BOARDWALK PIPELINE PARTNERS, LP, 10-K filed on 2/11/2025
Annual Report
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Document And Entity Information - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Feb. 11, 2025
Jun. 30, 2024
Cover [Abstract]      
Document Type 10-K    
Document Annual Report true    
Document Period End Date Dec. 31, 2024    
Current Fiscal Year End Date --12-31    
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 Well-known Seasoned Issuer Yes    
Entity Voluntary Filers No    
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    
ICFR Auditor Attestation Flag false    
Document Financial Statement Error Correction false    
Entity Shell Company false    
Documents Incorporated by Reference None.    
Entity Central Index Key 0001336047    
Document Fiscal Year Focus 2024    
Document Fiscal Period Focus FY    
Amendment Flag false    
Entity Common Stock, Shares Outstanding (in shares)   0  
Entity Public Float     $ 0.0
No Insider Trading Flag true    
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Audit Information
 12 Months Ended
Dec. 31, 2024
Audit Information [Abstract]  
Auditor Location Houston, Texas
Auditor Name Deloitte & Touche LLP
Auditor Firm ID 34
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CONSOLIDATED BALANCE SHEETS - USD ($)
$ in Millions
Dec. 31, 2024
Dec. 31, 2023
Current Assets:    
Cash and cash equivalents $ 117.9 $ 20.1
Receivables:    
Trade, net 210.7 204.6
Other 21.4 24.9
Gas transportation receivables 7.4 7.0
Prepayments 25.2 24.3
Other current assets 18.5 7.8
Total current assets 401.1 288.7
Property, Plant and Equipment:    
Property, plant and equipment, gross 13,857.8 13,529.5
Less—accumulated depreciation and amortization 5,045.1 4,672.9
Property, plant and equipment, net 8,812.7 8,856.6
Other Assets:    
Goodwill 237.4 237.4
Gas stored underground 98.3 99.3
Other 229.9 214.4
Total other assets 565.6 551.1
Total Assets 9,779.4 9,696.4
Payables:    
Trade 100.9 113.2
Gas transportation payables 11.7 7.8
Accrued taxes, other 67.0 67.9
Accrued interest 46.7 34.2
Accrued payroll and employee benefits 48.6 44.0
Regulatory liabilities 18.3 15.1
Other current liabilities 30.2 60.3
Total current liabilities 345.6 362.3
Long-term debt and finance lease obligation 3,234.4 3,261.9
Other Liabilities and Deferred Credits:    
Asset retirement obligations 70.0 59.2
Provision for other asset retirement 103.6 98.1
Total other liabilities and deferred credits 293.4 281.1
Commitments and Contingencies
Partners' Capital:    
Partners' capital 5,978.6 5,867.7
Accumulated other comprehensive loss (72.6) (76.6)
Total partners' capital 5,906.0 5,791.1
Total Liabilities and Partners' Capital 9,779.4 9,696.4
Affiliates    
Payables:    
Payables 0.5 3.4
Other Liabilities and Deferred Credits:    
Other 4.8 0.0
Other    
Payables:    
Payables 21.7 16.4
Other Liabilities and Deferred Credits:    
Other 115.0 123.8
Pipelines, storage and other plant    
Property, Plant and Equipment:    
Property, plant and equipment, gross 13,667.7 13,242.3
Construction work in progress    
Property, Plant and Equipment:    
Property, plant and equipment, gross $ 190.1 $ 287.2
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CONSOLIDATED STATEMENTS OF INCOME - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Operating Revenues:      
Transportation $ 1,361.3 $ 1,287.0 $ 1,228.8
Storage, parking and lending 211.0 160.9 129.2
Product sales 378.7 100.3 11.1
Other 77.1 69.5 62.9
Total operating revenues 2,028.1 1,617.7 1,432.0
Operating Costs and Expenses:      
Costs associated with service revenues 29.1 26.3 22.4
Costs associated with product sales 303.5 87.8 1.0
Operation and maintenance 310.3 281.0 250.9
Administrative and general 186.1 171.9 147.7
Depreciation and amortization 424.8 408.7 392.3
(Gain) loss on sale of assets, impairments and other (5.5) 0.3 4.0
Taxes other than income taxes 122.1 115.5 114.5
Total operating costs and expenses 1,370.4 1,091.5 932.8
Operating income 657.7 526.2 499.2
Other Deductions (Income):      
Interest expense 182.9 155.6 165.9
Interest income (31.1) (12.1) (3.3)
Miscellaneous other income, net (6.1) (4.1) (6.4)
Total other deductions 145.7 139.4 156.2
Income before income taxes 512.0 386.8 343.0
Income taxes 1.1 0.8 0.8
Net income $ 510.9 $ 386.0 $ 342.2
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CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Statement of Comprehensive Income [Abstract]      
Net income $ 510.9 $ 386.0 $ 342.2
Other comprehensive income (loss):      
Reclassification adjustment transferred to Net income from cash flow hedges 0.1 0.1 0.5
Pension and other postretirement benefit costs, net of tax 3.9 2.8 (7.4)
Total Comprehensive Income $ 514.9 $ 388.9 $ 335.3
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CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
OPERATING ACTIVITIES:      
Net income $ 510.9 $ 386.0 $ 342.2
Adjustments to reconcile net income to cash provided by operations:      
Depreciation and amortization 424.8 408.7 392.3
Amortization of deferred costs and other 13.8 18.5 4.0
(Gain) loss on sale of assets, impairments and other (5.5) 0.3 4.0
Interest income from short-term investments (19.8) 0.0 0.0
Changes in operating assets and liabilities:      
Trade and other receivables (2.8) (7.8) (16.7)
Gas transportation receivables, storage assets and other product inventory (15.2) 70.6 (63.4)
Prepayments and other assets (7.7) 3.1 (9.8)
Trade and other payables 11.9 11.5 15.6
Other payables, affiliates 0.1 0.1 (0.2)
Gas transportation payables (8.6) (20.8) 21.0
Accrued liabilities 17.1 7.4 (0.9)
Regulatory assets and liabilities 2.7 (40.3) 49.3
Other liabilities (21.2) (19.9) (10.6)
Net cash provided by operating activities 900.5 817.4 726.8
INVESTING ACTIVITIES:      
Capital expenditures (392.4) (382.4) (344.3)
Proceeds from sale of operating assets 0.5 0.3 1.5
Acquisition of business 0.0 (355.0) 0.0
Purchases of short-term investments (1,102.2) 0.0 0.0
Proceeds from the maturity of short-term investments 1,122.0 0.0 0.0
Net cash used in investing activities (372.1) (737.1) (342.8)
FINANCING ACTIVITIES:      
Proceeds from long-term debt, net of issuance cost 593.5 0.0 495.0
Repayment of borrowings from long-term debt (600.0) 0.0 (600.0)
Proceeds from borrowings on revolving credit facility 170.0 155.0 0.0
Repayments of borrowings on revolving credit facility, including financing fees (195.0) (130.6) (0.6)
Principal payment of finance lease obligation (0.9) (0.9) (0.8)
Advances from affiliates 1.8 0.7 1.1
Distributions paid (400.0) (300.0) (102.2)
Net cash used in financing activities (430.6) (275.8) (207.5)
Increase (decrease) in cash and cash equivalents 97.8 (195.5) 176.5
Cash and cash equivalents at beginning of period 20.1 215.6 39.1
Cash and cash equivalents at end of period $ 117.9 $ 20.1 $ 215.6
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CONSOLIDATED STATEMENTS OF CHANGES IN PARTNERS' CAPITAL - USD ($)
$ in Millions
Total
Accumulated Other Comprehensive (Loss) Income
Partners' Capital
Beginning Balance at Dec. 31, 2021 $ 5,469.1 $ (72.6) $ 5,541.7
Add (deduct):      
Net income 342.2   342.2
Distributions paid (102.2)   (102.2)
Other comprehensive income (loss), net of tax (6.9) (6.9)  
Ending Balance at Dec. 31, 2022 5,702.2 (79.5) 5,781.7
Add (deduct):      
Net income 386.0   386.0
Distributions paid (300.0)   (300.0)
Other comprehensive income (loss), net of tax 2.9 2.9  
Ending Balance at Dec. 31, 2023 5,791.1 (76.6) 5,867.7
Add (deduct):      
Net income 510.9   510.9
Distributions paid (400.0)   (400.0)
Other comprehensive income (loss), net of tax 4.0 4.0  
Ending Balance at Dec. 31, 2024 $ 5,906.0 $ (72.6) $ 5,978.6
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Corporate Structure
 12 Months Ended
Dec. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]  
Corporate Structure Corporate Structure
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, Gulf South Pipeline Company, LLC (Gulf South), Texas Gas Transmission, LLC (Texas Gas), Boardwalk Louisiana Midstream, LLC (Louisiana Midstream), Boardwalk Louisiana Gas Transmission, LLC, Boardwalk Texas Intrastate, LLC, Boardwalk Petrochemical Pipeline, LLC (Boardwalk Petrochemical), and Boardwalk Ethane Pipeline Company, LLC (together, the 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). All of the Company's operations are conducted by the operating subsidiaries.

As of December 31, 2024, Boardwalk Pipelines Holding Corp. (BPHC), a wholly owned subsidiary of Loews Corporation (Loews), owned directly or indirectly, 100% of the Company's capital.
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Basis of Presentation and Significant Accounting Policies
 12 Months Ended
Dec. 31, 2024
Accounting Policies [Abstract]  
Basis of Presentation and Significant Accounting Policies Basis of Presentation and Significant Accounting Policies
Basis of Presentation

The accompanying consolidated financial statements of the Company have been prepared in accordance with accounting principles generally accepted in the United States of America (U.S.) (GAAP).

Principles of Consolidation

The consolidated financial statements include the Company's accounts and those of its wholly owned subsidiaries after elimination of intercompany transactions.

Use of Estimates

The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses, disclosure of contingent assets and liabilities and the fair values of certain items. The Company bases its estimates on historical experience and on various other assumptions that are believed to be reasonable under the circumstances, which form the basis for making judgments about the carrying amounts of assets and liabilities that are not readily apparent from other sources. Actual results could differ from such estimates.

Segment Information

The Company determines its operating and reportable segments based on how the Chief Operating Decision Maker (CODM), who is the Chief Executive Officer (CEO), reviews and manages the business, including determining how to allocate resources and assess performance. Historically, the Company concluded that it had a single operating and reportable segment. Due to changes in its internal reporting and the information evaluated by the CODM, the Company concluded that it operated in three operating segments as of December 31, 2024. The Company reported the financial results in two reportable segments because two operating segments met the aggregation criteria to be reported as one reportable segment. The Company’s two reportable segments are Natural Gas and Natural Gas Liquids.

Note 18 contains more information about the Company’s segment information, including the 2023 and 2022 financial information presented under the 2024 reportable segment presentation.

Regulatory Accounting

Most of the Company's natural gas pipeline subsidiaries and its interstate ethane transportation pipeline are regulated by the Federal Energy Regulatory Commission (FERC). When certain criteria are met, GAAP requires that certain rate-regulated entities account for and report assets and liabilities consistent with the economic effect of the manner in which independent third-party regulators establish rates (regulatory accounting). This basis of accounting is applicable to operations of
the Company's Texas Gas subsidiary, which records certain costs and benefits as regulatory assets and liabilities in order to provide for recovery from or refunds to customers in future periods, but is not applicable to the operations associated with the Fayetteville and Greenville Laterals due to rates charged under negotiated rate agreements and a portion of Texas Gas' storage capacity due to the regulatory treatment associated with the rates charged for that capacity.

The Company also applies regulatory accounting for its fuel trackers on Gulf South, under which the value of fuel received from customers paying the maximum tariff rate and the related value of fuel used in transportation are recorded to a regulatory asset or liability depending on whether Gulf South uses more fuel than it collects from customers or collects more fuel than it uses. Other than as described for Texas Gas and for the fuel trackers on Gulf South, regulatory accounting is not applicable to the Company's other FERC-regulated operations.

The Company monitors the regulatory and competitive environment in which it operates to determine whether its regulatory assets continue to be probable of recovery. If the Company determines that all or a portion of its regulatory assets no longer meets the criteria for recognition as regulatory assets, that portion which is not recoverable will be written off, net of any regulatory liabilities.

Note 11 contains more information regarding the Company's regulatory assets and liabilities.

Fair Value Measurements

Fair value refers to an exit price that would be received to sell an asset or paid to transfer a liability in an orderly transaction in the principal market in which the reporting entity transacts based on the assumptions market participants would use when pricing the asset or liability assuming its highest and best use. A fair value hierarchy has been established that prioritizes the information used to develop those assumptions giving priority, from highest to lowest, to quoted prices in active markets for identical assets and liabilities (Level 1); observable inputs not included in Level 1, for example, quoted prices for similar assets and liabilities (Level 2); and unobservable data (Level 3), for example, a reporting entity's own internal data based on the best information available in the circumstances. The Company uses fair value measurements to account for equity securities, asset retirement obligations (ARO), pension and postretirement benefits other than pension (PBOP) assets and any impairment charges.

Notes 7 and 13 contain more information regarding fair value measurements.

Cash and Cash Equivalents

Cash equivalents are highly liquid investments with an original maturity of three months or less and are stated at cost plus accrued interest, which approximates fair value. The Company had no restricted cash at December 31, 2024 and 2023.

Short-Term Investments

During 2024, the Company invested in U.S. treasury bills that were classified as held-to-maturity short-term investments and matured in December 2024. Income related to the U.S. treasury bills was recorded in Interest Income on the Consolidated Statements of Income. The Company had no outstanding short-term investments as of December 31, 2024 and 2023.

Trade and Other Receivables

Trade and other receivables are stated at their historical carrying amount, net of allowances for doubtful accounts. The Company establishes an allowance for doubtful accounts under an expected credit loss model based on historical credit loss experience and specific facts and circumstances. Uncollectible receivables are written off when a settlement is reached for an amount that is less than the outstanding historical balance or a receivable amount is deemed otherwise unrealizable.

Gas Stored Underground and Gas Receivables and Payables

Certain of the Company's operating subsidiaries have underground gas in storage which is utilized for system management and operational balancing, as well as for services including firm and interruptible storage associated with certain no-notice and parking and lending (PAL) services. Gas stored underground includes the historical cost of natural gas volumes owned by the operating subsidiaries, at times reduced by certain operational encroachments upon that gas.
The operating subsidiaries provide storage services whereby they store natural gas or NGLs on behalf of customers and also periodically hold customer gas under PAL services. Since the customers retain title to the gas held by the Company in providing these services, the Company does not record the related gas on the Consolidated Balance Sheets. Certain of the Company's operating subsidiaries also periodically lend gas and NGLs to customers.

In the course of providing transportation and storage services to customers, the operating subsidiaries may receive different quantities of gas from shippers and operators than the quantities delivered on behalf of those shippers and operators. This results in transportation and exchange gas receivables and payables, commonly known as imbalances, which are primarily settled in cash or the receipt or delivery of gas in the future. Settlement of imbalances requires agreement between the pipelines and shippers or operators as to allocations of volumes to specific transportation contracts and timing of delivery of gas based on operational conditions. The receivables and payables are valued at market price for operations where regulatory accounting is not applicable and are valued at the historical value of gas in storage for operations where regulatory accounting is applicable.

Product Inventory

Product inventory, primarily ethane used in the Company’s ethane supply services, is included in Other Current Assets on the Consolidated Balance Sheets. Product inventory is recorded at the lower of weighted-average cost or net realizable value. At December 31, 2024 and 2023, the Company held $12.7 million and $2.4 million of product inventory.

Materials and Supplies

Materials and supplies are carried at average cost and are included in Other Assets on the Consolidated Balance Sheets. The Company expects its materials and supplies to be used for projects related to its property, plant and equipment (PPE) and for future growth projects. At December 31, 2024 and 2023, the Company held approximately $42.4 million and $38.1 million of materials and supplies.

Property, Plant and Equipment and Repair and Maintenance Costs

PPE is recorded at its original cost of construction or fair value of assets purchased. Construction costs and expenditures for major renewals and improvements which extend the lives of the respective assets are capitalized. Construction work in progress is included in the financial statements as a component of PPE. Repair and maintenance costs are expensed as incurred.

Depreciation of PPE related to operations for which regulatory accounting does not apply is provided for using the straight-line method of depreciation over the estimated useful lives of the assets, which range from 3 to 35 years. The ordinary sale or retirement of PPE for these assets could result in a gain or loss being recorded in the income statement. Depreciation of PPE related to operations for which regulatory accounting is applicable is provided for primarily on the straight-line method at FERC-prescribed rates over estimated useful lives of 5 to 62 years. Reflecting the application of composite depreciation, gains and losses from the ordinary sale or retirement of PPE for these assets are not recognized in earnings and generally do not impact PPE, net.
    
Note 8 contains more information regarding the Company's PPE.

Goodwill and Intangible Assets

Goodwill represents the excess of the cost of an acquisition over the fair value of the net identifiable assets acquired and liabilities assumed. Goodwill is tested for impairment at the reporting unit level at least annually, as of November 30, or more frequently when events occur and circumstances change that would more likely than not reduce the fair value of a reporting unit below its carrying amount. A reporting entity may perform an optional qualitative assessment on an annual basis to determine whether events occurred or circumstances changed that would more likely than not reduce the fair value of a reporting unit below its carrying amount. If an initial qualitative assessment identifies that it is more likely than not that the fair value of a reporting unit is less than its carrying amount, or the optional qualitative assessment is not performed, a quantitative analysis is performed. The quantitative goodwill impairment test is performed by calculating the fair value of the reporting unit and comparing it to the reporting unit's carrying amount. If the fair value of a reporting unit exceeds its carrying amount, goodwill of the reporting unit is not impaired. However, if the carrying amount of a reporting unit exceeds its fair value, an impairment loss is recognized in an amount equal to that excess, limited to the total amount of goodwill recorded on the reporting unit.
Intangible assets are those assets which provide future economic benefit but have no physical substance. The Company recorded intangible assets for customer relationships obtained through its acquisitions. The customer relationships, which are included in Other Assets on the Consolidated Balance Sheets, have a finite life and are being amortized over their estimated useful lives, which is generally 35 years.

Note 9 contains more information regarding the Company's goodwill and intangible assets.

Impairment of Long-lived Assets (including Tangible and Definite-lived Intangible Assets)

The Company evaluates its long-lived and intangible assets for impairment when, in management's judgment, events or changes in circumstances indicate that the carrying amount of such assets may not be recoverable. When such a determination has been made, management's estimate of undiscounted future cash flows attributable to the remaining economic useful life of the asset (or asset group) is compared to the carrying amount of the asset (or asset group) to determine whether an impairment has occurred. If an impairment of the carrying amount has occurred, the amount of impairment recognized in the financial statements is determined by estimating the fair value of the assets (or asset group) and recording a loss to the extent that the carrying amount exceeds the estimated fair value.

Capitalized Interest and Allowance for Funds Used During Construction (AFUDC)

The Company records capitalized interest, which represents the cost of borrowed funds used to finance construction activities for operations where regulatory accounting is not applicable. The Company records AFUDC, which represents the cost of funds, including equity funds, applicable to regulated natural gas transmission plant under construction as permitted by FERC regulatory practices, in connection with the Company's operations where regulatory accounting is applicable. Capitalized interest and the allowance for borrowed funds used during construction are recognized as a reduction to Interest expense and the allowance for equity funds used during construction is included in Miscellaneous other income, net on the Consolidated Statements of Income. The following table summarizes capitalized interest and the allowance for borrowed funds and allowance for equity funds used during construction (in millions):
 For the Year Ended
December 31,
 202420232022
Capitalized interest and allowance for borrowed funds used during construction$5.5 $3.6 $2.2 
Allowance for equity funds used during construction4.5 5.7 6.2 

Income Taxes

The Company is not a taxable entity for federal income tax purposes. As such, it does not directly pay federal income tax. The Company's taxable income or loss, which may vary substantially from the net income or loss reported on the Consolidated Statements of Income, is includable in the federal income tax returns of each of its partners. The aggregate difference in the basis of the Company's net assets for financial and income tax purposes is $5.7 billion. The subsidiaries of the Company directly incur some income-based state taxes which are presented in Income taxes on the Consolidated Statements of Income.

Note 14 contains more information regarding the Company's income taxes.

Asset Retirement Obligations

The accounting requirements for existing legal obligations associated with the future retirement of long-lived assets require entities to record the fair value of a liability for an ARO in the period during which the liability is incurred. The liability is initially recognized at fair value and is increased with the passage of time as accretion expense is recorded, until the liability is ultimately settled. The accretion expense is included within Operation and maintenance costs on the Consolidated Statements of Income. An amount corresponding to the amount of the initial liability is capitalized as part of the carrying amount of the related long-lived asset and depreciated over the useful life of that asset.

Note 10 contains more information regarding the Company's ARO.
Environmental Liabilities

The Company records environmental liabilities based on management's estimates of the undiscounted future obligation for probable costs associated with environmental assessment and remediation of operating sites. These estimates are based on evaluations and discussions with counsel and operating personnel and the current known facts and circumstances related to these environmental matters.

Note 6 contains more information regarding the Company's environmental liabilities.

Defined Benefit Plans

The Company maintains postretirement benefit plans for certain employees. The Company funds these plans through periodic contributions which are invested until the benefits are paid out to the participants, and records an asset or liability based on the overfunded or underfunded status of the plan. The net benefit costs of the plans are recorded on the Consolidated Statements of Income. Any deferred amounts related to unrecognized gains and losses or changes in actuarial assumptions are recorded as either a regulatory asset or liability or recorded as a component of accumulated other comprehensive income until those gains or losses are recognized on the Consolidated Statements of Income.

Note 13 contains more information regarding the Company's pension and other postretirement benefit obligations.

Long-Term Compensation

The Company provides performance awards (Performance Awards) to certain of its employees under its 2018 Long-Term Incentive Plan (2018 LTIP). A Performance Award is a long-term incentive award with a stated target amount which is payable in cash, after certain adjustments, upon vesting based on certain specified performance criteria being met.

The Company measures the cost of an award issued in exchange for employee services based on the stated target amount for Performance Awards. All outstanding awards are required to be settled in cash and are classified as a liability until settlement. The related compensation expense, less forfeitures, is recognized over the period that employees are required to provide services in exchange for the awards, usually the vesting period.

Note 13 contains more information regarding the Company's long-term compensation.

Partner Capital Accounts

For purposes of maintaining capital accounts, items of income and loss of the Company are allocated among the partners each period, or portion thereof, in accordance with the partnership agreement, based on their respective ownership interests.

