transactions with Quicksilver subsequent to June 19, 2013, are now considered non-affiliated transactions.
	-2	Represents natural gas purchases from Sabine Oil and Gas.
	-3	Included in general and administrative expenses is approximately $6.9 million and $4.4 million of net unit-based compensation charges allocated to us from CEQP for the years ended December 31, 2014 and 2013.
Schedule of Related Party Receivables and Payables	The following table shows accounts receivable and accounts payable from our affiliates as of December 31, 2014 and 2013 (in millions):
		December 31,
		2014		2013
	Accounts receivable	$	0.3	$	1.1
	Accounts payable	$	6.3	$	8.7

Segments_Tables

Segments (Tables)	12 Months Ended
	Dec. 31, 2014
Segment Reporting [Abstract]
Reportable Segments	Below is a reconciliation of our net income to EBITDA (in millions):
		Year Ended December 31,
		2014			2013			2012
	Net income (loss)	$	(21.9	)	$	(15.1	)	$	38.9
	Add:
	Interest and debt expense, net	111.4			71.4			35.8
	Provision for income taxes	0.7			0.7			1.2
	Depreciation, amortization and accretion	221.7			121.7			51.9
	EBITDA	$	311.9		$	178.7		$	127.8
	The following tables summarize the reportable segment data for the years ended December 31, 2014, 2013 and 2012 (in millions).
		Year Ended December 31, 2014
		Gathering and Processing			Storage and Transportation			NGL and Crude Services			Corporate			Total
	Revenues	$	332.5		$	179.1		$	2,053.90		$	—		$	2,565.50
	Costs of product/services sold	71.3			14.3			1,851.90			—			1,937.50
	Operations and maintenance expense	62.9			16.6			59.5			—			139
	General and administrative expense	—			—			—			85.4			85.4
	Gain (loss) on long-lived assets, net	(32.7		)	0.6			(1.5		)	—			(33.6		)
	Goodwill impairment	(18.5		)	—			(30.3		)	—			(48.8		)
	Loss on contingent consideration	(8.6		)	—			—			—			(8.6		)
	Earnings (loss) from unconsolidated affiliates, net	0.5			0.2			(1.4		)	—			(0.7		)
	EBITDA	$	139		$	149		$	109.3		$	(85.4	)	$	311.9
	Goodwill	$	81.1		$	726.3		$	825.2		$	—		$	1,632.60
	Total assets	$	1,993.00		$	1,981.20		$	2,455.50		$	166.8		$	6,596.50
	Purchases of property, plant and equipment	$	245.7		$	9.1		$	147.8		$	4.4		$	407
		Year Ended December 31, 2013
		Gathering and Processing			Storage and Transportation			NGL and Crude Services			Corporate			Total
	Revenues	$	291.2		$	90.1		$	277.3		$	—		$	658.6
	Costs of product/services sold	56.6			8.7			230.4			—			295.7
	Operations and maintenance expense	54.9			9.9			8.5			—			73.3
	General and administrative expense	—			—			—			80.7			80.7
	Gain on long-lived assets	5.4			—			—			—			5.4
	Goodwill impairment	(4.1		)	—			—			—			(4.1		)
	Loss on contingent consideration	(31.4		)	—			—			—			(31.4		)
	Earnings (loss) from unconsolidated affiliates, net	0.1			—			(0.2		)	—			(0.1		)
	EBITDA	$	149.7		$	71.5		$	38.2		$	(80.7	)	$	178.7
	Goodwill	$	99.6		$	936.5		$	646.7		$	—		$	1,682.80
	Total assets	$	1,836.40		$	2,190.50		$	2,217.30		$	157.6		$	6,401.80
	Purchases of property, plant and equipment	$	271.2		$	10.3		$	52.1		$	1		$	334.6
		Year Ended December 31, 2012
		Gathering and Processing			Storage and Transportation			NGL and Crude Services			Corporate			Total
	Revenues	$	239.5		$	—		$	—		$	—		$	239.5
	Costs of product/services sold	39			—			—			—			39
	Operation and maintenance expense	43.1			—			—			—			43.1
	General and administrative expense	—			—			—			29.6			29.6
	EBITDA	$	157.4		$	—		$	—		$	(29.6	)	$	127.8
	Goodwill	$	95		$	—		$	—		$	—		$	95
	Total assets	$	1,587.90		$	—		$	—		$	22.7		$	1,610.60
	Purchases of property, plant and equipment	$	51.5		$	—		$	—		$	1.1		$	52.6

Condensed_Consolidating_Financ1

Condensed Consolidating Financial Information (Tables)	12 Months Ended
	Dec. 31, 2014
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Schedule of Error Corrections and Prior Period Adjustments	corrected for certain errors in presentation. There was no impact to our consolidated balance sheet or our consolidated statement of cash flows.
		Parent						Guarantor						Eliminations
								Subsidiaries
		As Adjusted			As Previously Reported			As Adjusted			As Previously Reported			As Adjusted			As Previously Reported
		(in millions)
	Assets
	Accounts receivable	$	4.4		$	466.8		$	199.4		$	197.8		$	—		$	(459.7	)
	Accounts receivable - related party	1.1			—			—			—			—			—
	Total accounts receivable	5.5			466.8			199.4			197.8			—			(459.7		)
	Total current assets	5.6			466.9			218.2			216.6			—			(459.7		)
	Goodwill and intangible assets, net	46.2			—			2,607.40			2,653.60			—			—
	Investment in consolidated affiliates	6,053.00			6,385.20			—			—			(6,053.0		)	(6,385.2		)
	Total assets	6,109.60			6,856.90			6,192.60			6,237.20			(6,053.0		)	(6,844.9		)
	Liabilities and partners' capital
	Accounts payable	$	15.1		$	782.7		$	139.4		$	(165.2	)	$	—		$	(459.7	)
	Accounts payable - related party	5.4			—			3.3			—			—			—
	Total accounts payable	20.5			782.7			142.7			(165.2		)	—			(459.7		)
	Other current liabilities	26.4			11.5			124.7			145			—			—
	Total current liabilities	46.9			794.2			267.4			(20.2		)	—			(459.7		)
	Partners' capital	4,092.10			4,092.10			5,900.60			6,232.80			(5,952.0		)	(6,284.2		)
	Total partners' capital	4,193.10			4,193.10			5,900.60			6,232.80			(6,053.0		)	(6,385.2		)
	Total liabilities and partners' capital	6,109.60			6,856.90			6,192.60			6,237.20			(6,053.0		)	(6,844.9		)
		Parent						Guarantor						Non-Guarantor						Eliminations
								Subsidiaries						Subsidiaries
		As Adjusted			As Previously Reported			As Adjusted			As Previously Reported			As Adjusted			As Previously Reported			As Adjusted			As Previously Reported
	Cash flows from operating activities:	$	(46.1	)	$	3.9		$	266.4		$	216.4		$	—		$	—		$	(33.8	)	$	(33.8	)
	Cash flows from investing activities:
	Investment in unconsolidated affiliates, net	—			—			—			(24.4		)	(151.5		)	(127.1		)	—			—
	Capital contributions from consolidated affiliates	(106.4		)	(82.0		)	—			—			—			—			106.4			82
	Other	—			(0.4		)	11.1			11.1			—			—			—			0.4
	Net cash provided by (used in) investing activities	(107.4		)	(83.4		)	(884.0		)	(908.4		)	(151.5		)	(127.1		)	106.4			82.4
	Cash flows from financing activities:
	Proceeds from the issuance of long-term debt	1,930.90			382.9			141.9			1,689.90			—			—			—			—
	Principal payments on long-term debt	(1,559.3		)	(202.0		)	(75.0		)	(1,432.3		)	—			—			—			—
	Payments for debt-related deferred costs	(32.0		)	(0.1		)	—			(31.9		)	—			—			—			—
	Distributions paid	(359.7		)	(219.3		)	(33.8		)	(174.2		)	—			—			33.8			33.8
	Contributions from parent	—			—			55.5			55.5			56.4			32			(106.4		)	(82.0		)
	Net proceeds from the issuance of common units	714			118.5			—			595.5			—			—			—			—
	Change in intercompany balances	(539.9		)	—			539.9			0.4			—			—			—			(0.4		)
	Net cash provided by (used in) financing activities	153.6			79.6			619.1			693.5			152.5			128.1			(72.6		)	(48.6		)
Consolidating Balance Sheet
	Condensed Consolidating Balance Sheet
	31-Dec-14
	(in millions)
		Parent			Guarantor			Non-			Eliminations			Consolidated
					Subsidiaries			Guarantor
								Subsidiaries
	Assets
	Current assets:
	Cash	$	—		$	4.6		$	—		$	—		$	4.6
	Accounts receivable	1.2			240.3			—			—			241.5
	Accounts receivable - related party	—			—			0.3			—			0.3
	Total accounts receivable	1.2			240.3			0.3			—			241.8
	Inventories	—			8			—			—			8
	Other current assets	—			18.7			—			—			18.7
	Total current assets	1.2			271.6			0.3			—			273.1
	Property, plant and equipment, net	7.9			3,510.20			—			—			3,518.10
	Goodwill and intangible assets, net	38			2,470.80			—			—			2,508.80
	Investment in consolidated affiliates	6,296.70			—			—			(6,296.7		)	—
	Investment in unconsolidated affiliates	—			—			295.1			—			295.1
	Other assets	—			1.4			—			—			1.4
	Total assets	$	6,343.80		$	6,254.00		$	295.4		$	(6,296.7	)	$	6,596.50
	Liabilities and partners' capital
	Current liabilities:
	Accounts payable	$	4.8		$	121.3		$	—		$	—		$	126.1
	Accounts payable - related party	4.2			1.9			0.2			—			6.3
	Total accounts payable	9			123.2			0.2			—			132.4
	Other current liabilities	23			99.7			—			—			122.7
	Total current liabilities	32			222.9			0.2			—			255.1
	Long-term liabilities:
	Long-term debt, less current portion	2,012.80			—			—			—			2,012.80
	Other long-term liabilities	1.6			29.6			—			—			31.2
	Total long-term liabilities	2,014.40			29.6			—			—			2,044.00
	Partners' capital	4,125.70			6,001.50			123.5			(6,125.0		)	4,125.70
	Interest of non-controlling partners in subsidiaries	171.7			—			171.7			(171.7		)	171.7
	Total partners' capital	4,297.40			6,001.50			295.2			(6,296.7		)	4,297.40
	Total liabilities and partners' capital	$	6,343.80		$	6,254.00		$	295.4		$	(6,296.7	)	$	6,596.50
	Condensed Consolidating Balance Sheet
	31-Dec-13
	(in millions)
		Parent			Guarantor			Non-			Eliminations			Consolidated
					Subsidiaries			Guarantor
								Subsidiaries
	Assets
	Current assets:
	Cash	$	0.1		$	1.6		$	1		$	—		$	2.7
	Accounts receivable	4.4			199.4			0.2			—			204
	Accounts receivable - related party	1.1			—			—			—			1.1
	Total accounts receivable	5.5			199.4			0.2			—			205.1
	Inventories	—			7			—			—			7
	Other current assets	—			10.2			—			—			10.2
	Total current assets	5.6			218.2			1.2			—			225
	Property, plant and equipment, net	4.8			3,345.30			—			—			3,350.10
	Goodwill and intangible assets, net	46.2			2,607.40			—			—			2,653.60
	Investment in consolidated affiliates	6,053.00			—			—			(6,053.0		)	—
	Investment in unconsolidated affiliates	—			—			151.4			—			151.4
	Other assets	—			21.7			—			—			21.7
	Total assets	$	6,109.60		$	6,192.60		$	152.6		$	(6,053.0	)	$	6,401.80
	Liabilities and partners' capital
	Current liabilities:
	Accounts payable	$	15.1		$	139.4		$	—		$	—		$	154.5
	Accounts payable - related party	5.4			3.3			—			—			8.7
	Total accounts payable	20.5			142.7			—			—			163.2
	Other current liabilities	26.4			124.7			0.2			—			151.3
Total current liabilities	46.9			267.4			0.2			—			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			5,900.60			51.4			(5,952.0		)	4,092.10
Interest of non-controlling partners in subsidiaries	101			—			101			(101.0		)	101
Total partners' capital	4,193.10			5,900.60			152.4			(6,053.0		)	4,193.10
Total liabilities and partners' capital	$	6,109.60		$	6,192.60		$	152.6		$	(6,053.0	)	$	6,401.80
Consolidating Statements of Operations
	Condensed Consolidating Statements of Operations
	Year Ended December 31, 2014
	(in millions)
		Parent			Guarantor			Non-			Eliminations			Consolidated
					Subsidiaries			Guarantor
								Subsidiaries
	Revenues:
	Gathering and processing	$	—		$	328.5		$	—		$	—		$	328.5
	Storage and transportation	—			179.1			—			—			179.1
	NGL and crude services	—			2,040.30			—			—			2,040.30
	Related party	—			17.6			—			—			17.6
		—			2,565.50			—			—			2,565.50
	Costs of product/services sold:
	Gathering and processing	—			29.1			—			—			29.1
	Storage and transportation	—			14.3			—			—			14.3
	NGL and crude services	—			1,851.90			—			—			1,851.90
	Related party	—			42.2			—			—			42.2
		—			1,937.50			—			—			1,937.50
	Expenses:
	Operations and maintenance	—			139			—			—			139
	General and administrative	49.4			36			—			—			85.4
	Depreciation, amortization and accretion	0.9			220.8			—			—			221.7
		50.3			395.8			—			—			446.1
	Other operating income (expense):
	Loss on long-lived assets, net	—			(33.6		)	—			—			(33.6		)
	Goodwill impairment	—			(48.8		)	—			—			(48.8		)
	Loss on contingent consideration	—			(8.6		)	—			—			(8.6		)
	Operating income (loss)	(50.3		)	141.2			—			—			90.9
	Loss from unconsolidated affiliates, net	—			—			(0.7		)	—			(0.7		)
	Interest and debt expense, net	(111.4		)	—			—			—			(111.4		)
	Equity in net income (loss) of subsidiary	139.8			—			—			(139.8		)	—
	Income (loss) before income taxes	(21.9		)	141.2			(0.7		)	(139.8		)	(21.2		)
	Provision for income taxes	—			0.7			—			—			0.7
	Net income (loss)	(21.9		)	140.5			(0.7		)	(139.8		)	(21.9		)
	Net (income) loss attributable to non-controlling partners	—			—			(16.8		)	—			(16.8		)
	Net income (loss) attributable to Crestwood Midstream Partners LP	(21.9		)	140.5			(17.5		)	(139.8		)	(38.7		)
	Net income attributable to Class A preferred units	(17.2		)	—			—			—			(17.2		)
	Net income (loss) attributable to partners	$	(39.1	)	$	140.5		$	(17.5	)	$	(139.8	)	$	(55.9	)
	Condensed Consolidating Statements of Operations
	Year Ended December 31, 2013
	(in millions)
		Parent			Guarantor			Non-			Eliminations			Consolidated
					Subsidiaries			Guarantor
								Subsidiaries
	Revenues:
	Gathering and processing	$	—		$	216.3		$	—		$	—		$	216.3
	Storage and transportation	—			90.1			—			—			90.1
	NGL and crude services	—			270.1			—			—			270.1
	Related party	—			82.1			—			—			82.1
		—			658.6			—			—			658.6
	Costs of product/services sold:
	Gathering and processing	—			24.1			—			—			24.1
	Storage and transportation	—			8.7			—			—			8.7
	NGL and crude services	—			230.4			—			—			230.4
	Related party	—			32.5			—			—			32.5
		—			295.7			—			—			295.7
	Expenses:
	Operations and maintenance	—			73.3			—			—			73.3
	General and administrative	46.5			34.2			—			—			80.7
	Depreciation, amortization and accretion	1			120.7			—			—			121.7
		47.5			228.2			—			—			275.7
	Other operating income (expense):
	Gain on long-lived assets, net	—			5.4			—			—			5.4
Goodwill impairment	—			(4.1		)	—			—			(4.1		)
Loss on contingent consideration	—			(31.4		)	—			—			(31.4		)
Operating income (loss)	(47.5		)	104.6			—			—			57.1
Loss from unconsolidated affiliates, net	—			—			(0.1		)	—			(0.1		)
Interest and debt expense, net	(68.7		)	(2.7		)	—			—			(71.4		)
Equity in net income (loss) of subsidiary	101.1			—			—			(101.1		)	—
Income (loss) before income taxes	(15.1		)	101.9			(0.1		)	(101.1		)	(14.4		)
Provision for income taxes	—			0.7			—			—			0.7
Net income (loss)	(15.1		)	101.2			(0.1		)	(101.1		)	(15.1		)
Net (income) loss attributable to non-controlling partners	—			—			(4.9		)	—			(4.9		)
Net income (loss) attributable to Crestwood Midstream Partners LP	$	(15.1	)	$	101.2		$	(5.0	)	$	(101.1	)	$	(20.0	)
Consolidating Statement of Cash Flows
	Condensed Consolidating Statements of Cash Flows
	Year Ended December 31, 2014
	(in millions)
		Parent			Guarantor			Non-			Eliminations			Consolidated
					Subsidiaries			Guarantor
								Subsidiaries
	Cash flows from operating activities:	$	(165.6	)	$	488.5		$	—		$	—		$	322.9
	Cash flows from investing activities:
	Acquisitions, net of cash acquired	—			(19.5		)	—			—			(19.5		)
	Purchases of property, plant and equipment	(4.3		)	(402.7		)	—			—			(407.0		)
	Investment in unconsolidated affiliates	—			—			(144.4		)	—			(144.4		)
	Capital contribution from consolidated affiliates	(89.5		)	—			—			89.5			—
	Net cash provided by (used in) investing activities	(93.8		)	(422.2		)	(144.4		)	89.5			(570.9		)
	Cash flows from financing activities:
	Proceeds from the issuance of long-term debt	2,089.90			—			—			—			2,089.90
	Principal payments on long-term debt	(1,949.8		)	—			—			—			(1,949.8		)
	Payments on capital leases	(1.3		)	(1.9		)	—			—			(3.2		)
	Payments for debt-related deferred costs	(0.1		)	—			—			—			(0.1		)
	Distributions paid	(368.9		)	—			—			—			(368.9		)
	Contributions from parent	—			—			89.5			(89.5		)	—
	Net proceeds from issuance of preferred equity of subsidiary	—			—			53.9			—			53.9
	Net proceeds from issuance of Class A preferred units	430.5			—			—			—			430.5
	Taxes paid for unit-based compensation vesting	—			(1.6		)	—			—			(1.6		)
	Change in intercompany balances	59.8			(59.8		)	—			—			—
	Other	(0.8		)	—			—			—			(0.8		)
	Net cash provided by (used in) financing activities	259.3			(63.3		)	143.4			(89.5		)	249.9
	Net change in cash	(0.1		)	3			(1.0		)	—			1.9
	Cash at beginning of period	0.1			1.6			1			—			2.7
	Cash at end of period	$	—		$	4.6		$	—		$	—		$	4.6
	Condensed Consolidating Statements of Cash Flows
	Year Ended December 31, 2013
	(in millions)
		Parent			Guarantor			Non-			Eliminations			Consolidated
					Subsidiaries			Guarantor
								Subsidiaries
	Cash flows from operating activities:	$	(46.1	)	$	266.4		$	—		$	(33.8	)	$	186.5
	Cash flows from investing activities:
	Acquisitions, net of cash acquired	—			(561.5		)	—			—			(561.5		)
	Purchases of property, plant and equipment	(1.0		)	(333.6		)	—			—			(334.6		)
	Investment in unconsolidated affiliates	—			—			(151.5		)	—			(151.5		)
	Capital contribution from consolidated affiliates	(106.4		)	—			—			106.4			—
	Other	—			11.1			—			—			11.1
	Net cash provided by (used in) investing activities	(107.4		)	(884.0		)	(151.5		)	106.4			(1,036.5		)
	Cash flows from financing activities:
	Proceeds from the issuance of long-term debt	1,930.90			141.9			—			—			2,072.80
	Principal payments on long-term debt	(1,559.3		)	(75.0		)	—			—			(1,634.3		)
	Payments on capital leases	(0.4		)	(3.9		)	—			—			(4.3		)
	Payments for debt-related deferred costs	(32.0		)	—			—			—			(32.0		)
	Distributions paid	(359.7		)	(33.8		)	—			33.8			(359.7		)
	Contributions from parent	—			55.5			56.4			(106.4		)	5.5
	Net proceeds from issuance of common units	714			—			—			—			714
	Net proceeds from issuance of preferred equity of subsidiary	—			—			96.1			—			96.1
	Taxes paid for unit-based compensation vesting	—			(5.5		)	—			—			(5.5		)
	Change in intercompany balances	(539.9		)	539.9			—			—			—
	Net cash provided by (used in) financing activities	153.6			619.1			152.5			(72.6		)	852.6
	Net change in cash	0.1			1.5			1			—			2.6
	Cash at beginning of period	—			0.1			—			—			0.1
	Cash at end of period	$	0.1		$	1.6		$	1		$	—		$	2.7

