Boardwalk Pipeline Partners (BWP) 10-Q4 Nov 142014 Q3 Quarterly reportFinancial data

Company Profile

Document_and_Entity_Informatio

Document and Entity Information (USD $)	9 Months Ended
	Sep. 30, 2014	Jun. 30, 2014	Nov. 03, 2014	Nov. 03, 2014
			Common Stock [Member]	Common Class B [Member]
			Subsequent Event	Subsequent Event
Entity Information [Line Items]	'	'	'	'
Entity Registrant Name	'Boardwalk Pipeline Partners, LP	'	'	'
Entity Central Index Key	'0001336047	'	'	'
Current Fiscal Year End Date	'--12-31	'	'	'
Entity Well-known Seasoned Issuer	'Yes	'	'	'
Entity Voluntary Filers	'No	'	'	'
Entity Current Reporting Status	'Yes	'	'	'
Entity Filer Category	'Large Accelerated Filer	'	'	'
Entity Public Float	'	$2,176,296,858	'	'
Entity Common Stock, Shares Outstanding	'	'	243,223,801	0
Document Fiscal Year Focus	'2014	'	'	'
Document Fiscal Period Focus	'Q3	'	'	'
Document Type	'10-Q	'	'	'
Amendment Flag	'false	'	'	'
Document Period End Date	30-Sep-14	'	'	'

CONDENSED_CONSOLIDATED_BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Current Assets:	'	'
Cash and cash equivalents	$6.20	$28.50
Receivables:	'	'
Trade, net	84.4	103.5
Affiliates	0	1.1
Other	10.2	15.7
Gas transportation receivables	8.8	7.8
Costs recoverable from customers	0.3	0.8
Gas and liquids stored underground	4.5	0.7
Prepayments	17.8	12.9
Other current assets	6.3	6.1
Total current assets	138.5	177.1
Property, Plant and Equipment:	'	'
Natural gas transmission and other plant	8,698.60	8,548.80
Construction work in progress	325.1	174.5
Property, plant and equipment, gross	9,023.70	8,723.30
Lessbaccumulated depreciation and amortization	1,692.40	1,489.20
Property, plant and equipment, net	7,331.30	7,234.10
Other Assets:	'	'
Goodwill	215.5	215.5
Gas stored underground	93.4	79.7
Investment in unconsolidated affiliates	0	78.6
Other	152.5	129.5
Total other assets	461.4	503.3
Total Assets	7,931.20	7,914.50
Payables:	'	'
Trade	53.7	65.1
Affiliates	0.8	1.2
Other	11.9	5.7
Gas Payables:	'	'
Transportation	7.8	8.8
Storage	0.3	0.2
Accrued taxes, other	67.3	46.1
Accrued interest	31.1	45.4
Accrued payroll and employee benefits	24.1	26.4
Deferred income	2.3	9.3
Other current liabilities	40	27.8
Total current liabilities	239.3	236
Long-term debt and capital lease obligations	3,410.60	3,424.40
Other Liabilities and Deferred Credits:	'	'
Pension liability	14.2	17.1
Asset retirement obligation	34.3	39.3
Provision for other asset retirement	59.8	57.6
Payable to affiliate	16	16
Other	61.9	60.7
Total other liabilities and deferred credits	186.2	190.7
Commitments and Contingencies	'	'
Partnersb Capital:	'	'
Common units b 243.3 million units issued and outstanding as of September 30, 2014, and December 31, 2013	4,083.40	3,963.40
General partner	79.7	77.3
Accumulated other comprehensive loss	-68.3	-63.8
Total partnersb capital	4,094.80	3,976.90
Noncontrolling interest	0.3	86.5
Total Equity	4,095.10	4,063.40
Total Liabilities and Equity	$7,931.20	$7,914.50

CONDENSED_CONSOLIDATED_BALANCE1

CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) (Parenthetical)	Sep. 30, 2014	Dec. 31, 2013
In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Common units issued	243.3	243.3
Common units outstanding	243.3	243.3

CONDENSED_CONSOLIDATED_STATEME

CONDENSED CONSOLIDATED STATEMENTS OF INCOME (Unaudited) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Operating Revenues:	'	'	'	'
Transportation	$238.90	$233.50	$788.90	$759.90
Parking and lending	3	4.9	21.4	19.9
Storage	19.2	27.4	70.1	82.9
Other	17.8	9.7	48.8	30
Total operating revenues	278.9	275.5	929.2	892.7
Operating Costs and Expenses:	'	'	'	'
Fuel and transportation	31.9	18.5	94.8	68.6
Operation and maintenance	50.3	47	136.9	131
Administrative and general	31.8	29.1	89.1	89.4
Depreciation and amortization	72.2	68.7	211	202.8
Asset impairment	0	0	8.6	1.2
Net loss (gain) on sale of operating assets	0.1	-13	-1.1	-29.2
Taxes other than income taxes	24.1	22	72.3	72.9
Total operating costs and expenses	210.4	172.3	611.6	536.7
Operating income	68.5	103.2	317.6	356
Other Deductions (Income):	'	'	'	'
Interest expense	40	41	121.1	122.2
Interest income	-0.1	-0.1	-0.4	-0.4
Equity losses in unconsolidated affiliates	0.3	0.6	86.9	0.6
Miscellaneous other income, net	-0.2	0	-0.3	-0.2
Total other deductions	40	41.5	207.3	122.2
Income before income taxes	28.5	61.7	110.3	233.8
Income taxes	0.1	0	0.4	0.3
Net income	28.4	61.7	109.9	233.5
Net loss attributable to noncontrolling interests	-0.8	-0.6	-86.9	-0.7
Net income attributable to controlling interests	$29.20	$62.30	$196.80	$234.20

CONDENSED_CONSOLIDATED_STATEME1

CONDENSED CONSOLIDATED STATEMENTS OF INCOME Net Income Per Unit: (USD $)	3 Months Ended		9 Months Ended
In Millions, except Per Share data, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Common Units	'	'	'	'
Net income per unit:	'	'	'	'
Basic net income per unit	$0.12	$0.27	$0.79	$0.96
Diluted net income per unit	$0.12	$0.21	$0.79	$0.90
Weighted-average number of units outstanding:	'	'	'	'
Weighted-average units outstanding - basic (in units)	243.3	220.4	243.3	213.5
Weighted-average units outstanding - diluted (in units)	243.3	243.3	243.3	221.2
Net Income per Unit:	'	'	'	'
Cash distribution declared and paid (in units)	$0.10	$0.53	$0.30	$1.60
Class B Units	'	'	'	'
Net income per unit:	'	'	'	'
Basic net income per unit	$0	($0.32)	$0	($0.11)
Diluted net income per unit	$0	$0	$0	$0.19
Weighted-average number of units outstanding:	'	'	'	'
Weighted-average units outstanding - basic (in units)	0	22.9	0	22.9
Weighted-average units outstanding - diluted (in units)	0	0	0	15.2
Net Income per Unit:	'	'	'	'
Cash distribution declared and paid (in units)	$0	$0.30	$0	$0.90

CONDENSED_CONSOLIDATED_STATEME2

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Net Income	$28.40	$61.70	$109.90	$233.50
Other comprehensive income (loss):	'	'	'	'
Gain (loss) on cash flow hedges	0.2	0	-0.7	2.5
Reclassification adjustment transferred to Net Income from cash flow hedges	0.5	-0.6	2.1	0.5
Pension and other postretirement benefit costs	-2	-0.4	-5.9	-4
Total Comprehensive Income	27.1	60.7	105.4	232.5
Comprehensive loss attributable to noncontrolling interests	-0.8	-0.6	-86.9	-0.7
Comprehensive income attributable to controlling interests	$27.90	$61.30	$192.30	$233.20

CONDENSED_CONSOLIDATED_STATEME3

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) (USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Operating Activities:	'	'
Net Income	$109.90	$233.50
Adjustments to reconcile net income to cash provided by operations:	'	'
Depreciation and amortization	211	202.8
Amortization of deferred costs	4.3	4
Asset impairment	8.6	1.2
Net gain on sale of operating assets	-1.1	-29.2
Equity losses in unconsolidated affiliates	86.9	0.6
Changes in operating assets and liabilities:	'	'
Trade and other receivables	24.7	-4.6
Other receivables, affiliates	0.9	0.8
Gas receivables and storage assets	-18.4	27.3
Costs recoverable from customers	1.7	2.6
Other assets	-3.6	-5.6
Trade and other payables	0.6	-26.3
Other payables, affiliates	-0.5	0.2
Gas payables	-6.6	-5.8
Accrued liabilities	5.9	11.6
Other liabilities	-11.8	-11.1
Net cash provided by operating activities	412.5	402
Investing Activities:	'	'
Capital expenditures	-315.9	-204.3
Proceeds from sale of operating assets	2.9	48.6
Proceeds from insurance and other recoveries	6.3	1.4
Advances to affiliates	0.1	-2.8
Investment in unconsolidated affiliates	-20.5	-25.6
Distribution from unconsolidated affiliates	10.7	0
Acquisition-related deposit	-29.5	0
Net cash used in investing activities	-345.9	-182.7
Financing Activities:	'	'
Proceeds from borrowings on revolving credit agreement	340	813
Repayment of borrowings on revolving credit agreement	-330	-1,030
Principal payment of capital lease obligation	-0.3	-0.1
Repayment of borrowings from term loan	-25	0
Advances from affiliate	0.1	-2.8
Distributions paid	-74.4	-392
Capital contributions from noncontrolling interests	8.2	37.2
Distributions paid to noncontrolling interests	-7.5	0
Proceeds from sale of common units	0	368.7
Capital contributions from general partner	0	7.8
Net cash used in financing activities	-88.9	-198.2
(Decrease) increase in cash and cash equivalents	-22.3	21.1
Cash and cash equivalents at beginning of period	28.5	3.9
Cash and cash equivalents at end of period	$6.20	$25

CONDENSED_CONSOLIDATED_STATEME4

CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY (Unaudited) (USD $)	Total	Accumulated Other Comprehensive Loss	Noncontrolling Interest	Limited Partner	Limited Partner	General Partner
In Millions, unless otherwise specified	Total	Accumulated Other Comprehensive Loss	Noncontrolling Interest	Common Units	Class B Units	General Partner
Beg Partners' Capital at Dec. 31, 2012	$3,877.10	($67.30)	$0	$3,190.30	$678.30	$75.80
Add (deduct):	'	'	'	'	'	'
Net income (loss)	233.5	0	-0.7	185.1	19.9	29.2
Distributions paid	-392	0	0	-338.5	-20.6	-32.9
Sale of common units, net of related transactions costs	368.7	0	0	368.7	0	0
Capital contributions from general partner	7.8	0	0	0	0	7.8
Capital contributions from noncontrolling interests	40.3	0	40.3	0	0	0
Other comprehensive loss	-1	-1	0	0	0	0
End Partners' Capital at Sep. 30, 2013	4,134.40	-68.3	39.6	3,405.60	677.6	79.9
Beg Partners' Capital at Dec. 31, 2013	4,063.40	-63.8	86.5	3,963.40	0	77.3
Add (deduct):	'	'	'	'	'	'
Net income (loss)	109.9	0	-86.9	192.9	0	3.9
Distributions paid	-74.4	0	0	-72.9	0	-1.5
Capital contributions from noncontrolling interests	8.2	0	8.2	0	0	0
Distributions paid to noncontrolling interests	-7.5	0	-7.5	0	0	0
Other comprehensive loss	-4.5	-4.5	0	0	0	0
End Partners' Capital at Sep. 30, 2014	$4,095.10	($68.30)	$0.30	$4,083.40	$0	$79.70

Basis_of_Presentation

Basis of Presentation	9 Months Ended
Basis of Presentation	Sep. 30, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Basis of Presentation	'
	Note 1: Basis of Presentation

	Boardwalk Pipeline Partners, LP (the Partnership) is a Delaware limited partnership formed in 2005 to own and operate the business conducted by its primary subsidiary Boardwalk Pipelines, LP (Boardwalk Pipelines) and its operating subsidiaries and consists of integrated natural gas and natural gas liquids (NGLs) pipeline and storage systems and natural gas gathering and processing.

	As of November 3, 2014, Boardwalk Pipelines Holding Corp. (BPHC), a wholly-owned subsidiary of Loews Corporation (Loews), owned 125.6 million of the Partnership’s common units, and, through Boardwalk GP, LP (Boardwalk GP), an indirect wholly-owned subsidiary of BPHC, holds the 2% general partner interest and all of the incentive distribution rights (IDRs). As of November 3, 2014, the common units and general partner interest owned by BPHC represent approximately 53% of the Partnership’s equity interests, excluding the IDRs. The Partnership’s common units are traded under the symbol “BWP” on the New York Stock Exchange.

	The accompanying unaudited condensed consolidated financial statements of the Partnership were prepared pursuant to the rules and regulations of the Securities and Exchange Commission. Certain information and footnote disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States of America (GAAP) have been condensed or omitted pursuant to such rules and regulations. In the opinion of management, the accompanying condensed consolidated financial statements reflect all adjustments (consisting of only normal recurring accruals) necessary to present fairly the financial position as of September 30, 2014, and December 31, 2013, and the results of operations and comprehensive income for the three and nine months ended September 30, 2014 and 2013, and changes in cash flows and changes in equity for the nine months ended September 30, 2014 and 2013. Reference is made to the Notes to Consolidated Financial Statements in the Annual Report on Form 10-K for the year ended December 31, 2013 (2013 Annual Report on Form 10-K), which should be read in conjunction with these unaudited condensed consolidated financial statements. The accounting policies described in Note 2 to the Consolidated Financial Statements included in such 2013 Annual Report on Form 10-K are the same used in preparing the accompanying unaudited condensed consolidated financial statements. Net income for interim periods may not necessarily be indicative of results for the full year.

Investments

Investments	9 Months Ended
Investments	Sep. 30, 2014
Investments [Abstract]	'
Consolidation, Variable Interest Entity, Policy [Policy Text Block]	'
	Note 2: Investments

	Bluegrass Pipeline, Moss Lake Fractionation and Moss Lake LPG Terminal Projects

	As discussed in Note 3 to the Partnership’s 2013 Annual Report on Form 10-K, the Partnership and The Williams Companies, Inc. (Williams) formed joint ventures for the development process of the Bluegrass Project. In the third quarter 2014, the Partnership and Williams agreed to dissolve the Bluegrass Project entities, including the dissolution of Bluegrass Pipeline, Moss Lake Fractionation and Moss Lake LPG. In the first quarter 2014, the Bluegrass Project entities expensed the previously capitalized project costs related to the development process due to lack of customer commitments, resulting in a $92.9 million charge, which was reflected in Equity losses in unconsolidated affiliates and Asset impairment on the income statement. Net of noncontrolling interests of $82.9 million associated with the Bluegrass investment, these expenses reduced the Partnership’s Net income attributable to controlling interests by $10.0 million.

	At September 30, 2014, Boardwalk Bluegrass and Boardwalk Moss Lake had no remaining investment balance related to the Bluegrass Project entities. As of September 30, 2014, the Partnership included in its Condensed Consolidated Balance Sheet $0.3 million of cash that represent amounts recorded by Boardwalk Bluegrass and Boardwalk Moss Lake. At December 31, 2013, the Partnership had included $15.0 million of cash, $78.6 million of investments in unconsolidated affiliates and $6.8 million of construction work in progress related to amounts recorded by Boardwalk Bluegrass and Boardwalk Moss Lake.

Gas_and_Liquids_Stored_Undergr

Gas and Liquids Stored Underground and Gas and NGLs Receivables and Payables	9 Months Ended
	Sep. 30, 2014
Gas and Liquids Stored Underground and Gas and NGLs Receivables and Payables [Abstract]	'
Gas Stored Underground and Gas Receivables and Payable [Text Block]	'
	Note 3: Gas and Liquids Stored Underground and Gas and NGLs Receivables and Payables

	Subsidiaries of the Partnership provide storage services whereby they store gas or NGLs on behalf of customers and also periodically hold customer gas under parking and lending (PAL) services. Since the customers retain title to the gas held by the Partnership in providing these services, the Partnership does not record the related gas on its balance sheet.

	Subsidiaries of the Partnership also periodically lend gas to customers under PAL and no-notice services. As of September 30, 2014, the amount of gas owed to the subsidiaries of the Partnership due to gas imbalances and gas loaned under PAL and no-notice services was approximately 7.2 trillion British thermal units (TBtu). Assuming an average market price during September 2014 of $3.87 per million British thermal unit, the market value of that gas was approximately $27.8 million. As of December 31, 2013, the amount of gas owed to the subsidiaries of the Partnership due to gas imbalances and gas loaned under PAL and no-notice services was approximately 19.6 TBtu. As of September 30, 2014, and December 31, 2013, there were no outstanding NGLs imbalances owed to the operating subsidiaries. If any significant customer should have credit or financial problems resulting in a delay or failure to repay the gas or NGLs owed to the operating subsidiaries, it could have a material adverse effect on the Partnership’s financial condition, results of operations or cash flows.

Fair_Values_Measurements_Deriv

Fair Values Measurements, Derivatives and Other Comprehensive Income (OCI)	9 Months Ended
	Sep. 30, 2014
Disclosure Text Block [Abstract]	'
Fair Value Measurements, Derivatives and Other Comprehensive Income (OCI) [Text Block]	'
	Note 4: Fair Value Measurements, Derivatives and Other Comprehensive Income (OCI)

	The Partnership’s assets that were recorded at fair value on a non-recurring basis as of September 30, 2014, were as follows (in millions):


						Fair Value Measurements at
						30-Sep-14

		September 30,				Quoted prices in active markets for identical assets				Significant other observable inputs			Significant unobservable inputs			Total Gains (losses) for the three months ended September 30,			Total
		2014				(Level 1)				(Level 2)			(Level 3)			2014			Gains
																			(losses) for the nine months ended
																			September 30,
																			2014

	Non-recurring fair value measurements - Assets
	Assets held and used	$	—			$	—			$	—		$	—		$	—		$	(7.1	)	(1)

	Investment in unconsolidated affiliates	—				—				—			—			—			(85.8		)	(1)



	-1	Net of noncontrolling interests of $82.9 million, the amount of the loss to the Partnership was $10.0 million. The impairment charge related to assets held and used represents the carrying amount of the assets. Note 2 contains more information regarding these measurements. Note 5 contains additional information related to asset impairment charges not included in the above table.

	There were no liabilities recorded at fair value on a non-recurring basis at September 30, 2014. The Partnership’s assets and liabilities recorded at fair value on a recurring basis as of September 30, 2014, and December 31, 2013, were related to its derivatives.

	Derivatives

	The Partnership uses futures, swaps and option contracts (collectively, derivatives) to hedge exposure to natural gas commodity price risk related to the future operational sales of natural gas and cash for fuel reimbursement where customers pay cash for the cost of fuel used in providing transportation services as opposed to having fuel retained in kind. This price risk exposure includes approximately $4.2 million and $0.3 million of gas stored underground at September 30, 2014, and December 31, 2013, which the Partnership owns and carries on its balance sheet as current Gas and liquids stored underground. The derivatives qualify for cash flow hedge accounting and are generally designated as such. The Partnership’s natural gas derivatives are reported at fair value based on New York Mercantile Exchange (NYMEX) quotes for natural gas futures and options. The NYMEX quotes are deemed to be observable inputs in an active market for similar assets and liabilities and are considered Level 2 inputs for purposes of fair value disclosures. The fair value of derivatives designated as cash flow hedges existing as of September 30, 2014, included in Other current assets in the Condensed Consolidated Balance Sheets was less than $0.1 million. The fair value of derivatives designated as cash flow hedges existing as of December 31, 2013, included in Other current assets in the Condensed Consolidated Balance Sheets was $0.5 million.