Leases

Operating lease right-of-use assets and lease liabilities are recognized at the lease commencement date based on the present value of lease payments over the lease term. The discount rate used to determine the commencement date present value of lease payments is typically the Company's secured borrowing rate, as the implicit rate of most of the Company's leases is not readily determinable. The Company has elected not to record any leases with terms of twelve months or less on the Consolidated Balance Sheets.

Note 5 contains more information regarding the Company's leases.

Revenue Recognition
Nature of Contracts

The Company primarily earns revenues from contracts with customers by providing transportation and storage services for natural gas and NGLs on a firm and interruptible basis and providing ethane supply and transportation services for industrial customers in Louisiana and Texas. The Company also provides interruptible natural gas PAL services. The Company's customers choose, based upon their particular needs, the applicable mix of services depending upon availability of pipeline and storage capacity, the price of services and the volume and timing of customer requirements. The maximum applicable rates that the majority of the Company's operating subsidiaries may charge for their services are established through the FERC's cost-
based rate-making process; however, the FERC also allows for discounted or negotiated rates as an alternative to cost-based rates. Under the FERC regulations, certain revenues that the Company's subsidiaries collect may be subject to possible refunds to customers. Accordingly, during a rate case, estimated refund liabilities are recorded considering regulatory proceedings, advice of counsel and estimated risk-adjusted total exposure, as well as other factors. The Company's service contracts can range from one to twenty years although the Company may enter into shorter- or longer-term contracts, and services are invoiced monthly with payment from the customer generally expected within ten to thirty days, depending on the terms of the contract. For the ethane supply contracts, the purchases and sales are with different counterparties and control transfers at different receipt and delivery points, resulting in the purchases and sales being presented on a gross basis in the Consolidated Statements of Income.
    
Firm Service Contracts: The Company offers firm services to its customers. The Company's customers can reserve a specific amount of pipeline capacity at specified receipt and delivery points on the Company's pipeline system (transportation service) or can reserve a specific amount of storage capacity at specified injection and withdrawal points at the Company's storage facilities (storage service). The Company accounts for firm services as a single promise to stand ready each month of the contract term to provide the committed capacity for either transportation or storage services when needed by the customer, which represents a series of distinct monthly services that are substantially the same with the same pattern of transfer to the customer. Although several activities may be required to provide the firm service, the individual activities do not represent distinct performance obligations because all of the activities must be performed in combination in order for the Company to provide the firm service.

The transaction price for firm service contracts is comprised of a fixed fee based on the quantity of capacity reserved, regardless of use (capacity reservation fee), plus variable fees in the form of a usage fee paid on the volume of commodity actually transported or injected and withdrawn from storage. Both the fixed and usage fees are allocated to the single performance obligation of providing transportation or storage service and recognized over time based upon the output measure of time as the Company completes its stand-ready obligation to provide contracted capacity and the customer receives and consumes the benefit of the reserved capacity, which corresponds with the transfer of control to the customer. The fixed fee is recognized ratably over the contract term, representative of the proportion of the committed stand-ready capacity obligation that has been fulfilled to date, and the usage fee is recognized upon satisfaction of each distinct monthly performance obligation, consistent with the allocation objective and based upon the level of effort required to satisfy the stand-ready obligation in a given month. Capacity reservation revenues derived from a firm service contract are generally consistent during the contract term, but can be higher in winter periods than the rest of the year based upon seasonal rates.

Interruptible Service Contracts: In providing interruptible services to customers, the Company agrees to transport or store natural gas or NGLs for a customer when capacity is available. The Company does not account for interruptible services with a customer as a contract until the customer nominates for service and the Company accepts the nomination based upon available pipeline or storage capacity or product availability because there are no enforceable rights and obligations until that time. The nomination and acceptance process is a daily activity and acceptance is granted based upon priority of service and availability of capacity and products. Upon acceptance, the Company accounts for interruptible services similarly to its firm services.

The transaction price for interruptible service contracts is comprised of a variable fee in the form of a usage fee paid on the volume of commodity actually transported or injected and withdrawn from storage. The transaction price is allocated to the single performance obligation of providing interruptible service. Interruptible service revenues for natural gas transportation and storage are generally recognized over time based on the output measure of volume transported or stored when services are rendered upon the successful allocation of the services provided to the customer's account, which best depicts the transfer of control to the customer and satisfaction of the promised service. Interruptible services are recognized in the month services are provided because the Company has a right to consideration from customers in amounts that correspond directly to the value that the customer receives from the Company's performance. The rates charged may vary on a daily, monthly or seasonal basis.

Minimum Volume Commitment (MVC) Contracts: Certain of the Company's transportation, storage or ethane supply contracts require customers to transport, store or purchase a minimum volume of commodity over a specified time period. If a customer fails to meet its MVC for the specified time period, the customer is obligated to pay a contractually-determined deficiency fee based upon the shortfall between the actual volumes transported, stored or purchased and the MVC for that period. MVC contracts are generally similar in nature to a firm service contract where the performance obligation is a stand-ready obligation that is a series of distinct services that are substantially the same with the same pattern of transfer to the customer. The transaction price for a MVC is a fee for the volume of commodity actually transported, stored or delivered, which is allocated to each distinct monthly performance obligation, consistent with the allocation objective and based upon the level of effort required to satisfy the obligation of the transacted activities in a given month. Revenues associated with transportation and storage services are generally recognized over time based on the output measure of volume transported or
stored and revenues associated with ethane supply are generally recognized at a point in time based on barrels delivered, with the recognition of the deficiency fee in the period when it is known the customer cannot make up the deficient volume in the specified period.
    
Other: Certain ethane supply contracts include a stated volume that the Company supplies to customers, and any volume requested above the stated volume is based on product availability. Revenues for these ethane supply contracts are generally recognized at a point in time when each barrel is transferred to the customer because the customer is able to direct the use of, and obtain substantially all of the remaining benefits from, the product at that time. Periodically, the Company may also enter into contracts with customers for the sale of natural gas or NGLs. The Company recognizes revenues for these transactions at the point in time of the physical sale of the commodity, which corresponds with the transfer of control of the commodity to the customer and the consideration is measured as the stated sales price in the contract.

Contract Balances

The Company records contract assets primarily related to performance obligations completed but not billed, or partially billed, as of the reporting date. The Company records contract liabilities, or deferred revenue, when payment is received in advance of satisfying its performance obligations.
v3.25.0.1
Acquisition
 12 Months Ended
Dec. 31, 2024
Business Combination, Asset Acquisition, and Joint Venture Formation [Abstract]  
Acquisition Acquisition
On September 29, 2023, Boardwalk Resources Company, LLC, a wholly owned subsidiary of the Company, acquired 100% of the equity interests of Williams Olefins Pipeline Holdco LLC, renamed Boardwalk Ethane Pipeline Holdco, LLC (Bayou Ethane) after the acquisition, from Williams Field Services Group, LLC for $355.0 million in cash. The acquisition was accounted for as a business combination. For the year ended December 31, 2023, the acquisition contributed $101.5 million to the Company's operating revenues and $5.5 million to net income.

Pro Forma Financial Information (unaudited)

The following unaudited pro forma results of operations of the Company are presented as if the acquisition occurred on January 1, 2022. Such results are not necessarily indicative of future results. These pro forma results also do not reflect any cost savings, operating synergies or revenue enhancements that the Company may achieve or the costs necessary to achieve those objectives (in millions):

Pro Forma
For the Year Ended December 31,
20232022
Operating revenue
$1,962.8 $2,253.4 
Net income
393.8 357.4 

The pro forma information was adjusted for the following items:

•Operating revenues and expenses were based on actual results for the periods indicated. Acquisition costs were not material and were excluded; and
•Depreciation and amortization expense was calculated using PPE and intangible asset amounts as determined by the purchase price allocation and estimated useful lives.
v3.25.0.1
Revenues
 12 Months Ended
Dec. 31, 2024
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 table presents the Company's revenues disaggregated by type of service by segment (in millions):
For the Year Ended December 31, 2024
Natural Gas
Natural Gas Liquids
EliminationsTotal
Revenues from Contracts with Customers
Firm Service (1)(2)
$1,353.9 $452.6 $(31.0)$1,775.5 
Interruptible Service 59.1 0.1 — 59.2 
Other revenues (2)
7.6 144.9 — 152.5 
Total Revenues from Contracts with Customers1,420.6 597.6 (31.0)1,987.2 
Other operating revenues (2)(3)
21.5 37.8 (18.4)40.9 
Total Operating Revenues$1,442.1 $635.4 $(49.4)$2,028.1 

(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)For the year ended December 31, 2024, revenues attributable to Bayou Ethane within the Natural Gas Liquids segment were $243.6 million included in firm service from product sales earned from contracts with MVCs; $114.4 million included in other revenues from product sales earned from contracts with no MVCs; and $4.9 million included in other operating revenues.
(3)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 Year Ended December 31, 2023
Natural Gas
Natural Gas Liquids
EliminationsTotal
Revenues from Contracts with Customers
Firm Service (1)(2)
$1,253.1 $262.7 $(26.1)$1,489.7 
Interruptible Service 51.6 — — 51.6 
Other revenues (2)
3.4 36.8 — 40.2 
Total Revenues from Contracts with Customers1,308.1 299.5 (26.1)1,581.5 
Other operating revenues (2)(3)
6.6 33.5 (3.9)36.2 
Total Operating Revenues$1,314.7 $333.0 $(30.0)$1,617.7 

(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)For the year ended December 31, 2023, revenues attributable to Bayou Ethane within the Natural Gas Liquids segment were $74.9 million included in firm service from product sales earned from contracts with MVCs; $25.4 million included in other revenues from product sales earned from contracts with no MVCs; and $1.2 million included in other operating revenues.
(3)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 Year Ended December 31, 2022
Natural Gas
Natural Gas Liquids
EliminationsTotal
Revenues from Contracts with Customers
Firm Service (1)
$1,157.8 $174.0 $(19.9)$1,311.9 
Interruptible Service 61.2 — (5.0)56.2 
Other revenues
9.4 20.5 — 29.9 
Total Revenues from Contracts with Customers1,228.4 194.5 (24.9)1,398.0 
Other operating revenues (2)
2.3 31.7 — 34.0 
Total Operating Revenues$1,230.7 $226.2 $(24.9)$1,432.0 

(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 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 December 31, 2024 and 2023, the Company had receivables recorded in Trade Receivables, net from contracts with customers of $210.7 million and $204.6 million, contract assets recorded in Other Assets from contracts with a customer of $11.9 million and $6.2 million, and contract liabilities recorded in Other Current Liabilities (current portion) and Other Liabilities (noncurrent portion) from contracts with customers of $17.9 million and $21.4 million.

As of December 31, 2024, contract liabilities are expected to be recognized through 2040. Significant changes in the contract liability balances during the year ended December 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		(4.1)
Increases due to cash received, excluding amounts recognized as
    revenues during the period		0.6 
Balance as of December 31, 2024(1)
$17.9 
(1)As of December 31, 2024 and 2023, $1.8 million and $3.5 million were recorded in Other Current Liabilities (current portion), and $16.1 million and $17.9 million were recorded in Other Liabilities (noncurrent portion).
Significant changes in the contract liability balances during the year ended December 31, 2023, were as follows (in millions):

Contract Liabilities
Balance as of December 31, 2022(1)
$23.0 
Revenues recognized that were included in the contract liability
    balances at the beginning of the period		(3.9)
Increases due to cash received, excluding amounts recognized as
    revenues during the period		1.8 
Other
0.5 
Balance as of December 31, 2023(1)
$21.4 
(1)As of December 31, 2023 and 2022, $3.5 million and $3.6 million was recorded in Other Current Liabilities (current portion) and $17.9 million and $19.4 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 December 31, 2024. 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 FERC-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 projects that are subject to regulatory approvals.
In millions
20252026ThereafterTotal
Estimated revenues from contracts with customers
    from unsatisfied performance obligations as of
    December 31, 2024(1)(2)
$1,484.5 $1,294.5 $11,214.0 $13,993.0 
Operating revenues which are fixed and
    determinable (operating leases)		27.5 27.5 136.0 191.0 
Total projected operating revenues under committed
    firm agreements as of December 31, 2024
$1,512.0 $1,322.0 $11,350.0 $14,184.0 

(1)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.
(2)The estimated revenues from contracts with customers from unsatisfied performance obligations as of December 31, 2024, that are anticipated under executed precedent transportation agreements associated with the Company's growth projects are $3.8 billion.
v3.25.0.1
Leases
 12 Months Ended
Dec. 31, 2024
Leases [Abstract]  
Leases Leases
The Company has various operating lease commitments extending through 2058, generally covering office space and equipment rentals, some of which contain options to renew or extend the lease term. The Company also has a finance lease related to the lease of an office building in Owensboro, Kentucky, entered into in 2013, that has a fifteen-year term with two renewal options for up to twenty additional years in total.

The components of lease cost were as follows (in millions):

For the Year Ended December 31,
202420232022
Operating lease cost$4.1 $3.8 $3.8 
Short-term lease cost5.4 4.7 3.1 
Finance lease cost:
      Amortization of right-of-use asset0.7 0.7 0.7 
      Interest on lease liability0.3 0.3 0.3 
        Total lease cost$10.5 $9.5 $7.9 

The following provides supplemental balance sheet information related to the Company's leases:
As of December 31,
20242023
Right-of-use assets (in millions)
Operating leases (recorded in Other Assets)
$24.9$18.9
Finance lease (recorded in Property, Plant and Equipment)
2.53.2
Lease liabilities (in millions)
Operating leases (recorded in Other Liabilities, current and
    non-current)
25.319.6
Finance lease (recorded in Other Current Liabilities and
    Long-term debt and finance lease obligation)
3.64.5
Weighted-average remaining lease term (years)
Operating leases13.69.9
Finance lease3.64.6
Weighted-average discount rate
Operating leases3.95 %3.20 %
Finance lease5.89 %5.89 %
The table below presents the maturities of lease liabilities (in millions):
As of December 31, 2024
Operating
Leases		Finance
Lease
2025$2.6 $1.1 
20262.6 1.1 
20272.2 1.1 
20280.8 0.7 
20292.1 — 
Thereafter24.4 — 
Total34.7 4.0 
Less: discount(9.4)(0.4)
Total lease liabilities$25.3 $3.6 
Leases Leases
The Company has various operating lease commitments extending through 2058, generally covering office space and equipment rentals, some of which contain options to renew or extend the lease term. The Company also has a finance lease related to the lease of an office building in Owensboro, Kentucky, entered into in 2013, that has a fifteen-year term with two renewal options for up to twenty additional years in total.

The components of lease cost were as follows (in millions):

For the Year Ended December 31,
202420232022
Operating lease cost$4.1 $3.8 $3.8 
Short-term lease cost5.4 4.7 3.1 
Finance lease cost:
      Amortization of right-of-use asset0.7 0.7 0.7 
      Interest on lease liability0.3 0.3 0.3 
        Total lease cost$10.5 $9.5 $7.9 

The following provides supplemental balance sheet information related to the Company's leases:
As of December 31,
20242023
Right-of-use assets (in millions)
Operating leases (recorded in Other Assets)
$24.9$18.9
Finance lease (recorded in Property, Plant and Equipment)
2.53.2
Lease liabilities (in millions)
Operating leases (recorded in Other Liabilities, current and
    non-current)
25.319.6
Finance lease (recorded in Other Current Liabilities and
    Long-term debt and finance lease obligation)
3.64.5
Weighted-average remaining lease term (years)
Operating leases13.69.9
Finance lease3.64.6
Weighted-average discount rate
Operating leases3.95 %3.20 %
Finance lease5.89 %5.89 %
The table below presents the maturities of lease liabilities (in millions):
As of December 31, 2024
Operating
Leases		Finance
Lease
2025$2.6 $1.1 
20262.6 1.1 
20272.2 1.1 
20280.8 0.7 
20292.1 — 
Thereafter24.4 — 
Total34.7 4.0 
Less: discount(9.4)(0.4)
Total lease liabilities$25.3 $3.6 
v3.25.0.1
Commitments and Contingencies
 12 Months Ended
Dec. 31, 2024
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 the appeal is ongoing and is expected to be completed in March 2025.

City of New Orleans Litigation

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 and Texas Gas have been named as defendants in several suits in the State of Louisiana that are similar in nature to the City of New Orleans Litigation discussed above. These cases were filed in Louisiana state courts and discovery is ongoing. Two of these cases were settled in 2024, which did not have a material impact to the Company's results of operations or equity.

Environmental and Safety Matters

The Company's 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 December 31, 2024 and 2023, the Company had an accrued liability of approximately $7.0 million and $10.1 million related to assessment and/or remediation costs associated with the historical use of polychlorinated biphenyls, petroleum hydrocarbons and mercury. The liability represents management's estimate of the undiscounted future obligations based on evaluations and discussions with counsel and operating personnel and the current known facts and circumstances related to these matters. The related expenditures are expected to occur over the next twenty years. As of December 31, 2024 and 2023, approximately $3.4 million and $6.7 million were recorded in Other Current Liabilities and approximately $3.6 million and $3.4 million were recorded in Other Liabilities and Deferred Credits.

Clean Air Act and Climate Change

The Company's pipelines and associated facilities are subject to the Clean Air Act (CAA) and comparable state laws and regulations, which regulate the emission of air pollutants from many sources and impose various compliance monitoring and reporting requirements. Under the CAA, the Company may be required to obtain pre-approval for the construction or modification of certain projects or facilities expected to produce or significantly increase air emissions, obtain and strictly comply with stringent air permit requirements or utilize specific equipment or technologies to control emissions. The need to obtain permits has the potential to delay the development or expansion of the Company's projects. Over the next several years, the Company may be required to incur certain capital expenditures for air pollution control equipment or other air emissions related issues. For example, in 2015, the Environmental Protection Agency (EPA) issued a final rule under the CAA, lowering the National Ambient Air Quality Standard (NAAQS) for ground-level ozone to 70 parts per billion under both the primary and secondary standards to provide requisite protection of public health and welfare. Since that time, the EPA issued area designations with respect to ground-level ozone, issued final requirements that apply to state, local and tribal air agencies for implementing the 2015 NAAQS for ground-level ozone and, on December 31, 2020, published notice of a final action to retain the 2015 ozone NAAQS without revision on a going-forward basis. However, several groups filed litigation over the December 2020 final action and in October 2021, the EPA announced that it would reconsider the December 2020 determination to maintain the November 2015 NAAQS. In August 2023, the EPA announced a new review of the ozone NAAQS to ensure the standards protect people’s health and reflect the most current, relevant science. The new review will incorporate the reconsideration of the December 2020 final action. Until a final decision following the review is released, the full extent of the impacts of any new standards are not clear. Additionally, it is not clear what actions the Trump Administration may take with respect to the review. States are also expected to implement more stringent regulations that could apply to the Company's
operations. Compliance with any final decision could, among other things, require installation of new emission controls on some of the Company's equipment, result in longer permitting timelines and significantly increase its capital expenditures and operating costs. Additionally, the threat of climate change continues to attract considerable public, governmental and scientific attention. As a result, numerous proposals have been made and are likely to continue to be made at the international, national, regional, state and local levels of government to monitor and limit emissions of greenhouse gases (GHGs). These efforts have included consideration of cap-and-trade programs, carbon taxes, and GHG reporting and tracking programs, and regulations that directly limit GHG emissions from certain sources. The EPA has determined that GHG emissions endanger public health and the environment and, as a result, has adopted regulations under the CAA related to GHG emissions.

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 December 31, 2024, the commitments were approximately $112.1 million, all of which are expected to be settled within the next twelve months.

Pipeline Capacity and Storage Agreements

The Company's operating subsidiaries have entered into pipeline capacity and storage agreements with third-party pipelines that allow the operating subsidiaries to transport gas to off-system markets on behalf of customers or store natural gas. Additionally, in connection with the Bayou Ethane acquisition, the Company has assumed a pipeline capacity agreement with a third party to facilitate the transportation of ethane and an ethane storage agreement. The Company incurred expenses of $11.2 million, $5.8 million and $3.2 million related to pipeline capacity and storage agreements for the years ended December 31, 2024, 2023 and 2022. The table below presents the future commitments related to these agreements as of December 31, 2024 (in millions):

2025$8.0 
20268.1 
20273.0 
20280.2 
2029— 
Thereafter— 
Total$19.3 
v3.25.0.1
Fair Value Measurements
 12 Months Ended
Dec. 31, 2024
Fair Value Disclosures [Abstract]  
Fair Value Measurements Fair Value Measurements
Financial Assets and Liabilities

The Company had equity securities recorded at fair value on a recurring basis in Other Current Assets of $1.8 million and $2.3 million as of December 31, 2024 and 2023. The equity securities were received as part of a settlement of a bankruptcy claim. The equity securities were valued based on quoted market prices at December 31, 2024 and 2023, and were considered Level 1 investments. The Company had no liabilities recorded at fair value on a recurring basis as of December 31, 2024 and 2023.

Financial Assets and Liabilities Not Measured at Fair Value

The following methods and assumptions were used in estimating the fair value amounts included in the disclosures for financial assets and liabilities:

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 Company's publicly traded debt is based on quoted market prices at December 31, 2024 and 2023. The fair market value of the debt that is not publicly traded is based on market prices of similar
debt at December 31, 2024 and 2023. The carrying amount of the Company's variable-rate debt at December 31, 2023, approximated fair value because the instruments bear a floating market-based interest rate.
    
The carrying amounts and estimated fair values of the Company's financial assets and liabilities which were not recorded at fair value on the Consolidated Balance Sheets as of December 31, 2024 and 2023, were as follows (in millions):

As of December 31, 2024
 Estimated 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.

As of December 31, 2023
Estimated Fair Value
Financial AssetsCarrying AmountLevel 1Level 2Level 3Total
   Cash and cash equivalents$20.1 $20.1 $— $— $20.1 
Financial Liabilities 
   Long-term debt$3,262.4 
(1)
$— $3,155.3 $— $3,155.3 

(1) The carrying amount of long-term debt excluded a $3.6 million long-term finance lease obligation and
$4.1 million of unamortized debt issuance costs.
v3.25.0.1
Property, Plant and Equipment
 12 Months Ended
Dec. 31, 2024
Property, Plant and Equipment [Abstract]  
Property, Plant and Equipment Property, Plant and Equipment
The following table presents the Company's PPE as of December 31, 2024 and 2023 (in millions):
Category2024
Amount
2024
Weighted-Average
Useful Lives
(Years)
2023
Amount
2023
Weighted-Average
Useful Lives
 (Years)
Depreciable plant:    
Transmission$11,750.7 38$11,405.4 38
Storage1,002.1 39951.3 39
Gathering108.8 25106.1 24
General, intangibles and other557.7 20535.4 20
Total utility depreciable plant13,419.3 3812,998.2 37
Non-depreciable:   
Construction work in progress190.1  287.2  
Storage196.8  197.5  
Land51.6  46.6  
Total non-depreciable assets438.5  531.3  
Total PPE, gross
13,857.8  13,529.5  
Less:  accumulated depreciation and amortization5,045.1  4,672.9  
Total PPE, net$8,812.7  $8,856.6  
 
The non-depreciable assets were not included in the calculation of the weighted-average useful lives. 
    
