SunCoke Energy (SXC) 10-K 22 Feb 24 2023 FY Annual report Financial data

Cover

Cover - USD ($)	12 Months Ended
	Dec. 31, 2023	Feb. 16, 2024	Jun. 30, 2023
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2023
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	001-35243
Entity Registrant Name	SUNCOKE ENERGY, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	90-0640593
Entity Address, Address Line One	1011 Warrenville Road
Entity Address, Address Line Two	Suite 600
Entity Address, City or Town	Lisle
Entity Address, State or Province	IL
Entity Address, Postal Zip Code	60532
City Area Code	630
Local Phone Number	824-1000
Title of 12(b) Security	Common Stock, $0.01 par value
Trading Symbol	SXC
Security Exchange Name	NYSE
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Document Financial Statement Error Correction	false
Entity Shell Company	false
Entity Public Float			$ 650,437,061
Entity Common Stock, Shares Outstanding (in shares)		83,776,463
Documents Incorporated by Reference	Portions of the SunCoke Energy, Inc. 2024 definitive Proxy Statement, which will be filed with the Securities and Exchange Commission within 120 days after December 31, 2023, are incorporated by reference into Part III of this Annual Report on Form 10-K.
Entity Central Index Key	0001514705
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	FY
Amendment Flag	false

Audit Information

Audit Information	12 Months Ended
	Dec. 31, 2023
Audit Information [Abstract]
Auditor Name	KPMG LLP
Auditor Location	Chicago, Illinois
Auditor Firm ID	185

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Revenues
Sales and other operating revenue	$ 2,063.2	$ 1,972.5	$ 1,456
Costs and operating expenses
Cost of products sold and operating expenses	1,724.6	1,604.9	1,118.8
Selling, general and administrative expenses	70.7	71.4	61.8
Depreciation and amortization expense	142.8	142.5	133.9
Total costs and operating expenses	1,938.1	1,818.8	1,314.5
Operating income	125.1	153.7	141.5
Interest expense, net	27.3	32	42.5
Loss on extinguishment of debt	0	0	31.9
Income before income tax expense	97.8	121.7	67.1
Income tax expense	34.3	16.8	18.3
Net income	63.5	104.9	48.8
Less: Net income attributable to noncontrolling interests	6	4.2	5.4
Net income attributable to SunCoke Energy, Inc.	$ 57.5	$ 100.7	$ 43.4
Earnings Per Share [Abstract]
Basic (in dollars per share)	$ 0.68	$ 1.20	$ 0.52
Diluted (in dollars per share)	$ 0.68	$ 1.19	$ 0.52
Weighted average number of common shares outstanding:
Basic (in shares)	84.7	83.8	83
Diluted (in shares)	84.9	84.6	83.7

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Statement of Comprehensive Income [Abstract]
Net income	$ 63.5	$ 104.9	$ 48.8
Other comprehensive income (loss):
Reclassifications of actuarial loss amortization and prior service benefit to earnings (net of related tax benefit of $0.1 million for all years)	0.1	0.4	0.3
Retirement benefit plans funded status adjustment (net of related tax benefit (expense) of $0.2 million, $(0.9) million and $(0.3) million, respectively)	(0.4)	3.1	1
Currency translation adjustment	0.5	0.2	(0.9)
Comprehensive income	63.7	108.6	49.2
Less: Comprehensive income attributable to noncontrolling interests	6	4.2	5.4
Comprehensive income attributable to SunCoke Energy, Inc.	$ 57.7	$ 104.4	$ 43.8

Consolidated Statements of Co_2

Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Statement of Comprehensive Income [Abstract]
Reclassifications of actuarial loss amortization and prior service benefit to earnings	$ 0.1	$ 0.1	$ 0.1
Retirement (expense) benefit plans funded status adjustment, tax	$ 0.2	$ (0.9)	$ (0.3)