	The Partnership had $11.3 million and $12.7 million of Accumulated other comprehensive loss (AOCI) related to cash flow hedges as of September 30, 2014, and December 31, 2013. The Partnership estimates that approximately $2.3 million of net losses from cash flow hedges reported in AOCI as of September 30, 2014, are expected to be reclassified into earnings within the next twelve months and primarily relates to previously settled Treasury rate locks that are being amortized to earnings over the terms of the related interest payments, generally the terms of the related debt.

	Other Comprehensive Income (OCI)

	The following table shows the components and reclassifications to net income of AOCI which is included in Partners' Capital on the Condensed Consolidated Balance Sheets for the three months ended September 30, 2014 (in millions):


		Cash Flow Hedges				Pension and Other Postretirement Costs				Total
	Beginning balance, July 1, 2014	$	(12.0	)		$	(55.0	)		$	(67.0	)
	Gain recorded in accumulated other comprehensive loss		0.2				—				0.2

	Reclassifications:
	Transportation operating revenues		(0.1	)			—				(0.1	)

	Interest expense		0.6				—				0.6

	Pension and other postretirement benefit costs		—				(2.0	)			(2.0	)


	Ending balance, September 30, 2014	$	(11.3	)		$	(57.0	)		$	(68.3	)

	The following table shows the components and reclassifications to net income of AOCI which is included in Partners' Capital on the Condensed Consolidated Balance Sheets for the three months ended September 30, 2013 (in millions):


		Cash Flow Hedges				Pension and Other Postretirement Costs				Total
	Beginning balance, July 1, 2013	$	(11.9	)		$	(55.4	)		$	(67.3	)
	Gain (loss) recorded in accumulated other comprehensive loss		—				—				—

	Reclassifications:
	Disposal of assets		(1.2	)			—				(1.2	)

	Interest expense		0.6				—				0.6

	Pension and other postretirement benefit costs		—				(0.4	)			(0.4	)


Ending balance, September 30, 2013	$	(12.5	)		$	(55.8	)		$	(68.3	)

The following table shows the components and reclassifications to net income of AOCI which is included in Partners' Capital on the Condensed Consolidated Balance Sheets for the nine months ended September 30, 2014 (in millions):


	Cash Flow Hedges				Pension and Other Postretirement Costs				Total
Beginning balance, January 1, 2014	$	(12.7	)		$	(51.1	)		$	(63.8	)
Loss recorded in accumulated other comprehensive loss		(0.7	)			—				(0.7	)

Reclassifications:
Transportation operating revenues		0.1				—				0.1

Other operating revenues		0.2				—				0.2

Interest expense		1.8				—				1.8

Pension and other postretirement benefit costs		—				(5.9	)			(5.9	)


Ending balance, September 30, 2014	$	(11.3	)		$	(57.0	)		$	(68.3	)

The following table shows the components and reclassifications to net income of AOCI which is included in Partners' Capital on the Condensed Consolidated Balance Sheets for the nine months ended September 30, 2013 (in millions):


	Cash Flow Hedges				Pension and Other Postretirement Costs				Total
Beginning balance, January 1, 2013	$	(15.5	)		$	(51.8	)		$	(67.3	)
Gain recorded in accumulated other comprehensive loss		2.5				—				2.5

Reclassifications:
Transportation operating revenues		0.1				—				0.1

Other operating revenues		(0.1	)			—				(0.1	)

Disposal of assets		(1.2	)			—				(1.2	)

Interest expense		1.7				—				1.7

Pension and other postretirement benefit costs		—				(4.0	)			(4.0	)


Ending balance, September 30, 2013	$	(12.5	)		$	(55.8	)		$	(68.3	)

Financial Assets and Liabilities

The following methods and assumptions were used in estimating the fair value amounts included in the disclosures for financial assets and liabilities, which are consistent with those disclosed in the 2013 Annual Report on Form 10-K:

Cash and Cash Equivalents: For cash and short-term financial assets, the carrying amount is a reasonable estimate of fair value due to the short maturity of those instruments.

Long-Term Debt: The estimated fair value of the Partnership's publicly traded debt is based on quoted market prices at September 30, 2014, and December 31, 2013. The fair market value of the debt that is not publicly traded is based on market prices of similar debt at September 30, 2014, and December 31, 2013. The carrying amount of the Partnership's variable rate debt approximates fair value because the instruments bear a floating market-based interest rate.

The carrying amount and estimated fair values of the Partnership's financial assets and liabilities which are not recorded at fair value on the Condensed Consolidated Balance Sheets as of September 30, 2014, and December 31, 2013, were as follows (in millions):


As of September 30, 2014							Estimated Fair Value
Financial Assets		Carrying Amount					Level 1				Level 2			Level 3			Total
Cash and cash equivalents		$	6.2				$	6.2			$	—		$	—		$	6.2


Financial Liabilities

Long-term debt		$	3,400.90		(1)		$	—			$	3,551.10		$	—		$	3,551.10

(1) The carrying amount of long-term debt excludes a $9.7 million capital lease obligation.



As of December 31, 2013						Estimated Fair Value
Financial Assets		Carrying Amount				Level 1				Level 2			Level 3			Total
Cash and cash equivalents		$	28.5			$	28.5			$	—		$	—		$	28.5


Financial Liabilities

Long-term debt		$	3,414.40		(1)	$	—			$	3,573.80		$	—		$	3,573.80

(1) The carrying amount of long-term debt excludes a $10.0 million capital lease obligation.

Property_Plant_and_Equipment

Property, Plant and Equipment	9 Months Ended
Property, Plant and Equipment	Sep. 30, 2014
Property, Plant and Equipment (PPE) [Abstract]	'
Property, Plant and Equipment Disclosure [Text Block]	'
	Note 5: Property, Plant and Equipment

	Gas Sales

	For the three and nine months ended September 30, 2013, the Partnership recognized a gain of $12.5 million and $29.5 million from the sale of approximately 9.7 Bcf and 14.7 Bcf of natural gas stored underground with a carrying amount of $23.1 million and $25.7 million. The gas was sold as a result of a change in the storage gas needed to support operations and no-notice services.

	Asset Impairments and Dispositions

	The Partnership recognized asset impairment charges of $8.6 million and $1.2 million for the nine months ended September 30, 2014 and 2013. There were no asset impairment charges for the three months ended September 30, 2014 and 2013. Most of the 2014 asset impairment charges are related to the Bluegrass Project. Refer to Note 2 for further information. The charges recorded in 2013 resulted from an increase in the estimate of existing asset retirement obligations related to retired assets.

Commitments_and_Contingencies

Commitments and Contingencies	9 Months Ended
Commitments and Contingencies	Sep. 30, 2014
Commitments and Contingencies Disclosure [Abstract]	'
Commitments and Contingencies	'
	Note 6: Commitments and Contingencies

	Legal Proceedings and Settlements

	The Partnership and its subsidiaries are parties to various legal actions arising in the normal course of business. Management believes the disposition of these outstanding legal actions will not have a material impact on the Partnership's financial condition, results of operations or cash flows.

	Whistler Junction Matter

	The Partnership's Gulf South subsidiary and several other defendants, including Mobile Gas Service Corporation (MGSC), have been named as defendants in nine lawsuits, including one purported class action suit, commenced by multiple plaintiffs in the Circuit Court of Mobile County, Alabama. The plaintiffs seek unspecified damages for personal injury and property damage related to an alleged release of mercaptan at the Whistler Junction facilities in Eight Mile, Alabama. Gulf South delivers natural gas to MGSC, the local distribution company for that region, at Whistler Junction where MGSC odorizes the gas prior to delivery to end user customers by injecting mercaptan into the gas stream, as required by law. The cases are: Parker, et al. v. MGSC, et al. (Case No. CV-12-900711), Crum, et al. v. MGSC, et al. (Case No. CV-12-901057), Austin, et al. v. MGSC, et al. (Case No. CV-12-901133), Moore, et al. v. MGSC, et al. (Case No. CV-12-901471), Davis, et al. v. MGSC, et al. (Case No. CV-12-901490), Joel G. Reed, et al. v. MGSC, et al. (Case No. CV-2013-922265), The Housing Authority of the City of Prichard, Alabama v. MGSC., et al. (Case No. CV-2013-901002), Robert Evans, et al. v. MGSC, et al. (Case No. CV-2013-902627), and Devin Nobles, et al. v. MGSC, et al. (Case No. CV-2013-902786). Gulf South has denied liability. Gulf South has demanded that MGSC indemnify Gulf South against all liability related to these matters pursuant to a right-of-way agreement between Gulf South and MGSC, and has filed cross-claims against MGSC for any such liability. MGSC has also filed cross-claims against Gulf South seeking indemnity and other relief from Gulf South.

	In May 2014, Gulf South and MGSC reached an agreement whereby MGSC fully indemnified Gulf South against all liability related to this matter and the cross-claims between Gulf South and MGSC were settled.

	Southeast Louisiana Flood Protection Litigation

	On August 13, 2013, the Partnership and its subsidiary, Gulf South, along with approximately 100 other energy companies operating in Southern Louisiana, have been named as defendants in a petition for damages and injunctive relief in state district court for Orleans Parish, Louisiana (Case No. 13-6911) by the Board of Commissioners of the Southeast Louisiana Flood Protection Authority - East (Flood Protection Authority). The case was filed in state court, but was removed to the United States District Court for the Eastern District of New Orleans. The plaintiff has moved for remand back to state court, but the Court denied the remand and the case will remain in Federal Court. The lawsuit claims include negligence, strict liability, public nuisance, private nuisance, breach of contract, and breach of the natural servitude of drain against the defendants, alleging that the defendants’ drilling, dredging, pipeline and industrial operations since the 1930s have caused increased storm surge risk, increased flood protection costs and unspecified damages to the Flood Protection Authority. In addition to attorney fees and unspecified monetary damages, the lawsuit seeks abatement and restoration of the coastal lands, including backfilling and re-vegetating of canals dredged and used by the defendants, and abatement and restoration activities such as wetlands creation, reef creation, land bridge construction, hydrologic restoration, shoreline protection, structural protection, bank stabilization, and ridge restoration.

	The outcome of the Southeast Louisiana Flood Protection Litigation case cannot be predicted at this time; however, based on the facts and circumstances presently known, in the opinion of management, this case will not be material to the Partnership's financial condition, results of operations or cash flows.

	Environmental and Safety Matters

	The operating subsidiaries are subject to federal, state and local environmental laws and regulations in connection with the operation and remediation of various operating sites. As of September 30, 2014, and December 31, 2013, the Partnership had an accrued liability of approximately $6.0 million and $6.5 million related to assessment and/or remediation costs associated with the historical use of polychlorinated biphenyls, petroleum hydrocarbons and mercury, groundwater protection measures and other costs. The liability represents management’s estimate of the undiscounted future obligations based on evaluations and discussions with counsel and operating personnel and the current facts and circumstances related to these matters. The related expenditures are expected to occur over the next eight years. As of September 30, 2014, and December 31, 2013, approximately $1.5 million was recorded in Other current liabilities and approximately $4.5 million and $5.0 million were recorded in Other Liabilities and Deferred Credits.

	Commitments for Construction

	The Partnership’s future capital commitments are comprised of binding commitments under purchase orders for materials ordered but not received and firm commitments under binding construction service agreements. The commitments as of September 30, 2014, were approximately $85.0 million, all of which are expected to be settled within the next twelve months.

	There were no substantial changes to the Partnership’s operating lease commitments, pipeline capacity agreements or capital lease obligation disclosed in Note 5 to the Partnership’s 2013 Annual Report on Form 10-K.

Cash_Distributions_and_Net_Inc

Cash Distributions and Net Income per Unit	9 Months Ended
	Sep. 30, 2014
Partners' Capital Notes [Abstract]	'
Cash Distributions and Net Income per Unit	'
	Note 7: Cash Distributions and Net Income per Unit

	Cash Distributions

	In the third quarter 2014, the Partnership declared and paid quarterly distributions to its common unitholders of record of $0.10 per common unit and an amount to the general partner on behalf of its 2% general partner interest. In the third quarter 2013, the Partnership declared and paid a quarterly distribution to its common unitholders of record of $0.5325 per common unit, $0.30 per class B unit to the holder of the class B units (which converted to common units in October 2013 on a one-for-one basis pursuant to the terms of the partnership agreement) and amounts to the general partner on behalf of its 2% general partner interest and as holder of the IDRs. In October 2014, the Partnership declared a quarterly cash distribution to unitholders of record of $0.10 per common unit.

	Net Income per Unit

	For purposes of calculating net income per unit, net income for the current period is reduced by the amount of available cash that will be distributed with respect to that period. Any residual amount representing undistributed net income (or loss) is assumed to be allocated to the various ownership interests in accordance with the contractual provisions of the partnership agreement.

	Under the Partnership’s partnership agreement, for any quarterly period, the IDRs participate in net income only to the extent of the amount of cash distributions actually declared, thereby excluding the IDRs from participating in undistributed net income or losses. Accordingly, undistributed net income is assumed to be allocated to the other ownership interests on a pro rata basis, except that the class B units’ participation in net income is limited to $0.30 per unit per quarter. The Class B units were converted to common units on a one-for-one basis in October 2013. Payments made on account of the Partnership’s various ownership interests are determined in relation to actual declared distributions, and are not based on the assumed allocations required under GAAP. Basic net income per unit is calculated based on the weighted-average number of units outstanding for the period. Diluted net income per unit is calculated assuming that the Class B units converted on the date that they became convertible, or July 1, 2013.

	The following table provides a reconciliation of net income and the assumed allocation of net income to the common units for purposes of computing net income per unit for the three months ended September 30, 2014, (in millions, except per unit data):


		Total				Common				General Partner and IDRs
						Units
	Net income	$	28.4

	Less: Net loss attributable to noncontrolling interests	(0.8		)
	Net income attributable to controlling interests	29.2

	Declared distribution	24.8				$	24.3			$	0.5

	Assumed allocation of undistributed net income	4.4				4.3				0.1

	Assumed allocation of net income attributable to limited	$	29.2			$	28.6			$	0.6
	partner unitholders and general partner
	Weighted-average units outstanding					243.3

	Net income per unit					$	0.12


	The following table provides a reconciliation of net income and the assumed allocation of net income to the common and class B units for purposes of computing basic and diluted net income per unit for the three months ended September 30, 2013, (in millions, except per unit data):


		Total				Common				Class B				General Partner and IDRs
						Units				Units
	Net income	$	61.7

	Less: Net loss attributable to noncontrolling interests	(0.6		)
	Net income attributable to controlling interests	62.3

	Declared distribution	141.9				$	129.5			$	—			$	12.4

	Assumed allocation of undistributed net loss - basic	(79.6		)		(70.7		)		(7.3		)		(1.6		)
	Assumed allocation of net income attributable to limited	62.3				58.8				(7.3		)		10.8
	partner unitholders and general partner - basic
	Allocation for diluted earnings per unit	—				(7.3		)		7.3				—

	Assumed allocation of net income attributable to limited	$	62.3			$	51.5			$	—			$	10.8
	partner unitholders and general partner - diluted
	Weighted-average units outstanding - basic					220.4				22.9

	Weighted-average units outstanding - diluted					243.3				—

	Net income per unit - basic					$	0.27			$	(0.32	)

	Net income per unit - diluted					$	0.21			$	—



	The following table provides a reconciliation of net income and the assumed allocation of net income to the common units for purposes of computing net income per unit for the nine months ended September 30, 2014, (in millions, except per unit data):


	Total				Common				General Partner and IDRs
					Units
Net income	$	109.9

Less: Net loss attributable to noncontrolling interests	(86.9		)
Net income attributable to controlling interests	196.8

Declared distribution	74.5				$	73			$	1.5

Assumed allocation of undistributed net income	122.3				119.9				2.4

Assumed allocation of net income attributable to limited	$	196.8			$	192.9			$	3.9
partner unitholders and general partner
Weighted-average units outstanding					243.3

Net income per unit					$	0.79


The following table provides a reconciliation of net income and the assumed allocation of net income to the common and class B units for purposes of computing basic and diluted net income per unit for the nine months ended September 30, 2013, (in millions, except per unit data):


	Total				Common				Class B				General Partner and IDRs
					Units				Units
Net income	$	233.5

Less: Net loss attributable to noncontrolling interests	(0.7		)
Net income attributable to controlling interests	234.2

Declared distribution	405.7				$	357.5			$	13.7			$	34.5

Assumed allocation of undistributed net loss - basic	(171.5		)		(151.9		)		(16.2		)		(3.4		)
Assumed allocation of net income attributable to limited	234.2				205.6				(2.5		)		31.1
partner unitholders and general partner - basic
Allocation for diluted earnings per unit	—				(5.4		)		5.4				—

Assumed allocation of net income attributable to limited	$	234.2			$	200.2			$	2.9			$	31.1
partner unitholders and general partner - diluted
Weighted-average units outstanding - basic					213.5				22.9

Weighted-average units outstanding - diluted					221.2				15.2

Net income per unit - basic					$	0.96			$	(0.11	)

Net income per unit - diluted					$	0.9			$	0.19

Financing

Financing	9 Months Ended
Financing	Sep. 30, 2014
Debt Disclosure [Abstract]	'
Financing	'
	Note 8: Financing

	Notes and Debentures

	As of September 30, 2014, and December 31, 2013, the Partnership had notes and debentures outstanding of $3.0 billion with a weighted-average interest rate of 5.32%, including $275.0 million of notes which mature in February 2015 and $250.0 million of notes which mature in June 2015. The notes which mature in 2015 were included with the other notes and debentures in long-term debt on the Condensed Consolidated Balance Sheets since the Partnership expects to refinance these notes on a long-term basis and there is adequate available capacity under the revolving credit facility to extend the amount that would otherwise come due in less than one year.

	The indentures governing the notes and debentures have restrictive covenants which provide that, with certain exceptions, neither the Partnership nor any of its subsidiaries may create, assume or suffer to exist any lien upon any property to secure any indebtedness unless the debentures and notes shall be equally and ratably secured. All debt obligations are unsecured. At September 30, 2014, the Partnership and its subsidiaries were in compliance with their debt covenants.

	Revolving Credit Facility

	Outstanding borrowings under the Partnership’s revolving credit facility as of September 30, 2014, and December 31, 2013, were $185.0 million and $175.0 million, with a weighted-average borrowing rate of 1.53% and 1.29%. As of November 4, 2014, we had outstanding borrowings under our revolving credit facility of $485.0 million, resulting in available borrowing capacity of $515.0 million.

	The credit facility contains various restrictive covenants and other usual and customary terms and conditions, including the incurrence of additional debt, the sale of assets and sale-leaseback transactions. The financial covenants under the credit facility require the Partnership and its subsidiaries to maintain, among other things, a ratio of total consolidated debt to consolidated EBITDA (as defined in the Amended Credit Agreement) measured for the previous twelve months of not more than 5.0 to 1.0, or up to 5.5 to 1.0 for the three quarters following an acquisition. The Partnership and its subsidiaries were in compliance with all covenant requirements under the credit facility as of September 30, 2014.

	Term Loan

	The Partnership has a $225.0 million variable-rate term loan due October 1, 2017 (2017 Term Loan), which bears interest at a rate that is based on the one-month London Interbank Offered Rate (LIBOR) plus an applicable margin. Any amounts repaid under the 2017 Term Loan may not be reborrowed. Outstanding borrowings as of September 30, 2014, and December 31, 2013, were $200.0 million and $225.0 million, with a weighted-average interest rate of 1.90% and 1.92%. No additional borrowing capacity is available under the 2017 Term Loan.

	Long-Term Debt - Affiliate

	In July 2014, the Partnership entered into a Subordinated Loan Agreement with BPHC under which the Partnership can borrow up to $300.0 million (Subordinated Loan) through December 31, 2015. The Subordinated Loan bears interest at increasing rates, ranging 5.75% to 9.75%, payable semi-annually in June and December, commencing December 2014, and maturing in July 2024. The Subordinated Loan must be prepaid with the net cash proceeds from the issuance of additional equity securities by the Partnership or the incurrence of certain indebtedness by the Partnership or its subsidiaries, although BPHC may waive such prepayment. The Subordinated Loan is subordinated in right of payment to the Partnership’s obligations under its revolving credit facility pursuant to the terms of a Subordination Agreement between BPHC and Wells Fargo, N.A., as representative of the lenders under the revolving credit facility. Through the filing date of this Quarterly Report on Form 10-Q, the Partnership has not borrowed any amounts under the Subordinated Loan.