For the years ended December 31, 2024, 2023 and 2022, depreciation expense for PPE was $421.9 million, $406.5 million and $390.4 million and was recorded in Depreciation and amortization on the Consolidated Statements of Income.

The Company holds undivided interests in certain assets, including the Mobile Bay Pipeline, of which the Company owns 64%, and offshore and other assets, comprised of pipeline and gathering assets in which the Company holds various ownership interests. In addition, the Company owns 83% of two ethylene wells and supporting surface facilities in Choctaw, Louisiana, and certain ethylene and propylene pipelines connecting Louisiana Midstream's storage facilities in Choctaw to chemical manufacturing plants in Geismar, Louisiana.

The proportionate share of investment associated with these interests has been recorded as PPE on the Consolidated Balance Sheets. The Company records its portion of direct operating expenses associated with the assets in Operation and maintenance expense. The following table presents the gross PPE investment and related accumulated depreciation for the Company's undivided interests as of December 31, 2024 and 2023 (in millions):

 20242023
 Gross PPE
Investment		Accumulated DepreciationGross PPE
Investment		Accumulated Depreciation
Mobile Bay Pipeline$15.4 $8.8 $15.4 $8.3 
NGLs pipelines and facilities55.1 15.1 54.6 13.5 
Offshore and other assets7.5 5.7 13.0 10.9 
Total$78.0 $29.6 $83.0 $32.7 
Asset Impairments

The Company recognized asset impairment charges of $2.4 million, $0.4 million and $7.5 million for the years ended December 31, 2024, 2023 and 2022.
v3.25.0.1
Goodwill and Intangible Assets
 12 Months Ended
Dec. 31, 2024
Goodwill and Intangible Assets Disclosure [Abstract]  
Goodwill and Intangible Assets Goodwill and Intangible Assets
Goodwill

As of December 31, 2024 and 2023, goodwill of $237.4 million was recorded on the Consolidated Balance Sheets, with $163.5 million being attributable to the Natural Gas reportable segment and $73.9 million to the Natural Gas Liquids reportable segment.

As of November 30, 2024, the Company elected to perform a qualitative assessment for its annual goodwill impairment test of its two reporting units. The qualitative assessment included the Company’s consideration of, among other things, the overall macroeconomic conditions, industry and market considerations, current discount rates and valuation multiples, overall financial performance and other relevant company specific events. Based on the assessment of these items, the Company concluded that it is more likely than not that the fair value of the two reporting units exceeded their respective carrying amounts. Accordingly, there were no indicators of impairment and quantitative impairment tests were not performed for its two reporting units.

As of November 30, 2023, the Company performed a quantitative annual goodwill impairment test for its two reporting units. The results of the quantitative goodwill impairment test indicated that the fair value of the Company's reporting units exceeded their carrying amounts. The fair value measurement of the reporting units was derived based on judgments and assumptions the Company believes market participants would use in assessing the fair value of the reporting units. These judgments and assumptions included the valuation premise, use of a discounted cash flow model to estimate fair value under an income approach and inputs to the valuation model. The inputs included the Company's five-year financial plan operating results, including operating revenues, the long-term outlook for growth in natural gas and NGLs demand, measures of the risk-free rate, equity premium and systematic risk used in the calculation of the applied discount rate under the capital asset pricing model and views regarding future market conditions, among others. The reasonableness of fair value estimates under the income approach were supported by a market approach under which the Company applied earnings before interest, income taxes, depreciation and amortization (EBITDA) multiples derived from publicly available information to each reporting unit's EBITDA.

No impairment charges related to goodwill were recorded for any of the Company's reporting units during 2024, 2023 or 2022.

Intangible Assets

The following table contains information regarding the Company's intangible assets, which includes customer relationships acquired as part of its acquisitions (in millions):
As of December 31,
20242023
Gross carrying amount
$92.9 $93.3 
Accumulated amortization(24.2)(21.3)
Net carrying amount$68.7 $72.0 
For the years ended December 31, 2024, 2023 and 2022, amortization expense for intangible assets was $2.9 million, $2.2 million and $1.9 million, and was recorded in Depreciation and amortization on the Consolidated Statements of Income. Amortization expense for the next five years and in total thereafter as of December 31, 2024, is expected to be as follows (in millions):

2025$3.0 
20262.9 
20272.9 
20282.9 
20292.9 
Thereafter54.1 
Total$68.7 

The weighted-average remaining useful life of the Company's intangible assets as of December 31, 2024, was 25 years.
v3.25.0.1
Asset Retirement Obligations
 12 Months Ended
Dec. 31, 2024
Asset Retirement Obligation Disclosure [Abstract]  
Asset Retirement Obligations Asset Retirement Obligations
The Company has identified and recorded legal obligations associated with the abandonment of certain pipeline and storage assets, brine ponds, offshore facilities and the abatement of asbestos, consisting of removal, transportation and disposal when removed from certain compressor stations and meter station buildings. Legal obligations exist for the main pipeline and certain other Company assets; however, the fair value of these obligations cannot be determined because the lives of the assets are indefinite. As a result, cash flows associated with retirement of the assets cannot be estimated with the degree of accuracy necessary to establish a liability for the obligations.

The following table summarizes the aggregate carrying amount of the Company's ARO (in millions):
As of December 31,
 20242023
Balance at beginning of year $74.1 $71.1 
Liabilities recorded5.0 8.4 
Liabilities settled(9.9)(10.0)
Accretion expense2.1 2.1 
Revision of estimates0.9 2.5 
Balance at end of year72.2 74.1 
Less:  Current portion of ARO(2.2)(14.9)
Long-term ARO$70.0 $59.2 

For the Company's operations where regulatory accounting is applicable, depreciation rates for PPE are comprised of two components. One component is based on economic service life (capital recovery) and the other is based on estimated costs of removal (as a component of negative salvage) which is collected in rates and does not represent an existing legal obligation. The Company has reflected $103.6 million and $98.1 million as of December 31, 2024 and 2023, on the Consolidated Balance Sheets as Provision for other asset retirement related to the estimated cost of removal collected in rates.
v3.25.0.1
Regulatory Assets and Liabilities
 12 Months Ended
Dec. 31, 2024
Regulatory Assets and Liabilities Disclosure [Abstract]  
Regulatory Assets and Liabilities Regulatory Assets and Liabilities
The amounts recorded as regulatory assets and liabilities on the Consolidated Balance Sheets as of December 31, 2024 and 2023, are summarized in the table below. The table also includes amounts related to unamortized debt issuance costs and unamortized discount on long-term debt, which while not regulatory assets and liabilities, are a component of the embedded cost of debt financing utilized in Texas Gas' rate proceedings. The tax effect of the equity component of AFUDC represents amounts recoverable from rate payers for the tax recorded in regulatory accounting. Certain amounts in the table are reflected as a negative, or a reduction, to be consistent with the regulatory books of account. The period of recovery for the regulatory assets included in rates varies from one to eighteen years. The remaining period of recovery for regulatory assets not yet included in rates would be determined in future rate proceedings. None of the regulatory assets shown below were earning a return as of December 31, 2024 and 2023 (in millions):
As of December 31,
 20242023
Regulatory Assets:  
Pension$8.0 $8.1 
Tax effect of AFUDC equity0.1 0.1 
Other0.5 0.5 
Total regulatory assets$8.6 $8.7 
Regulatory Liabilities:
Cashout and fuel tracker$18.3 $15.1 
Provision for other asset retirement103.6 98.1 
Unamortized debt issuance costs(0.7)(1.0)
Unamortized discount on long-term debt(0.1)(0.1)
Postretirement benefits other than pension62.8 60.6 
Total regulatory liabilities$183.9 $172.7 
v3.25.0.1
Financing
 12 Months Ended
Dec. 31, 2024
Debt Disclosure [Abstract]  
Financing Financing
Long-Term Debt

The following table presents all long-term debt issuances outstanding as of December 31, 2024 and 2023 (in millions):
 20242023
Notes and Debentures:  
Boardwalk Pipelines  
4.95% Notes due 2024 (Boardwalk Pipelines 2024 Notes)
$— $600.0 
5.95% Notes due 2026
550.0 550.0 
4.45% Notes due 2027
500.0 500.0 
4.80% Notes due 2029
500.0 500.0 
3.40% Notes due 2031
500.0 500.0 
3.60% Notes due 2032
500.0 500.0 
5.625% Notes due 2034
600.0 — 
Texas Gas  
7.25% Debentures due 2027
100.0 100.0 
Total notes and debentures3,250.0 3,250.0 
Revolving Credit Facility:  
Boardwalk Pipelines
— 25.0 
Total revolving credit facility— 25.0 
Finance lease obligation2.7 3.6 
 3,252.7 3,278.6 
Less:
Unamortized debt discount(13.5)(12.6)
Unamortized debt issuance costs(4.8)(4.1)
Total Long-Term Debt and Finance Lease Obligation$3,234.4 $3,261.9 

Maturities of the Company's long-term debt for the next five years and in total thereafter are as follows (in millions):
 
2025$— 
2026550.0 
2027600.0 
2028— 
2029500.0 
Thereafter1,600.0 
Total long-term debt
$3,250.0 
Notes and Debentures

As of December 31, 2024 and 2023, the weighted-average interest rates of the Company's notes and debentures were 4.95% and 4.84%.

For the twelve months ended December 31, 2024, the Company completed the following debt issuance (in millions, except interest rates):

Date of
Issuance		Issuing SubsidiaryAmount of
 Issuance		Purchaser
Discounts
and
Expenses		Net
Proceeds		 Interest
Rate		Maturity DateInterest
 Payable
February 2024Boardwalk Pipelines$600.0 $6.5 $593.5 
(1)
5.625 %August 1, 2034
February 1 and August 1

(1)The net proceeds of this offering were initially invested in U.S. treasury bills and used to retire the Boardwalk Pipelines 2024 Notes due December 2024 at maturity.

The Company's notes and debentures are redeemable, in whole or in part, at the Company's option at any time, at a redemption price equal to the greater of 100% of the principal amount of the notes to be redeemed or a "make whole" redemption price based on the remaining scheduled payments of principal and interest discounted to the date of redemption at a rate equal to the U.S. Treasury rate plus 20 to 50 basis points depending upon the particular issue of notes, plus accrued and unpaid interest, if any. Other customary covenants apply, including those concerning events of default.

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 December 31, 2024, the Company and its subsidiaries were in compliance with their covenants under the indentures.

Revolving Credit Facility

The Company has a revolving credit facility that includes Boardwalk Pipelines, Texas Gas and Gulf South as borrowers (Borrowers) that is evidenced by a credit agreement. Interest is determined, at the Company's election, by reference to (a) the base rate which is the highest of (1) the prime rate, (2) the federal funds rate plus 0.50% and (3) the one month term Secured Overnight Financing Rate plus 1.00%, or (b) the term Secured Overnight Financing Rate plus a flat 10 basis point credit spread adjustment across all available interest periods. The credit agreement provides for a quarterly commitment fee charged on the average daily unused amount of the revolving credit facility ranging from 0.10% to 0.275% which is determined based on the individual Borrower's credit rating from time to time. 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 credit agreement contains various restrictive covenants and other usual and customary terms and conditions, including restrictions regarding the incurrence of additional debt, the sale of assets and sale-leaseback transactions. The financial covenants under the credit agreement require the Company and its subsidiaries to maintain, among other things, a ratio of total consolidated debt to consolidated EBITDA (as defined in the 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 (i) the quarter in which the consummation of a qualified acquisition or series of acquisitions, where the purchase price exceeds $100.0 million over a rolling 12-month period and (ii) the three quarters following the qualified acquisition quarter. The Company and its subsidiaries were in compliance with all covenant requirements under the credit agreement as of December 31, 2024.

As of 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. As of December 31, 2023, outstanding borrowings under the Company's revolving credit facility were $25.0 million, with a weighted-average interest rate of 6.71%. As of February 7, 2025, the Company had no outstanding borrowings and $1.0 billion of available borrowing capacity under its revolving credit facility.
Cash Distributions    

Cash distributions the Company paid to BPHC and Boardwalk GP were $400.0 million, $300.0 million and $102.2 million for the years ended December 31, 2024, 2023 and 2022.
v3.25.0.1
Employee Benefits
 12 Months Ended
Dec. 31, 2024
Retirement Benefits [Abstract]  
Employee Benefits Employee Benefits
Retirement Plans

Defined Benefit Retirement Plans (Retirement Plans)

Texas Gas employees hired prior to November 1, 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 Company refers to the Pension Plan and the SRP as Retirement Plans. The Company uses a measurement date of December 31 for the Retirement Plans.

As a result of the Texas Gas rate case settlement in 2006, the Company is required to fund the amount of annual net periodic pension cost associated with the Pension Plan, including a minimum of $3.0 million, which is the amount included in rates. In 2024 and 2023, the Company funded $3.2 million and $4.9 million to the Pension Plan and expects to fund an additional $3.0 million to the plan in 2025. In 2024 and 2023, no SRP payments were made.
The Company recognizes in expense each year the actuarially determined amount of net periodic pension cost associated with the Retirement Plans, including a minimum amount of $3.0 million related to its Pension Plan, in accordance with the 2006 rate case settlement. Texas Gas is permitted to seek future rate recovery for amounts of annual Pension Plan costs in excess of $6.0 million and is precluded from seeking future recovery of annual Pension Plan costs between $3.0 million and $6.0 million. As a result, the Company would recognize a regulatory asset for amounts of annual Pension Plan costs in excess of $6.0 million and would reduce its regulatory asset to the extent that annual Pension Plan costs are less than $3.0 million. Annual Pension Plan costs between $3.0 million and $6.0 million will be charged to expense.

Postretirement Benefits Other Than Pension

Texas Gas provides postretirement medical benefits and life insurance to retired employees who were employed full time, hired prior to January 1, 1996, and have met certain other requirements. In 2024 and 2023, the Company contributed $0.2 million and $0.1 million to the PBOP plan. The PBOP plan is in an overfunded status; therefore, the Company does not expect to make any contributions to the plan in 2025. The Company does not anticipate that any plan assets will be returned to the Company during 2025. The Company uses a measurement date of December 31 for its PBOP plan.
Projected Benefit Obligation, Fair Value of Assets and Funded Status

The projected benefit obligation, fair value of assets, funded status and the amounts not yet recognized as components of net periodic pension and postretirement benefits cost for the Retirement Plans and PBOP at December 31, 2024 and 2023, were as follows (in millions):
 Retirement PlansPBOP
 For the Year Ended
December 31,		For the Year Ended December 31,
 2024202320242023
Change in benefit obligation:    
Benefit obligation at beginning of period$88.0 $86.4 $23.4 $23.7 
Service cost1.9 1.9 — — 
Interest cost4.0 4.1 1.1 1.2 
Plan participants' contributions— — 1.0 1.0 
Actuarial (gain) loss
(2.1)4.0 (0.1)2.3 
Benefits paid(0.5)(0.5)(4.1)(4.8)
Settlements(8.2)(7.9)— — 
Benefit obligation at end of period$83.1 $88.0 $21.3 $23.4 
Change in plan assets:    
Fair value of plan assets at beginning of period$83.3 $77.6 $82.3 $81.2 
Actual return on plan assets6.6 9.2 3.1 4.8 
Company's contribution3.2 4.9 0.2 0.1 
Plan participants' contributions— — 1.0 1.0 
Benefits paid(0.5)(0.5)(4.1)(4.8)
Settlements(8.2)(7.9)— — 
Fair value of plan assets at end of period$84.4 $83.3 $82.5 $82.3 
Funded status$1.3 $(4.7)$61.2 $58.9 
Items not recognized as components of net periodic cost:   
Net actuarial loss
$6.8 $12.7 $2.5 $3.0 

As of December 31, 2024, the Retirement Plans and PBOP were in an overfunded status. The following aggregate information relates only to the underfunded plans as of December 31, 2023 (in millions):
Retirement Plans
 For the Year Ended
December 31,
 2023
Projected benefit obligation$88.0 
Accumulated benefit obligation84.6 
Fair value of plan assets83.3 
Components of Net Periodic Benefit Cost

Components of net periodic benefit cost for both the Retirement Plans and PBOP for the years ended December 31, 2024, 2023 and 2022, were as follows (in millions):
 Retirement PlansPBOP
 For the Year Ended
December 31,		For the Year Ended
December 31,
 202420232022202420232022
Service cost$1.9 $1.9 $2.2 $— $— $— 
Interest cost4.0 4.1 3.1 1.1 1.2 0.8 
Expected return on plan assets(3.9)(3.6)(5.3)(2.6)(2.4)(1.8)
Amortization of prior service cost0.1 0.1 0.1 — — — 
Amortization of unrecognized net loss0.3 1.2 0.7 — — — 
Settlement charge0.7 1.3 2.9 — — — 
Regulatory asset decrease0.1 — — — — — 
Net periodic benefit cost (credit)
$3.2 $5.0 $3.7 $(1.5)$(1.2)$(1.0)

Due to the Texas Gas rate case settlement in 2006, Texas Gas is permitted to seek future rate recovery for amounts of annual Pension Plan costs in excess of $6.0 million.

Estimated Future Benefit Payments

The following table shows benefit payments, which reflect expected future service, as appropriate, which are expected to be paid for both the Retirement Plans and PBOP (in millions):
 
Retirement Plans
PBOP
2025$19.6 $2.0 
202611.4 1.9 
202710.8 1.8 
20288.3 1.7 
20296.9 1.6 
2030-2034
17.8 6.9 

Weighted-Average Assumptions

Weighted-average assumptions used to determine benefit obligations for the years ended December 31, 2024 and 2023, were as follows:
 Retirement PlansPBOP
For the Year Ended
December 31,		For the Year Ended
December 31,
 2024202320242023
 PensionSRPPensionSRP
Discount rate5.35 %5.25 %4.90 %4.90 %5.60 %5.10 %
Expected return on plan assets5.50 %5.50 %5.00 %5.00 %3.37 %3.25 %
Rate of compensation increase
4.00%-4.50%
4.00%-4.50%
3.00%-3.50%
3.00%-3.50%
— %— %
Weighted-average assumptions used to determine net periodic benefit cost for the periods indicated were as follows:
 Retirement PlansPBOP
For the Year Ended
December 31,		For the Year Ended
December 31,
 202420232022202420232022
Pension
SRP
Pension
SRPPensionSRP
Discount rate(1)5.25 %(1)4.90 %(1)(2)5.10 %5.40 %2.90 %
Expected return on plan assets5.00%5.00 %5.00%5.00 %6.25%6.25 %3.25 %2.99 %2.01 %
Rate of compensation increase
3.00% -
3.50%
3.00% -
3.50%
3.00% -
4.50%
3.00% -
4.50%
3.00%3.00 %— %— %— %
(1)Pension expense was remeasured quarterly in 2024, 2023 and 2022. The quarterly remeasurements for each quarter in 2024, 2023 and 2022 were as follows: Quarter 1: 5.25%, 5.35% and 3.00%; Quarter 2: 5.40%, 5.15% and 4.10%; Quarter 3: 4.80%, 5.45% and 4.65%; and Quarter 4: 5.35%, 4.90% and 5.30%.
(2)SRP expense was remeasured with discount rates of 4.15% at June 30, 2022, and 5.30% at December 31, 2022, to reflect settlements.

In determining the discount rate assumption, current market and liability information is utilized, including a discounted cash flow analysis of the pension and postretirement obligations. In particular, the basis for the discount rate selection was the yield on indices of highly rated fixed income debt securities with durations comparable to that of the Company's plan liabilities. The yield curve was applied to expected future retirement plan payments to adjust the discount rate to reflect the cash flow characteristics of the plans. The yield curves and indices evaluated in the selection of the discount rate were comprised of high-quality corporate bonds that are rated AA by an accepted rating agency.

The expected long-term rate of return for plan assets is determined based on widely-accepted capital market principles, long-term return analysis for global fixed income and equity markets as well as the active total return oriented portfolio management style. Long-term trends are evaluated relative to market factors such as inflation, interest rates and fiscal and monetary policies, in order to assess the capital market assumptions as applied to the plan. Consideration of diversification needs and rebalancing is maintained.

Pension Plan and PBOP Asset Allocation and Investment Strategy

Pension Plan

The Pension Plan assets are held in the Texas Gas Trust, established by Texas Gas, which manages and administers the Pension Plan. The Texas Gas Trust assets are measured at fair value. Equity securities are publicly traded securities which are valued using quoted market prices and are considered Level 1 investments under the fair value hierarchy. Short-term investments that are actively traded or have quoted prices, such as money market funds or treasury bills, are considered Level 1 investments. Fixed income mutual funds include highly liquid government securities and exchange traded bonds, valued using quoted market prices, and are considered Level 1 investments. Tax-exempt securities are valued using a methodology based on information generated by market transactions involving identical or comparable assets, a discounted cash flow methodology or a combination of both when necessary. Common inputs for these securities, which are considered Level 2 investments, include pricing for similar securities, marketplace quotes, benchmark yields, spreads off benchmark yields, interest rates, U.S. Treasury or swap curves and other pricing models utilizing observable inputs.
The following table sets forth, by level within the fair value hierarchy, a summary of the Texas Gas Trust's assets measured at fair value on a recurring basis at December 31, 2024 (in millions):

 Pension Plan Trust Assets
 Level 1Level 2Level 3Total
Equity securities$35.9 $— $— $35.9 
Short-term investments8.4 — — 8.4 
Fixed income mutual funds40.1 — — 40.1 
Total assets$84.4 $— $— $84.4 

The following table sets forth, by level within the fair value hierarchy, a summary of the Texas Gas Trust's assets measured at fair value on a recurring basis at December 31, 2023 (in millions):

 Pension Plan Trust Assets
 Level 1Level 2Level 3Total
Equity securities$34.6 $— $— $34.6 
Short-term investments17.3 — — 17.3 
Fixed income mutual funds26.3 — — 26.3 
Tax-exempt securities
— 5.1— 5.1 
Total assets$78.2 $5.1 $— $83.3 

PBOP

The PBOP plan assets are held in a trust and are measured at fair value. Short-term investments and other assets that are actively traded or have quoted prices, such as money market or mutual funds, are considered Level 1 investments. Fixed income securities, such as tax-exempt securities and corporate bonds, and asset-backed securities are valued using a methodology based on information generated by market transactions involving identical or comparable assets, a discounted cash flow methodology or a combination of both when necessary. Common inputs for these securities, which are considered Level 2 investments, include pricing for similar securities, marketplace quotes, benchmark yields, spreads off benchmark yields, interest rates, U.S. Treasury or swap curves and other pricing models utilizing observable inputs. Other assets and other liabilities are primarily pending sale and purchase transactions for certain investments that were executed on the last day of the year and not settled until the following year.

