BOARDWALK PIPELINE PARTNERS, LP, 10-Q filed on 5/5/2025
Quarterly Report
v3.25.1
Document and Entity Information - shares
 3 Months Ended
Mar. 31, 2025
May 05, 2025
Entity Information [Line Items]    
Document Type 10-Q  
Document Quarterly Report true  
Document Period End Date Mar. 31, 2025  
Document Transition Report false  
Entity File Number 01-32665  
Entity Registrant Name BOARDWALK PIPELINE PARTNERS, LP  
Entity Incorporation, State DE  
Entity Tax Identification Number 20-3265614  
Entity Address, Address Line One 9 Greenway Plaza,  
Entity Address, Address Line Two Suite 2800  
Entity Address, City Houston,  
Entity Address, State TX  
Entity Address, Postal Zip Code 77046  
City Area Code (866)  
Local Phone Number 913-2122  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Filer Category Non-accelerated Filer  
Entity Small Business false  
Entity Emerging Growth Company false  
Entity Shell Company false  
Amendment Flag false  
Document Fiscal Year Focus 2025  
Document Fiscal Period Focus Q1  
Entity Central Index Key 0001336047  
Current Fiscal Year End Date --12-31  
Entity Common Stock, Shares Outstanding   0
v3.25.1
CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($)
$ in Millions
Mar. 31, 2025
Dec. 31, 2024
Current Assets:    
Cash and cash equivalents $ 235.2 $ 117.9
Receivables:    
Trade, net 216.6 210.7
Other 21.7 21.4
Gas transportation receivables 21.7 7.4
Prepayments 18.3 25.2
Total current assets 531.9 401.1
Property, Plant and Equipment:    
Property, plant and equipment, gross 13,898.6 13,857.8
Less—accumulated depreciation and amortization 5,146.1 5,045.1
Property, plant and equipment, net 8,752.5 8,812.7
Other Assets:    
Goodwill 237.4 237.4
Gas stored underground 97.0 98.3
Other 230.8 229.9
Total other assets 565.2 565.6
Total Assets 9,849.6 9,779.4
Payables:    
Trade 79.7 100.9
Gas transportation payables 14.2 11.7
Accrued taxes, other 43.3 67.0
Accrued interest 36.4 46.7
Accrued payroll and employee benefits 29.6 48.6
Regulatory liabilities 25.2 18.3
Other current liabilities 27.7 30.2
Total current liabilities 279.7 345.6
Long-term debt and finance lease obligation 3,235.1 3,234.4
Other Liabilities and Deferred Credits:    
Asset retirement obligations 70.5 70.0
Provision for other asset retirement 105.6 103.6
Total other liabilities and deferred credits 296.9 293.4
Commitments and Contingencies
Partners' Capital:    
Partners' capital 6,110.2 5,978.6
Accumulated other comprehensive loss (72.3) (72.6)
Total partners' capital 6,037.9 5,906.0
Total Liabilities and Partners' Capital 9,849.6 9,779.4
Affiliates    
Receivables:    
Other current assets 0.7 0.0
Payables:    
Payables 0.5 0.5
Other Liabilities and Deferred Credits:    
Other 5.6 4.8
Other    
Receivables:    
Other current assets 17.7 18.5
Payables:    
Payables 23.1 21.7
Other Liabilities and Deferred Credits:    
Other 115.2 115.0
Pipelines, storage and other plant    
Property, Plant and Equipment:    
Property, plant and equipment, gross 13,708.8 13,667.7
Construction work in progress    
Property, Plant and Equipment:    
Property, plant and equipment, gross $ 189.8 $ 190.1
v3.25.1
CONDENSED CONSOLIDATED STATEMENTS OF INCOME (Unaudited) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2025
Mar. 31, 2024
Operating Revenues:    
Transportation $ 395.0 $ 361.3
Storage, parking and lending 52.7 46.1
Product sales 152.7 84.7
Other 18.2 18.4
Total operating revenues 618.6 510.5
Operating Costs and Expenses:    
Costs associated with service revenues 8.0 7.2
Costs associated with product sales 122.9 63.8
Operation and maintenance 58.2 58.9
Administrative and general 48.3 49.3
Depreciation and amortization 105.5 105.5
Gain on sale of assets, impairments and other (1.0) (7.7)
Taxes other than income taxes 32.3 31.7
Total operating costs and expenses 374.2 308.7
Operating income 244.4 201.8
Other Deductions (Income):    
Interest expense 39.5 43.3
Interest income (1.0) (3.7)
Miscellaneous other income, net (1.2) (3.0)
Total other deductions 37.3 36.6
Income before income taxes 207.1 165.2
Income taxes 0.5 0.4
Net income $ 206.6 $ 164.8
v3.25.1
CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2025
Mar. 31, 2024
Statement of Comprehensive Income [Abstract]    
Net income $ 206.6 $ 164.8
Other comprehensive income (loss):    
Reclassification adjustment transferred to Net income from cash flow hedges 0.4 0.0
Pension and other postretirement benefit costs, net of tax (0.1) 0.0
Total Comprehensive Income $ 206.9 $ 164.8
v3.25.1
CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2025
Mar. 31, 2024
Operating Activities:    
Net income $ 206.6 $ 164.8
Adjustments to reconcile net income to cash provided by operations:    
Depreciation and amortization 105.5 105.5
Amortization of deferred costs and other 3.9 1.8
Gain on sale of assets, impairments and other (1.0) (7.7)
Changes in operating assets and liabilities:    
Trade and other receivables (8.0) 36.2
Gas receivables and payables and product inventory (5.1) (12.3)
Prepayments and other assets 7.7 4.3
Trade and other payables (13.3) (19.5)
Other payables, affiliates 0.0 0.1
Accrued liabilities (52.9) (29.9)
Other liabilities 0.5 5.9
Net cash provided by operating activities 243.9 249.2
Investing Activities:    
Capital expenditures (51.6) (97.3)
Proceeds from sale of operating assets 0.1 0.2
Advances to affiliates (0.7) 0.0
Purchases of short-term investments 0.0 (244.2)
Net cash used in investing activities (52.2) (341.3)
Financing Activities:    
Proceeds from long-term debt, net of issuance cost 0.0 594.2
Proceeds from borrowings on revolving credit facility 0.0 170.0
Repayments of borrowings on revolving credit facility 0.0 (195.0)
Principal payment of finance lease obligation (0.2) (0.2)
Advances from affiliates 0.8 0.0
Distributions paid (75.0) (50.0)
Net cash (used in) provided by financing activities (74.4) 519.0
Increase in cash and cash equivalents 117.3 426.9
Cash and cash equivalents at beginning of period 117.9 20.1
Cash and cash equivalents at end of period $ 235.2 $ 447.0
v3.25.1
CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN PARTNERS' CAPITAL (Unaudited) - USD ($)
$ in Millions
Total
Accumulated Other Comprehensive (Loss)
Partners' Capital
Beginning balance at Dec. 31, 2023 $ 5,791.1 $ (76.6) $ 5,867.7
Add (deduct):      
Net income 164.8   164.8
Distributions paid (50.0)   (50.0)
Ending balance at Mar. 31, 2024 5,905.9 (76.6) 5,982.5
Beginning balance at Dec. 31, 2024 5,906.0 (72.6) 5,978.6
Add (deduct):      
Net income 206.6   206.6
Distributions paid (75.0)   (75.0)
Other comprehensive income, net of tax 0.3 0.3  
Ending balance at Mar. 31, 2025 $ 6,037.9 $ (72.3) $ 6,110.2
v3.25.1
Basis of Presentation
 3 Months Ended
Mar. 31, 2025
Organization, Consolidation and Presentation of Financial Statements [Abstract]  
Basis of Presentation Basis of Presentation
    
Boardwalk Pipeline Partners, LP (the Company) 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, which consists of integrated pipeline and storage systems for natural gas and natural gas liquids, olefins and other hydrocarbons (herein referred to together as NGLs). As of March 31, 2025, Boardwalk Pipelines Holding Corp. (BPHC), a wholly owned subsidiary of Loews Corporation (Loews), owned directly or indirectly, 100% of the Company's capital.