	Common Unit Offering

	In May 2013, the Partnership completed a public offering of 12.7 million common units at a price of $30.12 per unit. The Partnership received net proceeds of approximately $376.5 million after deducting underwriting discounts and offering expenses of $12.3 million and including a $7.8 million contribution received from its general partner to maintain its 2% general partner interest. The net proceeds were used to repay borrowings outstanding under the Partnership's credit facility and to create funding for future capital growth projects.

Employee_Benefits

Employee Benefits	9 Months Ended
	Sep. 30, 2014
Compensation and Retirement Disclosure [Abstract]	'
Employee Benefits	'
	Note 9: Employee Benefits

	Defined Benefit Retirement Plans and Postretirement Benefits Other Than Pension (PBOP)

	Texas Gas Transmission, LLC (Texas Gas) employees hired prior to November 2006, are covered under a non-contributory, defined benefit pension plan (Pension Plan). The Texas Gas Supplemental Retirement Plan (SRP) provides pension benefits for the portion of an eligible employee’s pension benefit under the Pension Plan that becomes subject to compensation limitations under the Internal Revenue Code. Collectively, the Partnership refers to the Pension Plan and the SRP as Retirement Plans. Texas Gas provides postretirement medical benefits and life insurance to retired employees who were employed full time, hired prior to 1996, and have met certain other requirements.

	Components of net periodic benefit cost for both the Retirement Plans and PBOP for the three months ended September 30, 2014 and 2013 were as follows (in millions):


		Retirement Plans						PBOP
		For the						For the
		Three Months Ended						Three Months Ended
		September 30,						September 30,
		2014			2013			2014			2013
	Service cost	$	0.9		$	0.8		$	0.1		$	0.1

	Interest cost	1.4			1.3			0.5			0.6

	Expected return on plan assets	(2.4		)	(2.4		)	(1.1		)	(1.1		)
	Amortization of prior service credit	—			—			(1.9		)	(2.0		)

	Amortization of unrecognized net loss	0.4			0.6			0.1			—

	Settlement charge	—			1.3			—			—

	Regulatory asset decrease	0.4			—			—			—

	Net periodic benefit cost	$	0.7		$	1.6		$	(2.3	)	$	(2.4	)


	Components of net periodic benefit cost for both the Retirement Plans and PBOP for the nine months ended September 30, 2014 and 2013 were as follows (in millions):


		Retirement Plans						PBOP
		For the						For the
		Nine Months Ended						Nine Months Ended
		September 30,						September 30,
		2014			2013			2014			2013
	Service cost	$	2.9		$	3		$	0.3		$	0.3

	Interest cost	4.2			3.7			1.6			1.5

	Expected return on plan assets	(7.1		)	(6.9		)	(3.2		)	(3.3		)
	Amortization of prior service credit	—			—			(5.8		)	(5.8		)

	Amortization of unrecognized net loss	1			1.8			0.2			—

	Settlement charge	—			1.3			—			—

	Regulatory asset decrease	1.3			—			—			—

	Net periodic benefit cost	$	2.3		$	2.9		$	(6.9	)	$	(7.3	)


	Through the date of this filing, the Partnership has made contributions of $3.0 million to the Pension Plan and does not expect to make additional contributions in 2014.

	Defined Contribution Plans

	The Partnership’s employees not covered under the Pension Plan are provided retirement benefits under a defined contribution money purchase plan. The Partnership also provides 401(k) plan benefits to its employees. Costs related to the Partnership’s defined contribution plans were $2.2 million for the three months ended September 30, 2014 and 2013, and were $6.6 million for the nine months ended September 30, 2014 and 2013.

Related_Party_Transactions

Related Party Transactions	9 Months Ended
Related Party Transactions	Sep. 30, 2014
Related Party Transactions [Abstract]	'
Related Party Transactions	'
	Note 10: Related Party Transactions

	Loews provides a variety of corporate services to the Partnership under services agreements, including but not limited to, information technology, tax, risk management, internal audit and corporate development services, plus allocated overheads. The Partnership incurred charges related to these services of $2.2 million and $2.1 million for the three months ended September 30, 2014 and 2013 and $6.6 million and $6.3 million for the nine months ended September 30, 2014 and 2013.

	Distributions paid related to limited partner units held by BPHC and the 2% general partner interest and IDRs held by Boardwalk GP were $13.0 million and $72.9 million for the three months ended September 30, 2014 and 2013, and $39.0 million and $217.6 million for the nine months ended September 30, 2014 and 2013.

	In the third quarter 2014, the Partnership and BPHC entered into a Subordinated Loan agreement whereby the Partnership can borrow up to $300.0 million. Note 8 contains more information related to affiliated long-term debt.

	In 2013, the Partnership entered into agreements with BPHC to form Boardwalk Bluegrass and Boardwalk Moss Lake. Through September 30, 2014 and December 31, 2013, the Partnership contributed $12.7 million and $11.9 million and BPHC contributed $97.8 million and $90.0 million of cash and other assets to these entities. In 2014, the Partnership received a $1.9 million distribution from Boardwalk Moss Lake and BPHC received a $7.1 million distribution.

Subsequent_Event_Subsequent_Ev

Subsequent Event Subsequent Event (Notes)	9 Months Ended
Subsequent Event Subsequent Event (Notes)	Sep. 30, 2014
Subsequent Events [Abstract]	'
Subsequent Events [Text Block]	'
	Note 11: Subsequent Event

	Acquisition of the Evangeline Pipeline System

	On October 8, 2014, the Partnership completed the acquisition of Chevron Petrochemical Pipeline, LLC, which owns the Evangeline ethylene pipeline system, from Chevron Pipe Line Company (Chevron), for $295.0 million in cash, subject to customary adjustments. The purchase price was funded through borrowings under the revolving credit facility. As of September 30, 2014, the Partnership had paid a $29.5 million deposit under the definitive agreement with Chevron and is recorded in Other Noncurrent Assets in its Condensed Consolidated Balance Sheet. The disclosures related to the pro-forma revenue and earnings information for the historical comparable period were not provided because the purchase price allocation, which determines the initial accounting, is not complete.

Recently_Issued_Accounting_Pro

Recently Issued Accounting Pronouncements Recently Issued Accounting Pronouncements	9 Months Ended
	Sep. 30, 2014
Disclosure Text Block [Abstract]	'
Description of New Accounting Pronouncements Not yet Adopted [Text Block]	'
	Note 12: Recently Issued Accounting Pronouncements

	In May 2014, the Financial Accounting Standards Board issued Accounting Standards Update 2014-09 (ASU 2014-09), Revenue from Contracts with Customers (Topic 606), which will require entities to recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled to in exchange for those goods or services. ASU 2014-09 also requires enhanced disclosures regarding the nature, amount, timing and uncertainty of revenues and cash flows from contracts with customers. ASU 2014-09 is effective for interim and annual reporting periods beginning after December 15, 2016. The Partnership is evaluating the impact, if any, that ASU 2014-09 will have on its financial statements.

Supplemental_Disclosure_of_Cas

Supplemental Disclosure of Cash Flow Information	9 Months Ended
	Sep. 30, 2014
Supplemental Cash Flow Elements [Abstract]	'
Supplemental Disclosure of Cash Flow Information	'
	Note 13: Supplemental Disclosure of Cash Flow Information (in millions):


		For the
		Nine Months Ended
		September 30,
		2014		2013
	Cash paid during the period for:
	Interest (net of amount capitalized)	$	127.6	$	126.9

	Non-cash adjustments:
	Capital lease obligations incurred	—		10.5

Guarantee_of_Securities_of_Sub

Guarantee of Securities of Subsidiaries	9 Months Ended
	Sep. 30, 2014
Condensed Financial Information of Parent Company Only Disclosure [Abstract]	'
Guarantee of Securities of Subsidiaries	'

	Note 14: Guarantee of Securities of Subsidiaries

	Boardwalk Pipelines (subsidiary issuer) has issued securities which have been fully and unconditionally guaranteed by the Partnership (parent guarantor). The Partnership's subsidiaries have no significant restrictions on their ability to pay distributions or make loans to the Partnership except as noted in the debt covenants and have no restricted assets at September 30, 2014, and December 31, 2013. Note 8 contains additional information regarding the Partnership's debt and related covenants.

	The Partnership has provided the following condensed consolidating financial information in accordance with Regulation S-X Rule 3-10, Financial Statements of Guarantors and Issuers of Guaranteed Securities Registered or Being Registered.




	Condensed Consolidating Balance Sheets as of September 30, 2014
	(Millions)



	Assets		Parent				Subsidiary				Non-guarantor Subsidiaries				Eliminations				Consolidated Boardwalk Pipeline Partners, LP
			Guarantor				Issuer
	Cash and cash equivalents		$	—			$	0.7			$	5.5			$	—			$	6.2

	Receivables		—				—				94.7				(0.1		)		94.6

	Receivables - affiliate		—				—				6.8				(6.8		)		—

	Gas and liquids stored underground		—				—				4.5				—				4.5

	Prepayments		0.4				—				17.4				—				17.8

	Advances to affiliates		—				2.4				42.1				(44.5		)		—

	Other current assets		—				—				22.9				(7.5		)		15.4

	Total current assets		0.4				3.1				193.9				(58.9		)		138.5

	Investment in consolidated subsidiaries		1,679.80				6,423.10				—				(8,102.9		)		—

	Property, plant and equipment, gross		0.6				—				9,023.10				—				9,023.70

	Less–accumulated depreciation and		0.6				—				1,691.80				—				1,692.40
	amortization
	Property, plant and equipment, net		—				—				7,331.30				—				7,331.30

	Other noncurrent assets		—				3				458.5				(0.1		)		461.4

	Advances to affiliates – noncurrent		2,431.40				201.2				1,082.40				(3,715.0		)		—

	Total other assets		2,431.40				204.2				1,540.90				(3,715.1		)		461.4


	Total Assets		$	4,111.60			$	6,630.40			$	9,066.10			$	(11,876.9	)		$	7,931.20




	Liabilities and Equity		Parent				Subsidiary				Non-guarantor Subsidiaries				Eliminations				Consolidated Boardwalk Pipeline Partners, LP
			Guarantor				Issuer
	Payables		$	—			$	0.1			$	65.4			$	0.1			$	65.6

	Payable to affiliates		0.8				—				6.8				(6.8		)		0.8

	Advances from affiliates		—				42.1				2.4				(44.5		)		—

	Other current liabilities		—				14				166.7				(7.8		)		172.9

Total current liabilities		0.8				56.2				241.3				(59.0		)		239.3

Total long-term debt and capital lease		—				1,380.60				2,030.00				—				3,410.60
obligation
Payable to affiliate - noncurrent		16				—				—				—				16

Advances from affiliates - noncurrent		—				3,513.80				201.2				(3,715.0		)		—

Other noncurrent liabilities		—				—				170.2				—				170.2

Total other liabilities and deferred		16				3,513.80				371.4				(3,715.0		)		186.2
credits
Total partners' capital		4,094.80				1,679.80				6,423.10				(8,102.9		)		4,094.80

Noncontrolling interest		—				—				0.3				—				0.3

Total Equity		4,094.80				1,679.80				6,423.40				(8,102.9		)		4,095.10

Total Liabilities and Equity		$	4,111.60			$	6,630.40			$	9,066.10			$	(11,876.9	)		$	7,931.20


Condensed Consolidating Balance Sheets as of December 31, 2013
(Millions)


Assets		Parent				Subsidiary				Non-guarantor Subsidiaries				Eliminations				Consolidated Boardwalk Pipeline Partners, LP
		Guarantor				Issuer
Cash and cash equivalents		$	0.2			$	9.2			$	19.1			$	—			$	28.5

Receivables		—				—				119.2				—				119.2

Receivables - affiliate		0.1				0.1				14.3				(13.4		)		1.1

Gas and liquids stored underground		—				—				0.7				—				0.7

Prepayments		0.3				—				12.6				—				12.9

Advances to affiliates		—				—				194.4				(194.4		)		—

Other current assets		—				—				23.8				(9.1		)		14.7

Total current assets		0.6				9.3				384.1				(216.9		)		177.1

Investment in consolidated subsidiaries		1,480.80				6,138.30				—				(7,619.1		)		—

Property, plant and equipment, gross		0.6				—				8,722.70				—				8,723.30

Less–accumulated depreciation and		0.6				—				1,488.60				—				1,489.20
amortization
Property, plant and equipment, net		—				—				7,234.10				—				7,234.10

Other noncurrent assets		0.3				3.7				420.7				—				424.7

Advances to affiliates – noncurrent		2,512.10				168.7				733.1				(3,413.9		)		—

Investment in unconsolidated affiliates		—				—				78.6				—				78.6

Total other assets		2,512.40				172.4				1,232.40				(3,413.9		)		503.3


Total Assets		$	3,993.80			$	6,320.00			$	8,850.60			$	(11,249.9	)		$	7,914.50




Liabilities & Equity		Parent				Subsidiary				Non-guarantor Subsidiaries				Eliminations				Consolidated Boardwalk Pipeline Partners, LP
		Guarantor				Issuer
Payables		$	0.2			$	—			$	70.6			$	—			$	70.8

Payable to affiliates		0.7				—				13.9				(13.4		)		1.2

Advances from affiliates		—				194.4				—				(194.4		)		—

Other current liabilities		—				19.7				153.3				(9.0		)		164

Total current liabilities		0.9				214.1				237.8				(216.8		)		236

Total long-term debt and capital lease		—				1,379.90				2,044.50				—				3,424.40
obligation
Payable to affiliate - noncurrent		16				—				—				—				16

Advances from affiliates - noncurrent		—				3,245.20				168.7				(3,413.9		)		—

Other noncurrent liabilities		—				—				174.8				(0.1		)		174.7

Total other liabilities and deferred		16				3,245.20				343.5				(3,414.0		)		190.7
credits
Total partners' capital		3,976.90				1,480.80				6,138.30				(7,619.1		)		3,976.90

Noncontrolling interest		—				—				86.5				—				86.5

Total Equity		3,976.90				1,480.80				6,224.80				(7,619.1		)		4,063.40

Total Liabilities and Equity		$	3,993.80			$	6,320.00			$	8,850.60			$	(11,249.9	)		$	7,914.50


Condensed Consolidating Statements of Income for the Three Months Ended September 30, 2014
(Millions)



	Parent				Subsidiary				Non-guarantor Subsidiaries				Eliminations				Consolidated Boardwalk Pipeline Partners, LP
	Guarantor				Issuer
Operating Revenues:
Transportation	$	—			$	—			$	261.3			$	(22.4	)		$	238.9

Parking and lending	—				—				3				—				3

Storage	—				—				19.6				(0.4		)		19.2

Other	—				—				17.8				—				17.8

Total operating revenues	—				—				301.7				(22.8		)		278.9


Operating Cost and Expenses:

Fuel and transportation	—				—				54.7				(22.8		)		31.9

Operation and maintenance	—				—				50.3				—				50.3

Administrative and general	0.2				—				31.6				—				31.8

Other operating costs and expenses	0.2				—				96.2				—				96.4

Total operating costs and expenses	0.4				—				232.8				(22.8		)		210.4

Operating (loss) income	(0.4		)		—				68.9				—				68.5


Other Deductions (Income):

Interest expense	—				18.7				21.3				—				40

Interest (income) expense - affiliates, net	(7.8		)		10.6				(2.8		)		—				—

Interest income	—				—				(0.1		)		—				(0.1		)

Equity in earnings of subsidiaries	(21.8		)		(51.1		)		—				72.9				—

Equity losses in unconsolidated	—				—				0.3				—				0.3
affiliates
Miscellaneous other income, net	—				—				(0.2		)		—				(0.2		)

Total other (income) deductions	(29.6		)		(21.8		)		18.5				72.9				40


Income (loss) before income taxes	29.2				21.8				50.4				(72.9		)		28.5

Income taxes	—				—				0.1				—				0.1

Net income (loss)	29.2				21.8				50.3				(72.9		)		28.4

Net loss attributable to noncontrolling	—				—				(0.8		)		—				(0.8		)
interests
Net income (loss) attributable to controlling	$	29.2			$	21.8			$	51.1			$	(72.9	)		$	29.2
interests

Condensed Consolidating Statements of Income for the Three Months Ended September 30, 2013
(Millions)



	Parent				Subsidiary				Non-guarantor Subsidiaries				Eliminations				Consolidated Boardwalk Pipeline Partners, LP
	Guarantor				Issuer
Operating Revenues:
Transportation	$	—			$	—			$	255.8			$	(22.3	)		$	233.5

Parking and lending	—				—				4.9				—				4.9

Storage	—				—				27.4				—				27.4

Other	—				—				9.7				—				9.7

Total operating revenues	—				—				297.8				(22.3		)		275.5


Operating Cost and Expenses:

Fuel and transportation	—				—				40.8				(22.3		)		18.5

Operation and maintenance	—				—				47				—				47

Administrative and general	—				—				29.1				—				29.1

Other operating costs and expenses	0.2				—				77.5				—				77.7

Total operating costs and expenses	0.2				—				194.4				(22.3		)		172.3

Operating (loss) income	(0.2		)		—				103.4				—				103.2


Other Deductions (Income):

Interest expense	—				18.7				22.3				—				41

Interest (income) expense - affiliates net	(8.8		)		10.4				(1.6		)		—				—

Interest income	—				—				(0.1		)		—				(0.1		)

Equity in earnings of subsidiaries	(53.7		)		(82.8		)		—				136.5				—

Equity losses in unconsolidated affiliates	—				—				0.6				—				0.6

Total other (income) deductions	(62.5		)		(53.7		)		21.2				136.5				41.5


Income (loss) before income taxes	62.3				53.7				82.2				(136.5		)		61.7

Income taxes	—				—				—				—				—

Net income (loss)	62.3				53.7				82.2				(136.5		)		61.7

Net loss attributable to noncontrolling	—				—				(0.6		)		—				(0.6		)
interests
Net income (loss) attributable to controlling	$	62.3			$	53.7			$	82.8			$	(136.5	)		$	62.3
interests






Condensed Consolidating Statements of Income for the Nine Months Ended September 30, 2014
(Millions)



	Parent				Subsidiary				Non-guarantor Subsidiaries				Eliminations				Consolidated Boardwalk Pipeline Partners, LP
	Guarantor				Issuer
Operating Revenues:
Transportation	$	—			$	—			$	856.9			$	(68.0	)		$	788.9

Parking and lending	—				—				21.4				—				21.4

Storage	—				—				70.6				(0.5		)		70.1

Other	—				—				48.8				—				48.8

Total operating revenues	—				—				997.7				(68.5		)		929.2


Operating Cost and Expenses:

Fuel and transportation	—				—				163.3				(68.5		)		94.8

Operation and maintenance	—				—				136.9				—				136.9

Administrative and general	0.1				—				89				—				89.1

Other operating costs and expenses	0.3				—				290.5				—				290.8

Total operating costs and expenses	0.4				—				679.7				(68.5		)		611.6

Operating (loss) income	(0.4		)		—				318				—				317.6


Other Deductions (Income):

Interest expense	—				56.1				65				—				121.1

Interest (income) expense - affiliates, net	(23.2		)		31				(7.8		)		—				—

Interest income	—				—				(0.4		)		—				(0.4		)

Equity in earnings of subsidiaries	(174.0		)		(261.1		)		—				435.1				—

Equity losses in unconsolidated	—				—				86.9				—				86.9
affiliates
Miscellaneous other income, net	—				—				(0.3		)		—				(0.3		)