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Assets
Cash and cash equivalents	$ 140.1	$ 90
Receivables, net	88.3	104.8
Inventories	182.6	175.2
Income tax receivable	1.4	0
Other current assets	4.4	4
Total current assets	416.8	374
Properties, plants and equipment (net of accumulated depreciation of $1,383.6 and $1,276.0 at December 31, 2023 and 2022, respectively)	1,191.1	1,229.3
Intangible assets, net	31.1	33.2
Deferred charges and other assets	21.4	18.1
Total assets	1,660.4	1,654.6
Liabilities and Equity
Accounts payable	172.1	159.3
Accrued liabilities	51.7	61.4
Current portion of financing obligation	0	3.3
Total current liabilities	223.8	224
Long-term debt and financing obligation	490.3	528.9
Accrual for black lung benefits	53.2	52.2
Retirement benefit liabilities	15.8	16.4
Deferred income taxes	190.4	172.3
Asset retirement obligations	14.1	13.4
Other deferred credits and liabilities	27.3	24.7
Total liabilities	1,014.9	1,031.9
Equity
Preferred stock, $0.01 par value. Authorized 50,000,000 shares; no issued shares at both December 31, 2023 and 2022	0	0
Common stock, $0.01 par value. Authorized 300,000,000 shares; issued 99,161,446 and 98,815,780 shares at December 31, 2023 and 2022, respectively	1	1
Treasury stock, 15,404,482 shares at both December 31, 2023 and 2022	(184)	(184)
Additional paid-in capital	729.8	728.1
Accumulated other comprehensive loss	(12.8)	(13)
Retained earnings	80.2	53.5
Total SunCoke Energy, Inc. stockholders' equity	614.2	585.6
Noncontrolling interests	31.3	37.1
Total equity	645.5	622.7
Total liabilities and equity	$ 1,660.4	$ 1,654.6

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Statement of Financial Position [Abstract]
Accumulated depreciation	$ 1,383.6	$ 1,276
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	50,000,000	50,000,000
Preferred stock, shares issued (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	300,000,000	300,000,000
Common stock, shares, issued (in shares)	99,161,446	98,815,780
Treasury stock, shares (in shares)	15,404,482	15,404,482

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Cash Flows from Operating Activities:
Net income	$ 63.5	$ 104.9	$ 48.8
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization expense	142.8	142.5	133.9
Deferred income tax expense	18.6	2.3	9.3
Share-based compensation expense	5.1	6.7	6.1
Loss on extinguishment of debt	0	0	31.9
Changes in working capital pertaining to operating activities:
Receivables, net	16.8	(32.3)	(31.3)
Inventories	(7.2)	(48.2)	(1.1)
Accounts payable	19.7	27.4	29.5
Accrued liabilities	(10.2)	8.4	0.8
Income taxes	(1.4)	0	5.5
Other	1.3	(2.8)	(0.3)
Net cash provided by operating activities	249	208.9	233.1
Cash Flows from Investing Activities:
Capital expenditures	(109.2)	(75.5)	(98.6)
Other investing activities	0	5.3	(0.7)
Net cash used in investing activities	(109.2)	(70.2)	(99.3)
Cash Flows from Financing Activities:
Proceeds from issuance of long-term debt	0	0	500
Repayment of long-term debt	0	0	(609.3)
Proceeds from revolving facility	291	596	690.1
Repayment of revolving facility	(326)	(676)	(663.4)
Repayment of financing obligation	(8.8)	(3.2)	(2.9)
Debt issuance costs	0	0	(12)
Dividends paid	(30.7)	(23.6)	(20.1)
Cash distributions to noncontrolling interests	(11.8)	(4.4)	0
Other financing activities	(3.4)	(1.3)	(0.8)
Net cash used in financing activities	(89.7)	(112.5)	(118.4)
Net increase in cash and cash equivalents	50.1	26.2	15.4
Cash and cash equivalents at beginning of year	90	63.8	48.4
Cash and cash equivalents at end of year	140.1	90	63.8
Supplemental Disclosure of Cash Flow Information
Interest paid, net of capitalized interest of zero, zero and $0.5 million, respectively	25.7	28.5	40
Income taxes paid, net of refunds of zero, $0.5 million and $2.9 million, respectively	$ 17.7	$ 14.5	$ 2.9