Quarterly_Financial_Data_Unaud1

Quarterly Financial Data (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Schedule of Quarterly Financial Information	Summarized unaudited quarterly financial data is presented below (in millions, except per unit information):
		Quarter Ended
		March 31				June 30			September 30			31-Dec
	2014
	Revenues	$	537			$	675.7		$	738.4		$	614.4
	Operating income (loss)	34.4				42.3			48.7			(34.5		)	(1)
	Earnings (loss) from unconsolidated affiliates, net	(0.1		)		(1.5		)	0.3			0.6
	Net income (loss)	5.5				11.7			21.3			(60.4		)
	Net income (loss) attributable to partners	2.4				6.9			7.7			(72.9		)
	Net income (loss) per limited partner unit:
	Basic	$	(0.03	)		$	—		$	—		$	(0.43	)
	Diluted	$	(0.03	)		$	—		$	—		$	(0.43	)
	2013
	Revenues	$	72.4			$	80.1		$	140.1		$	366
	Operating income (loss)	20.7				19.5			31.8			(14.9		)	(2)
	Earnings (loss) from unconsolidated affiliates, net	—				—			(0.4		)	0.3
	Net income (loss)	8.9				6.7			11.6			(42.3		)
	Net income (loss) attributable to partners	8.9				6.7			9.7			(45.3		)
	Net income (loss) per limited partner unit:
	Basic(4)	$	0.06		(3)	$	(0.01	)	$	0.02		$	(0.50	)
	Diluted(4)	$	0.06		(3)	$	(0.01	)	$	0.02		$	(0.50	)
	-1	Includes goodwill, property, plant and equipment and intangible impairments of approximately $48.8 million, $13.2 million and $21.3 million, respectively. See Note 2 for a further discussion of our impairments recorded during 2014.
	-2	Includes a $31.4 million loss on contingent consideration which reflects the fair value of an earn-out premium associated with the original acquisition of our Antero assets. See Note 3 for a further discussion of this non-cash charge.
	-3	Basic and diluted net income for each of the quarters ended September 30, 2013, were computed based on the number of common units issued by Legacy Inergy to Legacy Crestwood unitholders as part of the Crestwood Merger.
	-4	The accumulation of basic and diluted net income (loss) per limited partner unit does not total the amount for the year due to changes in ownership percentages throughout the year.

Organization_and_Description_o1

Organization and Description of Business (Details) (USD $)	0 Months Ended	3 Months Ended				12 Months Ended			0 Months Ended	9 Months Ended	0 Months Ended
In Millions, except Share data, unless otherwise specified	Jun. 19, 2013	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Oct. 07, 2013	Jun. 30, 2013	Jun. 05, 2013
Partnership Organization And Basis Of Presentation [Line Items]
Distribution Made to Limited Partner, Unit Distribution						387,991
Distribution Made to Limited Partner, Cash Distributions Paid		$74.10	$74.10	$74.20	$74.10	296.5	$204.50	$77.70
Limited Liability Company (LLC) or Limited Partnership (LP), Managing Member or General Partner, Ownership Interest	100.00%
Number of operating segments						3
CEQP
Partnership Organization And Basis Of Presentation [Line Items]
Limited Liability Company (LLC) or Limited Partnership (LP), Managing Member or General Partner, Ownership Interest						4.00%
Parent
Partnership Organization And Basis Of Presentation [Line Items]
Percentage of distribution entitled to receive						50.00%				50.00%
Cash									24.9
CMLP
Partnership Organization And Basis Of Presentation [Line Items]
Business Combination, Equity Interest Issued or Issuable, Conversion Ratio									1.07
Affiliated Entity | Majority Shareholder | Unit Distribution
Partnership Organization And Basis Of Presentation [Line Items]
Distribution Made to Limited Partner, Cash Distributions Paid	56.4
Crestwood Holdings | Majority Shareholder
Partnership Organization And Basis Of Presentation [Line Items]
Cash									10
First Reserve
Partnership Organization And Basis Of Presentation [Line Items]
Percentage of distribution entitled to receive						11.00%
Capital Units | Affiliated Entity | Majority Shareholder | Unit Distribution
Partnership Organization And Basis Of Presentation [Line Items]
Distribution Made to Limited Partner, Unit Distribution											137,105
Capital Unit, Class D | Affiliated Entity | Majority Shareholder | Unit Distribution
Partnership Organization And Basis Of Presentation [Line Items]
Distribution Made to Limited Partner, Unit Distribution											21,588
CMLP
Partnership Organization And Basis Of Presentation [Line Items]
Cash									$34.90
Business Combination, Cash Payments to Unitholders Upon Completion of Merger, Per Unit									1.03
Distribution Rights
Partnership Organization And Basis Of Presentation [Line Items]
Distribution declared per limited partner unit						0.37				0.37
Distribution Rights | CEQP
Partnership Organization And Basis Of Presentation [Line Items]
Percentage of distribution entitled to receive						100.00%
Crestwood Holdings | Majority Shareholder
Partnership Organization And Basis Of Presentation [Line Items]
Shares exchanged by acquirer									7,100,000
Crestwood Holdings | CEQP
Partnership Organization And Basis Of Presentation [Line Items]
Shares issued by acquiree									14,300,000