The accompanying unaudited condensed consolidated financial statements of the Company have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission. Certain information and footnote disclosures normally included in annual financial statements prepared in accordance with accounting principles generally accepted in the United States of America (U.S.) (GAAP) have been condensed or omitted pursuant to such rules and regulations. In the opinion of management, the accompanying unaudited condensed consolidated financial statements reflect all adjustments (consisting of only normal recurring accruals) necessary to present fairly the Company's financial position as of March 31, 2025, and December 31, 2024, and its results of operations, comprehensive income and changes in cash flow and partners' capital for the three months ended March 31, 2025 and 2024, in each case in accordance with GAAP. Reference is made to the Notes to the Consolidated Financial Statements in the Company's Annual Report on Form 10-K for the year ended December 31, 2024 (2024 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 of Part II, Item 8. of the Company's 2024 Annual Report on Form 10-K are the same policies that were used in preparing the accompanying unaudited condensed consolidated financial statements. Results of operations for interim periods may not necessarily be indicative of results for the full year.

The Company recently reorganized its legal entity structure which impacted its reporting units for purposes of goodwill. Goodwill was reallocated based on the relative fair value approach, resulting in $4.5 million of goodwill being transferred to a different reporting unit. The Company now has three reporting units for goodwill testing. This reorganization was considered a triggering event for purposes of interim goodwill impairment testing. As a result, quantitative goodwill impairment tests were performed during the first quarter 2025 on the impacted reporting units and the results of the goodwill impairment tests indicated that the fair value of the Company's impacted reporting units exceeded their carrying amounts.

In the fourth quarter 2024, the Company began reporting its financial results in two reportable segments, Natural Gas and Natural Gas Liquids, whereas it previously reported under a single operating and reportable segment. Certain information for 2024 in Notes 2 and 10 has been recast or presented under the Company’s reportable segment presentation.
v3.25.1
Revenues
 3 Months Ended
Mar. 31, 2025
Revenue from Contract with Customer [Abstract]  
Revenues Revenues
The Company contracts directly with end-use customers, including electric power generators, local distribution companies, industrial users and exporters of liquefied natural gas. The Company also contracts with other customers, including producers and marketers of natural gas and interstate and intrastate pipelines, who, in turn, provide transportation and storage services for end-users. The following tables present the Company's revenues disaggregated by type of service by segment (in millions):
For the Three Months Ended March 31, 2025
Natural Gas
Natural Gas Liquids
Eliminations
Total
Revenues from Contracts with Customers
Firm Service (1)
$401.6 $152.8 $(8.3)$546.1 
Interruptible Service13.0 — — 13.0 
Other revenues
3.2 46.2 — 49.4 
Total Revenues from Contracts with Customers417.8 199.0 (8.3)608.5 
Other operating revenues (2)
5.9 8.9 (4.7)10.1 
Total Operating Revenues$423.7 $207.9 $(13.0)$618.6 

(1)Revenues earned from contracts with minimum volume commitments (MVCs) are included in firm service given the stand-ready nature of the performance obligation and the guaranteed nature of the fees over the contract term.

(2)Other operating revenues include certain revenues earned from operating leases, pipeline management fees, intrasegment licensing fees and other activities that are not considered central and ongoing major business operations of the Company and do not represent revenues earned from contracts with customers.

For the Three Months Ended March 31, 2024
Natural GasNatural Gas LiquidsEliminationsTotal
Revenues from Contracts with Customers
Firm Service (1)
$362.1 $85.6 $(7.5)$440.2 
Interruptible Service11.9 — — 11.9 
Other revenues
6.3 42.3 — 48.6 
Total Revenues from Contracts with Customers380.3 127.9 (7.5)500.7 
Other operating revenues (2)
5.4 9.3 (4.9)9.8 
Total Operating Revenues$385.7 $137.2 $(12.4)$510.5 

(1)Revenues earned from contracts with MVCs are included in firm service given the stand-ready nature of the performance obligation and the guaranteed nature of the fees over the contract term.

(2)Other operating revenues include certain revenues earned from operating leases, pipeline management fees, intrasegment licensing fees and other activities that are not considered central and ongoing major business operations of the Company and do not represent revenues earned from contracts with customers.

Contract Balances

As of March 31, 2025, and December 31, 2024, the Company had receivables recorded in Trade Receivables, net from contracts with customers of $216.6 million and $210.7 million, contract assets recorded in Other Assets from contracts with a customer of $12.7 million and $11.9 million, and contract liabilities recorded in Other Current Liabilities (current portion) and Other Liabilities (noncurrent portion) from contracts with customers of $19.4 million and $17.9 million.
As of March 31, 2025, contract liabilities are expected to be recognized through 2040. Significant changes in the contract liability balances during the three months ended March 31, 2025, were as follows (in millions):
Contract Liabilities
Balance as of December 31, 2024 (1)
$17.9 
Revenues recognized that were included in the contract liability
    balances at the beginning of the period		(0.6)
Increases due to cash received, excluding amounts recognized as
    revenues during the period		2.1 
Balance as of March 31, 2025 (1)
$19.4 

(1)As of March 31, 2025, and December 31, 2024, $3.8 million and $1.8 million were recorded in Other Current Liabilities (current portion), and $15.6 million and $16.1 million were recorded in Other Liabilities (noncurrent portion).

Significant changes in the contract liability balances during the three months ended March 31, 2024, were as follows (in millions):
Contract Liabilities
Balance as of December 31, 2023 (1)
$21.4 
Revenues recognized that were included in the contract liability
    balances at the beginning of the period		(1.3)
Increases due to cash received, excluding amounts recognized as
    revenues during the period		4.6 
Balance as of March 31, 2024 (1)
$24.7 

(1)As of March 31, 2024, and December 31, 2023, $7.2 million and $3.5 million were recorded in Other Current Liabilities (current portion), and $17.5 million and $17.9 million were recorded in Other Liabilities (noncurrent portion).

Performance Obligations

The following table includes estimated operating revenues expected to be recognized in the future related to agreements that contain performance obligations that were unsatisfied as of March 31, 2025. The amounts presented primarily consist of fixed fees or MVCs which are typically recognized over time as the performance obligation is satisfied, in accordance with firm service contracts, or at a point in time as guaranteed minimum fees associated with the performance obligation are satisfied under certain ethane supply contracts. For the Company's customers that are charged maximum tariff rates related to its Federal Energy Regulatory Commission regulated operating subsidiaries, the amounts below reflect the current tariff rate for such services for the term of the agreements; however, the tariff rates may be subject to future adjustment. The Company has elected to exclude the following from the table: (a) unsatisfied performance obligations from usage fees associated with its firm services because of the variable nature of such services; (b) unsatisfied performance obligations from the ethane commodity indexed portion of ethane supply contracts because of the variable nature of ethane prices, and (c) consideration in contracts that is recognized in revenue as invoiced, such as for interruptible services. The estimated revenues reflected in the table include estimated revenues that are anticipated under executed precedent transportation agreements for growth projects that are subject to regulatory approvals.
In millions
2025 (1)
2026ThereafterTotal
Estimated revenues from contracts with customers
    from unsatisfied performance obligations as of
    March 31, 2025 (2)
$1,146.5 $1,409.0 $11,579.0 $14,134.5 
Operating revenues which are fixed and
    determinable (operating leases)		21.0 27.5 136.0 184.5 
Total projected operating revenues under committed
    firm agreements as of March 31, 2025 (3)
$1,167.5 $1,436.5 $11,715.0 $14,319.0 

(1)The 2025 period is for the remaining nine months ending December 31, 2025. For the three months ended March 31, 2025, the Company recognized $426.2 million of fixed fee revenues for the fulfillment of performance obligations.