Total other (income) deductions	(197.2		)		(174.0		)		143.4				435.1				207.3


Income (loss) before income taxes	196.8				174				174.6				(435.1		)		110.3

Income taxes	—				—				0.4				—				0.4

Net income (loss)	196.8				174				174.2				(435.1		)		109.9

Net loss attributable to noncontrolling	—				—				(86.9		)		—				(86.9		)
interests
Net income (loss) attributable to controlling	$	196.8			$	174			$	261.1			$	(435.1	)		$	196.8
interests

Condensed Consolidating Statements of Income for the Nine Months Ended September 30, 2013
(Millions)



	Parent				Subsidiary				Non-guarantor Subsidiaries				Eliminations				Consolidated Boardwalk Pipeline Partners, LP
	Guarantor				Issuer
Operating Revenues:
Transportation	$	—			$	—			$	826.2			$	(66.3	)		$	759.9

Parking and lending	—				—				19.9				—				19.9

Storage	—				—				83				(0.1		)		82.9

Other	—				—				30				—				30

Total operating revenues	—				—				959.1				(66.4		)		892.7


Operating Cost and Expenses:

Fuel and transportation	—				—				135				(66.4		)		68.6

Operation and maintenance	—				0.3				130.7				—				131

Administrative and general	—				0.8				88.6				—				89.4

Other operating costs and expenses	0.3				0.1				247.3				—				247.7

Total operating costs and expenses	0.3				1.2				601.6				(66.4		)		536.7

Operating (loss) income	(0.3		)		(1.2		)		357.5				—				356


Other Deductions (Income):

Interest expense	—				53.9				68.3				—				122.2

Interest (income) expense - affiliates net	(25.4		)		30.9				(5.5		)		—				—

Interest income	—				—				(0.4		)		—				(0.4		)

Equity in earnings of subsidiaries	(209.1		)		(295.1		)		—				504.2				—

Equity losses in unconsolidated affiliates	—				—				0.6				—				0.6

Miscellaneous other income, net	—				—				(0.2		)		—				(0.2		)

Total other (income) deductions	(234.5		)		(210.3		)		62.8				504.2				122.2


Income (loss) before income taxes	234.2				209.1				294.7				(504.2		)		233.8

Income taxes	—				—				0.3				—				0.3

Net income (loss)	234.2				209.1				294.4				(504.2		)		233.5

Net loss attributable to noncontrolling	—				—				(0.7		)		—				(0.7		)
interests
Net income (loss) attributable to controlling	$	234.2			$	209.1			$	295.1			$	(504.2	)		$	234.2
interests







Condensed Consolidating Statements of Comprehensive Income for the Three Months Ended September 30, 2014
(Millions)



	Parent				Subsidiary				Non-guarantor Subsidiaries				Eliminations				Consolidated Boardwalk Pipeline Partners, LP
	Guarantor				Issuer
Net income (loss)	$	29.2			$	21.8			$	50.3			$	(72.9	)		$	28.4

Other comprehensive income (loss):

Gain (loss) on cash flow hedges	0.2				0.2				0.2				(0.4		)		0.2

Reclassification adjustment transferred	0.5				0.5				0.1				(0.6		)		0.5
to Net Income from cash flow hedges
Pension and other postretirement	(2.0		)		(2.0		)		(2.0		)		4				(2.0		)
benefit costs
Total Comprehensive Income (Loss)	27.9				20.5				48.6				(69.9		)		27.1

Comprehensive loss attributable to	—				—				(0.8		)		—				(0.8		)
noncontrolling interests
Comprehensive income (loss) attributable to	$	27.9			$	20.5			$	49.4			$	(69.9	)		$	27.9
controlling interests

Condensed Consolidating Statements of Comprehensive Income for the Three Months Ended September 30, 2013
(Millions)



	Parent				Subsidiary				Non-guarantor Subsidiaries				Eliminations				Consolidated Boardwalk Pipeline Partners, LP
	Guarantor				Issuer
Net income (loss)	$	62.3			$	53.7			$	82.2			$	(136.5	)		$	61.7

Other comprehensive income (loss):

Reclassification adjustment transferred	(0.6		)		(0.6		)		(1.0		)		1.6				(0.6		)
to Net Income from cash flow hedges
Pension and other postretirement	(0.4		)		(0.4		)		(0.4		)		0.8				(0.4		)
benefit costs
Total Comprehensive Income (Loss)	61.3				52.7				80.8				(134.1		)		60.7

Comprehensive loss attributable to	—				—				(0.6		)		—				(0.6		)
noncontrolling interests
Comprehensive income (loss) attributable to	$	61.3			$	52.7			$	81.4			$	(134.1	)		$	61.3
controlling interests


Condensed Consolidating Statements of Comprehensive Income for the Nine Months Ended September 30, 2014
(Millions)



	Parent				Subsidiary				Non-guarantor Subsidiaries				Eliminations				Consolidated Boardwalk Pipeline Partners, LP
	Guarantor				Issuer
Net income (loss)	$	196.8			$	174			$	174.2			$	(435.1	)		$	109.9

Other comprehensive income (loss):

(Loss) gain on cash flow hedges	(0.7		)		(0.7		)		(0.7		)		1.4				(0.7		)

Reclassification adjustment transferred	2.1				2.1				0.8				(2.9		)		2.1
to Net Income from cash flow hedges
Pension and other postretirement	(5.9		)		(5.9		)		(5.9		)		11.8				(5.9		)
benefit costs
Total Comprehensive Income (Loss)	192.3				169.5				168.4				(424.8		)		105.4

Comprehensive loss attributable to	—				—				(86.9		)		—				(86.9		)
noncontrolling interests
Comprehensive income (loss) attributable to	$	192.3			$	169.5			$	255.3			$	(424.8	)		$	192.3
controlling interests

Condensed Consolidating Statements of Comprehensive Income for the Nine Months Ended September 30, 2013
(Millions)



	Parent				Subsidiary				Non-guarantor Subsidiaries				Eliminations				Consolidated Boardwalk Pipeline Partners, LP
	Guarantor				Issuer
Net income (loss)	$	234.2			$	209.1			$	294.4			$	(504.2	)		$	233.5

Other comprehensive income (loss):

Gain (loss) on cash flow hedges	2.5				2.5				2.5				(5.0		)		2.5

Reclassification adjustment transferred	0.5				0.5				(0.8		)		0.3				0.5
to Net Income from cash flow hedges
Pension and other postretirement	(4.0		)		(4.0		)		(4.0		)		8				(4.0		)
benefit costs
Total Comprehensive Income (Loss)	233.2				208.1				292.1				(500.9		)		232.5

Comprehensive loss attributable to	—				—				(0.7		)		—				(0.7		)
noncontrolling interests
Comprehensive income (loss) attributable to	$	233.2			$	208.1			$	292.8			$	(500.9	)		$	233.2
controlling interests



Condensed Consolidating Statements of Cash Flow for the Nine Months Ended September 30, 2014
(Millions)



	Parent				Subsidiary				Non-guarantor Subsidiaries				Eliminations					Consolidated Boardwalk Pipeline Partners, LP
	Guarantor				Issuer
Net cash provided by (used in)	$	22.8			$	(89.9	)		$	479.6			$	—				$	412.5
operating activities

INVESTING ACTIVITIES:

Capital expenditures	—				—				(315.9		)		—					(315.9		)

Proceeds from sale of operating assets	—				—				2.9				—					2.9

Proceeds from insurance and other	—				—				6.3				—					6.3
recoveries
Advances to affiliates, net	80.8				(34.9		)		(197.0		)		151.2					0.1

Investment in unconsolidated affiliates	—				—				(20.5		)		—					(20.5		)

Distribution from unconsolidated	—				—				10.7				—					10.7
affiliates
Acquisition-related deposit	(29.5		)		—				—				—					(29.5		)

Net cash provided by (used in)	51.3				(34.9		)		(513.5		)		151.2					(345.9		)
investing activities

FINANCING ACTIVITIES:

Proceeds from borrowings on revolving	—				—				340				—					340
credit agreement
Repayment of borrowings on revolving	—				—				(330.0		)		—					(330.0		)
credit agreement
Principal payment of capital lease	—				—				(0.3		)		—					(0.3		)
obligation
Repayment of borrowings from term	—				—				(25.0		)		—					(25.0		)
loan
Advances from affiliates, net	0.1				116.3				34.9				(151.2		)			0.1

Distributions paid	(74.4		)		—				—				—					(74.4		)

Capital contributions from	—				—				8.2				—			—		8.2
noncontrolling interests
Distributions paid to noncontrolling	—				—				(7.5		)		—					(7.5		)
interests
Net cash (used in) provided by	(74.3		)		116.3				20.3				(151.2		)			(88.9		)
financing activities

Decrease in cash and cash	(0.2		)		(8.5		)		(13.6		)		—					(22.3		)
equivalents
Cash and cash equivalents at	0.2				9.2				19.1				—					28.5
beginning of period
Cash and cash equivalents at	$	—			$	0.7			$	5.5			$	—				$	6.2
end of period

Condensed Consolidating Statements of Cash Flow for the Nine Months Ended September 30, 2013
(Millions)



	Parent				Subsidiary				Non-guarantor Subsidiaries				Eliminations				Consolidated Boardwalk Pipeline Partners, LP
	Guarantor				Issuer
Net cash provided by (used in)	$	26			$	(86.3	)		$	462.3			$	—			$	402
operating activities

INVESTING ACTIVITIES:

Capital expenditures	—				—				(204.3		)		—				(204.3		)

Proceeds from sale of operating assets	—				—				48.6				—				48.6

Proceeds from insurance and other	—				—				1.4				—				1.4
recoveries
Advances to affiliates, net	(7.6		)		(71.0		)		(168.7		)		244.5				(2.8		)

Investment in consolidated subsidiary	—				(15.1		)		—				15.1				—

Investment in unconsolidated affiliates	—				—				(25.6		)		—				(25.6		)

Net cash (used in) provided by	(7.6		)		(86.1		)		(348.6		)		259.6				(182.7		)
investing activities

FINANCING ACTIVITIES:

Proceeds from borrowings on revolving	—				—				813				—				813
credit agreement
Repayment of borrowings on revolving	—				—				(1,030.0		)		—				(1,030.0		)
credit agreement
Contribution from parent	—				—				15.1				(15.1		)		—

Principal payment of capital lease	—				—				(0.1		)		—				(0.1		)
obligation
Advances from affiliates, net	(2.8		)		173.5				71				(244.5		)		(2.8		)

Distributions paid	(392.0		)		—				—				—				(392.0		)

Capital contribution from	—				—				37.2				—				37.2
noncontrolling interests
Proceeds from sale of common units	368.7				—				—				—				368.7

Capital contributions from general	7.8				—				—				—				7.8
partner
Net cash (used in) provided by	(18.3		)		173.5				(93.8		)		(259.6		)		(198.2		)
financing activities

Increase in cash and cash	0.1				1.1				19.9				—				21.1
equivalents
Cash and cash equivalents at	0.1				1				2.8				—				3.9
beginning of period
Cash and cash equivalents at	$	0.2			$	2.1			$	22.7			$	—			$	25
end of period

Basis_of_Presentation_Basis_of

Basis of Presentation Basis of Presentation (Policies)	9 Months Ended
Basis of Presentation Basis of Presentation (Policies)	Sep. 30, 2014
Accounting Policies [Abstract]	'
Basis of Accounting, Policy [Policy Text Block]	'
	Basis of Presentation

	Boardwalk Pipeline Partners, LP (the Partnership) is a Delaware limited partnership formed in 2005 to own and operate the business conducted by its primary subsidiary Boardwalk Pipelines, LP (Boardwalk Pipelines) and its operating subsidiaries and consists of integrated natural gas and natural gas liquids (NGLs) pipeline and storage systems and natural gas gathering and processing.

	As of November 3, 2014, Boardwalk Pipelines Holding Corp. (BPHC), a wholly-owned subsidiary of Loews Corporation (Loews), owned 125.6 million of the Partnership’s common units, and, through Boardwalk GP, LP (Boardwalk GP), an indirect wholly-owned subsidiary of BPHC, holds the 2% general partner interest and all of the incentive distribution rights (IDRs). As of November 3, 2014, the common units and general partner interest owned by BPHC represent approximately 53% of the Partnership’s equity interests, excluding the IDRs. The Partnership’s common units are traded under the symbol “BWP” on the New York Stock Exchange.

	The accompanying unaudited condensed consolidated financial statements of the Partnership were prepared pursuant to the rules and regulations of the Securities and Exchange Commission. Certain information and footnote disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States of America (GAAP) have been condensed or omitted pursuant to such rules and regulations. In the opinion of management, the accompanying condensed consolidated financial statements reflect all adjustments (consisting of only normal recurring accruals) necessary to present fairly the financial position as of September 30, 2014, and December 31, 2013, and the results of operations and comprehensive income for the three and nine months ended September 30, 2014 and 2013, and changes in cash flows and changes in equity for the nine months ended September 30, 2014 and 2013. Reference is made to the Notes to Consolidated Financial Statements in the Annual Report on Form 10-K for the year ended December 31, 2013 (2013 Annual Report on Form 10-K), which should be read in conjunction with these unaudited condensed consolidated financial statements. The accounting policies described in Note 2 to the Consolidated Financial Statements included in such 2013 Annual Report on Form 10-K are the same used in preparing the accompanying unaudited condensed consolidated financial statements. Net income for interim periods may not necessarily be indicative of results for the full year.

Gas_and_Liquids_Stored_Undergr1

Gas and Liquids Stored Underground and Gas and NGLs Receivables and Payables Gas and Liquids Stored Underground and Gas and NGLs Receivables and Payables (Policies)	9 Months Ended
	Sep. 30, 2014
Accounting Policies [Abstract]	'
Gas Balancing Arrangements, Policy [Policy Text Block]	'
	Gas and Liquids Stored Underground and Gas and NGLs Receivables and Payables

	Subsidiaries of the Partnership provide storage services whereby they store gas or NGLs on behalf of customers and also periodically hold customer gas under parking and lending (PAL) services. Since the customers retain title to the gas held by the Partnership in providing these services, the Partnership does not record the related gas on its balance sheet.

	Subsidiaries of the Partnership also periodically lend gas to customers under PAL and no-notice services.

Fair_Value_Measurements_Deriva

Fair Value Measurements, Derivatives and Other Comprehensive Income (OCI) Derivatives (Policies)	9 Months Ended
	Sep. 30, 2014
Accounting Policies [Abstract]	'
Derivatives, Policy [Policy Text Block]	'
	Derivatives

	The Partnership uses futures, swaps and option contracts (collectively, derivatives) to hedge exposure to natural gas commodity price risk related to the future operational sales of natural gas and cash for fuel reimbursement where customers pay cash for the cost of fuel used in providing transportation services as opposed to having fuel retained in kind.

Fair_Value_Measurements_Deriva1

Fair Value Measurements, Derivatives and Other Comprehensive Income (OCI) Fair Value Measurement (Policies)	9 Months Ended
	Sep. 30, 2014
Accounting Policies [Abstract]	'
Fair Value Measurement, Policy [Policy Text Block]	'
	Financial Assets and Liabilities

	The following methods and assumptions were used in estimating the fair value amounts included in the disclosures for financial assets and liabilities, which are consistent with those disclosed in the 2013 Annual Report on Form 10-K:

	Cash and Cash Equivalents: For cash and short-term financial assets, the carrying amount is a reasonable estimate of fair value due to the short maturity of those instruments.

	Long-Term Debt: The estimated fair value of the Partnership's publicly traded debt is based on quoted market prices at September 30, 2014, and December 31, 2013. The fair market value of the debt that is not publicly traded is based on market prices of similar debt at September 30, 2014, and December 31, 2013. The carrying amount of the Partnership's variable rate debt approximates fair value because the instruments bear a floating market-based interest rate.

Cash_Distributions_and_Net_Inc1

Cash Distributions and Net Income per Unit Cash Distributions and Net Income per Unit (Policies)	9 Months Ended
	Sep. 30, 2014
Accounting Policies [Abstract]	'
Earnings Per Share, Policy [Policy Text Block]	'
	Net Income per Unit

	For purposes of calculating net income per unit, net income for the current period is reduced by the amount of available cash that will be distributed with respect to that period. Any residual amount representing undistributed net income (or loss) is assumed to be allocated to the various ownership interests in accordance with the contractual provisions of the partnership agreement.

	Under the Partnership’s partnership agreement, for any quarterly period, the IDRs participate in net income only to the extent of the amount of cash distributions actually declared, thereby excluding the IDRs from participating in undistributed net income or losses. Accordingly, undistributed net income is assumed to be allocated to the other ownership interests on a pro rata basis, except that the class B units’ participation in net income is limited to $0.30 per unit per quarter. The Class B units were converted to common units on a one-for-one basis in October 2013. Payments made on account of the Partnership’s various ownership interests are determined in relation to actual declared distributions, and are not based on the assumed allocations required under GAAP. Basic net income per unit is calculated based on the weighted-average number of units outstanding for the period. Diluted net income per unit is calculated assuming that the Class B units converted on the date that they became convertible, or July 1, 2013.

Fair_Value_Measurements_Deriva2

Fair Value Measurements, Derivatives and Other Comprehensive Income (OCI) Fair Value Assets and Liabilities Measured on Recurring and Nonrecurring Basis (Tables)	9 Months Ended
	Sep. 30, 2014
Table Text Block [Abstract]	'
Fair Value, Assets Measured on Recurring and Nonrecurring Basis [Table Text Block]	'
	The Partnership’s assets that were recorded at fair value on a non-recurring basis as of September 30, 2014, were as follows (in millions):


				Fair Value Measurements at
				30-Sep-14

		September 30,		Quoted prices in active markets for identical assets		Significant other observable inputs		Significant unobservable inputs		Total Gains (losses) for the three months ended September 30,		Total
		2014		(Level 1)		(Level 2)		(Level 3)		2014		Gains
												(losses) for the nine months ended
												September 30,
												2014

	Non-recurring fair value measurements - Assets
	Assets held and used	$	—	$	—	$	—	$	—	$	—	$	(7.1	)	(1)

	Investment in unconsolidated affiliates	—		—		—		—		—		(85.8		)	(1)



	-1	Net of noncontrolling interests of $82.9 million, the amount of the loss to the Partnership was $10.0 million. The impairment charge related to assets held and used represents the carrying amount of the assets. Note 2 contains more information regarding these measurements. Note 5 contains additional information related to asset impairment charges not included in the above table.