Basis_of_Presentation_and_Summ3

Basis of Presentation and Summary of Significant Accounting Policies (Narrative) (Details) (USD $)	9 Months Ended	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
		reporting_units
Significant Accounting Policies [Line Items]
Impaired Assets to be disposed of		$13.20
Impairment of intangible assets (excluding goodwill)		21.3
Property, plant and equipment		3,883.50	3,565.70
Goodwill impairment		48.8	4.1	0
Goodwill		1,632.60	1,682.80	95
Reporting units with goodwill impairment loss		4
Number of reporting units		10
Deferred revenue		11.6	1.6
Qualifying income percentage	90.00%
Fair Value Inputs, Discount Rate		9.00%
Granite Wash
Significant Accounting Policies [Line Items]
Property, plant and equipment		20.2
Goodwill impairment		14.2
US Salt
Significant Accounting Policies [Line Items]
Goodwill impairment		2.2
Goodwill		12.6
Fayetteville
Significant Accounting Policies [Line Items]
Goodwill impairment		4.3
Goodwill		72.5
Watkins Glen
Significant Accounting Policies [Line Items]
Goodwill impairment		28.1
Goodwill		$66.20

Basis_of_Presentation_and_Summ4

Basis of Presentation and Summary of Significant Accounting Policies (Estimated Useful Lives - Phantom) (Details)	12 Months Ended
	Dec. 31, 2014
Gathering systems and pipelines | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful lives	20 years
Gathering systems and pipelines | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful lives	20 years
Facilities and equipment | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful lives	20 years
Facilities and equipment | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful lives	25 years
Buildings and improvements | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful lives	20 years
Buildings and improvements | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful lives	40 years
Office furniture and fixtures | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful lives	5 years
Office furniture and fixtures | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful lives	10 years
Vehicles | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful lives	5 years
Vehicles | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful lives	5 years

Basis_of_Presentation_and_Summ5

Basis of Presentation and Summary of Significant Accounting Policies (Estimated Economic Lives Of Intangible Assets) (Details)	12 Months Ended
	Dec. 31, 2014
Customer accounts
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted-Average Life (years)	20 years
Covenants not to compete
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted-Average Life (years)	3 years
Trademarks
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted-Average Life (years)	5 years

Acquisitions_Details

Acquisitions (Details) (USD $)	0 Months Ended	12 Months Ended			0 Months Ended		6 Months Ended	0 Months Ended		3 Months Ended	0 Months Ended
	Jan. 08, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Mar. 21, 2014	9-May-14	Dec. 31, 2013	Nov. 08, 2013	Mar. 26, 2012	Dec. 31, 2014	Aug. 24, 2013	Aug. 24, 2012	Dec. 28, 2013	Dec. 28, 2012	Jun. 19, 2013	Dec. 31, 2018	Feb. 28, 2015
								acre								ft3
Business Acquisition [Line Items]
Consideration Transferred	$258,000,000
Goodwill		1,632,600,000	1,682,800,000	95,000,000			1,682,800,000			1,632,600,000
Payments to Acquire Businesses, Net of Cash Acquired		19,500,000	561,500,000	564,000,000
Asset Retirement Obligation		22,000,000	15,100,000	14,000,000			15,100,000			22,000,000
Incentive Distribution, Distribution		30,100,000	26,400,000	14,800,000
Fair Value Inputs, Discount Rate		9.00%
Business Acquisition, Pro Forma Information [Abstract]
Revenue			2,083,300,000	1,184,500,000
Net income			-21,000,000	50,100,000
Basic (usd per unit)			($0.61)	$0.29
Diluted (usd per unit)			($0.61)	$0.29
NGL and Crude Services
Business Acquisition [Line Items]
Goodwill		825,200,000	646,700,000	0			646,700,000			825,200,000
Storage and Transportation
Business Acquisition [Line Items]
Goodwill			936,500,000	0			936,500,000
Red Rock Transportation, Inc.
Business Acquisition [Line Items]
Consideration Transferred					13,800,000
Cash					12,100,000
Consideration Transferred, Liabilities Incurred					1,800,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Number					56
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Double Bottom Tanks					22
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Tractors					44
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Crude Hauling Capacity, Per Day					28,000
Property, plant and equipment					10,600,000
Goodwill					3,200,000
LT Enterprises
Business Acquisition [Line Items]
Consideration Transferred						10,700,000
Cash						9,000,000
Consideration Transferred, Liabilities Incurred						1,700,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Tractors						38
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Crude Trailers						51
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Service Vehicles						17
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Crude Hauling Capacity, Per Day						20,000
Business Acquisition, Pro Forma Information [Abstract]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Land, Area						20
Inergy Midstream
Business Acquisition [Line Items]
Property, plant and equipment															1,677,800,000
Goodwill															1,532,700,000
Current assets															49,100,000
Intangible assets															196,000,000
Other assets															2,900,000
Total identifiable assets acquired															1,925,800,000
Current liabilities															30,900,000
Long-term debt															745,000,000
Other long-term liabilities															5,300,000
Total liabilities assumed															781,200,000
Net identifiable assets acquired															1,144,600,000
Net assets acquired															2,677,300,000
Revenue of since acquisition							148,600,000
Operating income related to acquisition							29,800,000
Business Acquisition, Transaction Costs		2,100,000	24,700,000				24,700,000			2,100,000
Inergy Midstream | NGL and Crude Services
Business Acquisition [Line Items]
Goodwill		806,400,000								806,400,000
Inergy Midstream | Storage and Transportation
Business Acquisition [Line Items]
Goodwill		726,300,000								726,300,000
Arrow Midstream Holdings, LLC
Business Acquisition [Line Items]
Consideration Transferred								750,000,000
Cash								550,000,000
Property, plant and equipment								400,500,000
Goodwill								45,900,000
Current assets								192,700,000
Intangible assets								323,400,000
Other assets								19,500,000
Total identifiable assets acquired								936,100,000
Current liabilities								215,800,000
Asset Retirement Obligation								1,200,000
Other long-term liabilities								3,700,000
Total liabilities assumed								220,700,000
Net identifiable assets acquired								715,400,000
Net assets acquired								761,300,000
Revenue of since acquisition			218,800,000
Operating income related to acquisition			1,700,000
Business Acquisition, Transaction Costs		5,400,000	1,200,000				1,200,000			5,400,000
Business Combination, Consideration Transferred, Other								11,300,000
Incentive Distribution, Distribution								8,826,125
Central Delivery Point Acquired Asset, Area (in acres)								23
Antero
Business Acquisition [Line Items]
Consideration Transferred									376,800,000
Gathering Pipeline Acquired (in miles)									33
Business Combination, Contingent Consideration, Liability, Current									40,000,000
Contingent consideration		-40,000,000	-31,400,000				-31,400,000			-40,000,000
Fair Value Inputs, Discount Rate										5.90%
Purchase Agreement, Assets Acquired, Gross Acres									127,000
Purchase Agreement, Assets Acquired, Net Acres									104,000
Deferred Revenue									2,600,000
Accounts Payable, Other, Current		2,400,000								2,400,000
Commitment Period		20 years
Antero | Minimum
Business Acquisition [Line Items]
Volume of Natural Gas for System Acquired, Per Day (in cubic feet)									300,000,000
Antero | Average out put by 2018 | Minimum
Business Acquisition [Line Items]
Volume of Natural Gas for System Acquired, Per Day (in cubic feet)																450,000,000
Devon
Business Acquisition [Line Items]
Consideration Transferred												87,300,000
Cash											87,900,000
Property, plant and equipment											88,600,000
Payments to Acquire Businesses, Net of Cash Acquired											87,900,000
Liability for Asbestos and Environmental Claims, Gross											200,000
Total identifiable assets acquired											88,600,000
Asset Retirement Obligation											500,000
Total liabilities assumed											700,000
Depreciation, Depletion and Amortization												2,200,000
Commitment Period											20 years
EMAC
Business Acquisition [Line Items]
Consideration Transferred														95,000,000
Cash													95,000,000
Property, plant and equipment													53,400,000
Goodwill													8,600,000	8,600,000
Payments to Acquire Businesses, Net of Cash Acquired													95,000,000
Liability for Asbestos and Environmental Claims, Gross													100,000
Intangible assets													33,900,000
Total identifiable assets acquired													95,900,000
Asset Retirement Obligation													800,000
Total liabilities assumed													900,000
Depreciation, Depletion and Amortization			700,000
Subsequent event | Antero
Business Acquisition [Line Items]
Business Combination, Contingent Consideration, Liability, Current																	$40,000,000

Certain_Balance_Sheet_Informat2

Certain Balance Sheet Information (Inventories) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Balance Sheet Related Disclosures [Abstract]
Parts and supplies	$5.90	$4.50
Crude oil	0.9	1.4
Raw materials	0.3	0.4
Finished goods	0.9	0.7
Inventory	$8	$7

Certain_Balance_Sheet_Informat3

Certain Balance Sheet Information (Property Plant and Equipment) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Property, Plant and Equipment [Line Items]
Property, plant and equipment (Note 4)	$3,883.50	$3,565.70
Less: accumulated depreciation and depletion	365.4	215.6
Property, plant and equipment, net	3,518.10	3,350.10
Depreciation	148.3	87.1	40.8
Depletion	0.7	0.4
Capitalized interest	7.5	3.4
Capital lease assets	2.8	5
Sale of long lived assets		11
Gathering systems and pipelines
Property, Plant and Equipment [Line Items]
Property, plant and equipment (Note 4)	1,276.60	1,231.10
Facilities and equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment (Note 4)	1,468.80	1,041
Buildings, land, rights-of-way, storage contracts and easements
Property, Plant and Equipment [Line Items]
Property, plant and equipment (Note 4)	806.4	766.2
Vehicles
Property, Plant and Equipment [Line Items]
Property, plant and equipment (Note 4)	13.6	4.1
Construction in process
Property, Plant and Equipment [Line Items]
Property, plant and equipment (Note 4)	153.7	360.5
Base gas
Property, Plant and Equipment [Line Items]
Property, plant and equipment (Note 4)	37.5	36.3
Salt deposits
Property, Plant and Equipment [Line Items]
Property, plant and equipment (Note 4)	120.5	120.5
Office furniture and fixtures
Property, Plant and Equipment [Line Items]
Property, plant and equipment (Note 4)	6.4	6
Cryogenic plant
Property, Plant and Equipment [Line Items]
Gain (loss) on long-lived assets, net		$4.40

Certain_Balance_Sheet_Informat4

Certain Balance Sheet Information (Intangible Assets) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross	$1,013.20	$1,025.10
Less: accumulated amortization	137	54.3
Total intangible assets, net	876.2	970.8
Amortization And Interest Expense Relating To Intangible Assets	81	43.1	15.9
Customer accounts
Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross	483.2	476.4
Less: accumulated amortization	57	13.4
Covenants not to compete
Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross	5.6	3
Less: accumulated amortization	2.1	0.6
Facilities and equipment
Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross	431.4	451.4
Less: accumulated amortization	47.9	27.9
Acquired storage contracts
Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross	29	29
Less: accumulated amortization	12.7	4
Trademarks
Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross	9.7	11
Less: accumulated amortization	0.9	0.3
Deferred financing costs
Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross	54.3	54.3
Less: accumulated amortization	$16.40	$8.10

Certain_Balance_Sheet_Informat5

Certain Balance Sheet Information (Amortization and Interest Expense, Fiscal Year Maturity) (Details) (USD $)	Dec. 31, 2014
In Millions, unless otherwise specified
Goodwill and Intangible Assets Disclosure [Abstract]
2015	$89.60
2016	76.4
2017	63.5
2018	51.5
2019	$44.60

Certain_Balance_Sheet_Informat6

Certain Balance Sheet Information (Accrued Expenses and Other Liabilities) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Payables and Accruals [Abstract]
Accrued expenses	$23.70	$20
Accrued property taxes	2.1	7.6
Accrued product purchases payable	0.7	1.6
Tax payable	0.4	10.6
Interest payable	22	14.9
Accrued additions to property, plant and equipment	20	58.1
Commitments and contingent liabilities (Note 12)	40	31.4
Capital leases	1.3	2.6
Deferred revenue	11.6	1.6
Other	0.2	0
Total accrued expenses and other liabilities	$122	$148.40

Asset_Retirement_Obligations_D

Asset Retirement Obligations (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Net asset retirement obligation at January 1	$15.10	$14
Liabilities incurred	4.6	0
Acquisitions	1.2	0
Accretion expense	-1.1	-0.8
Changes in estimate	0	0.3
Net asset retirement obligation at December 31	$22	$15.10