(2)In March 2024, the Company executed a 108-year firm storage agreement with a customer. The estimated annual revenue from this contract is $3.1 million, with $328.5 million of unsatisfied performance obligations included in the “Thereafter” column. Per the tariff provisions, this customer was required to provide 90 days of collateral and the Company can suspend services due to non-payment.

(3)The estimated revenues from contracts with customers from unsatisfied performance obligations as of March 31, 2025, that are anticipated under executed precedent transportation agreements associated with the Company's growth projects are $4.0 billion.
v3.25.1
Gas and Liquids Stored Underground and Gas and NGLs Receivables and Payables
 3 Months Ended
Mar. 31, 2025
Oil and Gas, Gas-Balancing Arrangement [Abstract]  
Gas and liquids stored underground and gas and NGLs receivables and payables Gas and Liquids Stored Underground and Gas and NGLs Receivables and Payables
The operating subsidiaries of the Company provide storage services whereby they store natural 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 or NGLs held by the Company in providing these services, the Company does not record the related gas or NGLs on its Condensed Consolidated Balance Sheets.

The operating subsidiaries of the Company also periodically lend gas to customers under PAL and certain firm services, and lend ethylene to customers under exchange agreements, and gas or NGLs may be owed to the Company's operating subsidiaries as a result of transportation imbalances. As of March 31, 2025, the amount of gas owed to the Company's operating subsidiaries due to gas imbalances and gas loaned under PAL and certain firm service agreements was approximately 26.7 trillion British thermal units (TBtu). Assuming an average market price during March 2025 of $3.80 per million British thermal unit (MMBtu), the market value of that gas was approximately $101.5 million. As of March 31, 2025, the amount of ethylene owed to the Company’s operating subsidiaries from ethylene loaned under exchange agreements was approximately 33.0 million pounds. Assuming an average market price during March 2025 of $0.23 per pound, the market value of that ethylene was approximately $7.6 million. As of March 31, 2025, there were no outstanding NGLs imbalances owed to the Company's operating subsidiaries. As of December 31, 2024, the amount of gas owed to the Company's operating subsidiaries due to gas imbalances and gas loaned under PAL and certain firm service agreements was approximately 9.8 TBtu. Assuming an average market price during December 2024 of $2.98 per MMBtu, the market value of that gas was approximately $29.2 million. As of December 31, 2024, the amount of NGLs owed to the Company's operating subsidiaries due to imbalances was less than 0.1 million barrels, which had a market value of approximately $0.3 million. As of December 31, 2024, there were no amounts of ethylene owed to the Company's operating subsidiaries under exchange agreements.
v3.25.1
Fair Value Measurements and Investments
 3 Months Ended
Mar. 31, 2025
Fair Value Disclosures [Abstract]  
Fair Value Measurements and Investments Fair Value Measurements and Investments
Financial Assets and Liabilities

The methods and assumptions used in estimating the fair value amounts included in the disclosures for financial assets and liabilities are consistent with those disclosed in the Company's 2024 Annual Report on Form 10-K.

The carrying amounts and estimated fair values of the Company's financial assets and liabilities which were not recorded at fair value on the Condensed Consolidated Balance Sheets as of March 31, 2025, and December 31, 2024, were as follows (in millions):

As of March 31, 2025 Estimated Fair Value
Financial AssetsCarrying AmountLevel 1Level 2Level 3Total
Cash and cash equivalents$235.2 $235.2 $— $— $235.2 
Financial Liabilities     
Long-term debt
$3,237.2 
(1)
$— $3,160.9 $— $3,160.9 

(1)The carrying amount of long-term debt excluded a $2.5 million long-term finance lease obligation and $4.6 million of unamortized debt issuance costs.

As of December 31, 2024Estimated Fair Value
Financial AssetsCarrying AmountLevel 1Level 2Level 3Total
Cash and cash equivalents$117.9 $117.9 $— $— $117.9 
Financial Liabilities 
Long-term debt$3,236.5 
(1)
$— $3,129.7 $— $3,129.7 

(1)The carrying amount of long-term debt excluded a $2.7 million long-term finance lease obligation and $4.8 million of unamortized debt issuance costs.
v3.25.1
Commitments and Contingencies
 3 Months Ended
Mar. 31, 2025
Commitments and Contingencies Disclosure [Abstract]  
Commitments and Contingencies Commitments and Contingencies
Legal Proceedings and Settlements

The Company 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, including the legal actions identified below, will not have a material impact on the Company's financial condition, results of operations or cash flows.

Mishal and Berger Litigation

On May 25, 2018, plaintiffs Tsemach Mishal and Paul Berger (on behalf of themselves and the purported class, Plaintiffs) initiated a purported class action in the Court of Chancery of the State of Delaware (the Trial Court) against the following defendants: the Company, Boardwalk GP, LP (Boardwalk GP), Boardwalk GP, LLC and BPHC (together, Defendants), regarding the potential exercise by Boardwalk GP of its right to purchase the issued and outstanding common units of the Company not already owned by Boardwalk GP or its affiliates (Purchase Right).

On June 25, 2018, Plaintiffs and Defendants entered into a Stipulation and Agreement of Compromise and Settlement, subject to the approval of the Trial Court (the Proposed Settlement). Under the terms of the Proposed Settlement, the lawsuit would be dismissed, and related claims against the Defendants would be released by the Plaintiffs, if BPHC, the sole member of the general partner of Boardwalk GP, elected to cause Boardwalk GP to exercise its Purchase Right for a cash purchase price, as determined by the Company's Third Amended and Restated Agreement of Limited Partnership, as amended (the Limited Partnership Agreement), and gave notice of such election as provided in the Limited Partnership Agreement within a period specified by the Proposed Settlement. On June 29, 2018, Boardwalk GP elected to exercise the Purchase Right and gave notice
within the period specified by the Proposed Settlement. On July 18, 2018, Boardwalk GP completed the purchase of the Company's common units pursuant to the Purchase Right.

On September 28, 2018, the Trial Court denied approval of the Proposed Settlement. On February 11, 2019, a substitute verified class action complaint was filed in this proceeding, which, among other things, added Loews as a Defendant. The Defendants filed a motion to dismiss, which was heard by the Trial Court in July 2019. In October 2019, the Trial Court ruled on the motion and granted a partial dismissal, with certain aspects of the case proceeding to trial. A trial was held the week of February 22, 2021, and post-trial oral arguments were held on July 14, 2021.

On November 12, 2021, the Trial Court issued a ruling in the case. The Trial Court held that Boardwalk GP breached the Limited Partnership Agreement and found that Boardwalk GP was liable to the Plaintiffs for approximately $690.0 million in damages, plus pre-judgment interest (approximately $166.0 million), post-judgment interest and attorneys' fees. The Trial Court's ruling and damages award was against Boardwalk GP, and not the Company or its subsidiaries.