The following table sets forth, by level within the fair value hierarchy, a summary of the PBOP trust investments measured at fair value on a recurring basis at December 31, 2024 (in millions):
 PBOP Trust Assets
 Level 1Level 2Level 3Total
Short-term investments$1.6 $— $— $1.6 
Other assets15.7 — — 15.7 
Asset-backed securities— 0.5 — 0.5 
Corporate bonds— 47.8 — 47.8 
Tax-exempt securities— 34.9 — 34.9 
Total assets$17.3 $83.2 $— $100.5 
Other liabilities(18.0)— — (18.0)
Total liabilities$(18.0)$— $— $(18.0)
The following table sets forth, by level within the fair value hierarchy, a summary of the PBOP trust investments measured at fair value on a recurring basis at December 31, 2023 (in millions):
 PBOP Trust Assets
 Level 1Level 2Level 3Total
Short-term investments$12.8 $— $— $12.8 
Other assets
2.1 — — 2.1 
Asset-backed securities— 0.8 — 0.8 
Corporate bonds— 67.0 — 67.0 
Tax-exempt securities
— 38.9 — 38.9 
Total assets$14.9 $106.7 $— $121.6 
Other liabilities(39.3)— — (39.3)
Total liabilities$(39.3)$— $— $(39.3)
    
Investment Strategy

Pension Plan: The Company employs a total-return approach using a mix of equities and fixed income securities designed to maximize the long-term return on plan assets for a prudent level of risk and generate cash flows adequate to meet plan requirements. The intent of this strategy is to minimize plan expenses by generating investment returns that exceed the growth of the plan liabilities over the long run. Risk tolerance is established through careful consideration of the plan liabilities, plan funded status and corporate financial conditions. The target allocation of plan assets is 85% of the investment portfolio to equity and fixed income securities, with the remainder primarily invested in cash. Investment risk is monitored through annual liability measurements, periodic asset and liability studies and quarterly investment portfolio reviews.

PBOP: The investment strategy for the PBOP assets is to reduce the volatility of plan investments while protecting the initial investment given the overfunded status of the plan. The Company uses a broad array of public and private assets and investment vehicles to achieve a return that is targeted to meet or exceed the plan blended benchmark indices. At December 31, 2024 and 2023, the investment portfolio contained a diversified blend of fixed income securities, such as tax-exempt securities and corporate bonds, asset-backed securities, short-term securities and other assets.

Defined Contribution Plan

Texas Gas 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 $14.7 million, $14.0 million and $12.7 million for the years ended December 31, 2024, 2023 and 2022.

Long-Term Incentive Compensation Plans

The 2018 LTIP provides for grants of Performance Awards to selected employees of the Company. A Performance Award is a long-term incentive award with a stated target amount which is payable in cash, after adjustments, upon vesting based on certain specified performance criteria being met. In the case of retirement, any outstanding and unvested awards would become fully vested upon retirement and the Performance Awards will be paid at the original vesting date. In 2024 and 2023, the Company granted to certain employees $17.2 million and $16.3 million of Performance Awards. The Company recorded compensation expense of $17.1 million, $14.2 million and $12.3 million related to Performance Awards for the years ended December 31, 2024, 2023 and 2022, and had $10.5 million and $9.8 million of remaining unrecognized compensation expense related to Performance Awards as of December 31, 2024 and 2023.
v3.25.0.1
Income Taxes
 12 Months Ended
Dec. 31, 2024
Income Tax Disclosure [Abstract]  
Income Taxes Income Taxes
The Company is not a taxable entity for federal income tax purposes. The following is a summary of the provision for income taxes for the years ended December 31, 2024, 2023 and 2022 (in millions):
 For the Year Ended December 31,
 202420232022
Current expense:   
State$0.8 $0.8 $0.8 
Deferred provision:   
State0.3 — — 
Income taxes$1.1 $0.8 $0.8 

The Company's tax years 2021 through 2024 remain subject to examination by the Internal Revenue Service and the states in which it operates. There were no differences between the provision at the statutory rate to the income tax provision at December 31, 2024, 2023 and 2022. As of December 31, 2024 and 2023, there were no significant deferred income tax assets or liabilities.
v3.25.0.1
Credit Risk
 12 Months Ended
Dec. 31, 2024
Risks and Uncertainties [Abstract]  
Credit Risk Credit Risk
Major Customers

For the years ended December 31, 2024, 2023 and 2022, no customer comprised 10% or more of the Company's operating revenues.

Gas Loaned to Customers

Natural gas price volatility can cause changes in credit risk related to gas and NGLs loaned to customers. 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 trillion British thermal units (TBtu). Assuming an average market price during December 2024 of $2.98 per million British thermal unit (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, 2023, 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 11.2 TBtu. Assuming an average market price during December 2023 of $2.33 per MMBtu, the market value of that gas was approximately $26.1 million. As of December 31, 2023, there were no outstanding NGLs imbalances owed to the Company's operating subsidiaries. As of December 31, 2024 and 2023, there were no amounts of ethylene owed to the Company's operating subsidiaries under exchange agreements. If any significant customer should have credit or financial problems resulting in a delay or failure to pay for services provided or repay the gas owed to the operating subsidiaries, it could have a material adverse effect on the Company's financial condition, results of operations and cash flows.
v3.25.0.1
Related Party Transactions
 12 Months Ended
Dec. 31, 2024
Related Party Transactions [Abstract]  
Related Party Transactions Related Party Transactions
Loews provides a variety of corporate services to the Company under services 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 $5.4 million, $4.3 million and $3.7 million for the years ended December 31, 2024, 2023 and 2022, which were recorded in Administrative and general on the Consolidated Statements of Income.
    
Total distributions paid to BPHC and Boardwalk GP were $400.0 million, $300.0 million and $102.2 million for the years ended December 31, 2024, 2023 and 2022.
v3.25.0.1
Supplemental Disclosure of Cash Flow Information
 12 Months Ended
Dec. 31, 2024
Supplemental Cash Flow Elements [Abstract]  
Supplemental Disclosure of Cash Flow Information Supplemental Disclosure of Cash Flow Information (in millions):
 For the Year Ended December 31,
 202420232022
Cash paid during the period for:   
Amounts included in the measurement of operating lease liabilities $4.2 $4.9 $3.7 
Amounts included in the measurement of finance lease liability
1.1 1.1 1.1 
Interest (net of amount capitalized) 162.1 147.3 156.3 
Income taxes, net0.8 0.7 0.6 
Non-cash investing activities:
   
Accounts payable and PPE30.4 47.7 44.4 
Right-of-use asset obtained in exchange for lease obligations9.9 3.4 0.2 
Gas stored underground and PPE
— 47.8 — 
v3.25.0.1
Reportable Segments
 12 Months Ended
Dec. 31, 2024
Segment Reporting [Abstract]  
Reportable Segments Reportable Segments
Identification of Segments

Prior to the fourth quarter 2024, the Company reported in one single operating and reportable segment – the operation of interstate natural gas and NGLs pipeline systems and integrated storage facilities in the U.S. In 2024, the Company’s previous CEO retired and a new CEO was appointed. In the fourth quarter 2024, new internal reports and information began to be provided to and evaluated by the CODM, the CEO, to reflect the CEO’s method of viewing information to manage the business, assess performance, and allocate resources. This change in financial information provided to the CEO required the Company to reassess its operating and reportable segments.

At the end of the fourth quarter 2024, the Company completed the reassessment of its segment reporting. Based on the reassessment, the Company identified three operating segments in accordance with ASC 280, Segment Reporting (ASC 280). They are: (1) Texas Gas; (2) Gulf South and the Company’s other natural gas businesses; and (3) Louisiana Midstream, Boardwalk Petrochemical and Bayou Ethane (collectively, Natural Gas Liquids).

The Company aggregated the Texas Gas operating segment and the Gulf South and the Company’s other natural gas businesses operating segment into one reportable segment in accordance with ASC 280, because the Company concluded that: (1) both operating segments had similar economic characteristics; (2) both operating segments had similar product and service lines, customer base, production processes, distribution methods, and regulatory environments; and (3) aggregation would be consistent with the objectives and basic principles of ASC 280.

Accordingly, as of December 31, 2024, the Company has the following two reportable segments, which comprise 100% of the Company’s operating revenues. The segments are generally organized and managed according to products.

•Natural Gas (Texas Gas, Gulf South and the Company’s other natural gas businesses): This segment consists of the ownership and operation of the Company’s interstate and intrastate natural gas pipelines and storage facilities. This segment earns revenues from contracts with customers by providing transportation and storage services for natural gas on a firm and interruptible basis.

•Natural Gas Liquids: This segment consists of the ownership and operation of the Company’s interstate and intrastate NGLs pipelines and storage facilities and the operations of brine supply services and NGL marketing activities, which primarily consist of purchases and sales of ethane under supply service agreements. This segment earns revenues from contracts with customers by providing transportation and storage services for NGLs on a firm basis as well as providing brine and ethane supply services. Through Louisiana Midstream’s ownership of Boardwalk Storage Company, LLC, it also contains the results for one natural gas storage cavern.

Measures of Segment Profit or Loss Used

The CODM uses EBITDA to assess each of the Company’s segments performance and to determine how to allocate resources. The CODM uses EBITDA in the annual budget process and considers budget-to-actual variances of the segments,
which is reviewed at least quarterly, when making decisions about the allocation of operating and capital resources for the segments of the Company. The CODM uses this measure, together with other non-financial measures, such as safety, emissions and reliability initiatives, commercial opportunities and compliance with the Company’s rules and regulations, when assessing performance of the Company and establishing management’s compensation.

Segment Expenses and Other Segment Items

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. The Company accounts for intrasegment sales and transfers as if the sales or transfers were to third parties, or at fair market value.

Information about Reportable Segments

The below tables provide information about the Company’s reportable segments as provided to the CODM, including information about segment operating revenues; EBITDA, the performance measure of the Company’s segments; significant segment expenses; segment asset information and segment capital expenditures. Interest expense and interest income are not allocated to nor used in the performance measures of the Company’s reportable segments. The Company’s segments pipeline, storage and other fixed assets are all operated and located within the U.S. and follow the accounting policies as described in Note 2.

Financial information by segment follows (in millions):
For the year ended December 31, 2024
Natural Gas
Natural Gas LiquidsTotal
Revenues
Revenue from external customers$1,392.7 $635.4 $2,028.1 
Intrasegment revenues
49.4 — 49.4 
$1,442.1 $635.4 $2,077.5 
Reconciliation of revenues:
Elimination of intrasegment revenues
(49.4)
Total consolidated revenues$2,028.1 
Less:
Costs associated with service revenues$41.1 $19.0 
Costs associated with product sales— 303.5 
Operation and maintenance253.1 57.2 
Administrative and general176.9 27.6 
Taxes other than income taxes109.0 13.1 
(Gain) loss on sale of assets, impairments and other
(6.6)1.1 
Miscellaneous other income, net(6.1)— 
Segment EBITDA
$874.7 $213.9 $1,088.6 
Reconciliation of profit or loss:
Depreciation and amortization$424.8 
Interest expense182.9 
Interest income(31.1)
Consolidated income before income taxes
$512.0 
For the year ended December 31, 2023
Natural GasNatural Gas LiquidsTotal
Revenues
Revenue from external customers$1,284.7 $333.0 $1,617.7 
Intrasegment revenues
30.0 — 30.0 
$1,314.7 $333.0 $1,647.7 
Reconciliation of revenues:
Elimination of intrasegment revenues
(30.0)
Total consolidated revenues$1,617.7 
Less:
Costs associated with service revenues$37.1 $15.3 
Costs associated with product sales— 87.8 
Operation and maintenance229.1 51.9 
Administrative and general151.7 24.1 
Taxes other than income taxes106.1 9.4 
Loss on sale of assets, impairments and other
0.3 — 
Miscellaneous other income, net(4.0)(0.1)
Segment EBITDA
$794.4 $144.6 $939.0 
Reconciliation of profit or loss:
Depreciation and amortization$408.7 
Interest expense155.6 
Interest income(12.1)
Consolidated income before income taxes
$386.8 
For the year ended December 31, 2022
Natural GasNatural Gas LiquidsTotal
Revenues
Revenue from external customers$1,205.8 $226.2 $1,432.0 
Intrasegment revenues
24.9 — 24.9 
$1,230.7 $226.2 $1,456.9 
Reconciliation of revenues:
Elimination of intrasegment revenues
(24.9)
Total consolidated revenues$1,432.0 
Less:
Costs associated with service revenues$37.1 $10.2 
Costs associated with product sales— 1.0 
Operation and maintenance208.6 42.3 
Administrative and general129.0 18.7 
Taxes other than income taxes106.1 8.4 
Loss on sale of assets, impairments and other
4.0 — 
Miscellaneous other income, net(6.3)(0.1)
Segment EBITDA
$752.2 $145.7 $897.9 
Reconciliation of profit or loss:
Depreciation and amortization$392.3 
Interest expense165.9 
Interest income(3.3)
Consolidated income before income taxes
$343.0 

Segment assets include Property, plant, and equipment – net, Intangible assets – net of accumulated amortization and Goodwill. The following table reflects segment assets and a reconciliation to Total Assets (in millions):
Segment Assets
As of December 31,
20242023
Natural Gas
$7,490.1 $7,515.2 
Natural Gas Liquids1,628.7 1,650.8 
Total Segment Assets
9,118.8 9,166.0 
Total current assets
401.1 288.7 
Gas stored underground and Other assets
259.5 241.7 
Total Assets
$9,779.4 $9,696.4 

The following table reflects capital expenditures by segment (in millions):
Capital Expenditures
For the year ended
 December 31,
202420232022
Natural Gas
$340.6 $321.5 $291.3 
Natural Gas Liquids51.8 60.9 53.0 
Total
$392.4 $382.4 $344.3 
v3.25.0.1
Basis of Presentation and Significant Accounting Policies (Policies)
 12 Months Ended
Dec. 31, 2024
Accounting Policies [Abstract]  
Basis of Presentation
Basis of Presentation
The accompanying consolidated financial statements of the Company have been prepared in accordance with accounting principles generally accepted in the United States of America (U.S.) (GAAP).
Principles of Consolidation
Principles of Consolidation

The consolidated financial statements include the Company's accounts and those of its wholly owned subsidiaries after elimination of intercompany transactions.
Use of Estimates
Use of Estimates

The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses, disclosure of contingent assets and liabilities and the fair values of certain items. The Company bases its estimates on historical experience and on various other assumptions that are believed to be reasonable under the circumstances, which form the basis for making judgments about the carrying amounts of assets and liabilities that are not readily apparent from other sources. Actual results could differ from such estimates.
Segment Information
Segment Information

The Company determines its operating and reportable segments based on how the Chief Operating Decision Maker (CODM), who is the Chief Executive Officer (CEO), reviews and manages the business, including determining how to allocate resources and assess performance. Historically, the Company concluded that it had a single operating and reportable segment. Due to changes in its internal reporting and the information evaluated by the CODM, the Company concluded that it operated in three operating segments as of December 31, 2024. The Company reported the financial results in two reportable segments because two operating segments met the aggregation criteria to be reported as one reportable segment. The Company’s two reportable segments are Natural Gas and Natural Gas Liquids.
Regulatory Accounting
Regulatory Accounting

Most of the Company's natural gas pipeline subsidiaries and its interstate ethane transportation pipeline are regulated by the Federal Energy Regulatory Commission (FERC). When certain criteria are met, GAAP requires that certain rate-regulated entities account for and report assets and liabilities consistent with the economic effect of the manner in which independent third-party regulators establish rates (regulatory accounting). This basis of accounting is applicable to operations of
the Company's Texas Gas subsidiary, which records certain costs and benefits as regulatory assets and liabilities in order to provide for recovery from or refunds to customers in future periods, but is not applicable to the operations associated with the Fayetteville and Greenville Laterals due to rates charged under negotiated rate agreements and a portion of Texas Gas' storage capacity due to the regulatory treatment associated with the rates charged for that capacity.

The Company also applies regulatory accounting for its fuel trackers on Gulf South, under which the value of fuel received from customers paying the maximum tariff rate and the related value of fuel used in transportation are recorded to a regulatory asset or liability depending on whether Gulf South uses more fuel than it collects from customers or collects more fuel than it uses. Other than as described for Texas Gas and for the fuel trackers on Gulf South, regulatory accounting is not applicable to the Company's other FERC-regulated operations.

The Company monitors the regulatory and competitive environment in which it operates to determine whether its regulatory assets continue to be probable of recovery. If the Company determines that all or a portion of its regulatory assets no longer meets the criteria for recognition as regulatory assets, that portion which is not recoverable will be written off, net of any regulatory liabilities.
Fair Value Measurements
Fair Value Measurements

Fair value refers to an exit price that would be received to sell an asset or paid to transfer a liability in an orderly transaction in the principal market in which the reporting entity transacts based on the assumptions market participants would use when pricing the asset or liability assuming its highest and best use. A fair value hierarchy has been established that prioritizes the information used to develop those assumptions giving priority, from highest to lowest, to quoted prices in active markets for identical assets and liabilities (Level 1); observable inputs not included in Level 1, for example, quoted prices for similar assets and liabilities (Level 2); and unobservable data (Level 3), for example, a reporting entity's own internal data based on the best information available in the circumstances. The Company uses fair value measurements to account for equity securities, asset retirement obligations (ARO), pension and postretirement benefits other than pension (PBOP) assets and any impairment charges.
Cash and Cash Equivalents
Cash and Cash Equivalents
Cash equivalents are highly liquid investments with an original maturity of three months or less and are stated at cost plus accrued interest, which approximates fair value.
Short-Term Investments
Short-Term Investments
During 2024, the Company invested in U.S. treasury bills that were classified as held-to-maturity short-term investments and matured in December 2024. Income related to the U.S. treasury bills was recorded in Interest Income on the Consolidated Statements of Income.
Trade and Other Receivables
Trade and Other Receivables

Trade and other receivables are stated at their historical carrying amount, net of allowances for doubtful accounts. The Company establishes an allowance for doubtful accounts under an expected credit loss model based on historical credit loss experience and specific facts and circumstances. Uncollectible receivables are written off when a settlement is reached for an amount that is less than the outstanding historical balance or a receivable amount is deemed otherwise unrealizable.
Gas Stored Underground and Gas Receivables and Payables
Gas Stored Underground and Gas Receivables and Payables

Certain of the Company's operating subsidiaries have underground gas in storage which is utilized for system management and operational balancing, as well as for services including firm and interruptible storage associated with certain no-notice and parking and lending (PAL) services. Gas stored underground includes the historical cost of natural gas volumes owned by the operating subsidiaries, at times reduced by certain operational encroachments upon that gas.
The operating subsidiaries provide storage services whereby they store natural gas or NGLs on behalf of customers and also periodically hold customer gas under PAL services. Since the customers retain title to the gas held by the Company in providing these services, the Company does not record the related gas on the Consolidated Balance Sheets. Certain of the Company's operating subsidiaries also periodically lend gas and NGLs to customers.