Investments_in_Unconsolidated_1

Investments in Unconsolidated Affiliates (Details) (USD $)	0 Months Ended	1 Months Ended	3 Months Ended								12 Months Ended			1 Months Ended	6 Months Ended	0 Months Ended	4 Months Ended	1 Months Ended	0 Months Ended	1 Months Ended
In Millions, unless otherwise specified	Jan. 08, 2013	Feb. 29, 2012	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2014	Dec. 31, 2013	Sep. 04, 2013	Dec. 31, 2013	Jul. 31, 2013	Jul. 19, 2013	Feb. 28, 2015
														mi
Schedule of Equity Method Investments [Line Items]
Equity method investment ownership percentage		35.00%
General Partners' Capital Account, Period Distribution Amount											$41.80	$26.20	$25.80
Consideration Transferred	258
Investment in unconsolidated affiliates in period		131.3									144.4	151.5	0
Loss from unconsolidated affiliates, net			0.6	0.3	-1.5	-0.1	0.3	-0.4	0	0	-0.7	-0.1	0
Investment in unconsolidated affiliates			295.1				151.4				295.1	151.4		295.1	151.4		151.4
Jackalope Gas Gathering Services, LLC
Schedule of Equity Method Investments [Line Items]
Investment in unconsolidated affiliates			232.9				127.2				232.9	127.2		232.9	127.2		127.2
Tres Palacios Holdings LLC
Schedule of Equity Method Investments [Line Items]
Equity method investment ownership percentage			50.01%								50.01%			50.01%
Investment in unconsolidated affiliates in period														132.8
Loss from unconsolidated affiliates, net											0.1
Amortization											0.1
Miles of Pipeline			60								60			60
Diameter Of Pipeline			24								24			24
Number of Pipeline Systems			10								10			10
Investment in unconsolidated affiliates			36								36			36
PRBIC
Schedule of Equity Method Investments [Line Items]
Equity method investment ownership percentage																50.00%
Investment in unconsolidated affiliates			26.2				24.2				26.2	24.2		26.2	24.2		24.2
Crestwood Niobrara LLC | Jackalope Gas Gathering Services, LLC
Schedule of Equity Method Investments [Line Items]
Equity method investment ownership percentage																			50.00%
Investment in unconsolidated affiliates in period											105.2				19.6
CEQP | Tres Palacios Storage Company LLC
Schedule of Equity Method Investments [Line Items]
Equity method investment ownership percentage			100.00%								100.00%			100.00%
CEQP | Tres Palacios Holdings LLC
Schedule of Equity Method Investments [Line Items]
Equity method investment ownership percentage			50.01%								50.01%			50.01%
General Partners' Capital Account, Period Distribution Amount											30.6
Investment in unconsolidated affiliates in period														66
Difference between carrying amount and underlying equity			30.6								30.6			30.6
Investment in unconsolidated affiliates			35.8								35.8			35.8
Brookfield Infrastructure Group | Tres Palacios Holdings LLC
Schedule of Equity Method Investments [Line Items]
Equity method investment ownership percentage			49.99%								49.99%			49.99%
Tres Palacios Storage Company LLC
Schedule of Equity Method Investments [Line Items]
Storage Capacity			38,400,000,000								38,400,000,000			38,400,000,000
Access Midstream Partners, L.P. | Jackalope Gas Gathering Services, LLC
Schedule of Equity Method Investments [Line Items]
Equity method investment ownership percentage																			50.00%
Crude Logistics LLC | PRBIC
Schedule of Equity Method Investments [Line Items]
Investment in unconsolidated affiliates in period											3.4					22.5	1.9
RKI Exploration and Production, LLC's | Jackalope Gas Gathering Services, LLC
Schedule of Equity Method Investments [Line Items]
Loss from unconsolidated affiliates, net											3.6	1.5
Difference between carrying amount and underlying equity			53.7								53.7			53.7
Amortization											-3.1	-1.4
RKI Exploration and Production, LLC's | Crestwood Niobrara LLC
Schedule of Equity Method Investments [Line Items]
Consideration Transferred																		107.5
RKI Exploration and Production, LLC's | Access Midstream Partners, L.P.
Schedule of Equity Method Investments [Line Items]
Commitment Period																			20 years
Majority Shareholder | PRBIC
Schedule of Equity Method Investments [Line Items]
Loss from unconsolidated affiliates, net											-1.4	-0.2
Tres Palacios North Pipeline Lateral | Tres Palacios Holdings LLC
Schedule of Equity Method Investments [Line Items]
Miles of Pipeline			51								51			51
Tres Palacios South Pipeline Lateral | Tres Palacios Holdings LLC
Schedule of Equity Method Investments [Line Items]
Miles of Pipeline			11								11			11
Subsequent event | PRBIC
Schedule of Equity Method Investments [Line Items]
Proceeds from Equity Method Investment, Dividends or Distributions, Return of Capital																				$0.30

Financial_Instruments_Narrativ

Financial Instruments (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Feb. 29, 2012	Nov. 14, 2012	Apr. 30, 2011	Oct. 22, 2013
Debt Instrument [Line Items]
Equity method investment ownership percentage			35.00%
Senior notes	2,008,500,000
Long-term Debt, Gross	2,013,500,000	1,870,800,000
Obligations Under Noncompetition Agreements And Notes To Former Owners Of Businesses Acquired [Member]
Debt Instrument [Line Items]
Senior notes	4,000,000
Debt Instrument, Imputed Interest	5.02%
Debt Instrument, Unamortized Discount	500,000
Crestwood Midstream Revolver
Debt Instrument [Line Items]
Current debt to EBITDA ratio	4.5
Consolidated EBITDA to interest expense ratio	3.99
Crestwood Midstream Revolver | Line of Credit, Excluding Bridge Loans | Minimum
Debt Instrument [Line Items]
Additional margin on variable rate based on leverage ratio	0.75%
Crestwood Midstream Revolver | Line of Credit, Excluding Bridge Loans | Maximum
Debt Instrument [Line Items]
Additional margin on variable rate based on leverage ratio	1.75%
Crestwood Midstream Revolver | Line of Credit, Excluding Bridge Loans | Federal Funds Rate
Debt Instrument [Line Items]
Margin on variable rate	0.50%
Crestwood Midstream Revolver | Line of Credit, Excluding Bridge Loans | Adjusted London Interbank Offered Rate
Debt Instrument [Line Items]
Margin on variable rate	1.00%
Crestwood Midstream Revolver | Line of Credit, Excluding Bridge Loans | London Interbank Offered Rate | Minimum
Debt Instrument [Line Items]
Margin on variable rate	1.75%
Crestwood Midstream Revolver | Line of Credit, Excluding Bridge Loans | London Interbank Offered Rate | Maximum
Debt Instrument [Line Items]
Margin on variable rate	2.75%
Crestwood Midstream Revolver | Revolver
Debt Instrument [Line Items]
Term of debt instrument	5 years
Line of credit, maximum capacity	1,000,000,000
Outstanding balance on the credit facility	555,000,000	414,900,000
Letters of credit outstanding	15,100,000	30,700,000
Remaining borrowing capacity	429,900,000
Weighted average interest rate	2.86%	2.75%
Maximum leverage ratio	5
Maximum leverage ratio, certain periods post acquisition	5.5
Minimum interest coverage ratio	2.5
Crestwood Midstream Revolver | Revolver | Minimum
Debt Instrument [Line Items]
Line of Credit Facility, Interest Rate at Period End	2.66%	2.67%
Unused capacity commitment fee	0.30%
Crestwood Midstream Revolver | Revolver | Maximum
Debt Instrument [Line Items]
Line of Credit Facility, Interest Rate at Period End	4.75%	4.75%
Unused capacity commitment fee	0.50%
Crestwood Midstream Revolver | Standby Letters of Credit
Debt Instrument [Line Items]
Line of credit, maximum capacity	250,000,000
Crestwood Midstream Revolver | Swing Line Loans
Debt Instrument [Line Items]
Line of credit, maximum capacity	25,000,000
Crestwood Midstream Revolver | Swing Line Loans | Alternate Base Rate | Minimum
Debt Instrument [Line Items]
Margin on variable rate	0.75%
Crestwood Midstream Revolver | Swing Line Loans | Alternate Base Rate | Maximum
Debt Instrument [Line Items]
Margin on variable rate	1.75%
2019 Senior Notes | Senior Notes
Debt Instrument [Line Items]
Face amount of debt				-150,000,000	-200,000,000
Interest rate on debt					8.00%
Senior notes	350,000,000	350,000,000
2020 Senior Notes | Senior Notes
Debt Instrument [Line Items]
Interest rate on debt	6.00%
Senior notes	500,000,000	500,000,000
Fair value adjustment of 2020 Senior Notes	4,000,000	4,700,000
2022 Senior Notes | Senior Notes
Debt Instrument [Line Items]
Face amount of debt						600,000,000
Interest rate on debt						6.13%
Senior notes	600,000,000	$600,000,000
Tres Palacios Holdings LLC
Debt Instrument [Line Items]
Equity method investment ownership percentage	50.01%

Financial_Instruments_Schedule

Financial Instruments (Schedule of Carrying Values and Estimated Fair Values of Senior Notes) (Details) (Unsecured Debt, USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Carrying Amount | 2019 senior unsecured notes
Debt Instrument [Line Items]
Fair value of senior notes	$351	$351.20
Carrying Amount | 2020 senior unsecured notes
Debt Instrument [Line Items]
Fair value of senior notes	504	504.7
Carrying Amount | 2022 senior unsecured notes
Debt Instrument [Line Items]
Fair value of senior notes	600	600
Fair Value | 2019 senior unsecured notes
Debt Instrument [Line Items]
Long-term Debt, Fair Value	360.5	379.3
Fair Value | 2020 senior unsecured notes
Debt Instrument [Line Items]
Long-term Debt, Fair Value	481.6	513.8
Fair Value | 2022 senior unsecured notes
Debt Instrument [Line Items]
Long-term Debt, Fair Value	$568.50	$617.30

Financial_Instruments_Debt_Det

Financial Instruments (Debt) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Debt Instrument [Line Items]
Senior notes	$2,008.50
Other	3.5	0
Total debt	2,013.50	1,870.80
Less: current portion	0.7	2.9
Total long-term debt	2,012.80	1,867.90
Senior Notes | 2019 Senior Notes
Debt Instrument [Line Items]
Senior notes	350	350
Premium on senior notes	1	1.2
Senior Notes | 2020 Senior Notes
Debt Instrument [Line Items]
Senior notes	500	500
Fair value adjustment of 2020 Senior Notes	4	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	$555	$414.90

Financial_Instruments_Principa

Financial Instruments (Principal and Interest) (Details) (USD $)	Dec. 31, 2014
In Millions, unless otherwise specified
Long-term Debt, Fiscal Year Maturity [Abstract]
2015	$0.70
2016	0.7
2017	0.7
2018	555.8
2019	350.6
Thereafter	1,100
Total debt	$2,008.50

Earnings_Per_Limited_Partner_U2

Earnings Per Limited Partner Unit (Allocation of Net Income to General and Limited Partners) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Earnings Per Share [Abstract]
Net income (loss) attributable to CMLP	($38.70)	($20)	$38.90
Net income attributable to Class A preferred units	-17.2	0	0
General partner’s incentive distributions	-30.1	-26.4	-14.8
General partner’s interest in net income attributable to CMLP after incentive distributions	0	-0.4	-7.4
Payment to Legacy Crestwood unitholders	0	-34.9	0
Limited partners’ interest in net income (loss) attributable to CMLP after incentive distributions	($86)	($81.70)	$16.70

Earnings_Per_Limited_Partner_U3

Earnings Per Limited Partner Unit (Schedule of Reconciliation of Earnings Per Share) (Details) (USD $)	3 Months Ended								12 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Earnings Per Share [Abstract]
Limited partners’ interest in net income (loss)									($86)	($81.70)	$16.70
Basic (units)									187,942,000	99,183,000	64,656,000
Incremental Common Shares Attributable to Share-based Payment Arrangements									0	0	0
Diluted (units)									187,942,000	99,183,000	64,656,000
Basic, in dollars per unit	($0.43)	$0	$0	($0.03)	($0.50)	$0.02	($0.01)	$0.06	($0.46)	($0.82)	$0.26
Diluted, in dollars per unit	($0.43)	$0	$0	($0.03)	($0.50)	$0.02	($0.01)	$0.06	($0.46)	($0.82)	$0.26

Earnings_Per_Limited_Partner_U4

Earnings Per Limited Partner Unit (Narrative) (Details) (USD $)	12 Months Ended			9 Months Ended
	Dec. 31, 2012	Dec. 31, 2014	Dec. 31, 2013	Jun. 30, 2013
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		9,089,196	1,891,326
Class A Preferred Units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount		7,441,255
Parent
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Percentage of cash distributions entitled to receive from operating surplus		50.00%		50.00%
General Partner
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Incentive Distribution, Distribution Per Unit		0.45
General Partner | Maximum
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Percentage of cash distributions entitled to receive from operating surplus		50.00%
Distribution Rights
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Distribution declared per limited partner unit		0.37		0.37

Income_Taxes_Narrative_Details

Income Taxes Narrative (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Provision for income taxes	$700,000	$700,000	$1,200,000
Deferred Tax Liabilities, Other	$600,000	$0