Fair_Value_Measurements_Deriva3

Fair Value Measurements, Derivatives and Other Comprehensive Income (OCI) Accumulated Other Comprehensive Income (Loss) (Tables)	9 Months Ended
	Sep. 30, 2014
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]	'
Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]	'

	The following table shows the components and reclassifications to net income of AOCI which is included in Partners' Capital on the Condensed Consolidated Balance Sheets for the three months ended September 30, 2014 (in millions):


		Cash Flow Hedges				Pension and Other Postretirement Costs				Total
	Beginning balance, July 1, 2014	$	(12.0	)		$	(55.0	)		$	(67.0	)
	Gain recorded in accumulated other comprehensive loss		0.2				—				0.2

	Reclassifications:
	Transportation operating revenues		(0.1	)			—				(0.1	)

	Interest expense		0.6				—				0.6

	Pension and other postretirement benefit costs		—				(2.0	)			(2.0	)


	Ending balance, September 30, 2014	$	(11.3	)		$	(57.0	)		$	(68.3	)

	The following table shows the components and reclassifications to net income of AOCI which is included in Partners' Capital on the Condensed Consolidated Balance Sheets for the three months ended September 30, 2013 (in millions):


		Cash Flow Hedges				Pension and Other Postretirement Costs				Total
	Beginning balance, July 1, 2013	$	(11.9	)		$	(55.4	)		$	(67.3	)
	Gain (loss) recorded in accumulated other comprehensive loss		—				—				—

	Reclassifications:
	Disposal of assets		(1.2	)			—				(1.2	)

	Interest expense		0.6				—				0.6

	Pension and other postretirement benefit costs		—				(0.4	)			(0.4	)


	Ending balance, September 30, 2013	$	(12.5	)		$	(55.8	)		$	(68.3	)

	The following table shows the components and reclassifications to net income of AOCI which is included in Partners' Capital on the Condensed Consolidated Balance Sheets for the nine months ended September 30, 2014 (in millions):


		Cash Flow Hedges				Pension and Other Postretirement Costs				Total
	Beginning balance, January 1, 2014	$	(12.7	)		$	(51.1	)		$	(63.8	)
	Loss recorded in accumulated other comprehensive loss		(0.7	)			—				(0.7	)

	Reclassifications:
	Transportation operating revenues		0.1				—				0.1

	Other operating revenues		0.2				—				0.2

	Interest expense		1.8				—				1.8

	Pension and other postretirement benefit costs		—				(5.9	)			(5.9	)


	Ending balance, September 30, 2014	$	(11.3	)		$	(57.0	)		$	(68.3	)

	The following table shows the components and reclassifications to net income of AOCI which is included in Partners' Capital on the Condensed Consolidated Balance Sheets for the nine months ended September 30, 2013 (in millions):


		Cash Flow Hedges				Pension and Other Postretirement Costs				Total
	Beginning balance, January 1, 2013	$	(15.5	)		$	(51.8	)		$	(67.3	)
	Gain recorded in accumulated other comprehensive loss		2.5				—				2.5

	Reclassifications:
	Transportation operating revenues		0.1				—				0.1

Other operating revenues		(0.1	)			—				(0.1	)

Disposal of assets		(1.2	)			—				(1.2	)

Interest expense		1.7				—				1.7

Pension and other postretirement benefit costs		—				(4.0	)			(4.0	)


Ending balance, September 30, 2013	$	(12.5	)		$	(55.8	)		$	(68.3	)

Financial_Assets_and_Liabiliti

Financial Assets and Liabilities (Tables)	9 Months Ended
	Sep. 30, 2014
Fair Value Disclosures [Abstract]	'
Fair Value, by Balance Sheet Grouping [Table Text Block]	'
	The carrying amount and estimated fair values of the Partnership's financial assets and liabilities which are not recorded at fair value on the Condensed Consolidated Balance Sheets as of September 30, 2014, and December 31, 2013, were as follows (in millions):


	As of September 30, 2014					Estimated Fair Value
	Financial Assets	Carrying Amount				Level 1			Level 2			Level 3			Total
	Cash and cash equivalents	$	6.2			$	6.2		$	—		$	—		$	6.2


	Financial Liabilities

	Long-term debt	$	3,400.90	(1)		$	—		$	3,551.10		$	—		$	3,551.10

	(1) The carrying amount of long-term debt excludes a $9.7 million capital lease obligation.



	As of December 31, 2013				Estimated Fair Value
	Financial Assets	Carrying Amount			Level 1			Level 2			Level 3			Total
	Cash and cash equivalents	$	28.5		$	28.5		$	—		$	—		$	28.5


	Financial Liabilities

	Long-term debt	$	3,414.40	(1)	$	—		$	3,573.80		$	—		$	3,573.80

	(1) The carrying amount of long-term debt excludes a $10.0 million capital lease obligation.

Cash_Distributions_and_Net_Inc2

Cash Distributions and Net Income per Unit (Tables)	9 Months Ended
	Sep. 30, 2014
Partners' Capital Notes [Abstract]	'
Distributions Made to Limited Partner, by Distribution [Table Text Block]	'

	The following table provides a reconciliation of net income and the assumed allocation of net income to the common units for purposes of computing net income per unit for the three months ended September 30, 2014, (in millions, except per unit data):


		Total				Common				General Partner and IDRs
						Units
	Net income	$	28.4

	Less: Net loss attributable to noncontrolling interests	(0.8		)
	Net income attributable to controlling interests	29.2

	Declared distribution	24.8				$	24.3			$	0.5

	Assumed allocation of undistributed net income	4.4				4.3				0.1

	Assumed allocation of net income attributable to limited	$	29.2			$	28.6			$	0.6
	partner unitholders and general partner
	Weighted-average units outstanding					243.3

	Net income per unit					$	0.12


	The following table provides a reconciliation of net income and the assumed allocation of net income to the common and class B units for purposes of computing basic and diluted net income per unit for the three months ended September 30, 2013, (in millions, except per unit data):


		Total				Common				Class B				General Partner and IDRs
						Units				Units
	Net income	$	61.7

	Less: Net loss attributable to noncontrolling interests	(0.6		)
	Net income attributable to controlling interests	62.3

	Declared distribution	141.9				$	129.5			$	—			$	12.4

	Assumed allocation of undistributed net loss - basic	(79.6		)		(70.7		)		(7.3		)		(1.6		)
	Assumed allocation of net income attributable to limited	62.3				58.8				(7.3		)		10.8
	partner unitholders and general partner - basic
	Allocation for diluted earnings per unit	—				(7.3		)		7.3				—

	Assumed allocation of net income attributable to limited	$	62.3			$	51.5			$	—			$	10.8
	partner unitholders and general partner - diluted
	Weighted-average units outstanding - basic					220.4				22.9

	Weighted-average units outstanding - diluted					243.3				—

	Net income per unit - basic					$	0.27			$	(0.32	)

	Net income per unit - diluted					$	0.21			$	—



	The following table provides a reconciliation of net income and the assumed allocation of net income to the common units for purposes of computing net income per unit for the nine months ended September 30, 2014, (in millions, except per unit data):


		Total				Common				General Partner and IDRs
						Units
	Net income	$	109.9

	Less: Net loss attributable to noncontrolling interests	(86.9		)
	Net income attributable to controlling interests	196.8

	Declared distribution	74.5				$	73			$	1.5

Assumed allocation of undistributed net income	122.3				119.9				2.4

Assumed allocation of net income attributable to limited	$	196.8			$	192.9			$	3.9
partner unitholders and general partner
Weighted-average units outstanding					243.3

Net income per unit					$	0.79


The following table provides a reconciliation of net income and the assumed allocation of net income to the common and class B units for purposes of computing basic and diluted net income per unit for the nine months ended September 30, 2013, (in millions, except per unit data):


	Total				Common				Class B				General Partner and IDRs
					Units				Units
Net income	$	233.5

Less: Net loss attributable to noncontrolling interests	(0.7		)
Net income attributable to controlling interests	234.2

Declared distribution	405.7				$	357.5			$	13.7			$	34.5

Assumed allocation of undistributed net loss - basic	(171.5		)		(151.9		)		(16.2		)		(3.4		)
Assumed allocation of net income attributable to limited	234.2				205.6				(2.5		)		31.1
partner unitholders and general partner - basic
Allocation for diluted earnings per unit	—				(5.4		)		5.4				—

Assumed allocation of net income attributable to limited	$	234.2			$	200.2			$	2.9			$	31.1
partner unitholders and general partner - diluted
Weighted-average units outstanding - basic					213.5				22.9

Weighted-average units outstanding - diluted					221.2				15.2

Net income per unit - basic					$	0.96			$	(0.11	)

Net income per unit - diluted					$	0.9			$	0.19

Employee_Benefits_Tables

Employee Benefits (Tables)	9 Months Ended
	Sep. 30, 2014
Compensation and Retirement Disclosure [Abstract]	'
Schedule of Net Benefit Costs [Table Text Block]	'
	Components of net periodic benefit cost for both the Retirement Plans and PBOP for the three months ended September 30, 2014 and 2013 were as follows (in millions):


		Retirement Plans						PBOP
		For the						For the
		Three Months Ended						Three Months Ended
		September 30,						September 30,
		2014			2013			2014			2013
	Service cost	$	0.9		$	0.8		$	0.1		$	0.1

	Interest cost	1.4			1.3			0.5			0.6

	Expected return on plan assets	(2.4		)	(2.4		)	(1.1		)	(1.1		)
	Amortization of prior service credit	—			—			(1.9		)	(2.0		)

	Amortization of unrecognized net loss	0.4			0.6			0.1			—

	Settlement charge	—			1.3			—			—

	Regulatory asset decrease	0.4			—			—			—

	Net periodic benefit cost	$	0.7		$	1.6		$	(2.3	)	$	(2.4	)


	Components of net periodic benefit cost for both the Retirement Plans and PBOP for the nine months ended September 30, 2014 and 2013 were as follows (in millions):


		Retirement Plans						PBOP
		For the						For the
		Nine Months Ended						Nine Months Ended
		September 30,						September 30,
		2014			2013			2014			2013
	Service cost	$	2.9		$	3		$	0.3		$	0.3

	Interest cost	4.2			3.7			1.6			1.5

	Expected return on plan assets	(7.1		)	(6.9		)	(3.2		)	(3.3		)
	Amortization of prior service credit	—			—			(5.8		)	(5.8		)

	Amortization of unrecognized net loss	1			1.8			0.2			—

	Settlement charge	—			1.3			—			—

	Regulatory asset decrease	1.3			—			—			—

	Net periodic benefit cost	$	2.3		$	2.9		$	(6.9	)	$	(7.3	)


	Through the date of this filing, the Partnership has made contributions of $3.0 million to the Pension Plan and does not expect to make additional contributions in 2014.

Supplemental_Disclosure_of_Cas1

Supplemental Disclosure of Cash Flow Information (Tables)	9 Months Ended
	Sep. 30, 2014
Supplemental Cash Flow Elements [Abstract]	'
Schedule of Cash Flow, Supplemental Disclosures [Table Text Block]	'
	Supplemental Disclosure of Cash Flow Information (in millions):


		For the
		Nine Months Ended
		September 30,
		2014		2013
	Cash paid during the period for:
	Interest (net of amount capitalized)	$	127.6	$	126.9

	Non-cash adjustments:
	Capital lease obligations incurred	—		10.5

Guarantee_of_Securities_of_Sub1

Guarantee of Securities of Subsidiaries (Tables)	9 Months Ended
	Sep. 30, 2014
Condensed Financial Information of Parent Company Only Disclosure [Abstract]	'
Condensed Consolidating Balance Sheet	'

	Condensed Consolidating Balance Sheets as of September 30, 2014
	(Millions)



	Assets		Parent				Subsidiary				Non-guarantor Subsidiaries				Eliminations				Consolidated Boardwalk Pipeline Partners, LP
			Guarantor				Issuer
	Cash and cash equivalents		$	—			$	0.7			$	5.5			$	—			$	6.2

	Receivables		—				—				94.7				(0.1		)		94.6

	Receivables - affiliate		—				—				6.8				(6.8		)		—

	Gas and liquids stored underground		—				—				4.5				—				4.5

	Prepayments		0.4				—				17.4				—				17.8

	Advances to affiliates		—				2.4				42.1				(44.5		)		—

	Other current assets		—				—				22.9				(7.5		)		15.4

	Total current assets		0.4				3.1				193.9				(58.9		)		138.5

	Investment in consolidated subsidiaries		1,679.80				6,423.10				—				(8,102.9		)		—

	Property, plant and equipment, gross		0.6				—				9,023.10				—				9,023.70

	Less–accumulated depreciation and		0.6				—				1,691.80				—				1,692.40
	amortization
	Property, plant and equipment, net		—				—				7,331.30				—				7,331.30

	Other noncurrent assets		—				3				458.5				(0.1		)		461.4

	Advances to affiliates – noncurrent		2,431.40				201.2				1,082.40				(3,715.0		)		—

	Total other assets		2,431.40				204.2				1,540.90				(3,715.1		)		461.4


	Total Assets		$	4,111.60			$	6,630.40			$	9,066.10			$	(11,876.9	)		$	7,931.20




	Liabilities and Equity		Parent				Subsidiary				Non-guarantor Subsidiaries				Eliminations				Consolidated Boardwalk Pipeline Partners, LP
			Guarantor				Issuer
	Payables		$	—			$	0.1			$	65.4			$	0.1			$	65.6

	Payable to affiliates		0.8				—				6.8				(6.8		)		0.8

	Advances from affiliates		—				42.1				2.4				(44.5		)		—

	Other current liabilities		—				14				166.7				(7.8		)		172.9

	Total current liabilities		0.8				56.2				241.3				(59.0		)		239.3

	Total long-term debt and capital lease		—				1,380.60				2,030.00				—				3,410.60
	obligation
	Payable to affiliate - noncurrent		16				—				—				—				16

	Advances from affiliates - noncurrent		—				3,513.80				201.2				(3,715.0		)		—

	Other noncurrent liabilities		—				—				170.2				—				170.2

Total other liabilities and deferred		16				3,513.80				371.4				(3,715.0		)		186.2
credits
Total partners' capital		4,094.80				1,679.80				6,423.10				(8,102.9		)		4,094.80

Noncontrolling interest		—				—				0.3				—				0.3

Total Equity		4,094.80				1,679.80				6,423.40				(8,102.9		)		4,095.10

Total Liabilities and Equity		$	4,111.60			$	6,630.40			$	9,066.10			$	(11,876.9	)		$	7,931.20


Condensed Consolidating Balance Sheets as of December 31, 2013
(Millions)


Assets		Parent				Subsidiary				Non-guarantor Subsidiaries				Eliminations				Consolidated Boardwalk Pipeline Partners, LP
		Guarantor				Issuer
Cash and cash equivalents		$	0.2			$	9.2			$	19.1			$	—			$	28.5

Receivables		—				—				119.2				—				119.2

Receivables - affiliate		0.1				0.1				14.3				(13.4		)		1.1

Gas and liquids stored underground		—				—				0.7				—				0.7

Prepayments		0.3				—				12.6				—				12.9

Advances to affiliates		—				—				194.4				(194.4		)		—

Other current assets		—				—				23.8				(9.1		)		14.7

Total current assets		0.6				9.3				384.1				(216.9		)		177.1

Investment in consolidated subsidiaries		1,480.80				6,138.30				—				(7,619.1		)		—

Property, plant and equipment, gross		0.6				—				8,722.70				—				8,723.30

Less–accumulated depreciation and		0.6				—				1,488.60				—				1,489.20
amortization
Property, plant and equipment, net		—				—				7,234.10				—				7,234.10

Other noncurrent assets		0.3				3.7				420.7				—				424.7

Advances to affiliates – noncurrent		2,512.10				168.7				733.1				(3,413.9		)		—

Investment in unconsolidated affiliates		—				—				78.6				—				78.6

Total other assets		2,512.40				172.4				1,232.40				(3,413.9		)		503.3


Total Assets		$	3,993.80			$	6,320.00			$	8,850.60			$	(11,249.9	)		$	7,914.50




Liabilities & Equity		Parent				Subsidiary				Non-guarantor Subsidiaries				Eliminations				Consolidated Boardwalk Pipeline Partners, LP
		Guarantor				Issuer
Payables		$	0.2			$	—			$	70.6			$	—			$	70.8

Payable to affiliates		0.7				—				13.9				(13.4		)		1.2

Advances from affiliates		—				194.4				—				(194.4		)		—

Other current liabilities		—				19.7				153.3				(9.0		)		164

Total current liabilities		0.9				214.1				237.8				(216.8		)		236

Total long-term debt and capital lease		—				1,379.90				2,044.50				—				3,424.40
obligation
Payable to affiliate - noncurrent		16				—				—				—				16

Advances from affiliates - noncurrent		—				3,245.20				168.7				(3,413.9		)		—

Other noncurrent liabilities		—				—				174.8				(0.1		)		174.7

Total other liabilities and deferred		16				3,245.20				343.5				(3,414.0		)		190.7
credits
Total partners' capital		3,976.90				1,480.80				6,138.30				(7,619.1		)		3,976.90

Noncontrolling interest		—				—				86.5				—				86.5

Total Equity		3,976.90				1,480.80				6,224.80				(7,619.1		)		4,063.40

Total Liabilities and Equity		$	3,993.80			$	6,320.00			$	8,850.60			$	(11,249.9	)		$	7,914.50

Condensed Consolidating Statements of Income	'

	Condensed Consolidating Statements of Income for the Three Months Ended September 30, 2014
	(Millions)



		Parent				Subsidiary				Non-guarantor Subsidiaries				Eliminations				Consolidated Boardwalk Pipeline Partners, LP
		Guarantor				Issuer
	Operating Revenues:
	Transportation	$	—			$	—			$	261.3			$	(22.4	)		$	238.9

	Parking and lending	—				—				3				—				3

	Storage	—				—				19.6				(0.4		)		19.2

	Other	—				—				17.8				—				17.8

	Total operating revenues	—				—				301.7				(22.8		)		278.9


	Operating Cost and Expenses:

	Fuel and transportation	—				—				54.7				(22.8		)		31.9

	Operation and maintenance	—				—				50.3				—				50.3

	Administrative and general	0.2				—				31.6				—				31.8

	Other operating costs and expenses	0.2				—				96.2				—				96.4

	Total operating costs and expenses	0.4				—				232.8				(22.8		)		210.4

	Operating (loss) income	(0.4		)		—				68.9				—				68.5


	Other Deductions (Income):

	Interest expense	—				18.7				21.3				—				40

	Interest (income) expense - affiliates, net	(7.8		)		10.6				(2.8		)		—				—

	Interest income	—				—				(0.1		)		—				(0.1		)

	Equity in earnings of subsidiaries	(21.8		)		(51.1		)		—				72.9				—

	Equity losses in unconsolidated	—				—				0.3				—				0.3
	affiliates
	Miscellaneous other income, net	—				—				(0.2		)		—				(0.2		)

	Total other (income) deductions	(29.6		)		(21.8		)		18.5				72.9				40


	Income (loss) before income taxes	29.2				21.8				50.4				(72.9		)		28.5

	Income taxes	—				—				0.1				—				0.1

	Net income (loss)	29.2				21.8				50.3				(72.9		)		28.4

	Net loss attributable to noncontrolling	—				—				(0.8		)		—				(0.8		)
	interests
	Net income (loss) attributable to controlling	$	29.2			$	21.8			$	51.1			$	(72.9	)		$	29.2
	interests

Condensed Consolidating Statements of Income for the Three Months Ended September 30, 2013
(Millions)



	Parent				Subsidiary				Non-guarantor Subsidiaries				Eliminations				Consolidated Boardwalk Pipeline Partners, LP
	Guarantor				Issuer
Operating Revenues:
Transportation	$	—			$	—			$	255.8			$	(22.3	)		$	233.5

Parking and lending	—				—				4.9				—				4.9

Storage	—				—				27.4				—				27.4

Other	—				—				9.7				—				9.7

Total operating revenues	—				—				297.8				(22.3		)		275.5


Operating Cost and Expenses:

Fuel and transportation	—				—				40.8				(22.3		)		18.5

Operation and maintenance	—				—				47				—				47

Administrative and general	—				—				29.1				—				29.1

Other operating costs and expenses	0.2				—				77.5				—				77.7

Total operating costs and expenses	0.2				—				194.4				(22.3		)		172.3

Operating (loss) income	(0.2		)		—				103.4				—				103.2


Other Deductions (Income):

Interest expense	—				18.7				22.3				—				41

Interest (income) expense - affiliates net	(8.8		)		10.4				(1.6		)		—				—

Interest income	—				—				(0.1		)		—				(0.1		)

Equity in earnings of subsidiaries	(53.7		)		(82.8		)		—				136.5				—

Equity losses in unconsolidated affiliates	—				—				0.6				—				0.6

Total other (income) deductions	(62.5		)		(53.7		)		21.2				136.5				41.5


Income (loss) before income taxes	62.3				53.7				82.2				(136.5		)		61.7

Income taxes	—				—				—				—				—

Net income (loss)	62.3				53.7				82.2				(136.5		)		61.7

Net loss attributable to noncontrolling	—				—				(0.6		)		—				(0.6		)
interests
Net income (loss) attributable to controlling	$	62.3			$	53.7			$	82.8			$	(136.5	)		$	62.3
interests