In the course of providing transportation and storage services to customers, the operating subsidiaries may receive different quantities of gas from shippers and operators than the quantities delivered on behalf of those shippers and operators. This results in transportation and exchange gas receivables and payables, commonly known as imbalances, which are primarily settled in cash or the receipt or delivery of gas in the future. Settlement of imbalances requires agreement between the pipelines and shippers or operators as to allocations of volumes to specific transportation contracts and timing of delivery of gas based on operational conditions. The receivables and payables are valued at market price for operations where regulatory accounting is not applicable and are valued at the historical value of gas in storage for operations where regulatory accounting is applicable.
Product Inventory
Product Inventory
Product inventory, primarily ethane used in the Company’s ethane supply services, is included in Other Current Assets on the Consolidated Balance Sheets. Product inventory is recorded at the lower of weighted-average cost or net realizable value.
Materials and Supplies
Materials and Supplies
Materials and supplies are carried at average cost and are included in Other Assets on the Consolidated Balance Sheets. The Company expects its materials and supplies to be used for projects related to its property, plant and equipment (PPE) and for future growth projects.
Property, Plant and Equipment and Repair and Maintenance Costs
Property, Plant and Equipment and Repair and Maintenance Costs

PPE is recorded at its original cost of construction or fair value of assets purchased. Construction costs and expenditures for major renewals and improvements which extend the lives of the respective assets are capitalized. Construction work in progress is included in the financial statements as a component of PPE. Repair and maintenance costs are expensed as incurred.
Depreciation of PPE related to operations for which regulatory accounting does not apply is provided for using the straight-line method of depreciation over the estimated useful lives of the assets, which range from 3 to 35 years. The ordinary sale or retirement of PPE for these assets could result in a gain or loss being recorded in the income statement. Depreciation of PPE related to operations for which regulatory accounting is applicable is provided for primarily on the straight-line method at FERC-prescribed rates over estimated useful lives of 5 to 62 years. Reflecting the application of composite depreciation, gains and losses from the ordinary sale or retirement of PPE for these assets are not recognized in earnings and generally do not impact PPE, net.
Goodwill and Intangible Assets
Goodwill and Intangible Assets

Goodwill represents the excess of the cost of an acquisition over the fair value of the net identifiable assets acquired and liabilities assumed. Goodwill is tested for impairment at the reporting unit level at least annually, as of November 30, or more frequently when events occur and circumstances change that would more likely than not reduce the fair value of a reporting unit below its carrying amount. A reporting entity may perform an optional qualitative assessment on an annual basis to determine whether events occurred or circumstances changed that would more likely than not reduce the fair value of a reporting unit below its carrying amount. If an initial qualitative assessment identifies that it is more likely than not that the fair value of a reporting unit is less than its carrying amount, or the optional qualitative assessment is not performed, a quantitative analysis is performed. The quantitative goodwill impairment test is performed by calculating the fair value of the reporting unit and comparing it to the reporting unit's carrying amount. If the fair value of a reporting unit exceeds its carrying amount, goodwill of the reporting unit is not impaired. However, if the carrying amount of a reporting unit exceeds its fair value, an impairment loss is recognized in an amount equal to that excess, limited to the total amount of goodwill recorded on the reporting unit.
Intangible assets are those assets which provide future economic benefit but have no physical substance. The Company recorded intangible assets for customer relationships obtained through its acquisitions. The customer relationships, which are included in Other Assets on the Consolidated Balance Sheets, have a finite life and are being amortized over their estimated useful lives, which is generally 35 years.
Impairment of Long-lived Assets (including Tangible and Definite-lived Intangible Assets)
Impairment of Long-lived Assets (including Tangible and Definite-lived Intangible Assets)

The Company evaluates its long-lived and intangible assets for impairment when, in management's judgment, events or changes in circumstances indicate that the carrying amount of such assets may not be recoverable. When such a determination has been made, management's estimate of undiscounted future cash flows attributable to the remaining economic useful life of the asset (or asset group) is compared to the carrying amount of the asset (or asset group) to determine whether an impairment has occurred. If an impairment of the carrying amount has occurred, the amount of impairment recognized in the financial statements is determined by estimating the fair value of the assets (or asset group) and recording a loss to the extent that the carrying amount exceeds the estimated fair value.
Capitalized Interest and Allowance for Funds Used During Construction (AFUDC)
Capitalized Interest and Allowance for Funds Used During Construction (AFUDC)
The Company records capitalized interest, which represents the cost of borrowed funds used to finance construction activities for operations where regulatory accounting is not applicable. The Company records AFUDC, which represents the cost of funds, including equity funds, applicable to regulated natural gas transmission plant under construction as permitted by FERC regulatory practices, in connection with the Company's operations where regulatory accounting is applicable. Capitalized interest and the allowance for borrowed funds used during construction are recognized as a reduction to Interest expense and the allowance for equity funds used during construction is included in Miscellaneous other income, net on the Consolidated Statements of Income.
Income Taxes
Income Taxes
The Company is not a taxable entity for federal income tax purposes. As such, it does not directly pay federal income tax. The Company's taxable income or loss, which may vary substantially from the net income or loss reported on the Consolidated Statements of Income, is includable in the federal income tax returns of each of its partners.
Asset Retirement Obligations
Asset Retirement Obligations
The accounting requirements for existing legal obligations associated with the future retirement of long-lived assets require entities to record the fair value of a liability for an ARO in the period during which the liability is incurred. The liability is initially recognized at fair value and is increased with the passage of time as accretion expense is recorded, until the liability is ultimately settled. The accretion expense is included within Operation and maintenance costs on the Consolidated Statements of Income. An amount corresponding to the amount of the initial liability is capitalized as part of the carrying amount of the related long-lived asset and depreciated over the useful life of that asset.
Environmental Liabilities
Environmental Liabilities
The Company records environmental liabilities based on management's estimates of the undiscounted future obligation for probable costs associated with environmental assessment and remediation of operating sites. These estimates are based on evaluations and discussions with counsel and operating personnel and the current known facts and circumstances related to these environmental matters.
Defined Benefit Plans
Defined Benefit Plans

The Company maintains postretirement benefit plans for certain employees. The Company funds these plans through periodic contributions which are invested until the benefits are paid out to the participants, and records an asset or liability based on the overfunded or underfunded status of the plan. The net benefit costs of the plans are recorded on the Consolidated Statements of Income. Any deferred amounts related to unrecognized gains and losses or changes in actuarial assumptions are recorded as either a regulatory asset or liability or recorded as a component of accumulated other comprehensive income until those gains or losses are recognized on the Consolidated Statements of Income.
Long-Term Compensation
Long-Term Compensation

The Company provides performance awards (Performance Awards) to certain of its employees under its 2018 Long-Term Incentive Plan (2018 LTIP). A Performance Award is a long-term incentive award with a stated target amount which is payable in cash, after certain adjustments, upon vesting based on certain specified performance criteria being met.
The Company measures the cost of an award issued in exchange for employee services based on the stated target amount for Performance Awards. All outstanding awards are required to be settled in cash and are classified as a liability until settlement. The related compensation expense, less forfeitures, is recognized over the period that employees are required to provide services in exchange for the awards, usually the vesting period.
Partner Capital Accounts
Partner Capital Accounts

For purposes of maintaining capital accounts, items of income and loss of the Company are allocated among the partners each period, or portion thereof, in accordance with the partnership agreement, based on their respective ownership interests.
Leases
Leases

Operating lease right-of-use assets and lease liabilities are recognized at the lease commencement date based on the present value of lease payments over the lease term. The discount rate used to determine the commencement date present value of lease payments is typically the Company's secured borrowing rate, as the implicit rate of most of the Company's leases is not readily determinable. The Company has elected not to record any leases with terms of twelve months or less on the Consolidated Balance Sheets.
Revenue Recognition and Contract Balances
Revenue Recognition
Nature of Contracts

The Company primarily earns revenues from contracts with customers by providing transportation and storage services for natural gas and NGLs on a firm and interruptible basis and providing ethane supply and transportation services for industrial customers in Louisiana and Texas. The Company also provides interruptible natural gas PAL services. The Company's customers choose, based upon their particular needs, the applicable mix of services depending upon availability of pipeline and storage capacity, the price of services and the volume and timing of customer requirements. The maximum applicable rates that the majority of the Company's operating subsidiaries may charge for their services are established through the FERC's cost-
based rate-making process; however, the FERC also allows for discounted or negotiated rates as an alternative to cost-based rates. Under the FERC regulations, certain revenues that the Company's subsidiaries collect may be subject to possible refunds to customers. Accordingly, during a rate case, estimated refund liabilities are recorded considering regulatory proceedings, advice of counsel and estimated risk-adjusted total exposure, as well as other factors. The Company's service contracts can range from one to twenty years although the Company may enter into shorter- or longer-term contracts, and services are invoiced monthly with payment from the customer generally expected within ten to thirty days, depending on the terms of the contract. For the ethane supply contracts, the purchases and sales are with different counterparties and control transfers at different receipt and delivery points, resulting in the purchases and sales being presented on a gross basis in the Consolidated Statements of Income.
    
Firm Service Contracts: The Company offers firm services to its customers. The Company's customers can reserve a specific amount of pipeline capacity at specified receipt and delivery points on the Company's pipeline system (transportation service) or can reserve a specific amount of storage capacity at specified injection and withdrawal points at the Company's storage facilities (storage service). The Company accounts for firm services as a single promise to stand ready each month of the contract term to provide the committed capacity for either transportation or storage services when needed by the customer, which represents a series of distinct monthly services that are substantially the same with the same pattern of transfer to the customer. Although several activities may be required to provide the firm service, the individual activities do not represent distinct performance obligations because all of the activities must be performed in combination in order for the Company to provide the firm service.

The transaction price for firm service contracts is comprised of a fixed fee based on the quantity of capacity reserved, regardless of use (capacity reservation fee), plus variable fees in the form of a usage fee paid on the volume of commodity actually transported or injected and withdrawn from storage. Both the fixed and usage fees are allocated to the single performance obligation of providing transportation or storage service and recognized over time based upon the output measure of time as the Company completes its stand-ready obligation to provide contracted capacity and the customer receives and consumes the benefit of the reserved capacity, which corresponds with the transfer of control to the customer. The fixed fee is recognized ratably over the contract term, representative of the proportion of the committed stand-ready capacity obligation that has been fulfilled to date, and the usage fee is recognized upon satisfaction of each distinct monthly performance obligation, consistent with the allocation objective and based upon the level of effort required to satisfy the stand-ready obligation in a given month. Capacity reservation revenues derived from a firm service contract are generally consistent during the contract term, but can be higher in winter periods than the rest of the year based upon seasonal rates.

Interruptible Service Contracts: In providing interruptible services to customers, the Company agrees to transport or store natural gas or NGLs for a customer when capacity is available. The Company does not account for interruptible services with a customer as a contract until the customer nominates for service and the Company accepts the nomination based upon available pipeline or storage capacity or product availability because there are no enforceable rights and obligations until that time. The nomination and acceptance process is a daily activity and acceptance is granted based upon priority of service and availability of capacity and products. Upon acceptance, the Company accounts for interruptible services similarly to its firm services.

The transaction price for interruptible service contracts is comprised of a variable fee in the form of a usage fee paid on the volume of commodity actually transported or injected and withdrawn from storage. The transaction price is allocated to the single performance obligation of providing interruptible service. Interruptible service revenues for natural gas transportation and storage are generally recognized over time based on the output measure of volume transported or stored when services are rendered upon the successful allocation of the services provided to the customer's account, which best depicts the transfer of control to the customer and satisfaction of the promised service. Interruptible services are recognized in the month services are provided because the Company has a right to consideration from customers in amounts that correspond directly to the value that the customer receives from the Company's performance. The rates charged may vary on a daily, monthly or seasonal basis.

Minimum Volume Commitment (MVC) Contracts: Certain of the Company's transportation, storage or ethane supply contracts require customers to transport, store or purchase a minimum volume of commodity over a specified time period. If a customer fails to meet its MVC for the specified time period, the customer is obligated to pay a contractually-determined deficiency fee based upon the shortfall between the actual volumes transported, stored or purchased and the MVC for that period. MVC contracts are generally similar in nature to a firm service contract where the performance obligation is a stand-ready obligation that is a series of distinct services that are substantially the same with the same pattern of transfer to the customer. The transaction price for a MVC is a fee for the volume of commodity actually transported, stored or delivered, which is allocated to each distinct monthly performance obligation, consistent with the allocation objective and based upon the level of effort required to satisfy the obligation of the transacted activities in a given month. Revenues associated with transportation and storage services are generally recognized over time based on the output measure of volume transported or
stored and revenues associated with ethane supply are generally recognized at a point in time based on barrels delivered, with the recognition of the deficiency fee in the period when it is known the customer cannot make up the deficient volume in the specified period.
    
Other: Certain ethane supply contracts include a stated volume that the Company supplies to customers, and any volume requested above the stated volume is based on product availability. Revenues for these ethane supply contracts are generally recognized at a point in time when each barrel is transferred to the customer because the customer is able to direct the use of, and obtain substantially all of the remaining benefits from, the product at that time. Periodically, the Company may also enter into contracts with customers for the sale of natural gas or NGLs. The Company recognizes revenues for these transactions at the point in time of the physical sale of the commodity, which corresponds with the transfer of control of the commodity to the customer and the consideration is measured as the stated sales price in the contract.

Contract Balances

The Company records contract assets primarily related to performance obligations completed but not billed, or partially billed, as of the reporting date. The Company records contract liabilities, or deferred revenue, when payment is received in advance of satisfying its performance obligations.
v3.25.0.1
Basis of Presentation and Significant Accounting Policies (Tables)
 12 Months Ended
Dec. 31, 2024
Accounting Policies [Abstract]  
Summary of Capitalized Interest and Allowance for Borrowed Funds The following table summarizes capitalized interest and the allowance for borrowed funds and allowance for equity funds used during construction (in millions):
 For the Year Ended
December 31,
 202420232022
Capitalized interest and allowance for borrowed funds used during construction$5.5 $3.6 $2.2 
Allowance for equity funds used during construction4.5 5.7 6.2 
v3.25.0.1
Acquisition (Tables)
 12 Months Ended
Dec. 31, 2024
Business Combination, Asset Acquisition, and Joint Venture Formation [Abstract]  
Pro Forma Information
The following unaudited pro forma results of operations of the Company are presented as if the acquisition occurred on January 1, 2022. Such results are not necessarily indicative of future results. These pro forma results also do not reflect any cost savings, operating synergies or revenue enhancements that the Company may achieve or the costs necessary to achieve those objectives (in millions):

Pro Forma
For the Year Ended December 31,
20232022
Operating revenue
$1,962.8 $2,253.4 
Net income
393.8 357.4 
v3.25.0.1
Revenues (Tables)
 12 Months Ended
Dec. 31, 2024
Revenue from Contract with Customer [Abstract]  
Disaggregation of Revenue The following table presents the Company's revenues disaggregated by type of service by segment (in millions):
For the Year Ended December 31, 2024
Natural Gas
Natural Gas Liquids
EliminationsTotal
Revenues from Contracts with Customers
Firm Service (1)(2)
$1,353.9 $452.6 $(31.0)$1,775.5 
Interruptible Service 59.1 0.1 — 59.2 
Other revenues (2)
7.6 144.9 — 152.5 
Total Revenues from Contracts with Customers1,420.6 597.6 (31.0)1,987.2 
Other operating revenues (2)(3)
21.5 37.8 (18.4)40.9 
Total Operating Revenues$1,442.1 $635.4 $(49.4)$2,028.1 

(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)For the year ended December 31, 2024, revenues attributable to Bayou Ethane within the Natural Gas Liquids segment were $243.6 million included in firm service from product sales earned from contracts with MVCs; $114.4 million included in other revenues from product sales earned from contracts with no MVCs; and $4.9 million included in other operating revenues.
(3)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 Year Ended December 31, 2023
Natural Gas
Natural Gas Liquids
EliminationsTotal
Revenues from Contracts with Customers
Firm Service (1)(2)
$1,253.1 $262.7 $(26.1)$1,489.7 
Interruptible Service 51.6 — — 51.6 
Other revenues (2)
3.4 36.8 — 40.2 
Total Revenues from Contracts with Customers1,308.1 299.5 (26.1)1,581.5 
Other operating revenues (2)(3)
6.6 33.5 (3.9)36.2 
Total Operating Revenues$1,314.7 $333.0 $(30.0)$1,617.7 

(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)For the year ended December 31, 2023, revenues attributable to Bayou Ethane within the Natural Gas Liquids segment were $74.9 million included in firm service from product sales earned from contracts with MVCs; $25.4 million included in other revenues from product sales earned from contracts with no MVCs; and $1.2 million included in other operating revenues.
(3)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 Year Ended December 31, 2022
Natural Gas
Natural Gas Liquids
EliminationsTotal
Revenues from Contracts with Customers
Firm Service (1)
$1,157.8 $174.0 $(19.9)$1,311.9 
Interruptible Service 61.2 — (5.0)56.2 
Other revenues
9.4 20.5 — 29.9 
Total Revenues from Contracts with Customers1,228.4 194.5 (24.9)1,398.0 
Other operating revenues (2)
2.3 31.7 — 34.0 
Total Operating Revenues$1,230.7 $226.2 $(24.9)$1,432.0 
Contract Liabilities Significant changes in the contract liability balances during the year ended December 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		(4.1)
Increases due to cash received, excluding amounts recognized as
    revenues during the period		0.6 
Balance as of December 31, 2024(1)
$17.9 
(1)As of December 31, 2024 and 2023, $1.8 million and $3.5 million were recorded in Other Current Liabilities (current portion), and $16.1 million and $17.9 million were recorded in Other Liabilities (noncurrent portion).
Significant changes in the contract liability balances during the year ended December 31, 2023, were as follows (in millions):

Contract Liabilities
Balance as of December 31, 2022(1)
$23.0 
Revenues recognized that were included in the contract liability
    balances at the beginning of the period		(3.9)
Increases due to cash received, excluding amounts recognized as
    revenues during the period		1.8 
Other
0.5 
Balance as of December 31, 2023(1)
$21.4 
(1)As of December 31, 2023 and 2022, $3.5 million and $3.6 million was recorded in Other Current Liabilities (current portion) and $17.9 million and $19.4 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 December 31, 2024. 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 FERC-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 projects that are subject to regulatory approvals.
In millions
20252026ThereafterTotal
Estimated revenues from contracts with customers
    from unsatisfied performance obligations as of
    December 31, 2024(1)(2)
$1,484.5 $1,294.5 $11,214.0 $13,993.0 
Operating revenues which are fixed and
    determinable (operating leases)		27.5 27.5 136.0 191.0 
Total projected operating revenues under committed
    firm agreements as of December 31, 2024
$1,512.0 $1,322.0 $11,350.0 $14,184.0 

(1)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.
(2)The estimated revenues from contracts with customers from unsatisfied performance obligations as of December 31, 2024, that are anticipated under executed precedent transportation agreements associated with the Company's growth projects are $3.8 billion.
v3.25.0.1
Leases (Tables)
 12 Months Ended
Dec. 31, 2024
Leases [Abstract]  
Components of Lease Cost
The components of lease cost were as follows (in millions):

For the Year Ended December 31,
202420232022
Operating lease cost$4.1 $3.8 $3.8 
Short-term lease cost5.4 4.7 3.1 
Finance lease cost:
      Amortization of right-of-use asset0.7 0.7 0.7 
      Interest on lease liability0.3 0.3 0.3 
        Total lease cost$10.5 $9.5 $7.9 
Schedule of Supplemental Balance Sheet Information Related to Leases
The following provides supplemental balance sheet information related to the Company's leases:
As of December 31,
20242023
Right-of-use assets (in millions)
Operating leases (recorded in Other Assets)
$24.9$18.9
Finance lease (recorded in Property, Plant and Equipment)
2.53.2
Lease liabilities (in millions)
Operating leases (recorded in Other Liabilities, current and
    non-current)
25.319.6
Finance lease (recorded in Other Current Liabilities and
    Long-term debt and finance lease obligation)
3.64.5
Weighted-average remaining lease term (years)
Operating leases13.69.9
Finance lease3.64.6
Weighted-average discount rate
Operating leases3.95 %3.20 %
Finance lease5.89 %5.89 %
Maturity of Operating Lease Liabilities
The table below presents the maturities of lease liabilities (in millions):
As of December 31, 2024
Operating
Leases		Finance
Lease
2025$2.6 $1.1 
20262.6 1.1 
20272.2 1.1 
20280.8 0.7 
20292.1 — 
Thereafter24.4 — 
Total34.7 4.0 
Less: discount(9.4)(0.4)
Total lease liabilities$25.3 $3.6 
Maturity of Finance Lease Liabilities
The table below presents the maturities of lease liabilities (in millions):
As of December 31, 2024
Operating
Leases		Finance
Lease
2025$2.6 $1.1 
20262.6 1.1 
20272.2 1.1 
20280.8 0.7 
20292.1 — 
Thereafter24.4 — 
Total34.7 4.0 
Less: discount(9.4)(0.4)
Total lease liabilities$25.3 $3.6 
v3.25.0.1
Commitment and Contingencies (Tables)
 12 Months Ended
Dec. 31, 2024
Commitments and Contingencies Disclosure [Abstract]  
Schedule of Pipeline Capacity and Storage Agreements Future Commitments The table below presents the future commitments related to these agreements as of December 31, 2024 (in millions):
2025$8.0 
20268.1 
20273.0 
20280.2 
2029— 
Thereafter— 
Total$19.3 
v3.25.0.1
Fair Value Measurements (Tables)
 12 Months Ended
Dec. 31, 2024
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 Consolidated Balance Sheets as of December 31, 2024 and 2023, were as follows (in millions):

As of December 31, 2024
 Estimated 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.

As of December 31, 2023
Estimated Fair Value
Financial AssetsCarrying AmountLevel 1Level 2Level 3Total
   Cash and cash equivalents$20.1 $20.1 $— $— $20.1 
Financial Liabilities 
   Long-term debt$3,262.4 
(1)
$— $3,155.3 $— $3,155.3 