Partners_Capital_Narrative_Det

Partners' Capital (Narrative) (Details) (USD $)	0 Months Ended				1 Months Ended	3 Months Ended				12 Months Ended			0 Months Ended	3 Months Ended				0 Months Ended			6 Months Ended
	Jul. 18, 2014	Jul. 10, 2014	Jun. 17, 2014	Jan. 08, 2013	Feb. 29, 2012	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Feb. 13, 2015	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2013	Oct. 07, 2013	Nov. 08, 2013	Jan. 30, 2015	Dec. 31, 2013	Jul. 19, 2013
Distribution Made to Limited Partner [Line Items]
Limited Partners' Capital Account, Distribution Amount											$24,900,000	$77,700,000
Net proceeds from issuance of preferred equity of subsidiary										150,000,000	-96,100,000
Distribution Made to Limited Partner, Unit Distribution										387,991
Net proceeds from issuance of Class A preferred units										430,500,000	0	0
Maximum Period For Distribution Of Available Cash										45 days
General Partners' Capital Account, Period Distribution Amount										41,800,000	26,200,000	25,800,000
Per unit rate, in dollars per unit						$0.41	$0.41	$0.41	$0.41
Incentive Distribution, Distribution										30,100,000	26,400,000	14,800,000
Investment in unconsolidated affiliates in period					131,300,000					144,400,000	151,500,000	0
Equity method investment ownership percentage					35.00%
Business Acquisition, Percentage of Voting Interests Acquired					65.00%
Consideration Transferred				258,000,000
Contributions from general partner										0	5,500,000	249,700,000
Contribution from issuance of units	26,299,076	300,000,000	500,000,000							17,529,879
Equity Distribution Agreement Management Fee Percent										2.00%
Partners' Capital Account, Private Placement of Units, Price Per Unit			$25.10							$25.10
Proceeds from Issuance of Preferred Limited Partners Units, Gross										440,000,000
Net Income (Loss) Attributable to Noncontrolling Interest										16,800,000	4,900,000	0
Partners' Capital, Distribution Amount Per Share						$0.58				$0.58
Partners' Capital, Contingent Distribution Amount Per Share						$0.71				$0.71
Partner's Capital, Unpaid Distribution, Accrual Percentage										3.00%
Preferred Units, Class C
Distribution Made to Limited Partner [Line Items]
Distribution Made to Limited Partner, Unit Distribution										183,995	633,084
Preferred Units, Class D
Distribution Made to Limited Partner [Line Items]
Distribution Made to Limited Partner, Unit Distribution				6,190,469						292,660
General Partner
Distribution Made to Limited Partner [Line Items]
Distribution Made to Limited Partner, Unit Distribution				133,060
Subsequent event
Distribution Made to Limited Partner [Line Items]
Distribution Made to Limited Partner, Unit Distribution													414,325
Legacy Crestwood
Distribution Made to Limited Partner [Line Items]
Net proceeds from issuance of Class A preferred units												5,900,000
Partners' Capital Account, Units, Sale of Units												215,722
Per unit rate, in dollars per unit														$0.51	$0.51	$0.51
Crestwood Holdings
Distribution Made to Limited Partner [Line Items]
Investment in unconsolidated affiliates in period					243,800,000
CMLP
Distribution Made to Limited Partner [Line Items]
Business Combination, Equity Interest Issued or Issuable, Conversion Ratio																		1.07
Legacy Inergy
Distribution Made to Limited Partner [Line Items]
Per unit rate, in dollars per unit														$0.40			$0.41
CMLP
Distribution Made to Limited Partner [Line Items]
Cash																		34,900,000
Arrow Midstream Holdings, LLC
Distribution Made to Limited Partner [Line Items]
Incentive Distribution, Distribution																			8,826,125
Cash																			550,000,000
Consideration Transferred																			750,000,000
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares																			8,826,125
Majority Shareholder | Crestwood Holdings
Distribution Made to Limited Partner [Line Items]
Cash																		10,000,000
Jackalope Gas Gathering Services, LLC | Preferred Units
Distribution Made to Limited Partner [Line Items]
Distribution Made to Limited Partner, Unit Distribution										11,419,241	2,161,657
Jackalope Gas Gathering Services, LLC | Subsequent event | Preferred Units
Distribution Made to Limited Partner [Line Items]
Distribution Made to Limited Partner, Unit Distribution																				3,680,570
Jackalope Gas Gathering Services, LLC | Crestwood Niobrara LLC
Distribution Made to Limited Partner [Line Items]
Investment in unconsolidated affiliates in period										105,200,000											19,600,000
Equity method investment ownership percentage																						50.00%
Minimum
Distribution Made to Limited Partner [Line Items]
Per unit rate, in dollars per unit										$0.30
Legacy Crestwood Credit Facility
Distribution Made to Limited Partner [Line Items]
Consideration Transferred				$129,000,000

Partners_Capital_Schedule_of_I

Partners' Capital (Schedule of Issuance of Units) (Details) (USD $)	0 Months Ended
In Millions, except Share data, unless otherwise specified	Oct. 24, 2013	Sep. 13, 2013	Mar. 22, 2013	Jul. 25, 2012	Jan. 13, 2012	Dec. 31, 2014	Dec. 31, 2013	Oct. 30, 2013	Oct. 23, 2013	Oct. 07, 2013	Apr. 30, 2013	Aug. 31, 2012
Distribution Made to Limited Partner [Line Items]
Units						187,965,105	187,243,989
Unit Distribution
Distribution Made to Limited Partner [Line Items]
Units		11,773,191	5,175,000	4,600,000	3,500,000			2,100,000	16,100,000	773,191	675,000	600,000
Per Unit Gross Price		$22.50	$23.90	$26	$30.73
Per Unit Net Price		$21.69	$23	$24.97	$29.50				$21.19
Net Proceeds	$340.30	$255.20	$118.50	$114.40	$103.10

Partners_Capital_Schedule_of_P

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

3 Months Ended

12 Months Ended

0 Months Ended

3 Months Ended

Dec. 31, 2014

Sep. 30, 2014

Jun. 30, 2014

Mar. 31, 2014

Dec. 31, 2014

Dec. 31, 2013

Dec. 31, 2012

Feb. 13, 2015

Sep. 30, 2013

Jun. 30, 2013

Mar. 31, 2013

Dec. 31, 2013

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

Distribution Made to Limited Partner, Distributions Paid, Per Unit

$0.41

$0.41

$0.41

$0.41

Distribution Made to Limited Partner, Cash Distributions Paid

$74,100,000

$74,100,000

$74,200,000

$74,100,000

$296,500,000

$204,500,000

$77,700,000

Distribution Made to Limited Partner, Date of Record

7-Nov-14

7-Aug-14

8-May-14

7-Feb-14

Distribution Made to Limited Partner, Distribution Date

14-Nov-14

14-Aug-14

15-May-14

14-Feb-14

Incentive Distribution, Distribution

30,100,000

26,400,000

14,800,000

Dividend Paid | Cash distribution | Subsequent event

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

Distribution declared per limited partner unit

$0.41

Legacy Crestwood

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

Distribution Made to Limited Partner, Distributions Paid, Per Unit

$0.51

$0.51

$0.51

Distribution Made to Limited Partner, Cash Distributions Paid

27,400,000

27,400,000

21,000,000

Distribution Made to Limited Partner, Date of Record

1-Aug-13

30-Apr-13

31-Jan-13

Distribution Made to Limited Partner, Distribution Date

9-Aug-13

10-May-13

12-Feb-13

Legacy Inergy

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

Distribution Made to Limited Partner, Distributions Paid, Per Unit

$0.40

$0.41

Distribution Made to Limited Partner, Cash Distributions Paid

$179,600,000

$34,300,000

$69,500,000

Distribution Made to Limited Partner, Date of Record

7-Aug-13

7-Nov-13

Distribution Made to Limited Partner, Distribution Date

14-Aug-13

14-Nov-13

Equity_Plans_Narrative_Details

Equity Plans (Narrative) (Details) (USD $)	12 Months Ended			1 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jan. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	$18.10	$15.80	$1.90
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent	10.00%
Employer Matching Contribution, Percent of Match	10.00%
Defined Contribution Plan, Maximum Purchasable Units	200,000
Phantom and Restricted Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense		6.5	1.9
Grants of units, estimated grant date fair value		4.6	4.7
Crestwood Long-Term Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	11.2	11.4
Common units to satisfy employee tax withholding obligations	71,484	21,014
Crestwood Long-Term Incentive Plan | Restricted units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation Cost Not yet Recognized	9.5	1.8
Grants of units, estimated grant date fair value	20.3
Common Stock, Capital Shares Reserved for Future Issuance	17,629,657
CMLP | Crestwood Long-Term Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unit-based compensation charges	$6.90	$4.40
Subsequent event
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unit Purchase Plan, Shares Purchased Under Plan				2,011

Equity_Plans_Schedule_of_Phant

Equity Plans (Schedule of Phantom and Restricted Unit Activity) (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2014	Dec. 31, 2012
Payable In Cash | Phantom and Restricted Units
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Unvested units - December 31, units			8,312
Unvested units - December 31			$26.45
Unvested units - December 31, units	0		8,312
Unvested units - December 31	$0		$26.45
Payable In Cash | Phantom Unit
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Vested, units	-7,958
Vested	$26.48
Granted, units	0
Granted	$0
Canceled, units	-354
Canceled	$25.81
Payable In Cash | Restricted units
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Vested, units	0
Vested	$0
Granted, units	0
Granted	$0
Payable In Units | Phantom and Restricted Units
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Unvested units - December 31, units			221,992
Unvested units - December 31			$28.35
Unvested units - December 31, units	0		221,992
Unvested units - December 31	$0		$28.35
Payable In Units | Phantom Unit
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Vested, units	-329,825
Vested	$26.69
Granted, units	161,807
Granted	$24.33
Canceled, units	-7,114
Canceled	$27.96
Payable In Units | Restricted units
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Vested, units	-74,760
Vested	$25.60
Granted, units	27,900
Granted	$24.86
Crestwood Long-Term Incentive Plan | Restricted units
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Unvested units - December 31, units		250,557
Unvested units - December 31		$22.13
Vested, units		-208,361
Vested		$22.15
Granted, units		871,078
Granted		$23.25
Canceled, units		-78,478
Canceled		$23.33
Unvested units - December 31, units		834,796
Unvested units - December 31		$23.18

Commitments_and_Contingencies_1

Commitments and Contingencies (Details) (USD $)	12 Months Ended			1 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Mar. 31, 2014	Nov. 08, 2013
				defendant	bbl
					people
Schedule Of Commitments And Contingencies [Line Items]
Loss contingency accrual, less than	$0.10	$0.10
Rent expense	8.7	7.6	7.4
Amortization of capital leases	2.9	3.6	3.1
Noncurrent capital lease obligations	2.8	4.7
Purchase commitments expected to occur over next twelve months	20
Other current liabilities	122.7	151.3
Accrual for environmental loss contingencies	1.1
Antero
Schedule Of Commitments And Contingencies [Line Items]
Contingent consideration	-40	-31.4
Arrow Acquisition Class Action Lawsuit
Schedule Of Commitments And Contingencies [Line Items]
Barrels of oil equivalents spilled					50,000
Loss of life, number					47
Number of defendants				53
Escrow deposit on common units	3,309,797
Number of pending claims	3
Other Growth and Maintenance Contractual Purchase Obligations
Schedule Of Commitments And Contingencies [Line Items]
Remaining amount of purchase commitments	9.8
Fort Berthold Indian Reservation
Schedule Of Commitments And Contingencies [Line Items]
Number of releases of produced water	3
Releases of produced water, sites	28,000
Operations and maintenance expense	4.6
Other current liabilities	1.1
Minimum
Schedule Of Commitments And Contingencies [Line Items]
Accrual for environmental loss contingencies	1.1
Maximum
Schedule Of Commitments And Contingencies [Line Items]
Accrual for environmental loss contingencies	$1.50

Commitments_and_Contingencies_2

Commitments and Contingencies (Schedule of Future Minimum Annual Rental Commitments) (Details) (USD $)	Dec. 31, 2014
In Millions, unless otherwise specified
Commitments and Contingencies Disclosure [Abstract]
2015	$6.60
2016	5.9
2017	5.3
2018	4.8
2019	4.6
Thereafter	16.3
Total minimum lease payments	$43.50

Commitments_and_Contingencies_3

Commitments and Contingencies (Schedule of Future Minimum Lease Payments) (Details) (USD $)	Dec. 31, 2014
In Millions, unless otherwise specified
Commitments and Contingencies Disclosure [Abstract]
2015	$1.40
2016	0.8
2017	0.5
2018	0.2
Total payments	2.9
Imputed interest	-0.1
Present value of future payments	$2.80

Related_Party_Transactions_Det

Related Party Transactions (Details) (USD $)	12 Months Ended			0 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Oct. 07, 2013
Disclosure Related Party Transaction Additional Information [Abstract]
Gathering and processing revenues	$17.60	$82.10	$113.70
Related Party Transaction, Due from (to) Related Party [Abstract]
Accounts receivable	0.3	1.1
Accounts payable	6.3	8.7
CEQP | Crestwood Holdings
Related Party Transaction, Due from (to) Related Party [Abstract]
Shares issued by acquiree				14,300,000
CEQP
Disclosure Related Party Transaction Additional Information [Abstract]
Gathering and processing revenues	4	74.9	113.7
NGL and crude services	13.6	7.2	0
Gathering and processing costs of product/services sold(2)	42.2	32.5	15.2
General and administrative expenses(3)	63.6	34.7	19.5
Affiliates
Related Party Transaction, Due from (to) Related Party [Abstract]
Accounts receivable	0.3	1.1
Accounts payable	$6.30	$8.70
Majority Shareholder | Crestwood Holdings
Related Party Transaction, Due from (to) Related Party [Abstract]
Shares exchanged by acquirer				7,100,000