Condensed Consolidating Statements of Income for the Nine Months Ended September 30, 2014
(Millions)



	Parent				Subsidiary				Non-guarantor Subsidiaries				Eliminations				Consolidated Boardwalk Pipeline Partners, LP
	Guarantor				Issuer
Operating Revenues:
Transportation	$	—			$	—			$	856.9			$	(68.0	)		$	788.9

Parking and lending	—				—				21.4				—				21.4

Storage	—				—				70.6				(0.5		)		70.1

Other	—				—				48.8				—				48.8

Total operating revenues	—				—				997.7				(68.5		)		929.2


Operating Cost and Expenses:

Fuel and transportation	—				—				163.3				(68.5		)		94.8

Operation and maintenance	—				—				136.9				—				136.9

Administrative and general	0.1				—				89				—				89.1

Other operating costs and expenses	0.3				—				290.5				—				290.8

Total operating costs and expenses	0.4				—				679.7				(68.5		)		611.6

Operating (loss) income	(0.4		)		—				318				—				317.6


Other Deductions (Income):

Interest expense	—				56.1				65				—				121.1

Interest (income) expense - affiliates, net	(23.2		)		31				(7.8		)		—				—

Interest income	—				—				(0.4		)		—				(0.4		)

Equity in earnings of subsidiaries	(174.0		)		(261.1		)		—				435.1				—

Equity losses in unconsolidated	—				—				86.9				—				86.9
affiliates
Miscellaneous other income, net	—				—				(0.3		)		—				(0.3		)

Total other (income) deductions	(197.2		)		(174.0		)		143.4				435.1				207.3


Income (loss) before income taxes	196.8				174				174.6				(435.1		)		110.3

Income taxes	—				—				0.4				—				0.4

Net income (loss)	196.8				174				174.2				(435.1		)		109.9

Net loss attributable to noncontrolling	—				—				(86.9		)		—				(86.9		)
interests
Net income (loss) attributable to controlling	$	196.8			$	174			$	261.1			$	(435.1	)		$	196.8
interests

Condensed Consolidating Statements of Income for the Nine Months Ended September 30, 2013
(Millions)



	Parent				Subsidiary				Non-guarantor Subsidiaries				Eliminations				Consolidated Boardwalk Pipeline Partners, LP
	Guarantor				Issuer
Operating Revenues:
Transportation	$	—			$	—			$	826.2			$	(66.3	)		$	759.9

Parking and lending	—				—				19.9				—				19.9

Storage	—				—				83				(0.1		)		82.9

Other	—				—				30				—				30

Total operating revenues	—				—				959.1				(66.4		)		892.7


Operating Cost and Expenses:

Fuel and transportation	—				—				135				(66.4		)		68.6

Operation and maintenance	—				0.3				130.7				—				131

Administrative and general	—				0.8				88.6				—				89.4

Other operating costs and expenses	0.3				0.1				247.3				—				247.7

Total operating costs and expenses	0.3				1.2				601.6				(66.4		)		536.7

Operating (loss) income	(0.3		)		(1.2		)		357.5				—				356


Other Deductions (Income):

Interest expense	—				53.9				68.3				—				122.2

Interest (income) expense - affiliates net	(25.4		)		30.9				(5.5		)		—				—

Interest income	—				—				(0.4		)		—				(0.4		)

Equity in earnings of subsidiaries	(209.1		)		(295.1		)		—				504.2				—

Equity losses in unconsolidated affiliates	—				—				0.6				—				0.6

Miscellaneous other income, net	—				—				(0.2		)		—				(0.2		)

Total other (income) deductions	(234.5		)		(210.3		)		62.8				504.2				122.2


Income (loss) before income taxes	234.2				209.1				294.7				(504.2		)		233.8

Income taxes	—				—				0.3				—				0.3

Net income (loss)	234.2				209.1				294.4				(504.2		)		233.5

Net loss attributable to noncontrolling	—				—				(0.7		)		—				(0.7		)
interests
Net income (loss) attributable to controlling	$	234.2			$	209.1			$	295.1			$	(504.2	)		$	234.2
interests
Condensed Consolidating Statements Of Comprehensive Income	'






	Condensed Consolidating Statements of Comprehensive Income for the Three Months Ended September 30, 2014
	(Millions)



		Parent				Subsidiary				Non-guarantor Subsidiaries				Eliminations				Consolidated Boardwalk Pipeline Partners, LP
		Guarantor				Issuer
	Net income (loss)	$	29.2			$	21.8			$	50.3			$	(72.9	)		$	28.4

	Other comprehensive income (loss):

	Gain (loss) on cash flow hedges	0.2				0.2				0.2				(0.4		)		0.2

	Reclassification adjustment transferred	0.5				0.5				0.1				(0.6		)		0.5
	to Net Income from cash flow hedges
	Pension and other postretirement	(2.0		)		(2.0		)		(2.0		)		4				(2.0		)
	benefit costs
	Total Comprehensive Income (Loss)	27.9				20.5				48.6				(69.9		)		27.1

	Comprehensive loss attributable to	—				—				(0.8		)		—				(0.8		)
	noncontrolling interests
	Comprehensive income (loss) attributable to	$	27.9			$	20.5			$	49.4			$	(69.9	)		$	27.9
	controlling interests

	Condensed Consolidating Statements of Comprehensive Income for the Three Months Ended September 30, 2013
	(Millions)



		Parent				Subsidiary				Non-guarantor Subsidiaries				Eliminations				Consolidated Boardwalk Pipeline Partners, LP
		Guarantor				Issuer
	Net income (loss)	$	62.3			$	53.7			$	82.2			$	(136.5	)		$	61.7

	Other comprehensive income (loss):

	Reclassification adjustment transferred	(0.6		)		(0.6		)		(1.0		)		1.6				(0.6		)
	to Net Income from cash flow hedges
	Pension and other postretirement	(0.4		)		(0.4		)		(0.4		)		0.8				(0.4		)
	benefit costs
	Total Comprehensive Income (Loss)	61.3				52.7				80.8				(134.1		)		60.7

	Comprehensive loss attributable to	—				—				(0.6		)		—				(0.6		)
	noncontrolling interests
	Comprehensive income (loss) attributable to	$	61.3			$	52.7			$	81.4			$	(134.1	)		$	61.3
	controlling interests


	Condensed Consolidating Statements of Comprehensive Income for the Nine Months Ended September 30, 2014
	(Millions)



		Parent				Subsidiary				Non-guarantor Subsidiaries				Eliminations				Consolidated Boardwalk Pipeline Partners, LP
		Guarantor				Issuer
	Net income (loss)	$	196.8			$	174			$	174.2			$	(435.1	)		$	109.9

	Other comprehensive income (loss):

(Loss) gain on cash flow hedges	(0.7		)		(0.7		)		(0.7		)		1.4				(0.7		)

Reclassification adjustment transferred	2.1				2.1				0.8				(2.9		)		2.1
to Net Income from cash flow hedges
Pension and other postretirement	(5.9		)		(5.9		)		(5.9		)		11.8				(5.9		)
benefit costs
Total Comprehensive Income (Loss)	192.3				169.5				168.4				(424.8		)		105.4

Comprehensive loss attributable to	—				—				(86.9		)		—				(86.9		)
noncontrolling interests
Comprehensive income (loss) attributable to	$	192.3			$	169.5			$	255.3			$	(424.8	)		$	192.3
controlling interests

Condensed Consolidating Statements of Comprehensive Income for the Nine Months Ended September 30, 2013
(Millions)



	Parent				Subsidiary				Non-guarantor Subsidiaries				Eliminations				Consolidated Boardwalk Pipeline Partners, LP
	Guarantor				Issuer
Net income (loss)	$	234.2			$	209.1			$	294.4			$	(504.2	)		$	233.5

Other comprehensive income (loss):

Gain (loss) on cash flow hedges	2.5				2.5				2.5				(5.0		)		2.5

Reclassification adjustment transferred	0.5				0.5				(0.8		)		0.3				0.5
to Net Income from cash flow hedges
Pension and other postretirement	(4.0		)		(4.0		)		(4.0		)		8				(4.0		)
benefit costs
Total Comprehensive Income (Loss)	233.2				208.1				292.1				(500.9		)		232.5

Comprehensive loss attributable to	—				—				(0.7		)		—				(0.7		)
noncontrolling interests
Comprehensive income (loss) attributable to	$	233.2			$	208.1			$	292.8			$	(500.9	)		$	233.2
controlling interests
Condensed Consolidating Statements of Cash Flows	'



	Condensed Consolidating Statements of Cash Flow for the Nine Months Ended September 30, 2014
	(Millions)



		Parent				Subsidiary				Non-guarantor Subsidiaries				Eliminations					Consolidated Boardwalk Pipeline Partners, LP
		Guarantor				Issuer
	Net cash provided by (used in)	$	22.8			$	(89.9	)		$	479.6			$	—				$	412.5
	operating activities

	INVESTING ACTIVITIES:

	Capital expenditures	—				—				(315.9		)		—					(315.9		)

	Proceeds from sale of operating assets	—				—				2.9				—					2.9

	Proceeds from insurance and other	—				—				6.3				—					6.3
	recoveries
	Advances to affiliates, net	80.8				(34.9		)		(197.0		)		151.2					0.1

	Investment in unconsolidated affiliates	—				—				(20.5		)		—					(20.5		)

	Distribution from unconsolidated	—				—				10.7				—					10.7
	affiliates
	Acquisition-related deposit	(29.5		)		—				—				—					(29.5		)

	Net cash provided by (used in)	51.3				(34.9		)		(513.5		)		151.2					(345.9		)
	investing activities

	FINANCING ACTIVITIES:

	Proceeds from borrowings on revolving	—				—				340				—					340
	credit agreement
	Repayment of borrowings on revolving	—				—				(330.0		)		—					(330.0		)
	credit agreement
	Principal payment of capital lease	—				—				(0.3		)		—					(0.3		)
	obligation
	Repayment of borrowings from term	—				—				(25.0		)		—					(25.0		)
	loan
	Advances from affiliates, net	0.1				116.3				34.9				(151.2		)			0.1

	Distributions paid	(74.4		)		—				—				—					(74.4		)

	Capital contributions from	—				—				8.2				—			—		8.2
	noncontrolling interests
	Distributions paid to noncontrolling	—				—				(7.5		)		—					(7.5		)
	interests
	Net cash (used in) provided by	(74.3		)		116.3				20.3				(151.2		)			(88.9		)
	financing activities

	Decrease in cash and cash	(0.2		)		(8.5		)		(13.6		)		—					(22.3		)
	equivalents
	Cash and cash equivalents at	0.2				9.2				19.1				—					28.5
	beginning of period
	Cash and cash equivalents at	$	—			$	0.7			$	5.5			$	—				$	6.2
	end of period

	Condensed Consolidating Statements of Cash Flow for the Nine Months Ended September 30, 2013
	(Millions)



	Parent				Subsidiary				Non-guarantor Subsidiaries				Eliminations				Consolidated Boardwalk Pipeline Partners, LP
	Guarantor				Issuer
Net cash provided by (used in)	$	26			$	(86.3	)		$	462.3			$	—			$	402
operating activities

INVESTING ACTIVITIES:

Capital expenditures	—				—				(204.3		)		—				(204.3		)

Proceeds from sale of operating assets	—				—				48.6				—				48.6

Proceeds from insurance and other	—				—				1.4				—				1.4
recoveries
Advances to affiliates, net	(7.6		)		(71.0		)		(168.7		)		244.5				(2.8		)

Investment in consolidated subsidiary	—				(15.1		)		—				15.1				—

Investment in unconsolidated affiliates	—				—				(25.6		)		—				(25.6		)

Net cash (used in) provided by	(7.6		)		(86.1		)		(348.6		)		259.6				(182.7		)
investing activities

FINANCING ACTIVITIES:

Proceeds from borrowings on revolving	—				—				813				—				813
credit agreement
Repayment of borrowings on revolving	—				—				(1,030.0		)		—				(1,030.0		)
credit agreement
Contribution from parent	—				—				15.1				(15.1		)		—

Principal payment of capital lease	—				—				(0.1		)		—				(0.1		)
obligation
Advances from affiliates, net	(2.8		)		173.5				71				(244.5		)		(2.8		)

Distributions paid	(392.0		)		—				—				—				(392.0		)

Capital contribution from	—				—				37.2				—				37.2
noncontrolling interests
Proceeds from sale of common units	368.7				—				—				—				368.7

Capital contributions from general	7.8				—				—				—				7.8
partner
Net cash (used in) provided by	(18.3		)		173.5				(93.8		)		(259.6		)		(198.2		)
financing activities

Increase in cash and cash	0.1				1.1				19.9				—				21.1
equivalents
Cash and cash equivalents at	0.1				1				2.8				—				3.9
beginning of period
Cash and cash equivalents at	$	0.2			$	2.1			$	22.7			$	—			$	25
end of period

Basis_of_Presentation_Details

Basis of Presentation (Details)	3 Months Ended		9 Months Ended			0 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Nov. 03, 2014	Nov. 03, 2014
					Boardwalk Pipelines Holding Company	Boardwalk GP, LP
					Subsequent Event	Subsequent Event
Basis of Presentation [Line Items]	'	'	'	'	'	'
Number Of Partnerships Common Units Owned By Holding Company	'	'	'	'	125.6	'
Percent of general partner interest owned by holding company	2.00%	2.00%	2.00%	2.00%	'	2.00%
Percentage of Partnership's equity interests owned by holding company (in hundredths)	'	'	'	'	53.00%	'

Investments_Details

Investments (Details) (USD $)	3 Months Ended		9 Months Ended						3 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013	Dec. 31, 2012	Sep. 30, 2014	Dec. 31, 2013	Mar. 31, 2014
							Bluegrass Pipeline, Moss Lake Fractionation and Moss Lake LPG	Bluegrass Pipeline, Moss Lake Fractionation and Moss Lake LPG	Boardwalk Bluegrass and Boardwalk Moss Lake, Bluegrass Pipeline, Moss Lake Fractionation and Moss Lake LPG [Member]
							Boardwalk Bluegrass and Boardwalk Moss Lake	Boardwalk Bluegrass and Boardwalk Moss Lake	Boardwalk Pipeline Partners, LP
Variable Interest Entity [Line Items]	'	'	'	'	'	'	'	'	'
Total Project Related Impairment	'	'	'	'	'	'	'	'	($92.90)
Income (Loss) from Impairment Attributable to Noncontrolling Interest	'	'	'	'	'	'	'	'	-82.9
Income (Loss) from Equity Method Investments	-0.3	-0.6	-86.9	-0.6	'	'	'	'	-10
Cash	6.2	25	6.2	25	28.5	3.9	0.3	15	'
Investment in unconsolidated affiliates	0	'	0	'	78.6	'	0	78.6	'
Construction work in progress	$325.10	'	$325.10	'	$174.50	'	'	$6.80	'

Gas_and_Liquids_Stored_Undergr2

Gas and Liquids Stored Underground And Gas and NGLs Receivables And Payables (Details) (Gas and NGLs Loaned to Customers [Member], USD $)	Sep. 30, 2014	Dec. 31, 2013
In Millions, unless otherwise specified	MMBTU	MMBTU
	MMBbls	MMBbls
Gas and NGLs Loaned to Customers [Member]	'	'
Gas and Liquids Stored Underground and Gas and NGLs Receivables and Payables [Line Items]	'	'
Gas Balancing Volume Amount (in MMBtu)	7,200,000	19,600,000
Average market price per million British thermal units	3.87	'
Market value of gas owed to operating subsidiaries due to gas imbalances and gas loaned under PAL and no-notice services	$27.80	'
Natural Gas Liquids Balancing Volume (in MMbbls)	0	0

Fair_Value_Measurements_Deriva4

Fair Value Measurements, Derivatives and Other Comprehensive Income (OCI) Fair Value Measurements Assets and Liabilities Measured on Recurring and Nonrecurring (Details) (Fair Value, Measurements, Nonrecurring, USD $)	3 Months Ended	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets held and used	$0	$0
Impaired Long-Lived Assets Held and Used, Asset Description	0	-7.1
Investment in unconsolidated affiliates	0	0
Equity Method Investment, Other than Temporary Impairment	0	-85.8
Income (Loss) from Impairment Attributable to Noncontrolling Interest	'	-82.9
Income (Loss) from Impairments Attributable to Parent	'	-10
Liabilities, Fair Value Disclosure, Nonrecurring	0	0
Fair Value, Inputs, Level 1	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets held and used	0	0
Investment in unconsolidated affiliates	0	0
Fair Value, Inputs, Level 2	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets held and used	0	0
Investment in unconsolidated affiliates	0	0
Fair Value, Inputs, Level 3	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets held and used	0	0
Investment in unconsolidated affiliates	$0	$0

Derivatives_Details

Derivatives (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Derivatives, Fair Value [Line Items]	'	'
Gas stored underground	$4.20	$0.30
Commodity Contract \| Designated as Hedging Instrument \| Other current assets	'	'
Derivatives, Fair Value [Line Items]	'	'
Derivative Asset, Fair Value, Amount Not Offset Against Collateral (less than $0.1 million)	$0.10	$0.50

Fair_Value_Measurements_Deriva5

Fair Value Measurements, Derivatives and Other Comprehensive Income (OCI) Accumulated Other Comprehensive Income (Loss) (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]	'	'	'	'
Beginning balance	($67)	($67.30)	($63.80)	($67.30)
Gain (loss) recorded in accumulated other comprehensive loss	0.2	0	-0.7	2.5
Transportation operating revenues	238.9	233.5	788.9	759.9
Interest expense	40	41	121.1	122.2
Pension and other postretirement benefit costs	-2	-0.4	-5.9	-4
Ending balance	-68.3	-68.3	-68.3	-68.3
Reclassification out of Accumulated Other Comprehensive Income [Member]	'	'	'	'
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]	'	'	'	'
Transportation operating revenues	-0.1	'	0.1	0.1
Other operating revenues	'	'	0.2	-0.1
Disposal of assets	'	-1.2	'	-1.2
Interest expense	0.6	0.6	1.8	1.7
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]	'	'	'	'
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]	'	'	'	'
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months	'	'	2.3	'
Beginning balance	-12	-11.9	-12.7	-15.5
Gain (loss) recorded in accumulated other comprehensive loss	0.2	0	-0.7	2.5
Pension and other postretirement benefit costs	0	0	0	0
Ending balance	-11.3	-12.5	-11.3	-12.5
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member] \| Reclassification out of Accumulated Other Comprehensive Income [Member]	'	'	'	'
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]	'	'	'	'
Transportation operating revenues	-0.1	'	0.1	0.1
Other operating revenues	'	'	0.2	-0.1
Disposal of assets	'	-1.2	'	-1.2
Interest expense	0.6	0.6	1.8	1.7
Accumulated Defined Benefit Plans Adjustment [Member]	'	'	'	'
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]	'	'	'	'
Beginning balance	-55	-55.4	-51.1	-51.8
Gain (loss) recorded in accumulated other comprehensive loss	0	0	0	0
Pension and other postretirement benefit costs	-2	-0.4	-5.9	-4
Ending balance	-57	-55.8	-57	-55.8
Accumulated Defined Benefit Plans Adjustment [Member] \| Reclassification out of Accumulated Other Comprehensive Income [Member]	'	'	'	'
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]	'	'	'	'
Transportation operating revenues	0	'	0	0
Other operating revenues	'	'	0	0
Disposal of assets	'	0	'	0
Interest expense	$0	$0	$0	$0

Financial_Assets_and_Liabiliti1

Financial Assets and Liabilities (Details) (USD $)	Sep. 30, 2014		Dec. 31, 2013		Sep. 30, 2013	Dec. 31, 2012
In Millions, unless otherwise specified	Sep. 30, 2014		Dec. 31, 2013		Sep. 30, 2013	Dec. 31, 2012
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'		'	'
Cash and cash equivalents	$6.20		$28.50		$25	$3.90
Capital Lease Obligations, Noncurrent	9.7		10		'	'
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]	'		'		'	'
Cash and Cash Equivalents - Fair Value	6.2		28.5		'	'
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]	'		'		'	'
Long-term Debt - Fair Value	3,551.10		3,573.80		'	'
Carrying Amount	'		'		'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'		'		'	'
Cash and cash equivalents	6.2		28.5		'	'
Long-term Debt	3,400.90	[1]	3,414.40	[2]	'	'
Fair Value \| Fair Value, Inputs, Level 1	'		'		'	'
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]	'		'		'	'
Cash and Cash Equivalents - Fair Value	6.2		28.5		'	'
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]	'		'		'	'
Long-term Debt - Fair Value	0		0		'	'
Fair Value \| Fair Value, Inputs, Level 2	'		'		'	'
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]	'		'		'	'
Cash and Cash Equivalents - Fair Value	0		0		'	'
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]	'		'		'	'
Long-term Debt - Fair Value	3,551.10		3,573.80		'	'
Fair Value \| Fair Value, Inputs, Level 3	'		'		'	'
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]	'		'		'	'
Cash and Cash Equivalents - Fair Value	0		0		'	'
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]	'		'		'	'
Long-term Debt - Fair Value	$0		$0		'	'

[1]	The carrying amount of long-term debt excludes a $9.7 million capital lease obligation.
[2]	The carrying amount of long-term debt excludes a $10.0 million capital lease obligation.