(1) The carrying amount of long-term debt excluded a $3.6 million long-term finance lease obligation and
$4.1 million of unamortized debt issuance costs.
v3.25.0.1
Property, Plant and Equipment (Tables)
 12 Months Ended
Dec. 31, 2024
Property, Plant and Equipment [Abstract]  
Schedule of Property, Plant and Equipment
The following table presents the Company's PPE as of December 31, 2024 and 2023 (in millions):
Category2024
Amount
2024
Weighted-Average
Useful Lives
(Years)
2023
Amount
2023
Weighted-Average
Useful Lives
 (Years)
Depreciable plant:    
Transmission$11,750.7 38$11,405.4 38
Storage1,002.1 39951.3 39
Gathering108.8 25106.1 24
General, intangibles and other557.7 20535.4 20
Total utility depreciable plant13,419.3 3812,998.2 37
Non-depreciable:   
Construction work in progress190.1  287.2  
Storage196.8  197.5  
Land51.6  46.6  
Total non-depreciable assets438.5  531.3  
Total PPE, gross
13,857.8  13,529.5  
Less:  accumulated depreciation and amortization5,045.1  4,672.9  
Total PPE, net$8,812.7  $8,856.6  
Schedule of Gross PPE Investment and Related Accumulated Depreciation The following table presents the gross PPE investment and related accumulated depreciation for the Company's undivided interests as of December 31, 2024 and 2023 (in millions):
 20242023
 Gross PPE
Investment		Accumulated DepreciationGross PPE
Investment		Accumulated Depreciation
Mobile Bay Pipeline$15.4 $8.8 $15.4 $8.3 
NGLs pipelines and facilities55.1 15.1 54.6 13.5 
Offshore and other assets7.5 5.7 13.0 10.9 
Total$78.0 $29.6 $83.0 $32.7 
v3.25.0.1
Goodwill and Intangible Assets (Tables)
 12 Months Ended
Dec. 31, 2024
Goodwill and Intangible Assets Disclosure [Abstract]  
Schedule of Finite-Lived Intangible Assets
The following table contains information regarding the Company's intangible assets, which includes customer relationships acquired as part of its acquisitions (in millions):
As of December 31,
20242023
Gross carrying amount
$92.9 $93.3 
Accumulated amortization(24.2)(21.3)
Net carrying amount$68.7 $72.0 
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense Amortization expense for the next five years and in total thereafter as of December 31, 2024, is expected to be as follows (in millions):
2025$3.0 
20262.9 
20272.9 
20282.9 
20292.9 
Thereafter54.1 
Total$68.7 
v3.25.0.1
Asset Retirement Obligations (Tables)
 12 Months Ended
Dec. 31, 2024
Asset Retirement Obligation Disclosure [Abstract]  
Asset Retirement Obligation
The following table summarizes the aggregate carrying amount of the Company's ARO (in millions):
As of December 31,
 20242023
Balance at beginning of year $74.1 $71.1 
Liabilities recorded5.0 8.4 
Liabilities settled(9.9)(10.0)
Accretion expense2.1 2.1 
Revision of estimates0.9 2.5 
Balance at end of year72.2 74.1 
Less:  Current portion of ARO(2.2)(14.9)
Long-term ARO$70.0 $59.2 
v3.25.0.1
Regulatory Assets and Liabilities (Tables)
 12 Months Ended
Dec. 31, 2024
Regulatory Assets and Liabilities Disclosure [Abstract]  
Schedule of Regulatory Assets
The amounts recorded as regulatory assets and liabilities on the Consolidated Balance Sheets as of December 31, 2024 and 2023, are summarized in the table below. The table also includes amounts related to unamortized debt issuance costs and unamortized discount on long-term debt, which while not regulatory assets and liabilities, are a component of the embedded cost of debt financing utilized in Texas Gas' rate proceedings. The tax effect of the equity component of AFUDC represents amounts recoverable from rate payers for the tax recorded in regulatory accounting. Certain amounts in the table are reflected as a negative, or a reduction, to be consistent with the regulatory books of account. The period of recovery for the regulatory assets included in rates varies from one to eighteen years. The remaining period of recovery for regulatory assets not yet included in rates would be determined in future rate proceedings. None of the regulatory assets shown below were earning a return as of December 31, 2024 and 2023 (in millions):
As of December 31,
 20242023
Regulatory Assets:  
Pension$8.0 $8.1 
Tax effect of AFUDC equity0.1 0.1 
Other0.5 0.5 
Total regulatory assets$8.6 $8.7 
Regulatory Liabilities:
Cashout and fuel tracker$18.3 $15.1 
Provision for other asset retirement103.6 98.1 
Unamortized debt issuance costs(0.7)(1.0)
Unamortized discount on long-term debt(0.1)(0.1)
Postretirement benefits other than pension62.8 60.6 
Total regulatory liabilities$183.9 $172.7 
Schedule of Regulatory Liabilities
The amounts recorded as regulatory assets and liabilities on the Consolidated Balance Sheets as of December 31, 2024 and 2023, are summarized in the table below. The table also includes amounts related to unamortized debt issuance costs and unamortized discount on long-term debt, which while not regulatory assets and liabilities, are a component of the embedded cost of debt financing utilized in Texas Gas' rate proceedings. The tax effect of the equity component of AFUDC represents amounts recoverable from rate payers for the tax recorded in regulatory accounting. Certain amounts in the table are reflected as a negative, or a reduction, to be consistent with the regulatory books of account. The period of recovery for the regulatory assets included in rates varies from one to eighteen years. The remaining period of recovery for regulatory assets not yet included in rates would be determined in future rate proceedings. None of the regulatory assets shown below were earning a return as of December 31, 2024 and 2023 (in millions):
As of December 31,
 20242023
Regulatory Assets:  
Pension$8.0 $8.1 
Tax effect of AFUDC equity0.1 0.1 
Other0.5 0.5 
Total regulatory assets$8.6 $8.7 
Regulatory Liabilities:
Cashout and fuel tracker$18.3 $15.1 
Provision for other asset retirement103.6 98.1 
Unamortized debt issuance costs(0.7)(1.0)
Unamortized discount on long-term debt(0.1)(0.1)
Postretirement benefits other than pension62.8 60.6 
Total regulatory liabilities$183.9 $172.7 
v3.25.0.1
Financing (Tables)
 12 Months Ended
Dec. 31, 2024
Debt Disclosure [Abstract]  
Schedule of Long-term Debt Instruments
The following table presents all long-term debt issuances outstanding as of December 31, 2024 and 2023 (in millions):
 20242023
Notes and Debentures:  
Boardwalk Pipelines  
4.95% Notes due 2024 (Boardwalk Pipelines 2024 Notes)
$— $600.0 
5.95% Notes due 2026
550.0 550.0 
4.45% Notes due 2027
500.0 500.0 
4.80% Notes due 2029
500.0 500.0 
3.40% Notes due 2031
500.0 500.0 
3.60% Notes due 2032
500.0 500.0 
5.625% Notes due 2034
600.0 — 
Texas Gas  
7.25% Debentures due 2027
100.0 100.0 
Total notes and debentures3,250.0 3,250.0 
Revolving Credit Facility:  
Boardwalk Pipelines
— 25.0 
Total revolving credit facility— 25.0 
Finance lease obligation2.7 3.6 
 3,252.7 3,278.6 
Less:
Unamortized debt discount(13.5)(12.6)
Unamortized debt issuance costs(4.8)(4.1)
Total Long-Term Debt and Finance Lease Obligation$3,234.4 $3,261.9 
For the twelve months ended December 31, 2024, the Company completed the following debt issuance (in millions, except interest rates):

Date of
Issuance		Issuing SubsidiaryAmount of
 Issuance		Purchaser
Discounts
and
Expenses		Net
Proceeds		 Interest
Rate		Maturity DateInterest
 Payable
February 2024Boardwalk Pipelines$600.0 $6.5 $593.5 
(1)
5.625 %August 1, 2034
February 1 and August 1
(1)The net proceeds of this offering were initially invested in U.S. treasury bills and used to retire the Boardwalk Pipelines 2024 Notes due December 2024 at maturity.
Schedule of Maturities of Long-term Debt
Maturities of the Company's long-term debt for the next five years and in total thereafter are as follows (in millions):
 
2025$— 
2026550.0 
2027600.0 
2028— 
2029500.0 
Thereafter1,600.0 
Total long-term debt
$3,250.0 
v3.25.0.1
Employee Benefits (Tables)
 12 Months Ended
Dec. 31, 2024
Retirement Benefits [Abstract]  
Schedule of Projected Benefit Obligation, Fair Value of Assets, Funded Status and the Amounts Not Yet Recognized As Components of Net Periodic Pension and Postretirement Benefits Cost
Projected Benefit Obligation, Fair Value of Assets and Funded Status

The projected benefit obligation, fair value of assets, funded status and the amounts not yet recognized as components of net periodic pension and postretirement benefits cost for the Retirement Plans and PBOP at December 31, 2024 and 2023, were as follows (in millions):
 Retirement PlansPBOP
 For the Year Ended
December 31,		For the Year Ended December 31,
 2024202320242023
Change in benefit obligation:    
Benefit obligation at beginning of period$88.0 $86.4 $23.4 $23.7 
Service cost1.9 1.9 — — 
Interest cost4.0 4.1 1.1 1.2 
Plan participants' contributions— — 1.0 1.0 
Actuarial (gain) loss
(2.1)4.0 (0.1)2.3 
Benefits paid(0.5)(0.5)(4.1)(4.8)
Settlements(8.2)(7.9)— — 
Benefit obligation at end of period$83.1 $88.0 $21.3 $23.4 
Change in plan assets:    
Fair value of plan assets at beginning of period$83.3 $77.6 $82.3 $81.2 
Actual return on plan assets6.6 9.2 3.1 4.8 
Company's contribution3.2 4.9 0.2 0.1 
Plan participants' contributions— — 1.0 1.0 
Benefits paid(0.5)(0.5)(4.1)(4.8)
Settlements(8.2)(7.9)— — 
Fair value of plan assets at end of period$84.4 $83.3 $82.5 $82.3 
Funded status$1.3 $(4.7)$61.2 $58.9 
Items not recognized as components of net periodic cost:   
Net actuarial loss
$6.8 $12.7 $2.5 $3.0 
Schedule of Accumulated Benefit Obligations in Excess of Fair Value of Plan Assets
As of December 31, 2024, the Retirement Plans and PBOP were in an overfunded status. The following aggregate information relates only to the underfunded plans as of December 31, 2023 (in millions):
Retirement Plans
 For the Year Ended
December 31,
 2023
Projected benefit obligation$88.0 
Accumulated benefit obligation84.6 
Fair value of plan assets83.3 
Schedule of Net Periodic Benefit Cost
Components of net periodic benefit cost for both the Retirement Plans and PBOP for the years ended December 31, 2024, 2023 and 2022, were as follows (in millions):
 Retirement PlansPBOP
 For the Year Ended
December 31,		For the Year Ended
December 31,
 202420232022202420232022
Service cost$1.9 $1.9 $2.2 $— $— $— 
Interest cost4.0 4.1 3.1 1.1 1.2 0.8 
Expected return on plan assets(3.9)(3.6)(5.3)(2.6)(2.4)(1.8)
Amortization of prior service cost0.1 0.1 0.1 — — — 
Amortization of unrecognized net loss0.3 1.2 0.7 — — — 
Settlement charge0.7 1.3 2.9 — — — 
Regulatory asset decrease0.1 — — — — — 
Net periodic benefit cost (credit)
$3.2 $5.0 $3.7 $(1.5)$(1.2)$(1.0)
Schedule of Expected Benefit Payments
The following table shows benefit payments, which reflect expected future service, as appropriate, which are expected to be paid for both the Retirement Plans and PBOP (in millions):
 
Retirement Plans
PBOP
2025$19.6 $2.0 
202611.4 1.9 
202710.8 1.8 
20288.3 1.7 
20296.9 1.6 
2030-2034
17.8 6.9 
Schedule of Weighted-Average Assumptions Used to Determine Benefit Obligations and Net Periodic Benefit Cost
Weighted-average assumptions used to determine benefit obligations for the years ended December 31, 2024 and 2023, were as follows:
 Retirement PlansPBOP
For the Year Ended
December 31,		For the Year Ended
December 31,
 2024202320242023
 PensionSRPPensionSRP
Discount rate5.35 %5.25 %4.90 %4.90 %5.60 %5.10 %
Expected return on plan assets5.50 %5.50 %5.00 %5.00 %3.37 %3.25 %
Rate of compensation increase
4.00%-4.50%
4.00%-4.50%
3.00%-3.50%
3.00%-3.50%
— %— %
Weighted-average assumptions used to determine net periodic benefit cost for the periods indicated were as follows:
 Retirement PlansPBOP
For the Year Ended
December 31,		For the Year Ended
December 31,
 202420232022202420232022
Pension
SRP
Pension
SRPPensionSRP
Discount rate(1)5.25 %(1)4.90 %(1)(2)5.10 %5.40 %2.90 %
Expected return on plan assets5.00%5.00 %5.00%5.00 %6.25%6.25 %3.25 %2.99 %2.01 %
Rate of compensation increase
3.00% -
3.50%
3.00% -
3.50%
3.00% -
4.50%
3.00% -
4.50%
3.00%3.00 %— %— %— %
(1)Pension expense was remeasured quarterly in 2024, 2023 and 2022. The quarterly remeasurements for each quarter in 2024, 2023 and 2022 were as follows: Quarter 1: 5.25%, 5.35% and 3.00%; Quarter 2: 5.40%, 5.15% and 4.10%; Quarter 3: 4.80%, 5.45% and 4.65%; and Quarter 4: 5.35%, 4.90% and 5.30%.
(2)SRP expense was remeasured with discount rates of 4.15% at June 30, 2022, and 5.30% at December 31, 2022, to reflect settlements.
Schedule of Fair Value of Plan Assets
The following table sets forth, by level within the fair value hierarchy, a summary of the Texas Gas Trust's assets measured at fair value on a recurring basis at December 31, 2024 (in millions):

 Pension Plan Trust Assets
 Level 1Level 2Level 3Total
Equity securities$35.9 $— $— $35.9 
Short-term investments8.4 — — 8.4 
Fixed income mutual funds40.1 — — 40.1 
Total assets$84.4 $— $— $84.4 

The following table sets forth, by level within the fair value hierarchy, a summary of the Texas Gas Trust's assets measured at fair value on a recurring basis at December 31, 2023 (in millions):

 Pension Plan Trust Assets
 Level 1Level 2Level 3Total
Equity securities$34.6 $— $— $34.6 
Short-term investments17.3 — — 17.3 
Fixed income mutual funds26.3 — — 26.3 
Tax-exempt securities
— 5.1— 5.1 
Total assets$78.2 $5.1 $— $83.3 
The following table sets forth, by level within the fair value hierarchy, a summary of the PBOP trust investments measured at fair value on a recurring basis at December 31, 2024 (in millions):
 PBOP Trust Assets
 Level 1Level 2Level 3Total
Short-term investments$1.6 $— $— $1.6 
Other assets15.7 — — 15.7 
Asset-backed securities— 0.5 — 0.5 
Corporate bonds— 47.8 — 47.8 
Tax-exempt securities— 34.9 — 34.9 
Total assets$17.3 $83.2 $— $100.5 
Other liabilities(18.0)— — (18.0)
Total liabilities$(18.0)$— $— $(18.0)
The following table sets forth, by level within the fair value hierarchy, a summary of the PBOP trust investments measured at fair value on a recurring basis at December 31, 2023 (in millions):
 PBOP Trust Assets
 Level 1Level 2Level 3Total
Short-term investments$12.8 $— $— $12.8 
Other assets
2.1 — — 2.1 
Asset-backed securities— 0.8 — 0.8 
Corporate bonds— 67.0 — 67.0 
Tax-exempt securities
— 38.9 — 38.9 
Total assets$14.9 $106.7 $— $121.6 
Other liabilities(39.3)— — (39.3)
Total liabilities$(39.3)$— $— $(39.3)
v3.25.0.1
Income Taxes (Tables)
 12 Months Ended
Dec. 31, 2024
Income Tax Disclosure [Abstract]  
Schedule of Components of Income Tax Expense The following is a summary of the provision for income taxes for the years ended December 31, 2024, 2023 and 2022 (in millions):
 For the Year Ended December 31,
 202420232022
Current expense:   
State$0.8 $0.8 $0.8 
Deferred provision:   
State0.3 — — 
Income taxes$1.1 $0.8 $0.8 
v3.25.0.1
Supplemental Disclosure of Cash Flow Information (Tables)
 12 Months Ended
Dec. 31, 2024
Supplemental Cash Flow Elements [Abstract]  
Schedule of Cash Flow, Supplemental Disclosures Supplemental Disclosure of Cash Flow Information (in millions):
 For the Year Ended December 31,
 202420232022
Cash paid during the period for:   
Amounts included in the measurement of operating lease liabilities $4.2 $4.9 $3.7 
Amounts included in the measurement of finance lease liability
1.1 1.1 1.1 
Interest (net of amount capitalized) 162.1 147.3 156.3 
Income taxes, net0.8 0.7 0.6 
Non-cash investing activities:
   