The Defendants believed that the Trial Court ruling included factual and legal errors. Therefore, on January 3, 2022, the Defendants appealed the Trial Court's ruling to the Supreme Court of the State of Delaware (the Supreme Court). On January 17, 2022, the Plaintiffs filed a cross-appeal to the Supreme Court contesting the calculation of damages by the Trial Court. Oral arguments were held on September 14, 2022, and on December 19, 2022, the Supreme Court reversed the Trial Court's ruling and remanded the case to the Trial Court for further proceedings related to claims not decided by the Trial Court's ruling. Briefing by the parties at the Trial Court on the remanded issues was completed in September 2023. A hearing on the remanded issues was held at the Trial Court in April 2024. In September 2024, the Trial Court ruled in favor of the Defendants on all of the remanded issues.

On October 21, 2024, the Plaintiffs appealed the Trial Court's ruling on the remanded issues to the Supreme Court. Briefing on this appeal was completed in March 2025 and a hearing on this appeal has been scheduled to occur in June 2025.

City of New Orleans Litigation

Gulf South Pipeline Company, LLC (Gulf South), along with several other energy companies operating in Southern Louisiana, has been named as a defendant in a petition for damages and injunctive relief in state district court for Orleans Parish, Louisiana, (Case No. 19-3466) by the City of New Orleans. The case was filed on March 29, 2019. The lawsuit claims include, among other things, negligence, strict liability, nuisance and breach of contract, 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 City of New Orleans. In October 2020, this case was stayed pending the outcome of a consolidated appeal to the Fifth Circuit Court of Appeals in a similar case. On August 5, 2021, the Fifth Circuit Court of Appeals ruled in favor of the oil-and-gas defendants in that consolidated appeal, finding that the two cases being appealed should be re-examined in federal district court since they involve operations that were federally overseen at the time. The ruling reverses a previous decision that allowed the cases to be heard in state court, which the plaintiffs had sought. As a result of the Fifth Circuit Court of Appeals' decision, it is anticipated that this case will be reviewed in federal district court to determine whether the case should be heard in that court. Discovery has been initiated.

Gulf South has been named as a defendant in another suit in the State of Louisiana that is similar in nature to the City of New Orleans Litigation discussed above. This case was filed in the Louisiana state courts and discovery is ongoing.

Commitments for Construction

The Company'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. As of March 31, 2025, the commitments were approximately $236.6 million, all of which are expected to be settled within the next twelve months.
v3.25.1
Financing
 3 Months Ended
Mar. 31, 2025
Debt Disclosure [Abstract]  
Financing Financing
Notes and Debentures

As of March 31, 2025, and December 31, 2024, the Company had principal amounts of notes and debentures outstanding of $3.3 billion, with a weighted-average interest rate of 4.95%.

The indentures governing the notes and debentures have restrictive covenants which provide that, with certain exceptions, neither the Company 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 of the Company's debt obligations are unsecured. As of March 31, 2025, the Company and its subsidiaries were in compliance with their covenants under the indentures.

Revolving Credit Facility

As of March 31, 2025, and December 31, 2024, the Company had no outstanding borrowings under its revolving credit facility and had the full borrowing capacity of $1.0 billion available. The revolving credit facility has a borrowing capacity of $1.0 billion through May 27, 2027, and a borrowing capacity of $912.2 million from May 28, 2027, to May 26, 2028. The Company and its subsidiaries were in compliance with the covenants under the revolving credit facility as of March 31, 2025.
v3.25.1
Employee Benefits
 3 Months Ended
Mar. 31, 2025
Retirement Benefits [Abstract]  
Employee Benefits Employee Benefits
Defined Benefit Retirement Plans (Retirement Plans) and Postretirement Benefits Other Than Pension (PBOP)

Components of net periodic benefit cost for both the Retirement Plans and PBOP were as follows (in millions):
Retirement PlansPBOP
For the
Three Months Ended
March 31,		For the
Three Months Ended
March 31,
2025202420252024
Service cost$0.5 $0.5 $— $— 
Interest cost1.0 1.0 0.3 0.3 
Expected return on plan assets(1.1)(1.0)(0.7)(0.6)
Amortization of unrecognized net loss— 0.2 — — 
Settlement charge0.3 0.1 — — 
Net periodic benefit cost (credit)
$0.7 $0.8 $(0.4)$(0.3)

During the three months ended March 31, 2025, the Company made $0.5 million in contributions to the defined benefit pension plan and expects to fund an additional $2.5 million in the remainder of 2025.

Defined Contribution Plan

Texas Gas Transmission, LLC employees hired on or after November 1, 2006, and all other employees of the Company are provided retirement benefits under a defined contribution plan, which also provides 401(k) plan benefits to its participants. Costs related to the Company's defined contribution plan were $3.8 million and $3.6 million for the three months ended March 31, 2025 and 2024.
v3.25.1
Related Party Transactions
 3 Months Ended
Mar. 31, 2025
Related Party Transactions [Abstract]  
Related Party Transactions Related Party Transactions
Loews provides a variety of corporate services to the Company under service agreements, including risk management, finance and accounting, legal, tax and corporate development services, and charges the Company for allocated overheads. The Company incurred charges related to these services of $1.5 million and $1.4 million for the three months ended March 31, 2025 and 2024, which were recorded in Administrative and general on the Condensed Consolidated Statements of Income.

Total distributions paid to BPHC and Boardwalk GP were $75.0 million and $50.0 million for the three months ended March 31, 2025 and 2024.
v3.25.1
Supplemental Disclosure of Cash Flow Information
 3 Months Ended
Mar. 31, 2025
Supplemental Cash Flow Elements [Abstract]  
Supplemental Disclosure of Cash Flow Information Supplemental Disclosure of Cash Flow Information (in millions):
 For the
Three Months Ended
March 31,
 20252024
Cash paid during the period for:  
Interest (net of amount capitalized)$48.1 $31.8 
Non-cash investing activities:
Accounts payable and PPE
26.1 46.5 
Right-of-use asset obtained in exchange for lease obligations0.1 7.8 
v3.25.1
Reportable Segments
 3 Months Ended
Mar. 31, 2025
Segment Reporting [Abstract]  
Reportable Segments Reportable Segments
The Company has two reportable segments, Natural Gas and Natural Gas Liquids, which comprise 100% of the Company’s operating revenues. The Chief Operating Decision Maker (CODM) uses earnings before interest, income taxes, depreciation and amortization (EBITDA) to assess each of the Company’s segments performance and to determine how to allocate resources. The CODM uses this measure, together with other non-financial measures, when assessing performance of the Company and establishing management’s compensation. The Company provides segment expenses to its CODM on the same basis as the expenses are provided in the Company’s income statement and used to calculate EBITDA. Refer to the Company's 2024 Annual Report on Form 10-K for further information.