Property_Plant_and_Equipment_P

Property, Plant and Equipment Property, Plant and Equipment (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
	Sep. 30, 2014	MMcf	Sep. 30, 2014	MMcf
Gain (Loss) on Disposition of Other Assets	'	$12.50	'	$29.50
Volume Of Gas Sold (in MMcf)	'	9,700	'	14,700
Carrying Value Before Sale or Impairment	'	23.1	'	25.7
Asset impairment	$0	$0	$8.60	$1.20

Commitments_and_Contingencies_

Commitments and Contingencies Legal Proceedings and Settlements (Details)	9 Months Ended
	Sep. 30, 2014
Whistler Junction Matter [Member]	'
Loss Contingencies [Line Items]	'
Number of Lawsuits Filed	9
Number of Class Action Lawsuits Filed	1
Southeast Louisiana Flood Protection Litigation [Member]	'
Loss Contingencies [Line Items]	'
Loss Contingency, Number of Defendants (in ones)	100

Commitments_and_Contingencies_1

Commitments and Contingencies (Details) (USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Environmental and Safety Matters [Abstract]	'	'
Accrual for Environmental Loss Contingencies	$6	$6.50
Number of years the related expenditures are expected to cover assessment and remediation costs (in years)	'8	'
Accrued Environmental Loss Contingencies, Current	1.5	1.5
Accrued Environmental Loss Contingencies, Noncurrent	4.5	5
Commitments for Construction [Abstract]	'	'
Purchase Commitment, Remaining Minimum Amount Committed	$85	'

Cash_Distributions_and_Net_Inc3

Cash Distributions and Net Income per Unit (Details) (USD $)

3 Months Ended

9 Months Ended

3 Months Ended

9 Months Ended

3 Months Ended

9 Months Ended

3 Months Ended

9 Months Ended

3 Months Ended

9 Months Ended

3 Months Ended

9 Months Ended

In Millions, except Per Share data, unless otherwise specified

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Oct. 30, 2014

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Common Units

Class B Units

General Partner and IDRs

Subsequent Event

Common Units

Class B Units

Reconciliation And Allocation of Net Income By Class of Stock [Line Items]

Class B unitholders' maximum quarterly distribution per unit

$0.30

Cash distribution declared and paid (in units)

$0.10

$0.53

$0.30

$1.60

$0.30

$0.90

Percent of general partner interest owned by holding company

2.00%

Dividends Payable, Amount Per Share

$0.10

Net Income

$28.40

$61.70

$109.90

$233.50

Less: Net loss attributable to noncontrolling interests

-0.8

-0.6

-86.9

-0.7

Net income attributable to controlling interests

29.2

62.3

196.8

234.2

Declared distribution

24.8

141.9

74.5

405.7

24.3

129.5

357.5

13.7

0.5

12.4

1.5

34.5

Assumed allocation of undistributed net income

4.4

-79.6

122.3

-171.5

4.3

-70.7

119.9

-151.9

-7.3

-16.2

0.1

-1.6

2.4

-3.4

Assumed allocation of net income attributable to limited partner unitholders and general partner

29.2

62.3

196.8

234.2

28.6

58.8

192.9

205.6

-7.3

-2.5

0.6

10.8

3.9

31.1

Allocation for diluted earnings per unit

-7.3

-5.4

7.3

5.4

Assumed allocation of net income attributable to limited partner unitholders and general partner - diluted

$62.30

$234.20

$51.50

$200.20

$2.90

$10.80

$31.10

Weighted-average units outstanding - basic (in units)

243.3

220.4

243.3

213.5

22.9

243.3

220.4

243.3

213.5

22.9

Weighted-average units outstanding - diluted (in units)

243.3

221.2

15.2

243.3

221.2

15.2

Basic net income per unit

$0.12

$0.27

$0.79

$0.96

($0.32)

($0.11)

$0.12

$0.27

$0.79

$0.96

($0.32)

($0.11)

Diluted net income per unit

$0.21

$0.90

$0.19

$0.12

$0.21

$0.79

$0.90

$0.19

Financing_Details

Financing (Details) (USD $)	9 Months Ended			9 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014	Sep. 30, 2014	Sep. 30, 2014	Sep. 30, 2014	Dec. 31, 2013	Nov. 03, 2014
		Unsecured Debt [Member]	Unsecured Debt [Member]	Line of Credit [Member]	Line of Credit [Member]	Subordinated Debt	Gulf South Notes Due 2015	Texas Gas Notes Due 2015	Term Loan Boardwalk Acquisition Company	Term Loan Boardwalk Acquisition Company	Scenario, Forecast
							Unsecured Debt [Member]	Unsecured Debt [Member]			Subsequent Event
Debt Instruments [Abstract]	'	'	'	'	'	'	'	'	'	'	'
Long-term Debt, Gross	'	$3,000	$3,000	'	'	'	$275	$250	$225	'	'
Debt, Weighted Average Interest Rate	'	5.32%	5.32%	1.53%	1.29%	'	'	'	1.90%	1.92%	'
Debt Instrument, Maturity Date	'	'	'	'	'	31-Jul-24	1-Feb-15	1-Jun-15	1-Oct-17	'	'
Debt Instrument, Covenant Compliance	'	'The Partnership and its subsidiaries were in compliance with their debt covenants.	'	'	'	'	'	'	'	'	'
Debt Instrument, Covenant Description	'	'	'	'	'	'	'	'	'The 2017 Term Loan bears interest at a rate that is based on the one-month London Interbank Offered Rate (LIBOR) plus an applicable margin.	'	'
Debt Instrument, Face Amount	'	'	'	'	'	'	'	'	200	225	'
Subordinated Loan Agreement Maximum Borrowing Capacity	'	'	'	'	'	300	'	'	'	'	'
Debt Instrument, Interest Rate, Stated Percentage Rate Range, Minimum	'	'	'	'	'	5.75%	'	'	'	'	'
Debt Instrument, Interest Rate, Stated Percentage Rate Range, Maximum	'	'	'	'	'	9.75%	'	'	'	'	'
Subordinated Borrowing Terms and Conditions	'	'	'	'	'	'The Subordinated Loan bears interest at increasing rates, ranging 5.75% to 9.75%, payable semi-annually in June and December, commencing December 2014, and maturing in July 2024	'	'	'	'	'
Line of Credit Facility [Abstract]	'	'	'	'	'	'	'	'	'	'	'
Long-term Line of Credit	'	'	'	185	175	'	'	'	'	'	485
Line of Credit Facility, Remaining Borrowing Capacity	'	'	'	'	'	'	'	'	'	'	$515
Covenant terms	'	'	'	'a ratio of total consolidated debt to consolidated EBITDA (as defined in the Amended Credit Agreement) measured for the previous twelve months of not more than 5.0 to 1.0, or up to 5.5 to 1.0 for the three quarters following an acquisition.	'	'	'	'	'	'	'
Line of Credit Facility, Covenant Compliance	'	'	'	'The Partnership and its subsidiaries were in compliance with all covenant requirements under the credit facility.	'	'	'	'	'	'	'
Maximum Ratio of Debt to EBITDA	'5.0 to 1.0	'	'	'	'	'	'	'	'	'	'
Maximum Ratio of Debt to EBITDA after Acquisition	'5.5 to 1.0	'	'	'	'	'	'	'	'	'	'

Financing_Equity_Offering_Deta

Financing Equity Offering (Details) (USD $)	3 Months Ended		9 Months Ended		3 Months Ended
In Millions, except Per Share data, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Jun. 30, 2013
					Common Units
					Second Quarter 2013 Offering [Member]
Capital Unit [Line Items]	'	'	'	'	'
Partners' Capital Account, Units, Sold in Public Offering	'	'	'	'	12.7
Issuance Price (in dollars per share)	'	'	'	'	$30.12
Proceeds from Issuance or Sale of Equity	'	'	'	'	$376.50
Less Underwriting Discounts and Expenses	'	'	'	'	12.3
General Partners' Contributed Capital	'	'	'	'	$7.80
Percent of general partner interest owned by holding company	2.00%	2.00%	2.00%	2.00%	2.00%

Employee_Benefits_Details

Employee Benefits (Details) (USD $)

3 Months Ended

9 Months Ended

3 Months Ended

9 Months Ended

3 Months Ended

9 Months Ended

0 Months Ended

In Millions, unless otherwise specified

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Nov. 03, 2014

Retirement Plans [Member]

PBOP [Member]

Subsequent Event

Scenario, Forecast

Subsequent Event

Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]

Service cost

$0.90

$0.80

$2.90

$0.10

$0.30

Interest cost

1.4

1.3

4.2

3.7

0.5

0.6

1.6

1.5

Expected return on plan assets

-2.4

-7.1

-6.9

-1.1

-3.2

-3.3

Amortization of prior service credit

-1.9

-2

-5.8

Amortization of unrecognized net loss

0.4

0.6

1.8

0.1

0.2

Settlement charge

1.3

Regulatory asset decrease

0.4

1.3

Net periodic benefit cost

0.7

1.6

2.3

2.9

-2.3

-2.4

-6.9

-7.3

Contribution to defined benefit pension plan

Defined benefit plan, estimated future employer contributions in current fiscal year

Defined Contribution Plan, Cost Recognized

$2.20

$6.60

Related_Party_Transactions_Det

Related Party Transactions (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Related Party Transaction [Line Items]	'	'	'	'	'
Related Party Transaction, Expenses from Transactions with Related Party	$2.20	$2.10	$6.60	$6.30	'
Percent of general partner interest owned by holding company	2.00%	2.00%	2.00%	2.00%	'
Cash dividends paid to parent company	13	72.9	39	217.6	'
Investment in unconsolidated affiliates	0	'	0	'	78.6
Distribution from unconsolidated affiliates	'	'	10.7	0	'
Payments of Ordinary Dividends, Noncontrolling Interest	'	'	7.5	0	'
Boardwalk Bluegrass and Boardwalk Moss Lake \| Boardwalk Pipeline Partners, LP	'	'	'	'	'
Related Party Transaction [Line Items]	'	'	'	'	'
Investment in unconsolidated affiliates	12.7	'	12.7	'	11.9
Boardwalk Bluegrass and Boardwalk Moss Lake \| Boardwalk Pipelines Holding Company	'	'	'	'	'
Related Party Transaction [Line Items]	'	'	'	'	'
Investment in unconsolidated affiliates	97.8	'	97.8	'	90
Boardwalk Moss Lake \| Boardwalk Pipeline Partners, LP	'	'	'	'	'
Related Party Transaction [Line Items]	'	'	'	'	'
Distribution from unconsolidated affiliates	'	'	1.9	'	'
Boardwalk Moss Lake \| Boardwalk Pipelines Holding Company	'	'	'	'	'
Related Party Transaction [Line Items]	'	'	'	'	'
Payments of Ordinary Dividends, Noncontrolling Interest	'	'	7.1	'	'
Subordinated Debt	'	'	'	'	'
Related Party Transaction [Line Items]	'	'	'	'	'
Subordinated Loan Agreement Maximum Borrowing Capacity	$300	'	$300	'	'

Subsequent_Event_Details

Subsequent Event (Details) (USD $)	9 Months Ended		0 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Oct. 08, 2014
			Subsequent Event
			Chevron Petrochemical Pipeline, LLC [Member]
Subsequent Event [Line Items]	'	'	'
Business Acquisition, Transaction Costs	'	'	$295
Other Payments to Acquire Businesses	$29.50	$0	$29.50

Supplemental_Disclosure_of_Cas2

Supplemental Disclosure of Cash Flow Information (Details) (USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Cash paid during the period for:	'	'
Interest (net of amount capitalized)	$127.60	$126.90
Capital Lease Obligations Incurred	$0	$10.50

Guarantee_of_Securities_of_Sub2

Guarantee of Securities of Subsidiaries Balance Sheets (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2013	Dec. 31, 2012
In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2013	Dec. 31, 2012
Assets	'	'	'	'
Cash and cash equivalents	$6.20	$28.50	$25	$3.90
Receivables	94.6	119.2	'	'
Receivables - affiliate	0	1.1	'	'
Gas and liquids stored underground	4.5	0.7	'	'
Prepayments	17.8	12.9	'	'
Advances to affiliates	0	0	'	'
Other current assets	15.4	14.7	'	'
Total current assets	138.5	177.1	'	'
Investment in consolidated subsidiaries	0	0	'	'
Property, plant and equipment, gross	9,023.70	8,723.30	'	'
Lessbaccumulated depreciation and amortization	1,692.40	1,489.20	'	'
Property, plant and equipment, net	7,331.30	7,234.10	'	'
Other noncurrent assets	461.4	424.7	'	'
Advances to affiliates - noncurrent	0	0	'	'
Investment in unconsolidated affiliates	0	78.6	'	'
Total other assets	461.4	503.3	'	'
Total Assets	7,931.20	7,914.50	'	'
Liabilities and Equity	'	'	'	'
Payables	65.6	70.8	'	'
Payable to affiliates	0.8	1.2	'	'
Advances from affiliates	0	0	'	'
Other current liabilities	172.9	164	'	'
Total current liabilities	239.3	236	'	'
Total long-term debt and capital lease obligation	3,410.60	3,424.40	'	'
Payable to affiliate - noncurrent	16	16	'	'
Advances from affiliates - noncurrent	0	0	'	'
Other noncurrent liabilities	170.2	174.7	'	'
Total other liabilities and deferred credits	186.2	190.7	'	'
Total partners' capital	4,094.80	3,976.90	'	'
Noncontrolling interest	0.3	86.5	'	'
Total Equity	4,095.10	4,063.40	4,134.40	3,877.10
Total Liabilities and Equity	7,931.20	7,914.50	'	'
Eliminations	'	'	'	'
Assets	'	'	'	'
Cash and cash equivalents	0	0	0	0
Receivables	-0.1	0	'	'
Receivables - affiliate	-6.8	-13.4	'	'
Gas and liquids stored underground	0	0	'	'
Prepayments	0	0	'	'
Advances to affiliates	-44.5	-194.4	'	'
Other current assets	-7.5	-9.1	'	'
Total current assets	-58.9	-216.9	'	'
Investment in consolidated subsidiaries	-8,102.90	-7,619.10	'	'
Property, plant and equipment, gross	0	0	'	'
Lessbaccumulated depreciation and amortization	0	0	'	'
Property, plant and equipment, net	0	0	'	'
Other noncurrent assets	-0.1	0	'	'
Advances to affiliates - noncurrent	-3,715	-3,413.90	'	'
Investment in unconsolidated affiliates	'	0	'	'
Total other assets	-3,715.10	-3,413.90	'	'
Total Assets	-11,876.90	-11,249.90	'	'
Liabilities and Equity	'	'	'	'
Payables	0.1	0	'	'
Payable to affiliates	-6.8	-13.4	'	'
Advances from affiliates	-44.5	-194.4	'	'
Other current liabilities	-7.8	-9	'	'
Total current liabilities	-59	-216.8	'	'
Total long-term debt and capital lease obligation	0	0	'	'
Payable to affiliate - noncurrent	0	0	'	'
Advances from affiliates - noncurrent	-3,715	-3,413.90	'	'
Other noncurrent liabilities	0	-0.1	'	'
Total other liabilities and deferred credits	-3,715	-3,414	'	'
Total partners' capital	-8,102.90	-7,619.10	'	'
Noncontrolling interest	0	0	'	'
Total Equity	-8,102.90	-7,619.10	'	'
Total Liabilities and Equity	-11,876.90	-11,249.90	'	'
Parent Guarantor	'	'	'	'
Assets	'	'	'	'
Cash and cash equivalents	0	0.2	0.2	0.1
Receivables	0	0	'	'
Receivables - affiliate	0	0.1	'	'
Gas and liquids stored underground	0	0	'	'
Prepayments	0.4	0.3	'	'
Advances to affiliates	0	0	'	'
Other current assets	0	0	'	'
Total current assets	0.4	0.6	'	'
Investment in consolidated subsidiaries	1,679.80	1,480.80	'	'
Property, plant and equipment, gross	0.6	0.6	'	'
Lessbaccumulated depreciation and amortization	0.6	0.6	'	'
Property, plant and equipment, net	0	0	'	'
Other noncurrent assets	0	0.3	'	'
Advances to affiliates - noncurrent	2,431.40	2,512.10	'	'
Investment in unconsolidated affiliates	'	0	'	'
Total other assets	2,431.40	2,512.40	'	'
Total Assets	4,111.60	3,993.80	'	'
Liabilities and Equity	'	'	'	'
Payables	0	0.2	'	'
Payable to affiliates	0.8	0.7	'	'
Advances from affiliates	0	0	'	'
Other current liabilities	0	0	'	'
Total current liabilities	0.8	0.9	'	'
Total long-term debt and capital lease obligation	0	0	'	'
Payable to affiliate - noncurrent	16	16	'	'
Advances from affiliates - noncurrent	0	0	'	'
Other noncurrent liabilities	0	0	'	'
Total other liabilities and deferred credits	16	16	'	'
Total partners' capital	4,094.80	3,976.90	'	'
Noncontrolling interest	0	0	'	'
Total Equity	4,094.80	3,976.90	'	'
Total Liabilities and Equity	4,111.60	3,993.80	'	'
Subsidiary Issuer	'	'	'	'
Assets	'	'	'	'
Cash and cash equivalents	0.7	9.2	2.1	1
Receivables	0	0	'	'
Receivables - affiliate	0	0.1	'	'
Gas and liquids stored underground	0	0	'	'
Prepayments	0	0	'	'
Advances to affiliates	2.4	0	'	'
Other current assets	0	0	'	'
Total current assets	3.1	9.3	'	'
Investment in consolidated subsidiaries	6,423.10	6,138.30	'	'
Property, plant and equipment, gross	0	0	'	'
Lessbaccumulated depreciation and amortization	0	0	'	'
Property, plant and equipment, net	0	0	'	'
Other noncurrent assets	3	3.7	'	'
Advances to affiliates - noncurrent	201.2	168.7	'	'
Investment in unconsolidated affiliates	'	0	'	'
Total other assets	204.2	172.4	'	'
Total Assets	6,630.40	6,320	'	'
Liabilities and Equity	'	'	'	'
Payables	0.1	0	'	'
Payable to affiliates	0	0	'	'
Advances from affiliates	42.1	194.4	'	'
Other current liabilities	14	19.7	'	'
Total current liabilities	56.2	214.1	'	'
Total long-term debt and capital lease obligation	1,380.60	1,379.90	'	'
Payable to affiliate - noncurrent	0	0	'	'
Advances from affiliates - noncurrent	3,513.80	3,245.20	'	'
Other noncurrent liabilities	0	0	'	'
Total other liabilities and deferred credits	3,513.80	3,245.20	'	'
Total partners' capital	1,679.80	1,480.80	'	'
Noncontrolling interest	0	0	'	'
Total Equity	1,679.80	1,480.80	'	'
Total Liabilities and Equity	6,630.40	6,320	'	'
Non-Guarantor Subsidiaries	'	'	'	'
Assets	'	'	'	'
Cash and cash equivalents	5.5	19.1	22.7	2.8
Receivables	94.7	119.2	'	'
Receivables - affiliate	6.8	14.3	'	'
Gas and liquids stored underground	4.5	0.7	'	'
Prepayments	17.4	12.6	'	'
Advances to affiliates	42.1	194.4	'	'
Other current assets	22.9	23.8	'	'
Total current assets	193.9	384.1	'	'
Investment in consolidated subsidiaries	0	0	'	'
Property, plant and equipment, gross	9,023.10	8,722.70	'	'
Lessbaccumulated depreciation and amortization	1,691.80	1,488.60	'	'
Property, plant and equipment, net	7,331.30	7,234.10	'	'
Other noncurrent assets	458.5	420.7	'	'
Advances to affiliates - noncurrent	1,082.40	733.1	'	'
Investment in unconsolidated affiliates	'	78.6	'	'
Total other assets	1,540.90	1,232.40	'	'
Total Assets	9,066.10	8,850.60	'	'
Liabilities and Equity	'	'	'	'
Payables	65.4	70.6	'	'
Payable to affiliates	6.8	13.9	'	'
Advances from affiliates	2.4	0	'	'
Other current liabilities	166.7	153.3	'	'
Total current liabilities	241.3	237.8	'	'
Total long-term debt and capital lease obligation	2,030	2,044.50	'	'
Payable to affiliate - noncurrent	0	0	'	'
Advances from affiliates - noncurrent	201.2	168.7	'	'
Other noncurrent liabilities	170.2	174.8	'	'
Total other liabilities and deferred credits	371.4	343.5	'	'
Total partners' capital	6,423.10	6,138.30	'	'
Noncontrolling interest	0.3	86.5	'	'
Total Equity	6,423.40	6,224.80	'	'
Total Liabilities and Equity	$9,066.10	$8,850.60	'	'