Segments_Narrative_Details

Segments (Narrative) (Details) (USD $)	3 Months Ended								12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
									segment
Revenue, Major Customer [Line Items]
Number of operating segments									3
Revenues	$614.40	$738.40	$675.70	$537	$366	$140.10	$80.10	$72.40	2,565.50	$658.60	$239.50
Concentration Risk, Percentage									10.00%	10.00%	10.00%
Tesoro Corporation
Revenue, Major Customer [Line Items]
Revenues									401.1
QEP Midstream Partners, LP
Revenue, Major Customer [Line Items]
Revenues									285.1
Eighty-Eight Oil LLC
Revenue, Major Customer [Line Items]
Revenues									286.9
Quicksilver Resources Inc
Revenue, Major Customer [Line Items]
Revenues										96.3	112.6
Antero
Revenue, Major Customer [Line Items]
Revenues											$25.50

Segments_Reconciliation_of_Net

Segments (Reconciliation of Net Income to EBITDA) (Details) (USD $)	3 Months Ended								12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting [Abstract]
Net income (loss)	($60.40)	$21.30	$11.70	$5.50	($42.30)	$11.60	$6.70	$8.90	($21.90)	($15.10)	$38.90
Interest and debt expense, net									111.4	71.4	35.8
Provision for income taxes									0.7	0.7	1.2
Depreciation, Amortization and Accretion, Net									221.7	121.7	51.9
EBITDA									$311.90	$178.70	$127.80

Segments_Schedule_of_Reportabl

Segments (Schedule of Reportable Segment Data) (Details) (USD $)	3 Months Ended								12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting Information [Line Items]
Revenues	$614.40	$738.40	$675.70	$537	$366	$140.10	$80.10	$72.40	$2,565.50	$658.60	$239.50
Costs of product/services sold									1,937.50	295.7	39
Operations and maintenance									139	73.3	43.1
Operations and maintenance expense									85.4	80.7	29.6
Gain (Loss) on Disposition of Assets and Impairments									-33.6	5.4	0
Goodwill impairment									-48.8	-4.1	0
Loss on contingent consideration (Note 12)									-8.6	-31.4	0
Loss from unconsolidated affiliates, net	0.6	0.3	-1.5	-0.1	0.3	-0.4	0	0	-0.7	-0.1	0
EBITDA									311.9	178.7	127.8
Goodwill	1,632.60				1,682.80				1,632.60	1,682.80	95
Total assets	6,596.50				6,401.80				6,596.50	6,401.80	1,610.60
Purchases of property, plant and equipment									407	334.6	52.6
Gathering and Processing
Segment Reporting Information [Line Items]
Revenues									332.5	291.2	239.5
Costs of product/services sold									71.3	56.6	39
Operations and maintenance									62.9	54.9	43.1
Operations and maintenance expense									0	0	0
Gain (Loss) on Disposition of Assets and Impairments									-32.7	5.4
Goodwill impairment									-18.5	-4.1
Loss on contingent consideration (Note 12)									-8.6	-31.4
Loss from unconsolidated affiliates, net									0.5	0.1
EBITDA									139	149.7	157.4
Goodwill	81.1				99.6				81.1	99.6	95
Total assets	1,993				1,836.40				1,993	1,836.40	1,587.90
Purchases of property, plant and equipment									245.7	271.2	51.5
Storage and Transportation
Segment Reporting Information [Line Items]
Revenues									179.1	90.1	0
Costs of product/services sold									14.3	8.7	0
Operations and maintenance									16.6	9.9	0
Operations and maintenance expense									0	0	0
Gain (Loss) on Disposition of Assets and Impairments									0.6	0
Goodwill impairment									0	0
Loss on contingent consideration (Note 12)									0	0
Loss from unconsolidated affiliates, net									0.2	0
EBITDA									149	71.5	0
Goodwill					936.5					936.5	0
Total assets	1,981.20				2,190.50				1,981.20	2,190.50	0
Purchases of property, plant and equipment									9.1	10.3	0
NGL and Crude Services
Segment Reporting Information [Line Items]
Revenues									2,053.90	277.3	0
Costs of product/services sold									1,851.90	230.4	0
Operations and maintenance									59.5	8.5	0
Operations and maintenance expense									0	0	0
Gain (Loss) on Disposition of Assets and Impairments									-1.5	0
Goodwill impairment									-30.3	0
Loss on contingent consideration (Note 12)									0	0
Loss from unconsolidated affiliates, net									-1.4	-0.2
EBITDA									109.3	38.2	0
Goodwill	825.2				646.7				825.2	646.7	0
Total assets	2,455.50				2,217.30				2,455.50	2,217.30	0
Purchases of property, plant and equipment									147.8	52.1	0
Corporate
Segment Reporting Information [Line Items]
Revenues									0	0	0
Costs of product/services sold									0	0	0
Operations and maintenance									0	0	0
Operations and maintenance expense									85.4	80.7	29.6
Gain (Loss) on Disposition of Assets and Impairments									0	0
Goodwill impairment									0	0
Loss on contingent consideration (Note 12)									0	0
Loss from unconsolidated affiliates, net									0	0
EBITDA									-85.4	-80.7	-29.6
Goodwill	0				0				0	0	0
Total assets	166.8				157.6				166.8	157.6	22.7
Purchases of property, plant and equipment									$4.40	$1	$1.10

Condensed_Consolidating_Financ2

Condensed Consolidating Financial Information (Balance Sheet Adjustments to Prior Periods) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Condensed Financial Statements, Captions [Line Items]
Other Receivables	$241.50	$204
Accounts receivable	241.8	205.1
Accounts receivable	0.3	1.1
Total current assets	273.1	225
Goodwill and intangible assets, net	2,508.80	2,653.60
Investment in consolidated affiliates	0	0
Assets	6,596.50	6,401.80	1,610.60
Accounts payable	126.1	154.5
Accounts payable - related party (Note 13)	6.3	8.7
Accounts payable	132.4	163.2
Other current liabilities	122.7	151.3
Total current liabilities	255.1	314.5
Partners' capital	4,125.70	4,092.10
Total partners’ capital	4,297.40	4,193.10
Total liabilities and partners’ capital	6,596.50	6,401.80
Parent
Condensed Financial Statements, Captions [Line Items]
Other Receivables	1.2	4.4
Accounts receivable	1.2	5.5
Accounts receivable	0	1.1
Total current assets	1.2	5.6
Goodwill and intangible assets, net	38	46.2
Investment in consolidated affiliates	6,296.70	6,053
Assets	6,343.80	6,109.60
Accounts payable	4.8	15.1
Accounts payable - related party (Note 13)	4.2	5.4
Accounts payable	9	20.5
Other current liabilities	23	26.4
Total current liabilities	32	46.9
Partners' capital	4,125.70	4,092.10
Total partners’ capital	4,297.40	4,193.10
Total liabilities and partners’ capital	6,343.80	6,109.60
Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Other Receivables	240.3	199.4
Accounts receivable	240.3	199.4
Accounts receivable	0	0
Total current assets	271.6	218.2
Goodwill and intangible assets, net	2,470.80	2,607.40
Investment in consolidated affiliates	0	0
Assets	6,254	6,192.60
Accounts payable	121.3	139.4
Accounts payable - related party (Note 13)	1.9	3.3
Accounts payable	123.2	142.7
Other current liabilities	99.7	124.7
Total current liabilities	222.9	267.4
Partners' capital	6,001.50	5,900.60
Total partners’ capital	6,001.50	5,900.60
Total liabilities and partners’ capital	6,254	6,192.60
Consolidation, Eliminations
Condensed Financial Statements, Captions [Line Items]
Other Receivables	0	0
Accounts receivable	0	0
Accounts receivable	0	0
Total current assets	0	0
Goodwill and intangible assets, net	0	0
Investment in consolidated affiliates	-6,296.70	-6,053
Assets	-6,296.70	-6,053
Accounts payable	0	0
Accounts payable - related party (Note 13)	0	0
Accounts payable	0	0
Other current liabilities	0	0
Total current liabilities	0	0
Partners' capital	-6,125	-5,952
Total partners’ capital	-6,296.70	-6,053
Total liabilities and partners’ capital	-6,296.70	-6,053
As Previously Reported | Parent
Condensed Financial Statements, Captions [Line Items]
Other Receivables		466.8
Accounts receivable		466.8
Accounts receivable		0
Total current assets		466.9
Goodwill and intangible assets, net		0
Investment in consolidated affiliates		6,385.20
Assets		6,856.90
Accounts payable		782.7
Accounts payable - related party (Note 13)		0
Accounts payable		782.7
Other current liabilities		11.5
Total current liabilities		794.2
Partners' capital		4,092.10
Total partners’ capital		4,193.10
Total liabilities and partners’ capital		6,856.90
As Previously Reported | Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Other Receivables		197.8
Accounts receivable		197.8
Accounts receivable		0
Total current assets		216.6
Goodwill and intangible assets, net		2,653.60
Investment in consolidated affiliates		0
Assets		6,237.20
Accounts payable		-165.2
Accounts payable - related party (Note 13)		0
Accounts payable		-165.2
Other current liabilities		145
Total current liabilities		-20.2
Partners' capital		6,232.80
Total partners’ capital		6,232.80
Total liabilities and partners’ capital		6,237.20
As Previously Reported | Consolidation, Eliminations
Condensed Financial Statements, Captions [Line Items]
Other Receivables		-459.7
Accounts receivable		-459.7
Accounts receivable		0
Total current assets		-459.7
Goodwill and intangible assets, net		0
Investment in consolidated affiliates		-6,385.20
Assets		-6,844.90
Accounts payable		-459.7
Accounts payable - related party (Note 13)		0
Accounts payable		-459.7
Other current liabilities		0
Total current liabilities		-459.7
Partners' capital		-6,284.20
Total partners’ capital		-6,385.20
Total liabilities and partners’ capital		($6,844.90)

Condensed_Consolidating_Financ3

Condensed Consolidating Financial Information (Cash Flow Adjustments to Prior Periods) (Details) (USD $)	1 Months Ended	12 Months Ended
In Millions, unless otherwise specified	Feb. 29, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Condensed Financial Statements, Captions [Line Items]
Net cash provided by operating activities		$322.90	$186.50	$102.10
Investment in unconsolidated affiliates	-131.3	-144.4	-151.5	0
Capital contribution from consolidated affiliates		0	0
Net cash used in investing activities		-570.9	-1,036.50	-616.6
Proceeds from the issuance of long-term debt		2,089.90	2,072.80	706.7
Principal payments on long-term debt		1,949.80	1,634.30	534
Payments for debt-related deferred costs		0.1	32	11.4
Distributions paid		368.9	359.7
Contributions from parent		0	5.5
Net proceeds from issuance of common units		0	714	217.5
Increase (Decrease) in Accounts Payable, Related Parties		0	0
Net Cash Provided by (Used in) Financing Activities		249.9	852.6	513.8
Parent
Condensed Financial Statements, Captions [Line Items]
Net cash provided by operating activities		-165.6	-46.1
Investment in unconsolidated affiliates		0	0
Capital contribution from consolidated affiliates		-89.5	-106.4
Other			0
Net cash used in investing activities		-93.8	-107.4
Proceeds from the issuance of long-term debt		2,089.90	1,930.90
Principal payments on long-term debt		1,949.80	1,559.30
Payments for debt-related deferred costs		0.1	32
Distributions paid		368.9	359.7
Contributions from parent		0	0
Net proceeds from issuance of common units			714
Increase (Decrease) in Accounts Payable, Related Parties		59.8	-539.9
Net Cash Provided by (Used in) Financing Activities		259.3	153.6
Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Net cash provided by operating activities		488.5	266.4
Investment in unconsolidated affiliates		0	0
Capital contribution from consolidated affiliates		0	0
Other			11.1
Net cash used in investing activities		-422.2	-884
Proceeds from the issuance of long-term debt		0	141.9
Principal payments on long-term debt		0	75
Payments for debt-related deferred costs		0	0
Distributions paid		0	33.8
Contributions from parent		0	55.5
Net proceeds from issuance of common units			0
Increase (Decrease) in Accounts Payable, Related Parties		-59.8	539.9
Net Cash Provided by (Used in) Financing Activities		-63.3	619.1
Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Net cash provided by operating activities		0	0
Investment in unconsolidated affiliates		-144.4	-151.5
Capital contribution from consolidated affiliates		0	0
Other			0
Net cash used in investing activities		-144.4	-151.5
Proceeds from the issuance of long-term debt		0	0
Principal payments on long-term debt		0	0
Payments for debt-related deferred costs		0	0
Distributions paid		0	0
Contributions from parent		89.5	56.4
Net proceeds from issuance of common units			0
Increase (Decrease) in Accounts Payable, Related Parties		0	0
Net Cash Provided by (Used in) Financing Activities		143.4	152.5
Consolidation, Eliminations
Condensed Financial Statements, Captions [Line Items]
Net cash provided by operating activities		0	-33.8
Investment in unconsolidated affiliates		0	0
Capital contribution from consolidated affiliates		89.5	106.4
Other			0
Net cash used in investing activities		89.5	106.4
Proceeds from the issuance of long-term debt		0	0
Principal payments on long-term debt		0	0
Payments for debt-related deferred costs		0	0
Distributions paid		0	-33.8
Contributions from parent		-89.5	-106.4
Net proceeds from issuance of common units			0
Increase (Decrease) in Accounts Payable, Related Parties		0	0
Net Cash Provided by (Used in) Financing Activities		-89.5	-72.6
As Previously Reported | Parent
Condensed Financial Statements, Captions [Line Items]
Net cash provided by operating activities			3.9
Investment in unconsolidated affiliates			0
Capital contribution from consolidated affiliates			-82
Other			-0.4
Net cash used in investing activities			-83.4
Proceeds from the issuance of long-term debt			382.9
Principal payments on long-term debt			202
Payments for debt-related deferred costs			0.1
Distributions paid			219.3
Contributions from parent			0
Net proceeds from issuance of common units			118.5
Increase (Decrease) in Accounts Payable, Related Parties			0
Net Cash Provided by (Used in) Financing Activities			79.6
As Previously Reported | Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Net cash provided by operating activities			216.4
Investment in unconsolidated affiliates			-24.4
Capital contribution from consolidated affiliates			0
Other			11.1
Net cash used in investing activities			-908.4
Proceeds from the issuance of long-term debt			1,689.90
Principal payments on long-term debt			1,432.30
Payments for debt-related deferred costs			31.9
Distributions paid			174.2
Contributions from parent			55.5
Net proceeds from issuance of common units			595.5
Increase (Decrease) in Accounts Payable, Related Parties			0.4
Net Cash Provided by (Used in) Financing Activities			693.5
As Previously Reported | Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Net cash provided by operating activities			0
Investment in unconsolidated affiliates			-127.1
Capital contribution from consolidated affiliates			0
Other			0
Net cash used in investing activities			-127.1
Proceeds from the issuance of long-term debt			0
Principal payments on long-term debt			0
Payments for debt-related deferred costs			0
Distributions paid			0
Contributions from parent			32
Net proceeds from issuance of common units			0
Increase (Decrease) in Accounts Payable, Related Parties			0
Net Cash Provided by (Used in) Financing Activities			128.1
As Previously Reported | Consolidation, Eliminations
Condensed Financial Statements, Captions [Line Items]
Net cash provided by operating activities			-33.8
Investment in unconsolidated affiliates			0
Capital contribution from consolidated affiliates			82
Other			0.4
Net cash used in investing activities			82.4
Proceeds from the issuance of long-term debt			0
Principal payments on long-term debt			0
Payments for debt-related deferred costs			0
Distributions paid			-33.8
Contributions from parent			-82
Net proceeds from issuance of common units			0
Increase (Decrease) in Accounts Payable, Related Parties			-0.4
Net Cash Provided by (Used in) Financing Activities			($48.60)