The tables below show financial information by segment (in millions):

For the Three Months Ended March 31, 2025
Natural Gas
Natural Gas LiquidsTotal
Revenues
Revenue from external customers$410.7 $207.9 $618.6 
Intrasegment revenues
13.0 — 13.0 
$423.7 $207.9 $631.6 
Reconciliation of revenues:
Elimination of intrasegment revenues
(13.0)
Total consolidated revenues$618.6 
Less:
Costs associated with service revenues$12.0 $4.3 
Costs associated with product sales— 122.9 
Operation and maintenance47.8 10.4 
Administrative and general46.5 6.5 
Taxes other than income taxes28.9 3.4 
Gain on sale of assets, impairments and other
(1.0)— 
Miscellaneous other income, net(1.1)(0.1)
Segment EBITDA
$290.6 $60.5 $351.1 
Reconciliation of profit or loss:
Depreciation and amortization$105.5 
Interest expense39.5 
Interest income(1.0)
Consolidated income before income taxes
$207.1 
For the Three Months Ended March 31, 2024
Natural GasNatural Gas LiquidsTotal
Revenues
Revenue from external customers$373.3 $137.2 $510.5 
Intrasegment revenues
12.4 — 12.4 
$385.7 $137.2 $522.9 
Reconciliation of revenues:
Elimination of intrasegment revenues
(12.4)
Total consolidated revenues$510.5 
Less:
Costs associated with service revenues$10.0 $4.7 
Costs associated with product sales— 63.8 
Operation and maintenance46.5 12.4 
Administrative and general47.2 7.0 
Taxes other than income taxes28.3 3.4 
Gain on sale of assets, impairments and other
(7.7)— 
Miscellaneous other income, net(2.9)(0.1)
Segment EBITDA
$264.3 $46.0 $310.3 
Reconciliation of profit or loss:
Depreciation and amortization$105.5 
Interest expense43.3 
Interest income(3.7)
Consolidated income before income taxes
$165.2 


Segment assets include Property, plant, and equipment – net, Intangible assets – net of accumulated amortization and Goodwill. The following table reflects segment assets (in millions):
Segment Assets
As of March 31, 2025As of December 31, 2024
Natural Gas
$7,547.0 $7,490.1 
Natural Gas Liquids1,510.9 1,628.7 
Total Segment Assets
$9,057.9 $9,118.8 


The following table reflects capital expenditures by segment (in millions):
Capital Expenditures
For the Three Months Ended March 31,
20252024
Natural Gas
$42.8 $79.0 
Natural Gas Liquids8.8 18.3 
Total
$51.6 $97.3 
v3.25.1
Basis of Presentation (Policies)
 3 Months Ended
Mar. 31, 2025
Organization, Consolidation and Presentation of Financial Statements [Abstract]  
Basis of Presentation
The accompanying unaudited condensed consolidated financial statements of the Company have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission. Certain information and footnote disclosures normally included in annual financial statements prepared in accordance with accounting principles generally accepted in the United States of America (U.S.) (GAAP) have been condensed or omitted pursuant to such rules and regulations. In the opinion of management, the accompanying unaudited condensed consolidated financial statements reflect all adjustments (consisting of only normal recurring accruals) necessary to present fairly the Company's financial position as of March 31, 2025, and December 31, 2024, and its results of operations, comprehensive income and changes in cash flow and partners' capital for the three months ended March 31, 2025 and 2024, in each case in accordance with GAAP. Reference is made to the Notes to the Consolidated Financial Statements in the Company's Annual Report on Form 10-K for the year ended December 31, 2024 (2024 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 of Part II, Item 8. of the Company's 2024 Annual Report on Form 10-K are the same policies that were used in preparing the accompanying unaudited condensed consolidated financial statements. Results of operations for interim periods may not necessarily be indicative of results for the full year.
v3.25.1
Gas and Liquids Stored Underground and Gas and NGLs Receivables and Payables (Policies)
 3 Months Ended
Mar. 31, 2025
Oil and Gas, Gas-Balancing Arrangement [Abstract]  
Gas and liquids stored underground and gas and NGLs receivables and payables The operating subsidiaries of the Company provide storage services whereby they store natural 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 or NGLs held by the Company in providing these services, the Company does not record the related gas or NGLs on its Condensed Consolidated Balance Sheets.
v3.25.1
Revenues (Tables)
 3 Months Ended
Mar. 31, 2025
Revenue from Contract with Customer [Abstract]  
Disaggregation of Revenue The following tables present the Company's revenues disaggregated by type of service by segment (in millions):
For the Three Months Ended March 31, 2025
Natural Gas
Natural Gas Liquids
Eliminations
Total
Revenues from Contracts with Customers
Firm Service (1)
$401.6 $152.8 $(8.3)$546.1 
Interruptible Service13.0 — — 13.0 
Other revenues
3.2 46.2 — 49.4 
Total Revenues from Contracts with Customers417.8 199.0 (8.3)608.5 
Other operating revenues (2)
5.9 8.9 (4.7)10.1 
Total Operating Revenues$423.7 $207.9 $(13.0)$618.6 

(1)Revenues earned from contracts with minimum volume commitments (MVCs) are included in firm service given the stand-ready nature of the performance obligation and the guaranteed nature of the fees over the contract term.

(2)Other operating revenues include certain revenues earned from operating leases, pipeline management fees, intrasegment licensing fees and other activities that are not considered central and ongoing major business operations of the Company and do not represent revenues earned from contracts with customers.

For the Three Months Ended March 31, 2024
Natural GasNatural Gas LiquidsEliminationsTotal
Revenues from Contracts with Customers
Firm Service (1)
$362.1 $85.6 $(7.5)$440.2 
Interruptible Service11.9 — — 11.9 
Other revenues
6.3 42.3 — 48.6 
Total Revenues from Contracts with Customers380.3 127.9 (7.5)500.7 
Other operating revenues (2)
5.4 9.3 (4.9)9.8 
Total Operating Revenues$385.7 $137.2 $(12.4)$510.5 

(1)Revenues earned from contracts with MVCs are included in firm service given the stand-ready nature of the performance obligation and the guaranteed nature of the fees over the contract term.

(2)Other operating revenues include certain revenues earned from operating leases, pipeline management fees, intrasegment licensing fees and other activities that are not considered central and ongoing major business operations of the Company and do not represent revenues earned from contracts with customers.
Contract Liabilities Significant changes in the contract liability balances during the three months ended March 31, 2025, were as follows (in millions):
Contract Liabilities
Balance as of December 31, 2024 (1)
$17.9 
Revenues recognized that were included in the contract liability
    balances at the beginning of the period		(0.6)
Increases due to cash received, excluding amounts recognized as
    revenues during the period		2.1 
Balance as of March 31, 2025 (1)
$19.4 

(1)As of March 31, 2025, and December 31, 2024, $3.8 million and $1.8 million were recorded in Other Current Liabilities (current portion), and $15.6 million and $16.1 million were recorded in Other Liabilities (noncurrent portion).