Consolidated Statements of Ca_2

Consolidated Statements of Cash Flows (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Statement of Cash Flows [Abstract]
Capitalized interest	$ 0	$ 0	$ 0.5
Tax refunds	$ 0	$ 0.5	$ 2.9

Consolidated Statements of Equi

Consolidated Statements of Equity - USD ($) $ in Millions	Total	Total SunCoke Energy, Inc. Equity	Common Stock	Treasury Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Loss	Retained (Deficit) Earnings	Non- controlling Interests
Common stock, beginning balance (in shares) at Dec. 31, 2020			98,177,941
Beginning balance at Dec. 31, 2020	$ 500.9	$ 469	$ 1	$ (184)	$ 715.7	$ (17.1)	$ (46.6)	$ 31.9
Treasury stock, beginning balance (in shares) at Dec. 31, 2020				15,404,482
Stockholders' Equity
Net income	48.8	43.4					43.4	5.4
Reclassification of prior service benefit and actuarial loss amortization to earnings	0.3	0.3				0.3
Retirement benefit plans funded status adjustment	1	1				1
Currency translation adjustment	(0.9)	(0.9)				(0.9)
Share-based compensation	6.1	6.1			6.1
Share-issuances, net of shares withheld for taxes, (in shares)			318,868
Share issuances, net of shares withheld for taxes	(0.6)	(0.6)			(0.6)
Dividends	(20.2)	(20.2)					(20.2)
Common stock, ending balance (in shares) at Dec. 31, 2021			98,496,809
Ending balance at Dec. 31, 2021	535.4	498.1	$ 1	$ (184)	721.2	(16.7)	(23.4)	37.3
Treasury stock, ending balance (in shares) at Dec. 31, 2021				15,404,482
Stockholders' Equity
Net income	104.9	100.7					100.7	4.2
Reclassification of prior service benefit and actuarial loss amortization to earnings	0.4	0.4				0.4
Retirement benefit plans funded status adjustment	3.1	3.1				3.1
Currency translation adjustment	0.2	0.2				0.2
Share-based compensation	8.1	8.1			8.1
Share-issuances, net of shares withheld for taxes, (in shares)			318,971
Share issuances, net of shares withheld for taxes	(1.2)	(1.2)			(1.2)
Dividends	(23.8)	(23.8)					(23.8)
Cash distribution to noncontrolling interests	(4.4)							(4.4)
Common stock, ending balance (in shares) at Dec. 31, 2022			98,815,780
Ending balance at Dec. 31, 2022	$ 622.7	585.6	$ 1	$ (184)	728.1	(13)	53.5	37.1
Treasury stock, ending balance (in shares) at Dec. 31, 2022	15,404,482			15,404,482
Stockholders' Equity
Net income	$ 63.5	57.5					57.5	6
Reclassification of prior service benefit and actuarial loss amortization to earnings	0.1	0.1				0.1
Retirement benefit plans funded status adjustment	(0.4)	(0.4)				(0.4)
Currency translation adjustment	0.5	0.5				0.5
Share-based compensation	5.1	5.1			5.1
Share-issuances, net of shares withheld for taxes, (in shares)			345,666
Share issuances, net of shares withheld for taxes	(3.4)	(3.4)			(3.4)
Dividends	(30.8)	(30.8)					(30.8)
Cash distribution to noncontrolling interests	(11.8)							(11.8)
Common stock, ending balance (in shares) at Dec. 31, 2023			99,161,446
Ending balance at Dec. 31, 2023	$ 645.5	$ 614.2	$ 1	$ (184)	$ 729.8	$ (12.8)	$ 80.2	$ 31.3
Treasury stock, ending balance (in shares) at Dec. 31, 2023	15,404,482			15,404,482

Consolidated Statements of Eq_2

Consolidated Statements of Equity (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Statement of Stockholders' Equity [Abstract]
Reclassification of prior service benefit and actuarial loss amortization to earnings, tax benefit	$ 0.1	$ 0.1	$ 0.1
Retirement (expense) benefit plans funded status adjustment, tax	$ (0.2)	$ 0.9	$ 0.3