Guarantee_of_Securities_of_Sub3

Guarantee of Securities of Subsidiaries Guarantee of Securities of Subsidiaries Statements of Income (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Operating Revenues:	'	'	'	'
Transportation	$238.90	$233.50	$788.90	$759.90
Parking and lending	3	4.9	21.4	19.9
Storage	19.2	27.4	70.1	82.9
Other	17.8	9.7	48.8	30
Total operating revenues	278.9	275.5	929.2	892.7
Operating Costs and Expenses:	'	'	'	'
Fuel and transportation	31.9	18.5	94.8	68.6
Operation and maintenance	50.3	47	136.9	131
Administrative and general	31.8	29.1	89.1	89.4
Other operating costs and expenses	96.4	77.7	290.8	247.7
Total operating costs and expenses	210.4	172.3	611.6	536.7
Operating (loss) income	68.5	103.2	317.6	356
Other Deductions (Income):	'	'	'	'
Interest expense	40	41	121.1	122.2
Interest (income) expense - affiliates, net	0	0	0	0
Interest income	-0.1	-0.1	-0.4	-0.4
Equity in earnings of subsidiaries	0	0	0	0
Equity losses in unconsolidated affiliates	0.3	0.6	86.9	0.6
Miscellaneous other income, net	-0.2	0	-0.3	-0.2
Total other deductions	40	41.5	207.3	122.2
Income (loss) before income taxes	28.5	61.7	110.3	233.8
Income taxes	0.1	0	0.4	0.3
Net income (loss)	28.4	61.7	109.9	233.5
Net loss attributable to noncontrolling interests	-0.8	-0.6	-86.9	-0.7
Net income attributable to controlling interests	29.2	62.3	196.8	234.2
Eliminations	'	'	'	'
Operating Revenues:	'	'	'	'
Transportation	-22.4	-22.3	-68	-66.3
Parking and lending	0	0	0	0
Storage	-0.4	0	-0.5	-0.1
Other	0	0	0	0
Total operating revenues	-22.8	-22.3	-68.5	-66.4
Operating Costs and Expenses:	'	'	'	'
Fuel and transportation	-22.8	-22.3	-68.5	-66.4
Operation and maintenance	0	0	0	0
Administrative and general	0	0	0	0
Other operating costs and expenses	0	0	0	0
Total operating costs and expenses	-22.8	-22.3	-68.5	-66.4
Operating (loss) income	0	0	0	0
Other Deductions (Income):	'	'	'	'
Interest expense	0	0	0	0
Interest (income) expense - affiliates, net	0	0	0	0
Interest income	0	0	0	0
Equity in earnings of subsidiaries	72.9	136.5	435.1	504.2
Equity losses in unconsolidated affiliates	0	0	0	0
Miscellaneous other income, net	0	'	0	0
Total other deductions	72.9	136.5	435.1	504.2
Income (loss) before income taxes	-72.9	-136.5	-435.1	-504.2
Income taxes	0	0	0	0
Net income (loss)	-72.9	-136.5	-435.1	-504.2
Net loss attributable to noncontrolling interests	0	0	0	0
Net income attributable to controlling interests	-72.9	-136.5	-435.1	-504.2
Parent Guarantor	'	'	'	'
Operating Revenues:	'	'	'	'
Transportation	0	0	0	0
Parking and lending	0	0	0	0
Storage	0	0	0	0
Other	0	0	0	0
Total operating revenues	0	0	0	0
Operating Costs and Expenses:	'	'	'	'
Fuel and transportation	0	0	0	0
Operation and maintenance	0	0	0	0
Administrative and general	0.2	0	0.1	0
Other operating costs and expenses	0.2	0.2	0.3	0.3
Total operating costs and expenses	0.4	0.2	0.4	0.3
Operating (loss) income	-0.4	-0.2	-0.4	-0.3
Other Deductions (Income):	'	'	'	'
Interest expense	0	0	0	0
Interest (income) expense - affiliates, net	-7.8	-8.8	-23.2	-25.4
Interest income	0	0	0	0
Equity in earnings of subsidiaries	-21.8	-53.7	-174	-209.1
Equity losses in unconsolidated affiliates	0	0	0	0
Miscellaneous other income, net	0	'	0	0
Total other deductions	-29.6	-62.5	-197.2	-234.5
Income (loss) before income taxes	29.2	62.3	196.8	234.2
Income taxes	0	0	0	0
Net income (loss)	29.2	62.3	196.8	234.2
Net loss attributable to noncontrolling interests	0	0	0	0
Net income attributable to controlling interests	29.2	62.3	196.8	234.2
Subsidiary Issuer	'	'	'	'
Operating Revenues:	'	'	'	'
Transportation	0	0	0	0
Parking and lending	0	0	0	0
Storage	0	0	0	0
Other	0	0	0	0
Total operating revenues	0	0	0	0
Operating Costs and Expenses:	'	'	'	'
Fuel and transportation	0	0	0	0
Operation and maintenance	0	0	0	0.3
Administrative and general	0	0	0	0.8
Other operating costs and expenses	0	0	0	0.1
Total operating costs and expenses	0	0	0	1.2
Operating (loss) income	0	0	0	-1.2
Other Deductions (Income):	'	'	'	'
Interest expense	18.7	18.7	56.1	53.9
Interest (income) expense - affiliates, net	10.6	10.4	31	30.9
Interest income	0	0	0	0
Equity in earnings of subsidiaries	-51.1	-82.8	-261.1	-295.1
Equity losses in unconsolidated affiliates	0	0	0	0
Miscellaneous other income, net	0	'	0	0
Total other deductions	-21.8	-53.7	-174	-210.3
Income (loss) before income taxes	21.8	53.7	174	209.1
Income taxes	0	0	0	0
Net income (loss)	21.8	53.7	174	209.1
Net loss attributable to noncontrolling interests	0	0	0	0
Net income attributable to controlling interests	21.8	53.7	174	209.1
Non-Guarantor Subsidiaries	'	'	'	'
Operating Revenues:	'	'	'	'
Transportation	261.3	255.8	856.9	826.2
Parking and lending	3	4.9	21.4	19.9
Storage	19.6	27.4	70.6	83
Other	17.8	9.7	48.8	30
Total operating revenues	301.7	297.8	997.7	959.1
Operating Costs and Expenses:	'	'	'	'
Fuel and transportation	54.7	40.8	163.3	135
Operation and maintenance	50.3	47	136.9	130.7
Administrative and general	31.6	29.1	89	88.6
Other operating costs and expenses	96.2	77.5	290.5	247.3
Total operating costs and expenses	232.8	194.4	679.7	601.6
Operating (loss) income	68.9	103.4	318	357.5
Other Deductions (Income):	'	'	'	'
Interest expense	21.3	22.3	65	68.3
Interest (income) expense - affiliates, net	-2.8	-1.6	-7.8	-5.5
Interest income	-0.1	-0.1	-0.4	-0.4
Equity in earnings of subsidiaries	0	0	0	0
Equity losses in unconsolidated affiliates	0.3	0.6	86.9	0.6
Miscellaneous other income, net	-0.2	'	-0.3	-0.2
Total other deductions	18.5	21.2	143.4	62.8
Income (loss) before income taxes	50.4	82.2	174.6	294.7
Income taxes	0.1	0	0.4	0.3
Net income (loss)	50.3	82.2	174.2	294.4
Net loss attributable to noncontrolling interests	-0.8	-0.6	-86.9	-0.7
Net income attributable to controlling interests	$51.10	$82.80	$261.10	$295.10

Guarantee_of_Securities_of_Sub4

Guarantee of Securities of Subsidiaries Guarantee of Securities of Subsidiaries Statements of Comprehensive Income (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Net income (loss)	$28.40	$61.70	$109.90	$233.50
Other comprehensive income (loss):	'	'	'	'
Gain (loss) on cash flow hedges	0.2	0	-0.7	2.5
Reclassification adjustment transferred to Net Income from cash flow hedges	0.5	-0.6	2.1	0.5
Pension and other postretirement benefit costs	-2	-0.4	-5.9	-4
Total Comprehensive Income (Loss)	27.1	60.7	105.4	232.5
Comprehensive loss attributable to noncontrolling interests	-0.8	-0.6	-86.9	-0.7
Comprehensive income (loss) attributable to controlling interests	27.9	61.3	192.3	233.2
Eliminations	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Net income (loss)	-72.9	-136.5	-435.1	-504.2
Other comprehensive income (loss):	'	'	'	'
Gain (loss) on cash flow hedges	-0.4	'	1.4	-5
Reclassification adjustment transferred to Net Income from cash flow hedges	-0.6	1.6	-2.9	0.3
Pension and other postretirement benefit costs	4	0.8	11.8	8
Total Comprehensive Income (Loss)	-69.9	-134.1	-424.8	-500.9
Comprehensive loss attributable to noncontrolling interests	0	0	0	0
Comprehensive income (loss) attributable to controlling interests	-69.9	-134.1	-424.8	-500.9
Parent Guarantor	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Net income (loss)	29.2	62.3	196.8	234.2
Other comprehensive income (loss):	'	'	'	'
Gain (loss) on cash flow hedges	0.2	'	-0.7	2.5
Reclassification adjustment transferred to Net Income from cash flow hedges	0.5	-0.6	2.1	0.5
Pension and other postretirement benefit costs	-2	-0.4	-5.9	-4
Total Comprehensive Income (Loss)	27.9	61.3	192.3	233.2
Comprehensive loss attributable to noncontrolling interests	0	0	0	0
Comprehensive income (loss) attributable to controlling interests	27.9	61.3	192.3	233.2
Subsidiary Issuer	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Net income (loss)	21.8	53.7	174	209.1
Other comprehensive income (loss):	'	'	'	'
Gain (loss) on cash flow hedges	0.2	'	-0.7	2.5
Reclassification adjustment transferred to Net Income from cash flow hedges	0.5	-0.6	2.1	0.5
Pension and other postretirement benefit costs	-2	-0.4	-5.9	-4
Total Comprehensive Income (Loss)	20.5	52.7	169.5	208.1
Comprehensive loss attributable to noncontrolling interests	0	0	0	0
Comprehensive income (loss) attributable to controlling interests	20.5	52.7	169.5	208.1
Non-Guarantor Subsidiaries	'	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'	'
Net income (loss)	50.3	82.2	174.2	294.4
Other comprehensive income (loss):	'	'	'	'
Gain (loss) on cash flow hedges	0.2	'	-0.7	2.5
Reclassification adjustment transferred to Net Income from cash flow hedges	0.1	-1	0.8	-0.8
Pension and other postretirement benefit costs	-2	-0.4	-5.9	-4
Total Comprehensive Income (Loss)	48.6	80.8	168.4	292.1
Comprehensive loss attributable to noncontrolling interests	-0.8	-0.6	-86.9	-0.7
Comprehensive income (loss) attributable to controlling interests	$49.40	$81.40	$255.30	$292.80

Guarantee_of_Securities_of_Sub5

Guarantee of Securities of Subsidiaries Guarantee of Securities of Subsidiaries Statements of Cash Flows (Details) (USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Statement of Cash Flows	'	'
Net cash provided by (used in) operating activities	$412.50	$402
Investing Activities:	'	'
Capital expenditures	-315.9	-204.3
Proceeds from sale of operating assets	2.9	48.6
Proceeds from insurance and other recoveries	6.3	1.4
Advances to affiliates, net	0.1	-2.8
Investment in consolidated subsidiary	'	0
Investment in unconsolidated affiliates	-20.5	-25.6
Distribution from unconsolidated affiliates	10.7	0
Acquisition-related deposit	-29.5	'
Net cash used in investing activities	-345.9	-182.7
Financing Activities:	'	'
Proceeds from borrowings on revolving credit agreement	340	813
Repayment of borrowings on revolving credit agreement	-330	-1,030
Contribution from parent	'	0
Principal payment of capital lease obligation	-0.3	-0.1
Repayment of borrowings from term loan	-25	0
Advances from affiliates, net	0.1	-2.8
Distributions paid	-74.4	-392
Capital contributions from noncontrolling interests	8.2	37.2
Proceeds from sale of common units	0	368.7
Capital contributions from general partner	0	7.8
Distributions paid to noncontrolling interests	-7.5	0
Net cash used in financing activities	-88.9	-198.2
(Decrease) increase in cash and cash equivalents	-22.3	21.1
Cash and cash equivalents at beginning of period	28.5	3.9
Cash and cash equivalents at end of period	6.2	25
Eliminations	'	'
Statement of Cash Flows	'	'
Net cash provided by (used in) operating activities	0	0
Investing Activities:	'	'
Capital expenditures	0	0
Proceeds from sale of operating assets	0	0
Proceeds from insurance and other recoveries	0	0
Advances to affiliates, net	151.2	244.5
Investment in consolidated subsidiary	'	15.1
Investment in unconsolidated affiliates	0	0
Distribution from unconsolidated affiliates	0	'
Acquisition-related deposit	0	'
Net cash used in investing activities	151.2	259.6
Financing Activities:	'	'
Proceeds from borrowings on revolving credit agreement	0	0
Repayment of borrowings on revolving credit agreement	0	0
Contribution from parent	'	-15.1
Principal payment of capital lease obligation	0	0
Repayment of borrowings from term loan	0	'
Advances from affiliates, net	-151.2	-244.5
Distributions paid	0	0
Capital contributions from noncontrolling interests	0	0
Proceeds from sale of common units	'	0
Capital contributions from general partner	'	0
Distributions paid to noncontrolling interests	0	'
Net cash used in financing activities	-151.2	-259.6
(Decrease) increase in cash and cash equivalents	0	0
Cash and cash equivalents at beginning of period	0	0
Cash and cash equivalents at end of period	0	0
Parent Guarantor	'	'
Statement of Cash Flows	'	'
Net cash provided by (used in) operating activities	22.8	26
Investing Activities:	'	'
Capital expenditures	0	0
Proceeds from sale of operating assets	0	0
Proceeds from insurance and other recoveries	0	0
Advances to affiliates, net	80.8	-7.6
Investment in consolidated subsidiary	'	0
Investment in unconsolidated affiliates	0	0
Distribution from unconsolidated affiliates	0	'
Acquisition-related deposit	-29.5	'
Net cash used in investing activities	51.3	-7.6
Financing Activities:	'	'
Proceeds from borrowings on revolving credit agreement	0	0
Repayment of borrowings on revolving credit agreement	0	0
Contribution from parent	'	0
Principal payment of capital lease obligation	0	0
Repayment of borrowings from term loan	0	'
Advances from affiliates, net	0.1	-2.8
Distributions paid	-74.4	-392
Capital contributions from noncontrolling interests	0	0
Proceeds from sale of common units	'	368.7
Capital contributions from general partner	'	7.8
Distributions paid to noncontrolling interests	0	'
Net cash used in financing activities	-74.3	-18.3
(Decrease) increase in cash and cash equivalents	-0.2	0.1
Cash and cash equivalents at beginning of period	0.2	0.1
Cash and cash equivalents at end of period	0	0.2
Subsidiary Issuer	'	'
Statement of Cash Flows	'	'
Net cash provided by (used in) operating activities	-89.9	-86.3
Investing Activities:	'	'
Capital expenditures	0	0
Proceeds from sale of operating assets	0	0
Proceeds from insurance and other recoveries	0	0
Advances to affiliates, net	-34.9	-71
Investment in consolidated subsidiary	'	-15.1
Investment in unconsolidated affiliates	0	0
Distribution from unconsolidated affiliates	0	'
Acquisition-related deposit	0	'
Net cash used in investing activities	-34.9	-86.1
Financing Activities:	'	'
Proceeds from borrowings on revolving credit agreement	0	0
Repayment of borrowings on revolving credit agreement	0	0
Contribution from parent	'	0
Principal payment of capital lease obligation	0	0
Repayment of borrowings from term loan	0	'
Advances from affiliates, net	116.3	173.5
Distributions paid	0	0
Capital contributions from noncontrolling interests	0	0
Proceeds from sale of common units	'	0
Capital contributions from general partner	'	0
Distributions paid to noncontrolling interests	0	'
Net cash used in financing activities	116.3	173.5
(Decrease) increase in cash and cash equivalents	-8.5	1.1
Cash and cash equivalents at beginning of period	9.2	1
Cash and cash equivalents at end of period	0.7	2.1
Non-Guarantor Subsidiaries	'	'
Statement of Cash Flows	'	'
Net cash provided by (used in) operating activities	479.6	462.3
Investing Activities:	'	'
Capital expenditures	-315.9	-204.3
Proceeds from sale of operating assets	2.9	48.6
Proceeds from insurance and other recoveries	6.3	1.4
Advances to affiliates, net	-197	-168.7
Investment in consolidated subsidiary	'	0
Investment in unconsolidated affiliates	-20.5	-25.6
Distribution from unconsolidated affiliates	10.7	'
Acquisition-related deposit	0	'
Net cash used in investing activities	-513.5	-348.6
Financing Activities:	'	'
Proceeds from borrowings on revolving credit agreement	340	813
Repayment of borrowings on revolving credit agreement	-330	-1,030
Contribution from parent	'	15.1
Principal payment of capital lease obligation	-0.3	-0.1
Repayment of borrowings from term loan	-25	'
Advances from affiliates, net	34.9	71
Distributions paid	0	0
Capital contributions from noncontrolling interests	8.2	37.2
Proceeds from sale of common units	'	0
Capital contributions from general partner	'	0
Distributions paid to noncontrolling interests	-7.5	'
Net cash used in financing activities	20.3	-93.8
(Decrease) increase in cash and cash equivalents	-13.6	19.9
Cash and cash equivalents at beginning of period	19.1	2.8
Cash and cash equivalents at end of period	$5.50	$22.70