Significant changes in the contract liability balances during the three months ended March 31, 2024, were as follows (in millions):
Contract Liabilities
Balance as of December 31, 2023 (1)
$21.4 
Revenues recognized that were included in the contract liability
    balances at the beginning of the period		(1.3)
Increases due to cash received, excluding amounts recognized as
    revenues during the period		4.6 
Balance as of March 31, 2024 (1)
$24.7 

(1)As of March 31, 2024, and December 31, 2023, $7.2 million and $3.5 million were recorded in Other Current Liabilities (current portion), and $17.5 million and $17.9 million were recorded in Other Liabilities (noncurrent portion).
Remaining Performance Obligation
The following table includes estimated operating revenues expected to be recognized in the future related to agreements that contain performance obligations that were unsatisfied as of March 31, 2025. The amounts presented primarily consist of fixed fees or MVCs which are typically recognized over time as the performance obligation is satisfied, in accordance with firm service contracts, or at a point in time as guaranteed minimum fees associated with the performance obligation are satisfied under certain ethane supply contracts. For the Company's customers that are charged maximum tariff rates related to its Federal Energy Regulatory Commission regulated operating subsidiaries, the amounts below reflect the current tariff rate for such services for the term of the agreements; however, the tariff rates may be subject to future adjustment. The Company has elected to exclude the following from the table: (a) unsatisfied performance obligations from usage fees associated with its firm services because of the variable nature of such services; (b) unsatisfied performance obligations from the ethane commodity indexed portion of ethane supply contracts because of the variable nature of ethane prices, and (c) consideration in contracts that is recognized in revenue as invoiced, such as for interruptible services. The estimated revenues reflected in the table include estimated revenues that are anticipated under executed precedent transportation agreements for growth projects that are subject to regulatory approvals.
In millions
2025 (1)
2026ThereafterTotal
Estimated revenues from contracts with customers
    from unsatisfied performance obligations as of
    March 31, 2025 (2)
$1,146.5 $1,409.0 $11,579.0 $14,134.5 
Operating revenues which are fixed and
    determinable (operating leases)		21.0 27.5 136.0 184.5 
Total projected operating revenues under committed
    firm agreements as of March 31, 2025 (3)
$1,167.5 $1,436.5 $11,715.0 $14,319.0 

(1)The 2025 period is for the remaining nine months ending December 31, 2025. For the three months ended March 31, 2025, the Company recognized $426.2 million of fixed fee revenues for the fulfillment of performance obligations.

(2)In March 2024, the Company executed a 108-year firm storage agreement with a customer. The estimated annual revenue from this contract is $3.1 million, with $328.5 million of unsatisfied performance obligations included in the “Thereafter” column. Per the tariff provisions, this customer was required to provide 90 days of collateral and the Company can suspend services due to non-payment.

(3)The estimated revenues from contracts with customers from unsatisfied performance obligations as of March 31, 2025, that are anticipated under executed precedent transportation agreements associated with the Company's growth projects are $4.0 billion.
v3.25.1
Fair Value Measurements and Investments (Tables)
 3 Months Ended
Mar. 31, 2025
Fair Value Disclosures [Abstract]  
Fair Value, by Balance Sheet Grouping
The carrying amounts and estimated fair values of the Company's financial assets and liabilities which were not recorded at fair value on the Condensed Consolidated Balance Sheets as of March 31, 2025, and December 31, 2024, were as follows (in millions):

As of March 31, 2025 Estimated Fair Value
Financial AssetsCarrying AmountLevel 1Level 2Level 3Total
Cash and cash equivalents$235.2 $235.2 $— $— $235.2 
Financial Liabilities     
Long-term debt
$3,237.2 
(1)
$— $3,160.9 $— $3,160.9 

(1)The carrying amount of long-term debt excluded a $2.5 million long-term finance lease obligation and $4.6 million of unamortized debt issuance costs.

As of December 31, 2024Estimated Fair Value
Financial AssetsCarrying AmountLevel 1Level 2Level 3Total
Cash and cash equivalents$117.9 $117.9 $— $— $117.9 
Financial Liabilities 
Long-term debt$3,236.5 
(1)
$— $3,129.7 $— $3,129.7 

(1)The carrying amount of long-term debt excluded a $2.7 million long-term finance lease obligation and $4.8 million of unamortized debt issuance costs.
v3.25.1
Employee Benefits (Tables)
 3 Months Ended
Mar. 31, 2025
Retirement Benefits [Abstract]  
Schedule of Net Benefit Costs
Components of net periodic benefit cost for both the Retirement Plans and PBOP were as follows (in millions):
Retirement PlansPBOP
For the
Three Months Ended
March 31,		For the
Three Months Ended
March 31,
2025202420252024
Service cost$0.5 $0.5 $— $— 
Interest cost1.0 1.0 0.3 0.3 
Expected return on plan assets(1.1)(1.0)(0.7)(0.6)
Amortization of unrecognized net loss— 0.2 — — 
Settlement charge0.3 0.1 — — 
Net periodic benefit cost (credit)
$0.7 $0.8 $(0.4)$(0.3)
v3.25.1
Supplemental Disclosure of Cash Flow Information (Tables)
 3 Months Ended
Mar. 31, 2025
Supplemental Cash Flow Elements [Abstract]  
Supplemental Disclosure of Cash Flow Information Supplemental Disclosure of Cash Flow Information (in millions):
 For the
Three Months Ended
March 31,
 20252024
Cash paid during the period for:  
Interest (net of amount capitalized)$48.1 $31.8 
Non-cash investing activities:
Accounts payable and PPE
26.1 46.5 
Right-of-use asset obtained in exchange for lease obligations0.1 7.8 
v3.25.1
Reportable Segments (Tables)
 3 Months Ended
Mar. 31, 2025
Segment Reporting [Abstract]  
Schedule of Segment Reporting Information, by Segment
The tables below show financial information by segment (in millions):

For the Three Months Ended March 31, 2025
Natural Gas
Natural Gas LiquidsTotal
Revenues
Revenue from external customers$410.7 $207.9 $618.6 
Intrasegment revenues
13.0 — 13.0 
$423.7 $207.9 $631.6 
Reconciliation of revenues:
Elimination of intrasegment revenues
(13.0)
Total consolidated revenues$618.6 
Less:
Costs associated with service revenues$12.0 $4.3 
Costs associated with product sales— 122.9 
Operation and maintenance47.8 10.4 
Administrative and general46.5 6.5 
Taxes other than income taxes28.9 3.4 
Gain on sale of assets, impairments and other
(1.0)— 
Miscellaneous other income, net(1.1)(0.1)
Segment EBITDA
$290.6 $60.5 $351.1 
Reconciliation of profit or loss:
Depreciation and amortization$105.5 
Interest expense39.5 
Interest income(1.0)
Consolidated income before income taxes
$207.1 
For the Three Months Ended March 31, 2024
Natural GasNatural Gas LiquidsTotal
Revenues
Revenue from external customers$373.3 $137.2 $510.5 
Intrasegment revenues
12.4 — 12.4 
$385.7 $137.2 $522.9 
Reconciliation of revenues:
Elimination of intrasegment revenues
(12.4)
Total consolidated revenues$510.5 
Less:
Costs associated with service revenues$10.0 $4.7 
Costs associated with product sales— 63.8 
Operation and maintenance46.5 12.4 
Administrative and general47.2 7.0 
Taxes other than income taxes28.3 3.4 
Gain on sale of assets, impairments and other
(7.7)— 
Miscellaneous other income, net(2.9)(0.1)
Segment EBITDA
$264.3 $46.0 $310.3 
Reconciliation of profit or loss:
Depreciation and amortization$105.5 
Interest expense43.3 
Interest income(3.7)
Consolidated income before income taxes
$165.2 


Segment assets include Property, plant, and equipment – net, Intangible assets – net of accumulated amortization and Goodwill. The following table reflects segment assets (in millions):
Segment Assets
As of March 31, 2025As of December 31, 2024
Natural Gas
$7,547.0 $7,490.1 
Natural Gas Liquids1,510.9 1,628.7 
Total Segment Assets
$9,057.9 $9,118.8 