Condensed_Consolidating_Financ4

Condensed Consolidating Financial Information (Condensed Consolidating Balance Sheet) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Condensed Financial Statements, Captions [Line Items]
Cash	$4.60	$2.70	$0.10	$0.80
Other Receivables	241.5	204
Accounts receivable	0.3	1.1
Accounts receivable	241.8	205.1
Inventory	8	7
Prepaid expenses and other current assets	18.7	10.2
Total current assets	273.1	225
Property, plant and equipment, net	3,518.10	3,350.10
Goodwill and intangible assets, net	2,508.80	2,653.60
Investment in consolidated affiliates	0	0
Investment in unconsolidated affiliates	295.1	151.4
Other assets	1.4	21.7
Total assets	6,596.50	6,401.80	1,610.60
Accounts payable	126.1	154.5
Accounts payable - related party (Note 13)	6.3	8.7
Loss on contingent consideration	-8.6	-31.4	0
Accounts payable	132.4	163.2
Other current liabilities	122.7	151.3
Total current liabilities	255.1	314.5
Long-term debt, less current portion	2,012.80	1,867.90
Other long-term liabilities	31.2	26.3
Total long-term liabilities	2,044	1,894.20
Partners' capital	4,125.70	4,092.10
Interest of non-controlling partners in subsidiary	171.7	101
Total partners’ capital	4,297.40	4,193.10
Total liabilities and partners’ capital	6,596.50	6,401.80
Parent
Condensed Financial Statements, Captions [Line Items]
Cash	0	0.1	0
Other Receivables	1.2	4.4
Accounts receivable	0	1.1
Accounts receivable	1.2	5.5
Inventory	0	0
Prepaid expenses and other current assets	0	0
Total current assets	1.2	5.6
Property, plant and equipment, net	7.9	4.8
Goodwill and intangible assets, net	38	46.2
Investment in consolidated affiliates	6,296.70	6,053
Investment in unconsolidated affiliates	0	0
Other assets	0	0
Total assets	6,343.80	6,109.60
Accounts payable	4.8	15.1
Accounts payable - related party (Note 13)	4.2	5.4
Loss on contingent consideration	0	0
Accounts payable	9	20.5
Other current liabilities	23	26.4
Total current liabilities	32	46.9
Long-term debt, less current portion	2,012.80	1,867.90
Other long-term liabilities	1.6	1.7
Total long-term liabilities	2,014.40	1,869.60
Partners' capital	4,125.70	4,092.10
Interest of non-controlling partners in subsidiary	171.7	101
Total partners’ capital	4,297.40	4,193.10
Total liabilities and partners’ capital	6,343.80	6,109.60
Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Cash	4.6	1.6	0.1
Other Receivables	240.3	199.4
Accounts receivable	0	0
Accounts receivable	240.3	199.4
Inventory	8	7
Prepaid expenses and other current assets	18.7	10.2
Total current assets	271.6	218.2
Property, plant and equipment, net	3,510.20	3,345.30
Goodwill and intangible assets, net	2,470.80	2,607.40
Investment in consolidated affiliates	0	0
Investment in unconsolidated affiliates	0	0
Other assets	1.4	21.7
Total assets	6,254	6,192.60
Accounts payable	121.3	139.4
Accounts payable - related party (Note 13)	1.9	3.3
Loss on contingent consideration	-8.6	-31.4
Accounts payable	123.2	142.7
Other current liabilities	99.7	124.7
Total current liabilities	222.9	267.4
Long-term debt, less current portion	0	0
Other long-term liabilities	29.6	24.6
Total long-term liabilities	29.6	24.6
Partners' capital	6,001.50	5,900.60
Interest of non-controlling partners in subsidiary	0	0
Total partners’ capital	6,001.50	5,900.60
Total liabilities and partners’ capital	6,254	6,192.60
Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Cash	0	1	0
Other Receivables	0	0.2
Accounts receivable	0.3	0
Accounts receivable	0.3	0.2
Inventory	0	0
Prepaid expenses and other current assets	0	0
Total current assets	0.3	1.2
Property, plant and equipment, net	0	0
Goodwill and intangible assets, net	0	0
Investment in consolidated affiliates	0	0
Investment in unconsolidated affiliates	295.1	151.4
Other assets	0	0
Total assets	295.4	152.6
Accounts payable	0	0
Accounts payable - related party (Note 13)	0.2	0
Loss on contingent consideration	0	0
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	123.5	51.4
Interest of non-controlling partners in subsidiary	171.7	101
Total partners’ capital	295.2	152.4
Total liabilities and partners’ capital	295.4	152.6
Consolidation, Eliminations
Condensed Financial Statements, Captions [Line Items]
Cash	0	0	0
Other Receivables	0	0
Accounts receivable	0	0
Accounts receivable	0	0
Inventory	0	0
Prepaid expenses and other current assets	0	0
Total current assets	0	0
Property, plant and equipment, net	0	0
Goodwill and intangible assets, net	0	0
Investment in consolidated affiliates	-6,296.70	-6,053
Investment in unconsolidated affiliates	0	0
Other assets	0	0
Total assets	-6,296.70	-6,053
Accounts payable	0	0
Accounts payable - related party (Note 13)	0	0
Loss on contingent consideration	0	0
Accounts payable	0	0
Other current liabilities	0	0
Total current liabilities	0	0
Long-term debt, less current portion	0	0
Other long-term liabilities	0	0
Total long-term liabilities	0	0
Partners' capital	-6,125	-5,952
Interest of non-controlling partners in subsidiary	-171.7	-101
Total partners’ capital	-6,296.70	-6,053
Total liabilities and partners’ capital	-6,296.70	-6,053
As Previously Reported | Parent
Condensed Financial Statements, Captions [Line Items]
Other Receivables		466.8
Accounts receivable		0
Accounts receivable		466.8
Total current assets		466.9
Goodwill and intangible assets, net		0
Investment in consolidated affiliates		6,385.20
Total assets		6,856.90
Accounts payable		782.7
Accounts payable - related party (Note 13)		0
Accounts payable		782.7
Other current liabilities		11.5
Total current liabilities		794.2
Partners' capital		4,092.10
Total partners’ capital		4,193.10
Total liabilities and partners’ capital		6,856.90
As Previously Reported | Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Other Receivables		197.8
Accounts receivable		0
Accounts receivable		197.8
Total current assets		216.6
Goodwill and intangible assets, net		2,653.60
Investment in consolidated affiliates		0
Total assets		6,237.20
Accounts payable		-165.2
Accounts payable - related party (Note 13)		0
Accounts payable		-165.2
Other current liabilities		145
Total current liabilities		-20.2
Partners' capital		6,232.80
Total partners’ capital		6,232.80
Total liabilities and partners’ capital		6,237.20
As Previously Reported | Consolidation, Eliminations
Condensed Financial Statements, Captions [Line Items]
Other Receivables		-459.7
Accounts receivable		0
Accounts receivable		-459.7
Total current assets		-459.7
Goodwill and intangible assets, net		0
Investment in consolidated affiliates		-6,385.20
Total assets		-6,844.90
Accounts payable		-459.7
Accounts payable - related party (Note 13)		0
Accounts payable		-459.7
Other current liabilities		0
Total current liabilities		-459.7
Partners' capital		-6,284.20
Total partners’ capital		-6,385.20
Total liabilities and partners’ capital		($6,844.90)