Accounts payable and PPE30.4 47.7 44.4 
Right-of-use asset obtained in exchange for lease obligations9.9 3.4 0.2 
Gas stored underground and PPE
— 47.8 — 
v3.25.0.1
Reportable Segments (Tables)
 12 Months Ended
Dec. 31, 2024
Segment Reporting [Abstract]  
Schedule of Segment Reporting Information, by Segment
Financial information by segment follows (in millions):
For the year ended December 31, 2024
Natural Gas
Natural Gas LiquidsTotal
Revenues
Revenue from external customers$1,392.7 $635.4 $2,028.1 
Intrasegment revenues
49.4 — 49.4 
$1,442.1 $635.4 $2,077.5 
Reconciliation of revenues:
Elimination of intrasegment revenues
(49.4)
Total consolidated revenues$2,028.1 
Less:
Costs associated with service revenues$41.1 $19.0 
Costs associated with product sales— 303.5 
Operation and maintenance253.1 57.2 
Administrative and general176.9 27.6 
Taxes other than income taxes109.0 13.1 
(Gain) loss on sale of assets, impairments and other
(6.6)1.1 
Miscellaneous other income, net(6.1)— 
Segment EBITDA
$874.7 $213.9 $1,088.6 
Reconciliation of profit or loss:
Depreciation and amortization$424.8 
Interest expense182.9 
Interest income(31.1)
Consolidated income before income taxes
$512.0 
For the year ended December 31, 2023
Natural GasNatural Gas LiquidsTotal
Revenues
Revenue from external customers$1,284.7 $333.0 $1,617.7 
Intrasegment revenues
30.0 — 30.0 
$1,314.7 $333.0 $1,647.7 
Reconciliation of revenues:
Elimination of intrasegment revenues
(30.0)
Total consolidated revenues$1,617.7 
Less:
Costs associated with service revenues$37.1 $15.3 
Costs associated with product sales— 87.8 
Operation and maintenance229.1 51.9 
Administrative and general151.7 24.1 
Taxes other than income taxes106.1 9.4 
Loss on sale of assets, impairments and other
0.3 — 
Miscellaneous other income, net(4.0)(0.1)
Segment EBITDA
$794.4 $144.6 $939.0 
Reconciliation of profit or loss:
Depreciation and amortization$408.7 
Interest expense155.6 
Interest income(12.1)
Consolidated income before income taxes
$386.8 
For the year ended December 31, 2022
Natural GasNatural Gas LiquidsTotal
Revenues
Revenue from external customers$1,205.8 $226.2 $1,432.0 
Intrasegment revenues
24.9 — 24.9 
$1,230.7 $226.2 $1,456.9 
Reconciliation of revenues:
Elimination of intrasegment revenues
(24.9)
Total consolidated revenues$1,432.0 
Less:
Costs associated with service revenues$37.1 $10.2 
Costs associated with product sales— 1.0 
Operation and maintenance208.6 42.3 
Administrative and general129.0 18.7 
Taxes other than income taxes106.1 8.4 
Loss on sale of assets, impairments and other
4.0 — 
Miscellaneous other income, net(6.3)(0.1)
Segment EBITDA
$752.2 $145.7 $897.9 
Reconciliation of profit or loss:
Depreciation and amortization$392.3 
Interest expense165.9 
Interest income(3.3)
Consolidated income before income taxes
$343.0 
The following table reflects capital expenditures by segment (in millions):
Capital Expenditures
For the year ended
 December 31,
202420232022
Natural Gas
$340.6 $321.5 $291.3 
Natural Gas Liquids51.8 60.9 53.0 
Total
$392.4 $382.4 $344.3 
Reconciliation of Assets from Segment to Consolidated
Segment assets include Property, plant, and equipment – net, Intangible assets – net of accumulated amortization and Goodwill. The following table reflects segment assets and a reconciliation to Total Assets (in millions):
Segment Assets
As of December 31,
20242023
Natural Gas
$7,490.1 $7,515.2 
Natural Gas Liquids1,628.7 1,650.8 
Total Segment Assets
9,118.8 9,166.0 
Total current assets
401.1 288.7 
Gas stored underground and Other assets
259.5 241.7 
Total Assets
$9,779.4 $9,696.4 
v3.25.0.1
Corporate Structure (Details)
Dec. 31, 2024
Boardwalk Pipelines Holding Corp. (BPHC) | Boardwalk Pipeline Partners, LP  
Noncontrolling Interest [Line Items]  
Ownership percentage 100.00%
v3.25.0.1
Basis of Presentation and Significant Accounting Policies - Narrative (Details)
 12 Months Ended
Dec. 31, 2024
USD ($)
reportable_segment
Dec. 31, 2023
USD ($)
Revenue Recognition [Line Items]    
Number of operating segments | reportable_segment 3  
Number of reportable segments | reportable_segment 2  
Restricted cash $ 0 $ 0
Short-term investments 0 0
Product inventory 12,700,000 2,400,000
Materials and supplies $ 42,400,000 $ 38,100,000
Intangible assets estimated useful life 35 years  
Aggregate basis difference in net assets for financial and income tax purposes $ 5,700,000,000  
Minimum    
Revenue Recognition [Line Items]    
Depreciation range for PPE related to operations for which regulatory accounting does not apply 3 years  
Depreciation range for PPE related to operations for which regulatory accounting is applicable 5 years  
Service contract duration (years) one  
Expected payment of invoiced services (days) 10 days  
Maximum    
Revenue Recognition [Line Items]    
Depreciation range for PPE related to operations for which regulatory accounting does not apply 35 years  
Depreciation range for PPE related to operations for which regulatory accounting is applicable 62 years  
Service contract duration (years) twenty years  
Expected payment of invoiced services (days) 30 days  
v3.25.0.1
Basis of Presentation and Significant Accounting Policies - Summary Capitalized Interest and Allowances (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Accounting Policies [Abstract]      
Capitalized interest and allowance for borrowed funds used during construction $ 5.5 $ 3.6 $ 2.2
Allowance for equity funds used during construction $ 4.5 $ 5.7 $ 6.2
v3.25.0.1
Acquisition - Narrative (Details) - Bayou Ethane - Boardwalk Resources Company, LLC - USD ($)
$ in Millions
 12 Months Ended
Sep. 29, 2023
Dec. 31, 2023
Business Acquisition [Line Items]    
Percentage of voting interests acquired 100.00%  
Payments to acquire business $ 355.0  
Acquisition, operating revenue contribution   $ 101.5
Acquisition, net income contribution   $ 5.5
v3.25.0.1
Acquisition - Pro Forma Financial Information (unaudited) (Details) - Bayou Ethane - Boardwalk Resources Company, LLC - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]    
Operating revenue $ 1,962.8 $ 2,253.4
Net income $ 393.8 $ 357.4
v3.25.0.1
Revenues - Narrative (Details) - USD ($)
$ in Millions
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Revenue from Contract with Customer [Abstract]      
Receivables from contracts with customers $ 210.7 $ 204.6  
Contract assets from contracts with a customer 11.9 6.2  
Contract liabilities from contracts with customers $ 17.9 $ 21.4 $ 23.0
v3.25.0.1
Revenues - Disaggregation of Revenue (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Disaggregation of Revenue [Line Items]      
Total Revenues from Contracts with Customers $ 1,987.2 $ 1,581.5 $ 1,398.0
Other operating revenues 40.9 36.2 34.0
Total operating revenues 2,028.1 1,617.7 1,432.0
Operating Segments      
Disaggregation of Revenue [Line Items]      
Total operating revenues 2,077.5 1,647.7 1,456.9
Intrasegment Eliminations      
Disaggregation of Revenue [Line Items]      
Total Revenues from Contracts with Customers (31.0) (26.1) (24.9)
Other operating revenues (18.4) (3.9) 0.0
Total operating revenues (49.4) (30.0) (24.9)
Natural Gas Reportable Segment | Operating Segments      
Disaggregation of Revenue [Line Items]      
Total Revenues from Contracts with Customers 1,420.6 1,308.1 1,228.4
Other operating revenues 21.5 6.6 2.3
Total operating revenues 1,442.1 1,314.7 1,230.7
Natural Gas Liquids Reportable Segment | Operating Segments      
Disaggregation of Revenue [Line Items]      
Total Revenues from Contracts with Customers 597.6 299.5 194.5
Other operating revenues 37.8 33.5 31.7
Total operating revenues 635.4 333.0 226.2
Firm Service      
Disaggregation of Revenue [Line Items]      
Total Revenues from Contracts with Customers 1,775.5 1,489.7 1,311.9
Firm Service | Intrasegment Eliminations      
Disaggregation of Revenue [Line Items]      
Total Revenues from Contracts with Customers (31.0) (26.1) (19.9)
Firm Service | Natural Gas Reportable Segment | Operating Segments      
Disaggregation of Revenue [Line Items]      
Total Revenues from Contracts with Customers 1,353.9 1,253.1 1,157.8
Firm Service | Natural Gas Liquids Reportable Segment | Operating Segments      
Disaggregation of Revenue [Line Items]      
Total Revenues from Contracts with Customers 452.6 262.7 174.0
Firm Service | Bayou Ethane | Boardwalk Resources Company, LLC | Natural Gas Liquids Reportable Segment      
Disaggregation of Revenue [Line Items]      
Total Revenues from Contracts with Customers 243.6 74.9  
Interruptible Service      
Disaggregation of Revenue [Line Items]      
Total Revenues from Contracts with Customers 59.2 51.6 56.2
Interruptible Service | Intrasegment Eliminations      
Disaggregation of Revenue [Line Items]      
Total Revenues from Contracts with Customers 0.0 0.0 (5.0)
Interruptible Service | Natural Gas Reportable Segment | Operating Segments      
Disaggregation of Revenue [Line Items]      
Total Revenues from Contracts with Customers 59.1 51.6 61.2
Interruptible Service | Natural Gas Liquids Reportable Segment | Operating Segments      
Disaggregation of Revenue [Line Items]      
Total Revenues from Contracts with Customers 0.1 0.0 0.0
Interruptible Service | Bayou Ethane | Boardwalk Resources Company, LLC | Natural Gas Liquids Reportable Segment      
Disaggregation of Revenue [Line Items]      
Total Revenues from Contracts with Customers 114.4 25.4  
Other revenues      
Disaggregation of Revenue [Line Items]      
Total Revenues from Contracts with Customers 152.5 40.2 29.9
Other revenues | Intrasegment Eliminations      
Disaggregation of Revenue [Line Items]      
Total Revenues from Contracts with Customers 0.0 0.0 0.0
Other revenues | Natural Gas Reportable Segment | Operating Segments      
Disaggregation of Revenue [Line Items]      
Total Revenues from Contracts with Customers 7.6 3.4 9.4
Other revenues | Natural Gas Liquids Reportable Segment | Operating Segments      
Disaggregation of Revenue [Line Items]      
Total Revenues from Contracts with Customers 144.9 36.8 $ 20.5
Other revenues | Bayou Ethane | Boardwalk Resources Company, LLC | Natural Gas Liquids Reportable Segment      
Disaggregation of Revenue [Line Items]      
Total Revenues from Contracts with Customers   $ 1.2  
Other operating revenues $ 4.9    
v3.25.0.1
Revenues - Contract Liability Balance Activity (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Contract With Customer, Liability [Roll Forward]      
Beginning Balance $ 21.4 $ 23.0  
Revenues recognized that were included in the contract liability balances at the beginning of the period (4.1) (3.9)  
Increases due to cash received, excluding amounts recognized as revenues during the period 0.6 1.8  
Contract with Customer, Liability, Increase (Decrease) for Contract Acquired in Business Combination   0.5  
Ending Balance 17.9 21.4  
Contract with customer, liability, current 1.8 3.5 $ 3.6
Contract with customer, liability, noncurrent $ 16.1 $ 17.9 $ 19.4
v3.25.0.1
Revenues - Performance Obligations (Details)
$ in Millions
 12 Months Ended
Dec. 31, 2024
USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]  
Estimated revenues from contracts with customers from unsatisfied performance obligations as of December 31, 2024(1)(2) $ 13,993.0
Operating revenues which are fixed and determinable (operating leases) 191.0
Total projected operating revenues under committed firm agreements as of December 31, 2024 $ 14,184.0
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 $ 3,800.0
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01  
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 December 31, 2024(1)(2) $ 1,484.5
Operating revenues which are fixed and determinable (operating leases) 27.5
Total projected operating revenues under committed firm agreements as of December 31, 2024 $ 1,512.0
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 December 31, 2024(1)(2) $ 1,294.5
Operating revenues which are fixed and determinable (operating leases) 27.5
Total projected operating revenues under committed firm agreements as of December 31, 2024 $ 1,322.0
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 December 31, 2024(1)(2) $ 11,214.0
Operating revenues which are fixed and determinable (operating leases) 136.0
Total projected operating revenues under committed firm agreements as of December 31, 2024 $ 11,350.0
v3.25.0.1
Leases - Narrative (Details)
 12 Months Ended
Dec. 31, 2024
lease_renewal
Leases [Abstract]  
Finance lease, term 15 years
Finance lease, number of renewal options 2
Finance lease, renewal term 20 years
v3.25.0.1
Leases - Lease Cost (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Leases [Abstract]      
Operating lease cost $ 4.1 $ 3.8 $ 3.8
Short-term lease cost 5.4 4.7 3.1
Finance lease cost:      
Amortization of right-of-use asset 0.7 0.7 0.7
Interest on lease liability 0.3 0.3 0.3
Total lease cost $ 10.5 $ 9.5 $ 7.9
v3.25.0.1
Leases - Supplemental Balance Sheet Information Related to Leases (Details) - USD ($)
$ in Millions
Dec. 31, 2024
Dec. 31, 2023
Right-of-use assets (in millions)    
Operating leases (recorded in Other Assets) $ 24.9 $ 18.9
Right-of-use assets operating leases, statement of financial position Other Other
Finance lease (recorded in Property, Plant and Equipment) $ 2.5 $ 3.2
Right-of-use assets finance lease, statement of financial position Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, after Accumulated Depreciation and Amortization Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, after Accumulated Depreciation and Amortization
Lease liabilities (in millions)    
Operating leases (recorded in Other Liabilities, current and non-current) $ 25.3 $ 19.6
Operating lease, liability, current, statement of financial position Other current liabilities Other current liabilities
Operating lease, liability, noncurrent, statement of financial position Other Other
Finance lease (recorded in Other Current Liabilities and Long-term debt and finance lease obligation) $ 3.6 $ 4.5
Finance lease liability, statement of financial position Long-term debt and finance lease obligation, Other current liabilities Long-term debt and finance lease obligation, Other current liabilities
Weighted-average remaining lease term (years)    
Operating leases 13 years 7 months 6 days 9 years 10 months 24 days
Finance lease 3 years 7 months 6 days 4 years 7 months 6 days
Weighted-average discount rate    
Operating leases 3.95% 3.20%
Finance lease 5.89% 5.89%
v3.25.0.1
Leases - Maturities of Operating and Finance Lease Liabilities (Details) - USD ($)
$ in Millions
Dec. 31, 2024
Dec. 31, 2023
Operating Leases    
2025 $ 2.6  
2026 2.6  
2027 2.2  
2028 0.8  
2029 2.1  
Thereafter 24.4  
Total 34.7  
Less: discount (9.4)  
Total lease liabilities 25.3 $ 19.6
Finance Lease    
2025 1.1  
2026 1.1  
2027 1.1  
Finance Lease, Liability, to be Paid, Year Four 0.7  
2029 0.0  
Thereafter 0.0  
Total 4.0  
Less: discount (0.4)  
Total lease liabilities $ 3.6 $ 4.5
v3.25.0.1
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  
v3.25.0.1
Commitments and Contingencies - Environmental and Safety Matters (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]    
Accrual for environmental loss contingencies $ 7.0 $ 10.1
Environmental Loss Contingency Statement Of Financial Position Extensible Enumeration Not Disclosed Flag $ 7.0 10.1
Number of years the related expenditures are expected to cover assessment and remediation costs (in years) 20 years  
Accrued environmental loss contingencies, current $ 3.4 $ 6.7
Accrued Environmental Loss Contingency, Current, Statement of Financial Position Other current liabilities Other current liabilities
Accrued environmental loss contingencies, noncurrent $ 3.6 $ 3.4
Accrued Environmental Loss Contingency, Noncurrent, Statement of Financial Position Other Other
v3.25.0.1
Commitments and Contingencies - Commitments for Construction (Details)
$ in Millions
Dec. 31, 2024
USD ($)
Commitments and Contingencies Disclosure [Abstract]  
Purchase commitment, expected to be settled in the next twelve months $ 112.1
v3.25.0.1
Commitments and Contingencies - Pipeline Capacity and Storage Agreements, Narrative (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Pipeline Capacity and Storage Agreements      
Unrecorded Unconditional Purchase Obligation [Line Items]      
Expenses related to pipeline capacity and storage agreements $ 11.2 $ 5.8 $ 3.2
v3.25.0.1
Commitments and Contingencies - Pipeline Capacity and Storage Agreements Future Commitments (Details) - Pipeline Capacity and Storage Agreements
$ in Millions
Dec. 31, 2024
USD ($)
Unrecorded Unconditional Purchase Obligation [Line Items]  
2025 $ 8.0
2026 8.1
2027 3.0
2028 0.2
2029 0.0
Thereafter 0.0
Total $ 19.3
v3.25.0.1
Fair Value Measurements - Narrative (Details) - Fair Value, Measurements, Recurring - USD ($)
Dec. 31, 2024
Dec. 31, 2023
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Liabilities, fair value, recurring basis $ 0 $ 0
Level 1    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Equity securities, fair value, recurring basis $ 1,800,000 $ 2,300,000
v3.25.0.1
Fair Value Measurements - Financial Assets and Liabilities (Details) - USD ($)
$ in Millions
Dec. 31, 2024
Dec. 31, 2023
Financial Assets    
Cash and cash equivalents $ 117.9 $ 20.1
Financial Liabilities    
Long-term debt 3,129.7 3,155.3
Long-term finance lease obligation 2.7 3.6
Unsecured Debt    
Financial Liabilities    
Unamortized debt issuance costs 4.8 4.1
Carrying Amount    
Financial Assets    
Cash and cash equivalents 117.9 20.1
Financial Liabilities    
Long-term debt 3,236.5 3,262.4
Estimated Fair Value | Level 1    
Financial Assets    
Cash and cash equivalents 117.9 20.1
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 3,129.7 3,155.3
Estimated Fair Value | Level 3    
Financial Assets    
Cash and cash equivalents 0.0 0.0
Financial Liabilities    
Long-term debt $ 0.0 $ 0.0
v3.25.0.1
Property, Plant and Equipment - Class and Useful Life (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Property, Plant and Equipment [Abstract]      
Depreciation expense for PPE $ 421.9 $ 406.5 $ 390.4
Property, Plant and Equipment [Line Items]      
Total PPE, gross 13,857.8 13,529.5  
Less:  accumulated depreciation and amortization 5,045.1 4,672.9  
Property, plant and equipment, net 8,812.7 8,856.6  
Depreciable plant:      
Property, Plant and Equipment [Line Items]      
Total PPE, gross $ 13,419.3 $ 12,998.2  
Weighted-Average Useful Lives 38 years 37 years  
Transmission      
Property, Plant and Equipment [Line Items]      
Total PPE, excluding finance lease $ 11,750.7 $ 11,405.4  
Weighted-Average Useful Lives 38 years 38 years  
Storage      
Property, Plant and Equipment [Line Items]      
Total PPE, excluding finance lease $ 1,002.1 $ 951.3  
Weighted-Average Useful Lives 39 years 39 years  
Gathering      
Property, Plant and Equipment [Line Items]      
Total PPE, excluding finance lease $ 108.8 $ 106.1  
Weighted-Average Useful Lives 25 years 24 years  
General, intangibles and other      
Property, Plant and Equipment [Line Items]      
Total PPE, gross $ 557.7 $ 535.4  
Weighted-Average Useful Lives 20 years 20 years  
Non-depreciable:      
Property, Plant and Equipment [Line Items]      
Total PPE, excluding finance lease $ 438.5 $ 531.3  
Construction work in progress      
Property, Plant and Equipment [Line Items]      
Total PPE, excluding finance lease 190.1 287.2  
Total PPE, gross 190.1 287.2  
Storage      
Property, Plant and Equipment [Line Items]      
Total PPE, excluding finance lease 196.8 197.5  
Land      
Property, Plant and Equipment [Line Items]      
Total PPE, excluding finance lease $ 51.6 $ 46.6  
v3.25.0.1
Property, Plant and Equipment - Undivided Interests (Details)
Dec. 31, 2024
well
Mobile Bay Pipeline  
Undivided Interest Property [Line Items]  
Undivided interest in pipeline 64.00%
NGLs pipelines and facilities  
Undivided Interest Property [Line Items]  
Undivided interest in ethylene wells 83.00%
Undivided interest, number of ethylene wells 2
v3.25.0.1
Property, Plant and Equipment - Undivided Interests Gross PPE and Accumulated Depreciation (Details) - USD ($)
$ in Millions
Dec. 31, 2024
Dec. 31, 2023
Undivided Interest Property [Line Items]    
Gross PPE Investment $ 78.0 $ 83.0
Accumulated Depreciation 29.6 32.7
Mobile Bay Pipeline    
Undivided Interest Property [Line Items]    
Gross PPE Investment 15.4 15.4
Accumulated Depreciation 8.8 8.3
NGLs pipelines and facilities    
Undivided Interest Property [Line Items]    
Gross PPE Investment 55.1 54.6
Accumulated Depreciation 15.1 13.5
Offshore and other assets    
Undivided Interest Property [Line Items]    
Gross PPE Investment 7.5 13.0
Accumulated Depreciation $ 5.7 $ 10.9
v3.25.0.1
Property, Plant and Equipment - Asset Impairments (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Property, Plant and Equipment [Abstract]      
Asset impairment charges $ 2.4 $ 0.4 $ 7.5
v3.25.0.1
Goodwill and Intangible Assets - Goodwill (Details)
 12 Months Ended
Nov. 30, 2024
report
Nov. 30, 2023
report
Dec. 31, 2024
USD ($)
Dec. 31, 2023
USD ($)
Dec. 31, 2022
USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]          
Number of reporting units | report 2 2      
Goodwill impairment loss     $ 0 $ 0 $ 0
Goodwill [Line Items]          
Goodwill     237,400,000 $ 237,400,000  
Natural Gas Reportable Segment          
Goodwill [Line Items]          
Goodwill     163,500,000    
Natural Gas Liquids Reportable Segment          
Goodwill [Line Items]          
Goodwill     $ 73,900,000    
v3.25.0.1
Goodwill and Intangible Assets - Intangible Assets (Details) - USD ($)
$ in Millions
Dec. 31, 2024
Dec. 31, 2023
Goodwill and Intangible Assets Disclosure [Abstract]    
Gross carrying amount $ 92.9 $ 93.3
Accumulated amortization (24.2) (21.3)
Net carrying amount $ 68.7 $ 72.0
v3.25.0.1
Goodwill and Intangible Assets - Amortization Expense, Narrative (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Goodwill and Intangible Assets Disclosure [Abstract]      
Intangible assets, amortization expense $ 2.9 $ 2.2 $ 1.9
Intangible assets, weighted-average useful life 25 years    
v3.25.0.1
Goodwill and Intangible Assets - Amortization Expense (Details) - USD ($)
$ in Millions
Dec. 31, 2024
Dec. 31, 2023
Goodwill and Intangible Assets Disclosure [Abstract]    
2025 $ 3.0  
2026 2.9  
2027 2.9  
2028 2.9  
2029 2.9  
Thereafter 54.1  
Net carrying amount $ 68.7 $ 72.0
v3.25.0.1
Asset Retirement Obligations - Aggregate Carrying Amount (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]    
Balance at beginning of year  $ 74.1 $ 71.1
Liabilities recorded 5.0 8.4
Liabilities settled (9.9) (10.0)
Accretion expense 2.1 2.1
Revision of estimates 0.9 2.5
Balance at end of year 72.2 74.1
Less:  Current portion of ARO (2.2) (14.9)
Long-term ARO $ 70.0 $ 59.2
v3.25.0.1
Asset Retirement Obligations - Narrative (Details) - USD ($)
$ in Millions
Dec. 31, 2024
Dec. 31, 2023
Asset Retirement Obligation Disclosure [Abstract]    
Provision for other asset retirement $ 103.6 $ 98.1
v3.25.0.1
Regulatory Assets and Liabilities - Narrative (Details)
 12 Months Ended
Dec. 31, 2024
Regulatory Assets and Liabilities Disclosure [Abstract]  
Period of recovery-minimum (in years) 1 year
Period of recovery-maximum (in years) 18 years
v3.25.0.1
Regulatory Assets and Liabilities - Regulatory Assets (Details) - USD ($)
$ in Millions
Dec. 31, 2024
Dec. 31, 2023
Regulatory Assets [Line Items]    
Total regulatory assets $ 8.6 $ 8.7
Pension    
Regulatory Assets [Line Items]    
Total regulatory assets 8.0 8.1
Tax effect of AFUDC equity    
Regulatory Assets [Line Items]    
Total regulatory assets 0.1 0.1
Other    
Regulatory Assets [Line Items]    
Total regulatory assets $ 0.5 $ 0.5
v3.25.0.1
Regulatory Assets and Liabilities - Regulatory Liabilities (Details) - USD ($)
$ in Millions
Dec. 31, 2024
Dec. 31, 2023
Regulatory Liabilities [Line Items]    
Total regulatory liabilities $ 183.9 $ 172.7
Total regulatory assets (8.6) (8.7)
Cashout and fuel tracker    
Regulatory Liabilities [Line Items]    
Total regulatory liabilities 18.3 15.1
Provision for other asset retirement    
Regulatory Liabilities [Line Items]    
Total regulatory liabilities 103.6 98.1
Postretirement benefits other than pension    
Regulatory Liabilities [Line Items]    
Total regulatory liabilities 62.8 60.6
Unamortized debt issuance costs    
Regulatory Liabilities [Line Items]    
Total regulatory assets (0.7) (1.0)
Unamortized discount on long-term debt    
Regulatory Liabilities [Line Items]    
Total regulatory assets $ (0.1) $ (0.1)
v3.25.0.1
Financing - Long-Term Debt (Details) - USD ($)
$ in Millions
Dec. 31, 2024
Feb. 29, 2024
Dec. 31, 2023
Debt Instruments [Abstract]      
Finance lease obligation $ 2.7   $ 3.6
Total notes and debentures, revolving credit facility and Finance lease obligation 3,252.7   3,278.6
Less:      
Total Long-Term Debt and Finance Lease Obligation 3,234.4   3,261.9
Unsecured Debt      
Debt Instruments [Abstract]      
Total notes and debentures 3,250.0    
Less:      
Unamortized debt discount (13.5)   (12.6)
Unamortized debt issuance costs $ (4.8)   $ (4.1)
Unsecured Debt | Boardwalk Pipelines 4.95% Notes Due 2024      
Debt Instruments [Abstract]      
Debt, interest rate 4.95%   4.95%
Total notes and debentures $ 0.0   $ 600.0