The following table reflects capital expenditures by segment (in millions):
Capital Expenditures
For the Three Months Ended March 31,
20252024
Natural Gas
$42.8 $79.0 
Natural Gas Liquids8.8 18.3 
Total
$51.6 $97.3 
v3.25.1
Basis of Presentation (Details)
$ in Millions
Mar. 31, 2025
USD ($)
Noncontrolling Interest [Line Items]  
Change In Goodwill Allocation Amount $ 4.5
Boardwalk Pipelines Holding Corp. (BPHC) | Boardwalk Pipeline Partners, LP  
Noncontrolling Interest [Line Items]  
Ownership percentage 100.00%
v3.25.1
Revenues - Narrative (Details) - USD ($)
$ in Millions
Mar. 31, 2025
Dec. 31, 2024
Mar. 31, 2024
Dec. 31, 2023
Revenue from Contract with Customer [Abstract]        
Receivables from contracts with customers $ 216.6 $ 210.7    
Contract assets from contracts with customers 12.7 11.9    
Contract liabilities from contracts with customers $ 19.4 $ 17.9 $ 24.7 $ 21.4
v3.25.1
Revenues - Disaggregation of Revenue (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2025
Mar. 31, 2024
Disaggregation of Revenue [Line Items]    
Revenues from Contracts with Customers $ 608.5 $ 500.7
Other operating revenues 10.1 9.8
Total operating revenues 618.6 510.5
Operating Segments    
Disaggregation of Revenue [Line Items]    
Total operating revenues 631.6 522.9
Operating Segments | Natural Gas Reportable Segment    
Disaggregation of Revenue [Line Items]    
Revenues from Contracts with Customers 417.8 380.3
Other operating revenues 5.9 5.4
Total operating revenues 423.7 385.7
Operating Segments | Natural Gas Liquids Reportable Segment    
Disaggregation of Revenue [Line Items]    
Revenues from Contracts with Customers 199.0 127.9
Other operating revenues 8.9 9.3
Total operating revenues 207.9 137.2
Intersegment Eliminations    
Disaggregation of Revenue [Line Items]    
Revenues from Contracts with Customers (8.3) (7.5)
Other operating revenues (4.7) (4.9)
Total operating revenues (13.0) (12.4)
Firm Service    
Disaggregation of Revenue [Line Items]    
Revenues from Contracts with Customers 546.1 440.2
Firm Service | Operating Segments | Natural Gas Reportable Segment    
Disaggregation of Revenue [Line Items]    
Revenues from Contracts with Customers 401.6 362.1
Firm Service | Operating Segments | Natural Gas Liquids Reportable Segment    
Disaggregation of Revenue [Line Items]    
Revenues from Contracts with Customers 152.8 85.6
Firm Service | Intersegment Eliminations    
Disaggregation of Revenue [Line Items]    
Revenues from Contracts with Customers (8.3) (7.5)
Interruptible Service    
Disaggregation of Revenue [Line Items]    
Revenues from Contracts with Customers 13.0 11.9
Interruptible Service | Operating Segments | Natural Gas Reportable Segment    
Disaggregation of Revenue [Line Items]    
Revenues from Contracts with Customers 13.0 11.9
Interruptible Service | Operating Segments | Natural Gas Liquids Reportable Segment    
Disaggregation of Revenue [Line Items]    
Revenues from Contracts with Customers 0.0 0.0
Interruptible Service | Intersegment Eliminations    
Disaggregation of Revenue [Line Items]    
Revenues from Contracts with Customers 0.0 0.0
Other revenues    
Disaggregation of Revenue [Line Items]    
Revenues from Contracts with Customers 49.4 48.6
Other revenues | Operating Segments | Natural Gas Reportable Segment    
Disaggregation of Revenue [Line Items]    
Revenues from Contracts with Customers 3.2 6.3
Other revenues | Operating Segments | Natural Gas Liquids Reportable Segment    
Disaggregation of Revenue [Line Items]    
Revenues from Contracts with Customers 46.2 42.3
Other revenues | Intersegment Eliminations    
Disaggregation of Revenue [Line Items]    
Revenues from Contracts with Customers $ 0.0 $ 0.0
v3.25.1
Revenues - Contract Liability Balance Activity (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2025
Mar. 31, 2024
Dec. 31, 2024
Dec. 31, 2023
Contract With Customer, Liability [Roll Forward]        
Beginning Balance $ 17.9 $ 21.4    
Revenues recognized that were included in the contract liability balances at the beginning of the period 0.6 (1.3)    
Increases due to cash received, excluding amounts recognized as revenues during the period 2.1 4.6    
Ending Balance 19.4 24.7    
Contract with customer, liability, current 3.8 7.2 $ 1.8 $ 3.5
Contract with customer, liability, noncurrent $ 15.6 $ 17.5 $ 16.1 $ 17.9
v3.25.1
Revenues - Performance Obligations (Details)
$ in Millions
 3 Months Ended
Mar. 31, 2025
USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Estimated revenues from contracts with customers from unsatisfied performance obligations as of March 31, 2025 (2) $ 14,134.5
Operating revenues which are fixed and determinable (operating leases) 184.5
Total projected operating revenues under committed firm agreements as of March 31, 2025 (3) 14,319.0
Fixed fee revenues recognized $ 426.2
Firm storage, term of contract for particular customer 108 years
Estimated annual revenue from particular customer $ 3.1
Revenue remaining performance obligation for particular customer $ 328.5
Days of collateral required for particular customer 90 days
Revenue Remaining Performance Obligation, Amount, Precedent Transportation Agreements $ 4,000.0
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-04-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Remaining performance obligation, expected timing of satisfaction, period 9 months
Estimated revenues from contracts with customers from unsatisfied performance obligations as of March 31, 2025 (2) $ 1,146.5
Operating revenues which are fixed and determinable (operating leases) 21.0
Total projected operating revenues under committed firm agreements as of March 31, 2025 (3) $ 1,167.5
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-01-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Remaining performance obligation, expected timing of satisfaction, period 1 year
Estimated revenues from contracts with customers from unsatisfied performance obligations as of March 31, 2025 (2) $ 1,409.0
Operating revenues which are fixed and determinable (operating leases) 27.5
Total projected operating revenues under committed firm agreements as of March 31, 2025 (3) $ 1,436.5
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2027-01-01  
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Remaining performance obligation, expected timing of satisfaction, period
Estimated revenues from contracts with customers from unsatisfied performance obligations as of March 31, 2025 (2) $ 11,579.0
Operating revenues which are fixed and determinable (operating leases) 136.0
Total projected operating revenues under committed firm agreements as of March 31, 2025 (3) $ 11,715.0
v3.25.1
Gas and Liquids Stored Underground and Gas and NGLs Receivables and Payables (Details)
MMBTU in Millions, $ in Millions
Mar. 31, 2025
USD ($)
$ / lb
$ / MMBTU
MMBTU
MMBbls
pounds
Dec. 31, 2024
USD ($)
$ / MMBTU
MMBTU
MMBbls
pounds
Oil and Gas, Gas-Balancing Arrangement [Abstract]    
Gas balancing measurement (in TBtu) | MMBTU 26.7 9.8
Average market price of gas assumed (in dollars per MMBTU) | $ / MMBTU 3.80 2.98
Gas imbalance to subsidiaries asset liability $ 101.5 $ 29.2
Ethylene loaned volume (in pounds) | pounds 33,000,000.0 0