Condensed_Consolidating_Financ5

Condensed Consolidating Financial Information (Condensed Consolidating Statement of Operations) (Details) (USD $)	3 Months Ended								12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Condensed Financial Statements, Captions [Line Items]
Gathering and processing									$328.50	$216.30	$125.80
Storage and transportation									179.1	90.1	0
NGL and crude services									2,040.30	270.1	0
Related party (Note 13)									17.6	82.1	113.7
Revenues	614.4	738.4	675.7	537	366	140.1	80.1	72.4	2,565.50	658.6	239.5
Gathering and processing									29.1	24.1	23.8
Storage and transportation									14.3	8.7	0
NGL and crude services									1,851.90	230.4	0
Related party									42.2	32.5	15.2
Cost of Revenue									1,937.50	295.7	39
Operations and maintenance									139	73.3	43.1
Operations and maintenance									446.1	275.7	124.6
General and administrative (Note 13)									85.4	80.7	29.6
Depreciation, amortization and accretion									221.7	121.7	51.9
Costs and Expenses, Total									446.1	275.7
Gain (Loss) on Disposition of Assets and Impairments									-33.6	5.4	0
Goodwill impairment									-48.8	-4.1	0
Loss on contingent consideration									-8.6	-31.4	0
Operating income	-34.5	48.7	42.3	34.4	-14.9	31.8	19.5	20.7	90.9	57.1	75.9
Loss from unconsolidated affiliates, net	0.6	0.3	-1.5	-0.1	0.3	-0.4	0	0	-0.7	-0.1	0
Interest and debt expense, net									-111.4	-71.4	-35.8
Equity in net income (loss) of subsidiary									0	0
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest									-21.2	-14.4	40.1
Provision for income taxes									0.7	0.7	1.2
Net income (loss)	-60.4	21.3	11.7	5.5	-42.3	11.6	6.7	8.9	-21.9	-15.1	38.9
Net (income) loss attributable to non-controlling partners									-16.8	-4.9	0
Net income (loss) attributable to CMLP									-38.7	-20	38.9
Net income attributable to Class A preferred units									-17.2	0	0
Net Income (Loss), Partners Interest in Net Income	-72.9	7.7	6.9	2.4	-45.3	9.7	6.7	8.9	-55.9	-20	38.9
Parent
Condensed Financial Statements, Captions [Line Items]
Gathering and processing									0	0
Storage and transportation									0	0
NGL and crude services									0	0
Related party (Note 13)									0	0
Revenues									0	0
Gathering and processing									0	0
Storage and transportation									0	0
NGL and crude services									0	0
Related party									0	0
Cost of Revenue									0	0
Operations and maintenance									0	0
General and administrative (Note 13)									49.4	46.5
Depreciation, amortization and accretion									0.9	1
Costs and Expenses, Total									50.3	47.5
Gain (Loss) on Disposition of Assets and Impairments									0	0
Goodwill impairment									0	0
Loss on contingent consideration									0	0
Operating income									-50.3	-47.5
Loss from unconsolidated affiliates, net									0	0
Interest and debt expense, net									-111.4	-68.7
Equity in net income (loss) of subsidiary									139.8	101.1
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest									-21.9	-15.1
Provision for income taxes									0	0
Net income (loss)									-21.9	-15.1
Net (income) loss attributable to non-controlling partners									0	0
Net income (loss) attributable to CMLP									-21.9	-15.1
Net income attributable to Class A preferred units									-17.2
Net Income (Loss), Partners Interest in Net Income									-39.1
Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Gathering and processing									328.5	216.3
Storage and transportation									179.1	90.1
NGL and crude services									2,040.30	270.1
Related party (Note 13)									17.6	82.1
Revenues									2,565.50	658.6
Gathering and processing									29.1	24.1
Storage and transportation									14.3	8.7
NGL and crude services									1,851.90	230.4
Related party									42.2	32.5
Cost of Revenue									1,937.50	295.7
Operations and maintenance									139	73.3
General and administrative (Note 13)									36	34.2
Depreciation, amortization and accretion									220.8	120.7
Costs and Expenses, Total									395.8	228.2
Gain (Loss) on Disposition of Assets and Impairments									-33.6	5.4
Goodwill impairment									-48.8	-4.1
Loss on contingent consideration									-8.6	-31.4
Operating income									141.2	104.6
Loss from unconsolidated affiliates, net									0	0
Interest and debt expense, net									0	-2.7
Equity in net income (loss) of subsidiary									0	0
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest									141.2	101.9
Provision for income taxes									0.7	0.7
Net income (loss)									140.5	101.2
Net (income) loss attributable to non-controlling partners									0	0
Net income (loss) attributable to CMLP									140.5	101.2
Net income attributable to Class A preferred units									0
Net Income (Loss), Partners Interest in Net Income									140.5
Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Gathering and processing									0	0
Storage and transportation									0	0
NGL and crude services									0	0
Related party (Note 13)									0	0
Revenues									0	0
Gathering and processing									0	0
Storage and transportation									0	0
NGL and crude services									0	0
Related party									0	0
Cost of Revenue									0	0
Operations and maintenance									0	0
General and administrative (Note 13)									0	0
Depreciation, amortization and accretion									0	0
Costs and Expenses, Total									0	0
Gain (Loss) on Disposition of Assets and Impairments									0	0
Goodwill impairment									0	0
Loss on contingent consideration									0	0
Operating income									0	0
Loss from unconsolidated affiliates, net									-0.7	-0.1
Interest and debt expense, net									0	0
Equity in net income (loss) of subsidiary									0	0
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest									-0.7	-0.1
Provision for income taxes									0	0
Net income (loss)									-0.7	-0.1
Net (income) loss attributable to non-controlling partners									-16.8	-4.9
Net income (loss) attributable to CMLP									-17.5	-5
Net income attributable to Class A preferred units									0
Net Income (Loss), Partners Interest in Net Income									-17.5
Consolidation, Eliminations
Condensed Financial Statements, Captions [Line Items]
Gathering and processing									0	0
Storage and transportation									0	0
NGL and crude services									0	0
Related party (Note 13)									0	0
Revenues									0	0
Gathering and processing									0	0
Storage and transportation									0	0
NGL and crude services									0	0
Related party									0	0
Cost of Revenue									0	0
Operations and maintenance									0	0
General and administrative (Note 13)									0	0
Depreciation, amortization and accretion									0	0
Costs and Expenses, Total									0	0
Gain (Loss) on Disposition of Assets and Impairments									0	0
Goodwill impairment									0	0
Loss on contingent consideration									0	0
Operating income									0	0
Loss from unconsolidated affiliates, net									0	0
Interest and debt expense, net									0	0
Equity in net income (loss) of subsidiary									-139.8	-101.1
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest									-139.8	-101.1
Provision for income taxes									0	0
Net income (loss)									-139.8	-101.1
Net (income) loss attributable to non-controlling partners									0	0
Net income (loss) attributable to CMLP									-139.8	-101.1
Net income attributable to Class A preferred units									0
Net Income (Loss), Partners Interest in Net Income									($139.80)

Condensed_Consolidating_Financ6

Condensed Consolidating Financial Information (Condensed Consolidating Statements of Cash Flows) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Condensed Financial Statements, Captions [Line Items]
Net cash provided by operating activities	$322.90	$186.50	$102.10
Acquisitions, net of cash acquired	-19.5	-561.5	-564
Purchases of property, plant and equipment	-407	-334.6	-52.6
Investment in unconsolidated affiliates	-144.4	-151.5	0
Capital contribution from consolidated affiliates	0	0
Other	0	11.1	0
Net cash used in investing activities	-570.9	-1,036.50	-616.6
Proceeds from the issuance of long-term debt	2,089.90	2,072.80	706.7
Principal payments on long-term debt	-1,949.80	-1,634.30	-534
Payments on capital leases	-3.2	-4.3	-3
Payments for debt-related deferred costs	-0.1	-32	-11.4
Distributions paid	-368.9	-359.7
Contributions from parent	0	5.5
Net proceeds from issuance of common units	0	714	217.5
Net proceeds from issuance of preferred equity of subsidiary	53.9	96.1	0
Net proceeds from issuance of preferred equity of subsidiary	-150	96.1
Net proceeds from issuance of Class A preferred units	430.5	0	0
Taxes paid for unit-based compensation vesting	-1.6	-5.5	-0.4
Change in intercompany balances	0	0
Other	-0.8	0	0
Net cash provided by financing activities	249.9	852.6	513.8
Net change in cash	1.9	2.6	-0.7
Cash at beginning of period	2.7	0.1	0.8
Cash at end of period	4.6	2.7	0.1
Parent
Condensed Financial Statements, Captions [Line Items]
Net cash provided by operating activities	-165.6	-46.1
Acquisitions, net of cash acquired	0	0
Purchases of property, plant and equipment	-4.3	-1
Investment in unconsolidated affiliates	0	0
Capital contribution from consolidated affiliates	-89.5	-106.4
Other		0
Net cash used in investing activities	-93.8	-107.4
Proceeds from the issuance of long-term debt	2,089.90	1,930.90
Principal payments on long-term debt	-1,949.80	-1,559.30
Payments on capital leases	-1.3	-0.4
Payments for debt-related deferred costs	-0.1	-32
Distributions paid	-368.9	-359.7
Contributions from parent	0	0
Net proceeds from issuance of common units		714
Net proceeds from issuance of preferred equity of subsidiary	0
Net proceeds from issuance of preferred equity of subsidiary		0
Net proceeds from issuance of Class A preferred units	430.5
Taxes paid for unit-based compensation vesting	0	0
Change in intercompany balances	59.8	-539.9
Other	-0.8
Net cash provided by financing activities	259.3	153.6
Net change in cash	-0.1	0.1
Cash at beginning of period	0.1	0
Cash at end of period	0	0.1
Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Net cash provided by operating activities	488.5	266.4
Acquisitions, net of cash acquired	-19.5	-561.5
Purchases of property, plant and equipment	-402.7	-333.6
Investment in unconsolidated affiliates	0	0
Capital contribution from consolidated affiliates	0	0
Other		11.1
Net cash used in investing activities	-422.2	-884
Proceeds from the issuance of long-term debt	0	141.9
Principal payments on long-term debt	0	-75
Payments on capital leases	-1.9	-3.9
Payments for debt-related deferred costs	0	0
Distributions paid	0	-33.8
Contributions from parent	0	55.5
Net proceeds from issuance of common units		0
Net proceeds from issuance of preferred equity of subsidiary	0
Net proceeds from issuance of preferred equity of subsidiary		0
Net proceeds from issuance of Class A preferred units	0
Taxes paid for unit-based compensation vesting	-1.6	-5.5
Change in intercompany balances	-59.8	539.9
Other	0
Net cash provided by financing activities	-63.3	619.1
Net change in cash	3	1.5
Cash at beginning of period	1.6	0.1
Cash at end of period	4.6	1.6
Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Net cash provided by operating activities	0	0
Acquisitions, net of cash acquired	0	0
Purchases of property, plant and equipment	0	0
Investment in unconsolidated affiliates	-144.4	-151.5
Capital contribution from consolidated affiliates	0	0
Other		0
Net cash used in investing activities	-144.4	-151.5
Proceeds from the issuance of long-term debt	0	0
Principal payments on long-term debt	0	0
Payments on capital leases	0	0
Payments for debt-related deferred costs	0	0
Distributions paid	0	0
Contributions from parent	89.5	56.4
Net proceeds from issuance of common units		0
Net proceeds from issuance of preferred equity of subsidiary	53.9
Net proceeds from issuance of preferred equity of subsidiary		96.1
Net proceeds from issuance of Class A preferred units	0
Taxes paid for unit-based compensation vesting	0	0
Change in intercompany balances	0	0
Other	0
Net cash provided by financing activities	143.4	152.5
Net change in cash	-1	1
Cash at beginning of period	1	0
Cash at end of period	0	1
Consolidation, Eliminations
Condensed Financial Statements, Captions [Line Items]
Net cash provided by operating activities	0	-33.8
Acquisitions, net of cash acquired	0	0
Purchases of property, plant and equipment	0	0
Investment in unconsolidated affiliates	0	0
Capital contribution from consolidated affiliates	89.5	106.4
Other		0
Net cash used in investing activities	89.5	106.4
Proceeds from the issuance of long-term debt	0	0
Principal payments on long-term debt	0	0
Payments on capital leases	0	0
Payments for debt-related deferred costs	0	0
Distributions paid	0	33.8
Contributions from parent	-89.5	-106.4
Net proceeds from issuance of common units		0
Net proceeds from issuance of preferred equity of subsidiary	0
Net proceeds from issuance of preferred equity of subsidiary		0
Net proceeds from issuance of Class A preferred units	0
Taxes paid for unit-based compensation vesting	0	0
Change in intercompany balances	0	0
Other	0
Net cash provided by financing activities	-89.5	-72.6
Net change in cash	0	0
Cash at beginning of period	0	0
Cash at end of period	0	0
As Previously Reported | Parent
Condensed Financial Statements, Captions [Line Items]
Net cash provided by operating activities		3.9
Investment in unconsolidated affiliates		0
Capital contribution from consolidated affiliates		-82
Net cash used in investing activities		-83.4
Proceeds from the issuance of long-term debt		382.9
Principal payments on long-term debt		-202
Payments for debt-related deferred costs		-0.1
Distributions paid		-219.3
Contributions from parent		0
Net proceeds from issuance of common units		118.5
Change in intercompany balances		0
Net cash provided by financing activities		79.6
As Previously Reported | Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Net cash provided by operating activities		216.4
Investment in unconsolidated affiliates		-24.4
Capital contribution from consolidated affiliates		0
Net cash used in investing activities		-908.4
Proceeds from the issuance of long-term debt		1,689.90
Principal payments on long-term debt		-1,432.30
Payments for debt-related deferred costs		-31.9
Distributions paid		-174.2
Contributions from parent		55.5
Net proceeds from issuance of common units		595.5
Change in intercompany balances		0.4
Net cash provided by financing activities		693.5
As Previously Reported | Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Net cash provided by operating activities		0
Investment in unconsolidated affiliates		-127.1
Capital contribution from consolidated affiliates		0
Net cash used in investing activities		-127.1
Proceeds from the issuance of long-term debt		0
Principal payments on long-term debt		0
Payments for debt-related deferred costs		0
Distributions paid		0
Contributions from parent		32
Net proceeds from issuance of common units		0
Change in intercompany balances		0
Net cash provided by financing activities		128.1
As Previously Reported | Consolidation, Eliminations
Condensed Financial Statements, Captions [Line Items]
Net cash provided by operating activities		-33.8
Investment in unconsolidated affiliates		0
Capital contribution from consolidated affiliates		82
Net cash used in investing activities		82.4
Proceeds from the issuance of long-term debt		0
Principal payments on long-term debt		0
Payments for debt-related deferred costs		0
Distributions paid		33.8
Contributions from parent		-82
Net proceeds from issuance of common units		0
Change in intercompany balances		-0.4
Net cash provided by financing activities		($48.60)

Quarterly_Financial_Data_Unaud2

Quarterly Financial Data (Unaudited) Quarterly Financial Data (Details) (USD $)	3 Months Ended								12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Business Acquisition [Line Items]
Revenues	$614.40	$738.40	$675.70	$537	$366	$140.10	$80.10	$72.40	$2,565.50	$658.60	$239.50
Operating income	-34.5	48.7	42.3	34.4	-14.9	31.8	19.5	20.7	90.9	57.1	75.9
Loss from unconsolidated affiliates, net	0.6	0.3	-1.5	-0.1	0.3	-0.4	0	0	-0.7	-0.1	0
Net income (loss)	-60.4	21.3	11.7	5.5	-42.3	11.6	6.7	8.9	-21.9	-15.1	38.9
Net income (loss) attributable to partners	-72.9	7.7	6.9	2.4	-45.3	9.7	6.7	8.9	-55.9	-20	38.9
Basic, in dollars per unit	($0.43)	$0	$0	($0.03)	($0.50)	$0.02	($0.01)	$0.06	($0.46)	($0.82)	$0.26
Diluted, in dollars per unit	($0.43)	$0	$0	($0.03)	($0.50)	$0.02	($0.01)	$0.06	($0.46)	($0.82)	$0.26
Goodwill impairment									-48.8	-4.1	0
Impaired Assets to be disposed of									13.2
Impairment of intangible assets (excluding goodwill)									21.3
Antero
Business Acquisition [Line Items]
Contingent consideration	($40)				($31.40)				($40)	($31.40)