Unsecured Debt | Boardwalk Pipelines 5.95% Notes Due 2026      
Debt Instruments [Abstract]      
Debt, interest rate 5.95%   5.95%
Total notes and debentures $ 550.0   $ 550.0
Unsecured Debt | Boardwalk Pipelines 4.45% Notes Due 2027      
Debt Instruments [Abstract]      
Debt, interest rate 4.45%   4.45%
Total notes and debentures $ 500.0   $ 500.0
Unsecured Debt | Boardwalk Pipelines 4.80% Notes Due 2029      
Debt Instruments [Abstract]      
Debt, interest rate 4.80%   4.80%
Total notes and debentures $ 500.0   $ 500.0
Unsecured Debt | Boardwalk Pipelines 3.40% Notes Due 2031      
Debt Instruments [Abstract]      
Debt, interest rate 3.40%   3.40%
Total notes and debentures $ 500.0   $ 500.0
Unsecured Debt | Boardwalk Pipelines 3.60% Notes Due 2032      
Debt Instruments [Abstract]      
Debt, interest rate 3.60%   3.60%
Total notes and debentures $ 500.0   $ 500.0
Unsecured Debt | Boardwalk Pipelines 5.625% Notes Due 2034      
Debt Instruments [Abstract]      
Debt, interest rate 5.625% 5.625% 5.625%
Total notes and debentures $ 600.0   $ 0.0
Unsecured Debt | Texas Gas 7.25% Debentures Due 2027      
Debt Instruments [Abstract]      
Debt, interest rate 7.25%   7.25%
Total notes and debentures $ 100.0   $ 100.0
Unsecured Debt | Total Notes and Debentures      
Debt Instruments [Abstract]      
Total notes and debentures 3,250.0   3,250.0
Line of Credit      
Debt Instruments [Abstract]      
Total revolving credit facility 0.0   25.0
Line of Credit | Boardwalk Pipelines Revolving Credit Facility      
Debt Instruments [Abstract]      
Total revolving credit facility $ 0.0   $ 25.0
v3.25.0.1
Financing - Long-Term Debt Maturities (Details) - Unsecured Debt
$ in Millions
Dec. 31, 2024
USD ($)
Debt Instrument [Line Items]  
2025 $ 0.0
2026 550.0
2027 600.0
2028 0.0
2029 500.0
Thereafter 1,600.0
Total long-term debt $ 3,250.0
v3.25.0.1
Financing - Debt Issuances (Details) - USD ($)
$ in Millions
 12 Months Ended
Feb. 29, 2024
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Debt Instrument [Line Items]        
Repayments of borrowings from long-term debt   $ 600.0 $ 0.0 $ 600.0
Unsecured Debt | Boardwalk Pipelines 5.625% Notes Due 2034        
Debt Instrument [Line Items]        
Amount of issuance $ 600.0      
Purchaser discounts and expenses 6.5      
Net proceeds $ 593.5      
Debt, interest rate 5.625% 5.625% 5.625%  
v3.25.0.1
Financing - Narrative (Details)
 12 Months Ended
Dec. 31, 2024
USD ($)
qtr
Dec. 31, 2023
USD ($)
Dec. 31, 2022
USD ($)
Feb. 07, 2025
USD ($)
Debt Instrument [Line Items]        
Cash dividends paid to parent company $ 400,000,000.0 $ 300,000,000.0 $ 102,200,000  
Unsecured Debt        
Debt Instrument [Line Items]        
Weighted-average interest rate 4.95% 4.84%    
Redemption price, percentage 100.00%      
Unsecured Debt | US Treasury Rate | Minimum        
Debt Instrument [Line Items]        
Basis spread on variable rate 0.20%      
Unsecured Debt | US Treasury Rate | Maximum        
Debt Instrument [Line Items]        
Basis spread on variable rate 0.50%      
Line of Credit        
Debt Instrument [Line Items]        
Weighted-average interest rate   6.71%    
Maximum ratio of debt to EBITDA 5.0      
Maximum ratio of debt to EBITDA, after acquisition 5.5      
Qualified acquisition purchase price target, over rolling 12-month period (exceeds) $ 100,000,000.0      
Qualified acquisition purchase price target, covenant, number of quarters following qualified acquisition quarter | qtr 3      
Line of credit, available borrowing capacity $ 1,000,000,000.0      
Line of credit, outstanding borrowings $ 0 $ 25,000,000    
Line of Credit | Subsequent Event        
Debt Instrument [Line Items]        
Line of credit, available borrowing capacity       $ 1,000,000,000
Line of credit, outstanding borrowings       $ 0
Line of Credit | Minimum        
Debt Instrument [Line Items]        
Commitment fee. percentage 0.10%      
Line of Credit | Maximum        
Debt Instrument [Line Items]        
Commitment fee. percentage 0.275%      
Line of Credit | Federal Funds Effective Swap Rate        
Debt Instrument [Line Items]        
Basis spread on variable rate 0.50%      
Line of Credit | SOFR Overnight Index Swap Rate        
Debt Instrument [Line Items]        
Basis spread on variable rate 1.00%      
Line of Credit | Amendment No. 4 Credit Agreement - 2022 | SOFR Overnight Index Swap Rate        
Debt Instrument [Line Items]        
Basis spread on variable rate 0.10%      
Line of Credit | Amendment No. 3 Credit Agreement - 2021        
Debt Instrument [Line Items]        
Borrowing capacity $ 1,000,000,000.0      
Line of Credit | Amendment No. 5 Credit Agreement - 2023        
Debt Instrument [Line Items]        
Borrowing capacity $ 912,200,000      
v3.25.0.1
Employee Benefits - Narrative (Details) - USD ($)
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]      
Defined contribution plan, cost $ 14,700,000 $ 14,000,000.0 $ 12,700,000
Pension      
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]      
Contribution to defined benefit pension plan 3,200,000 4,900,000  
Expected future contributions 3,000,000.0    
Minimum amount of recognized expense each year associated with retirement plan 3,000,000.0    
Future rate recovery amount $ 6,000,000    
Pension | Equity securities      
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]      
Target allocation percentage 85.00%    
Pension | Fixed income mutual funds      
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]      
Target allocation percentage 85.00%    
Pension | Minimum      
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]      
Required amount of funding of periodic pension cost $ 3,000,000.0    
Precluded future recovery of annual pension costs 3,000,000.0    
Recognition of regulatory assets (in excess of) 6,000,000    
Pension plan costs charged to expense 3,000,000.0    
Pension | Maximum      
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]      
Precluded future recovery of annual pension costs 6,000,000.0    
Reduction of regulatory assets (less than) 3,000,000    
Pension plan costs charged to expense 6,000,000.0    
SRP      
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]      
Contribution to defined benefit pension plan 0    
PBOP      
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]      
Contribution to defined benefit pension plan 200,000 $ 100,000  
Expected future contributions $ 0    
v3.25.0.1
Employee Benefits - Projected Benefit Obligation, Fair Value of Assets, Funded Status and the Amounts Not Yet Recognized As Components of Net Periodic Cost (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Retirement Plans      
Change in benefit obligation:      
Benefit obligation at beginning of period $ 88.0 $ 86.4  
Service cost 1.9 1.9 $ 2.2
Interest cost 4.0 4.1 3.1
Plan participants' contributions 0.0 0.0  
Actuarial (gain) loss (2.1) 4.0  
Benefits paid (0.5) (0.5)  
Settlements (8.2) (7.9)  
Benefit obligation at end of period 83.1 88.0 86.4
Change in plan assets:      
Fair value of plan assets at beginning of period 83.3 77.6  
Actual return on plan assets 6.6 9.2  
Company's contribution 3.2 4.9  
Plan participants' contributions 0.0 0.0  
Benefits paid (0.5) (0.5)  
Settlements (8.2) (7.9)  
Fair value of plan assets at end of period 84.4 83.3 77.6
Funded status 1.3 (4.7)  
Items not recognized as components of net periodic cost:      
Net actuarial loss 6.8 12.7  
PBOP      
Change in benefit obligation:      
Benefit obligation at beginning of period 23.4 23.7  
Service cost 0.0 0.0 0.0
Interest cost 1.1 1.2 0.8
Plan participants' contributions 1.0 1.0  
Actuarial (gain) loss (0.1) 2.3  
Benefits paid (4.1) (4.8)  
Settlements 0.0 0.0  
Benefit obligation at end of period 21.3 23.4 23.7
Change in plan assets:      
Fair value of plan assets at beginning of period 82.3 81.2  
Actual return on plan assets 3.1 4.8  
Company's contribution 0.2 0.1  
Plan participants' contributions 1.0 1.0  
Benefits paid (4.1) (4.8)  
Settlements 0.0 0.0  
Fair value of plan assets at end of period 82.5 82.3 $ 81.2
Funded status 61.2 58.9  
Items not recognized as components of net periodic cost:      
Net actuarial loss $ 2.5 $ 3.0  
v3.25.0.1
Employee Benefits - Aggregate Information Related Only to the Underfunded Plans (Details) - Retirement Plans
$ in Millions
Dec. 31, 2023
USD ($)
Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets [Abstract]  
Projected benefit obligation $ 88.0
Accumulated benefit obligation 84.6
Fair value of plan assets $ 83.3
v3.25.0.1
Employee Benefits - Components of Net Periodic Benefit Cost (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Retirement Plans      
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]      
Service cost $ 1.9 $ 1.9 $ 2.2
Interest cost 4.0 4.1 3.1
Expected return on plan assets (3.9) (3.6) (5.3)
Amortization of prior service cost 0.1 0.1 0.1
Amortization of unrecognized net loss 0.3 1.2 0.7
Settlement charge 0.7 1.3 2.9
Regulatory asset decrease 0.1 0.0 0.0
Net periodic benefit cost (credit) 3.2 5.0 3.7
PBOP      
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]      
Service cost 0.0 0.0 0.0
Interest cost 1.1 1.2 0.8
Expected return on plan assets (2.6) (2.4) (1.8)
Amortization of prior service cost 0.0 0.0 0.0
Amortization of unrecognized net loss 0.0 0.0 0.0
Settlement charge 0.0 0.0 0.0
Regulatory asset decrease 0.0 0.0 0.0
Net periodic benefit cost (credit) $ (1.5) $ (1.2) $ (1.0)
v3.25.0.1
Employee Benefits - Estimated Future Benefit Payments (Details)
$ in Millions
Dec. 31, 2024
USD ($)
Retirement Plans  
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]  
2025 $ 19.6
2026 11.4
2027 10.8
2028 8.3
2029 6.9
2030-2034 17.8
PBOP  
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]  
2025 2.0
2026 1.9
2027 1.8
2028 1.7
2029 1.6
2030-2034 $ 6.9
v3.25.0.1
Employee Benefits - Weighted-Average Assumptions Used to Determine Benefit Obligations (Details)
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Pension    
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]    
Discount rate 5.35% 4.90%
Expected return on plan assets 5.50% 5.00%
Pension | Minimum    
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]    
Rate of compensation increase 4.00% 3.00%
Pension | Maximum    
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]    
Rate of compensation increase 4.50% 3.50%
SRP    
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]    
Discount rate 5.25% 4.90%
Expected return on plan assets 5.50% 5.00%
SRP | Minimum    
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]    
Rate of compensation increase 4.00% 3.00%
SRP | Maximum    
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]    
Rate of compensation increase 4.50% 3.50%
PBOP    
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]    
Discount rate 5.60% 5.10%
Expected return on plan assets 3.37% 3.25%
Rate of compensation increase 0.00% 0.00%
v3.25.0.1
Employee Benefits - Weighted-Average Assumptions Used to Determine Net Periodic Benefit Cost (Details)
 3 Months Ended 12 Months Ended
Dec. 31, 2022
Jun. 30, 2022
Dec. 31, 2024
Sep. 30, 2024
Jun. 30, 2024
Mar. 31, 2024
Dec. 31, 2023
Sep. 30, 2023
Jun. 30, 2023
Mar. 31, 2023
Dec. 31, 2022
Sep. 30, 2022
Jun. 30, 2022
Mar. 31, 2022
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Pension                                  
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]                                  
Discount rate     5.35% 4.80% 5.40% 5.25% 4.90% 5.45% 5.15% 5.35% 5.30% 4.65% 4.10% 3.00%      
Expected return on plan assets                             5.00% 5.00% 6.25%
Rate of compensation increase                                 3.00%
Pension | Minimum                                  
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]                                  
Rate of compensation increase                             3.00% 3.00%  
Pension | Maximum                                  
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]                                  
Rate of compensation increase                             3.50% 4.50%  
SRP                                  
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]                                  
Discount rate 5.30% 4.15%                         5.25% 4.90%  
Expected return on plan assets                             5.00% 5.00% 6.25%
Rate of compensation increase                                 3.00%
SRP | Minimum                                  
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]                                  
Rate of compensation increase                             3.00% 3.00%  
SRP | Maximum                                  
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]                                  
Rate of compensation increase                             3.50% 4.50%  
PBOP                                  
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]                                  
Discount rate                             5.10% 5.40% 2.90%
Expected return on plan assets                             3.25% 2.99% 2.01%
Rate of compensation increase                             0.00% 0.00% 0.00%
v3.25.0.1
Employee Benefits - Master Trust Pension Fair Value Hierarchy (Details) - Fair Value, Measurements, Recurring - Pension Plan - USD ($)
$ in Millions
Dec. 31, 2024
Dec. 31, 2023
Defined Contribution Plan Disclosure [Line Items]    
Total assets $ 84.4 $ 83.3
Equity securities    
Defined Contribution Plan Disclosure [Line Items]    
Total assets 35.9 34.6
Short-term investments    
Defined Contribution Plan Disclosure [Line Items]    
Total assets 8.4 17.3
Fixed income mutual funds    
Defined Contribution Plan Disclosure [Line Items]    
Total assets 40.1 26.3
Tax-exempt securities    
Defined Contribution Plan Disclosure [Line Items]    
Total assets   5.1
Level 1    
Defined Contribution Plan Disclosure [Line Items]    
Total assets 84.4 78.2
Level 1 | Equity securities    
Defined Contribution Plan Disclosure [Line Items]    
Total assets 35.9 34.6
Level 1 | Short-term investments    
Defined Contribution Plan Disclosure [Line Items]    
Total assets 8.4 17.3
Level 1 | Fixed income mutual funds    
Defined Contribution Plan Disclosure [Line Items]    
Total assets 40.1 26.3
Level 1 | Tax-exempt securities    
Defined Contribution Plan Disclosure [Line Items]    
Total assets   0.0
Level 2    
Defined Contribution Plan Disclosure [Line Items]    
Total assets 0.0 5.1
Level 2 | Equity securities    
Defined Contribution Plan Disclosure [Line Items]    
Total assets 0.0 0.0
Level 2 | Short-term investments    
Defined Contribution Plan Disclosure [Line Items]    
Total assets 0.0 0.0
Level 2 | Fixed income mutual funds    
Defined Contribution Plan Disclosure [Line Items]    
Total assets 0.0 0.0
Level 2 | Tax-exempt securities    
Defined Contribution Plan Disclosure [Line Items]    
Total assets   5.1
Level 3    
Defined Contribution Plan Disclosure [Line Items]    
Total assets 0.0 0.0
Level 3 | Equity securities    
Defined Contribution Plan Disclosure [Line Items]    
Total assets 0.0 0.0
Level 3 | Short-term investments    
Defined Contribution Plan Disclosure [Line Items]    
Total assets 0.0 0.0
Level 3 | Fixed income mutual funds    
Defined Contribution Plan Disclosure [Line Items]    
Total assets $ 0.0 0.0
Level 3 | Tax-exempt securities    
Defined Contribution Plan Disclosure [Line Items]    
Total assets   $ 0.0
v3.25.0.1
Employee Benefits - Master Trust PBOP Fair Value Hierarchy (Details) - PBOP - USD ($)
$ in Millions
Dec. 31, 2024
Dec. 31, 2023
Other liabilities    
Defined Contribution Plan Disclosure [Line Items]    
Total liabilities $ (18.0) $ (39.3)
Short-term investments    
Defined Contribution Plan Disclosure [Line Items]    
Total assets 1.6 12.8
Other assets    
Defined Contribution Plan Disclosure [Line Items]    
Total assets 15.7 2.1
Asset-backed securities    
Defined Contribution Plan Disclosure [Line Items]    
Total assets 0.5 0.8
Corporate bonds    
Defined Contribution Plan Disclosure [Line Items]    
Total assets 47.8 67.0
Tax-exempt securities    
Defined Contribution Plan Disclosure [Line Items]    
Total assets 34.9 38.9
Total assets    
Defined Contribution Plan Disclosure [Line Items]    
Total assets 100.5 121.6
Level 1 | Other liabilities    
Defined Contribution Plan Disclosure [Line Items]    
Total liabilities (18.0) (39.3)
Level 2 | Other liabilities    
Defined Contribution Plan Disclosure [Line Items]    
Total liabilities 0.0 0.0
Level 3 | Other liabilities    
Defined Contribution Plan Disclosure [Line Items]    
Total liabilities 0.0 0.0
Fair Value, Measurements, Recurring | Level 1 | Short-term investments    
Defined Contribution Plan Disclosure [Line Items]    
Total assets 1.6 12.8
Fair Value, Measurements, Recurring | Level 1 | Other assets    
Defined Contribution Plan Disclosure [Line Items]    
Total assets 15.7 2.1
Fair Value, Measurements, Recurring | Level 1 | Asset-backed securities    
Defined Contribution Plan Disclosure [Line Items]    
Total assets 0.0 0.0
Fair Value, Measurements, Recurring | Level 1 | Corporate bonds    
Defined Contribution Plan Disclosure [Line Items]    
Total assets 0.0 0.0
Fair Value, Measurements, Recurring | Level 1 | Tax-exempt securities    
Defined Contribution Plan Disclosure [Line Items]    
Total assets 0.0 0.0
Fair Value, Measurements, Recurring | Level 1 | Total assets    
Defined Contribution Plan Disclosure [Line Items]    
Total assets 17.3 14.9
Fair Value, Measurements, Recurring | Level 2 | Short-term investments    
Defined Contribution Plan Disclosure [Line Items]    
Total assets 0.0 0.0
Fair Value, Measurements, Recurring | Level 2 | Other assets    
Defined Contribution Plan Disclosure [Line Items]    
Total assets 0.0 0.0
Fair Value, Measurements, Recurring | Level 2 | Asset-backed securities    
Defined Contribution Plan Disclosure [Line Items]    
Total assets 0.5 0.8
Fair Value, Measurements, Recurring | Level 2 | Corporate bonds    
Defined Contribution Plan Disclosure [Line Items]    
Total assets 47.8 67.0
Fair Value, Measurements, Recurring | Level 2 | Tax-exempt securities    
Defined Contribution Plan Disclosure [Line Items]    
Total assets 34.9 38.9
Fair Value, Measurements, Recurring | Level 2 | Total assets    
Defined Contribution Plan Disclosure [Line Items]    
Total assets 83.2 106.7
Fair Value, Measurements, Recurring | Level 3 | Short-term investments    
Defined Contribution Plan Disclosure [Line Items]    
Total assets 0.0 0.0
Fair Value, Measurements, Recurring | Level 3 | Other assets    
Defined Contribution Plan Disclosure [Line Items]    
Total assets 0.0 0.0
Fair Value, Measurements, Recurring | Level 3 | Asset-backed securities    
Defined Contribution Plan Disclosure [Line Items]    
Total assets 0.0 0.0
Fair Value, Measurements, Recurring | Level 3 | Corporate bonds    
Defined Contribution Plan Disclosure [Line Items]    
Total assets 0.0 0.0
Fair Value, Measurements, Recurring | Level 3 | Tax-exempt securities    
Defined Contribution Plan Disclosure [Line Items]    
Total assets 0.0 0.0
Fair Value, Measurements, Recurring | Level 3 | Total assets    
Defined Contribution Plan Disclosure [Line Items]    
Total assets $ 0.0 $ 0.0
v3.25.0.1
Employee Benefits - Long-Term Incentive Compensation Plans (Details) - Performance Awards - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]      
Granted amount $ 17.2 $ 16.3  
Compensation expense 17.1 14.2 $ 12.3
Unrecognized compensation expense $ 10.5 $ 9.8  
v3.25.0.1
Income Taxes - Provision for Income Taxes (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Current expense:      
State $ 0.8 $ 0.8 $ 0.8
Deferred provision:      
State 0.3 0.0 0.0
Income taxes $ 1.1 $ 0.8 $ 0.8
v3.25.0.1
Income Taxes - Narrative (Details) - USD ($)
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Income Tax Disclosure [Abstract]    
Open tax year 2021 2022 2023 2024  
Significant deferred tax assets or liabilities $ 0 $ 0
v3.25.0.1
Credit Risk (Details)
pounds in Millions, MMBTU in Millions, $ in Millions
Dec. 31, 2024
USD ($)
$ / MMBTU
MMBTU
MMBbls
pounds
Dec. 31, 2023
USD ($)
$ / MMBTU
MMBTU
MMBbls
pounds
Risks and Uncertainties [Abstract]    
Gas balancing measurement (in TBtu) | MMBTU 9.8 11.2
Average market price of gas assumed (in dollars per MMBTU) | $ / MMBTU 2.98 2.33
Gas imbalance to subsidiaries asset liability $ 29.2 $ 26.1
Natural gas liquids balancing volume (in MMBbls) (less than) | MMBbls 100,000 0
Natural gas liquids imbalance to subsidiaries asset liability $ 0.3  
Ethylene loaned volume | pounds 0.0 0.0
v3.25.0.1
Related Party Transactions (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Related Party Transaction [Line Items]      
Administrative and general $ 186.1 $ 171.9 $ 147.7
Cash dividends paid to parent company 400.0 300.0 102.2
Parent Company      
Related Party Transaction [Line Items]      
Cash dividends paid to parent company 400.0 300.0 102.2
Affiliates      
Related Party Transaction [Line Items]      
Administrative and general $ 5.4 $ 4.3 $ 3.7
v3.25.0.1
Supplemental Disclosure of Cash Flow Information (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Cash paid during the period for:      
Amounts included in the measurement of operating lease liabilities $ 4.2 $ 4.9 $ 3.7
Amounts included in the measurement of finance lease liability 1.1 1.1 1.1
Interest (net of amount capitalized) 162.1 147.3 156.3
Income taxes, net 0.8 0.7 0.6
Non-cash investing activities:      
Accounts payable and PPE 30.4 47.7 44.4
Right-of-use asset obtained in exchange for lease obligations 9.9 3.4 0.2
Gas stored underground and PPE $ 0.0 $ 47.8 $ 0.0
v3.25.0.1
Reportable Segments (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Segment Reporting Information [Line Items]      
Operating revenues $ 2,028.1 $ 1,617.7 $ 1,432.0
Costs associated with service revenues 29.1 26.3 22.4
Costs associated with product sales 303.5 87.8 1.0
Operation and maintenance 310.3 281.0 250.9
Administrative and general 186.1 171.9 147.7
Taxes other than income taxes 122.1 115.5 114.5
(Gain) loss on sale of assets, impairments and other (5.5) 0.3 4.0
Miscellaneous other income, net 6.1 4.1 6.4
Segment EBITDA 1,088.6 939.0 897.9
Depreciation and amortization 424.8 408.7 392.3
Interest expense 182.9 155.6 165.9
Interest income (31.1) (12.1) (3.3)
Consolidated income before income taxes 512.0 386.8 343.0
Capital expenditures 392.4 382.4 344.3
Operating Segments      
Segment Reporting Information [Line Items]      
Revenue from external customers 2,028.1 1,617.7 1,432.0
Intrasegment revenues (49.4) (30.0) (24.9)
Operating revenues 2,077.5 1,647.7 1,456.9
Intrasegment Eliminations      
Segment Reporting Information [Line Items]      
Intrasegment revenues (49.4) (30.0) (24.9)
Operating revenues (49.4) (30.0) (24.9)
Natural Gas Reportable Segment      
Segment Reporting Information [Line Items]      
Revenue from external customers 1,392.7 1,284.7 1,205.8
Natural Gas Reportable Segment | Operating Segments      
Segment Reporting Information [Line Items]      
Intrasegment revenues (49.4) (30.0) (24.9)
Operating revenues 1,442.1 1,314.7 1,230.7
Costs associated with service revenues 41.1 37.1 37.1
Costs associated with product sales 0.0 0.0 0.0
Operation and maintenance 253.1 229.1 208.6
Administrative and general 176.9 151.7 129.0
Taxes other than income taxes 109.0 106.1 106.1
(Gain) loss on sale of assets, impairments and other (6.6) 0.3 4.0
Miscellaneous other income, net (6.1) (4.0) (6.3)
Segment EBITDA 874.7 794.4 752.2
Capital expenditures 340.6 321.5 291.3
Natural Gas Liquids Reportable Segment      
Segment Reporting Information [Line Items]      
Revenue from external customers 635.4 333.0 226.2
Natural Gas Liquids Reportable Segment | Operating Segments      
Segment Reporting Information [Line Items]      
Operating revenues 635.4 333.0 226.2
Costs associated with service revenues 19.0 15.3 10.2
Costs associated with product sales 303.5 87.8 1.0
Operation and maintenance 57.2 51.9 42.3
Administrative and general 27.6 24.1 18.7
Taxes other than income taxes 13.1 9.4 8.4
(Gain) loss on sale of assets, impairments and other 1.1 0.0 0.0
Miscellaneous other income, net 0.0 (0.1) (0.1)
Segment EBITDA 213.9 144.6 145.7
Capital expenditures $ 51.8 $ 60.9 $ 53.0
v3.25.0.1
Reportable Segments Assets Reconciliation (Details) - USD ($)
$ in Millions
Dec. 31, 2024
Dec. 31, 2023
Segment Reporting, Asset Reconciling Item [Line Items]    
Total Segment Assets $ 9,779.4 $ 9,696.4
Total current assets 401.1 288.7
Total Assets 9,779.4 9,696.4
Operating Segments    
Segment Reporting, Asset Reconciling Item [Line Items]    
Total Segment Assets 9,118.8 9,166.0
Total Assets 9,118.8 9,166.0
Operating Segments | Natural Gas Reportable Segment    
Segment Reporting, Asset Reconciling Item [Line Items]    
Total Segment Assets 7,490.1 7,515.2
Total Assets 7,490.1 7,515.2
Operating Segments | Natural Gas Liquids Reportable Segment    
Segment Reporting, Asset Reconciling Item [Line Items]    
Total Segment Assets 1,628.7 1,650.8
Total Assets 1,628.7 1,650.8
Segment Reporting, Reconciling Item, Excluding Corporate Nonsegment    
Segment Reporting, Asset Reconciling Item [Line Items]    
Total current assets 401.1 288.7
Gas stored underground and Other assets $ 259.5 $ 241.7