Average market price of ethylene assumed (in dollars per pound) | $ / lb 0.23  
Ethylene loaned balance due to operating subsidiaries (asset) $ 7.6  
Natural gas liquids balancing measurement (in MMBbls) | MMBbls 0 100,000
Natural gas liquids imbalance to subsidiaries of asset liability   $ 0.3
v3.25.1
Fair Value Measurements and Investments - Financial Assets and Liabilities (Details) - USD ($)
$ in Millions
Mar. 31, 2025
Dec. 31, 2024
Financial Assets    
Cash and cash equivalents $ 235.2 $ 117.9
Financial Liabilities    
Long-term debt 3,160.9 3,129.7
Long-term finance lease obligation 2.5 2.7
Unsecured Debt    
Financial Liabilities    
Unamortized debt issuance costs 4.6 4.8
Carrying Amount    
Financial Assets    
Cash and cash equivalents 235.2 117.9
Financial Liabilities    
Long-term debt 3,237.2 3,236.5
Estimated Fair Value | Level 1    
Financial Assets    
Cash and cash equivalents 235.2 117.9
Financial Liabilities    
Long-term debt 0.0 0.0
Estimated Fair Value | Level 2    
Financial Assets    
Cash and cash equivalents 0.0 0.0
Financial Liabilities    
Long-term debt 3,160.9 3,129.7
Estimated Fair Value | Level 3    
Financial Assets    
Cash and cash equivalents 0.0 0.0
Financial Liabilities    
Long-term debt $ 0.0 $ 0.0
v3.25.1
Commitments and Contingencies - Legal Proceedings and Settlements (Details)
$ in Millions
Nov. 12, 2021
USD ($)
Aug. 05, 2021
case
City Of New Orleans Litigation | Pending Litigation    
Loss Contingencies [Line Items]    
Number of cases | case   2
Boardwalk GP, LP    
Loss Contingencies [Line Items]    
Legal damages awarded to other party (approximately) $ 690.0  
Pre-judgment interest awarded to other party (approximately) $ 166.0  
v3.25.1
Commitments and Contingencies - Commitments for Construction (Details)
$ in Millions
Mar. 31, 2025
USD ($)
Commitments and Contingencies Disclosure [Abstract]  
Purchase commitment, expected to be settled in the next twelve months $ 236.6
v3.25.1
Financing (Details) - USD ($)
Mar. 31, 2025
Dec. 31, 2024
Unsecured Debt    
Debt Instrument [Line Items]    
Weighted-average interest rates 4.95% 4.95%
Unsecured Debt | Total Notes And Debentures    
Debt Instrument [Line Items]    
Total notes and debentures $ 3,300,000,000 $ 3,300,000,000
Line of Credit    
Line of Credit Facility [Abstract]    
Line of credit, outstanding borrowings 0  
Available borrowing capacity 1,000,000,000.0  
Line of Credit | Amendment No. 3 Credit Agreement - 2021    
Line of Credit Facility [Abstract]    
Maximum borrowing capacity 1,000,000,000.0  
Line of Credit | Amendment No. 5 Credit Agreement - 2023    
Line of Credit Facility [Abstract]    
Maximum borrowing capacity $ 912,200,000  
v3.25.1
Employee Benefits - Narrative (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2025
Mar. 31, 2024
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]    
Defined contribution plan, cost $ 3.8 $ 3.6
Pension    
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]    
Contribution to defined benefit pension plan 0.5  
Expected future contributions $ 2.5  
v3.25.1
Employee Benefits - Components of Net Periodic Benefit Cost (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2025
Mar. 31, 2024
Retirement Plans    
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]    
Service cost $ 0.5 $ 0.5
Interest cost 1.0 1.0
Expected return on plan assets (1.1) (1.0)
Amortization of unrecognized net loss 0.0 0.2
Settlement charge 0.3 0.1
Net periodic benefit cost (credit) 0.7 0.8
PBOP    
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]    
Service cost 0.0 0.0
Interest cost 0.3 0.3
Expected return on plan assets (0.7) (0.6)
Amortization of unrecognized net loss 0.0 0.0
Settlement charge 0.0 0.0
Net periodic benefit cost (credit) $ (0.4) $ (0.3)
v3.25.1
Related Party Transactions (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2025
Mar. 31, 2024
Related Party Transaction [Line Items]    
Administrative and general $ 48.3 $ 49.3
Cash dividends paid to parent company 75.0 50.0
Parent Company    
Related Party Transaction [Line Items]    
Cash dividends paid to parent company 75.0 50.0
Affiliates    
Related Party Transaction [Line Items]    
Administrative and general $ 1.5 $ 1.4
v3.25.1
Supplemental Disclosure of Cash Flow Information (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2025
Mar. 31, 2024
Cash paid during the period for:    
Interest (net of amount capitalized) $ 48.1 $ 31.8
Non-cash investing activities:    
Accounts payable and PPE 26.1 46.5
Right-of-use asset obtained in exchange for lease obligations $ 0.1 $ 7.8
v3.25.1
Reportable Segments (Details)
$ in Millions
 3 Months Ended
Mar. 31, 2025
USD ($)
segments
Mar. 31, 2024
USD ($)
Dec. 31, 2024
USD ($)
Segment Reporting Information [Line Items]      
Number of reportable segments | segments 2    
Operating Revenues $ 618.6 $ 510.5  
Costs associated with service revenues 8.0 7.2  
Costs associated with product sales 122.9 63.8  
Operation and maintenance 58.2 58.9  
Administrative and general 48.3 49.3  
Taxes other than income taxes 32.3 31.7  
Gain on sale of assets, impairments and other (1.0) (7.7)  
Miscellaneous other income, net 1.2 3.0  
Segment EBITDA 351.1 310.3  
Depreciation and amortization 105.5 105.5  
Interest expense 39.5 43.3  
Interest income (1.0) (3.7)  
Consolidated income before income taxes 207.1 165.2  
Total Assets 9,849.6   $ 9,779.4
Capital expenditures 51.6 97.3  
Operating Segments      
Segment Reporting Information [Line Items]      
Revenue From External Customers 618.6 510.5  
Intrasegment revenues 13.0 12.4  
Operating Revenues 631.6 522.9  
Total Assets 9,057.9   9,118.8
Intersegment Eliminations      
Segment Reporting Information [Line Items]      
Intrasegment revenues 13.0 12.4  
Operating Revenues (13.0) (12.4)  
Natural Gas Reportable Segment      
Segment Reporting Information [Line Items]      
Revenue From External Customers 410.7 373.3  
Natural Gas Reportable Segment | Operating Segments      
Segment Reporting Information [Line Items]      
Intrasegment revenues 13.0 12.4  
Operating Revenues 423.7 385.7  
Costs associated with service revenues 12.0 10.0  
Costs associated with product sales 0.0 0.0  
Operation and maintenance 47.8 46.5  
Administrative and general 46.5 47.2  
Taxes other than income taxes 28.9 28.3  
Gain on sale of assets, impairments and other (1.0) (7.7)  
Miscellaneous other income, net (1.1) (2.9)  
Segment EBITDA 290.6 264.3  
Total Assets 7,547.0   7,490.1
Capital expenditures 42.8 79.0  
Natural Gas Liquids Reportable Segment      
Segment Reporting Information [Line Items]      
Revenue From External Customers 207.9 137.2  
Natural Gas Liquids Reportable Segment | Operating Segments      
Segment Reporting Information [Line Items]      
Operating Revenues 207.9 137.2  
Costs associated with service revenues 4.3 4.7  
Costs associated with product sales 122.9 63.8  
Operation and maintenance 10.4 12.4  
Administrative and general 6.5 7.0  
Taxes other than income taxes 3.4 3.4  
Gain on sale of assets, impairments and other 0.0 0.0  
Miscellaneous other income, net (0.1) (0.1)  
Segment EBITDA 60.5 46.0  
Total Assets 1,510.9   $ 1,628.7
Capital expenditures $ 8.8 $ 18.3