General and Basis of Presentati

General and Basis of Presentation	12 Months Ended
	Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
General and Basis of Presentation	1. General and Basis of Presentation Description of Business SunCoke Energy, Inc. (“SunCoke Energy,” “SunCoke,” “Company,” “we,” “our” and “us”) is the largest independent producer of high-quality coke in the Americas, as measured by tons of coke produced each year, and has more than 60 years of coke production experience. Coke is produced by heating metallurgical coal in a refractory oven, which releases certain volatile components from the coal, thus transforming the coal into coke. Our coke is primarily used as a principal raw material in the blast furnace steelmaking process as well as in the foundry production of casted iron, and the majority of our sales are derived from blast furnace coke sales made under long-term, take-or-pay agreements. We also sell coke produced utilizing capacity in excess of that reserved for our long-term, take-or-pay agreements to customers in both the export and North American domestic coke markets seeking high-quality product for their blast furnaces. We have designed, developed and built, and we currently own and operate five cokemaking facilities in the United States (“U.S.”) with collective nameplate capacity to produce approximately 4.2 million tons of blast furnace coke per year. Additionally, we designed and currently operate one cokemaking facility in Brazil under licensing and operating agreements on behalf of ArcelorMittal Brasil S.A. (“ArcelorMittal Brazil”), which has approximately 1.7 million tons of annual cokemaking capacity. We also own and operate a logistics business that provides export and domestic material handling and/or mixing services to steel, coke (including some of our domestic cokemaking facilities), electric utility, coal producing and other manufacturing based customers. Our logistics terminals, which are strategically located to reach Gulf Coast, East Coast, Great Lakes and international ports, have the collective capacity to mix and/or transload more than 40 million tons of coal and other aggregates annually and has storage capacity of approximately 3 million tons. Consolidation and Basis of Presentation

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Actual amounts could differ from these estimates. Revenue Recognition The Company sells coke as well as steam and electricity and also provides mixing and/or handling services of coal and other aggregates. The Company also receives fees for operating the cokemaking plant in Brazil and for the licensing of its proprietary technology for use at this facility as well as reimbursement of substantially all of its operating costs. See Note 18. Cash Equivalents The Company considers all highly liquid investments with a remaining maturity of three months or less at the time of purchase to be cash equivalents. These cash equivalents consist principally of money market funds. Inventories Inventories are valued at the lower of cost or net realizable value. Cost is determined using the first-in, first-out method, except for the Company’s materials and supplies inventory, which are determined using the average-cost method. The Company primarily utilizes the contracted sales prices under its coke sales contracts to record lower of cost or net realizable value inventory adjustments. See Note 5. Properties, Plants and Equipment Plants and equipment are depreciated on a straight-line basis over their estimated useful lives. Coke and energy plant, machinery and equipment are generally depreciated over 20 to 30 years. Logistics plant, machinery and equipment are generally depreciated over 15 to 30 years. Depreciation and amortization is excluded from cost of products sold and operating expenses and is presented separately on the Consolidated Statements of Income. Gains and losses on the disposal or retirement of fixed assets are reflected in earnings when the assets are sold or retired. Amounts incurred that extend an asset’s useful life, increase its productivity or add production capacity are capitalized. Additionally, the Company generally capitalizes interest on capital projects with an expected construction period of one year or longer. The Company accounts for changes in useful lives, when appropriate, as a change in estimate, with prospective application only. Direct costs, such as outside labor, materials, internal payroll and benefits costs incurred during capital projects are capitalized; indirect costs are not capitalized. Normal repairs and maintenance costs are expensed as incurred. The amounts of accrued capital expenditures for the years ended December 31, 2023, 2022 and 2021 were $8.7 million, $15.6 million and $9.6 million, respectively. See Note 6 and the Consolidated Statements of Cash Flows. Intangible Assets Intangible assets are primarily comprised of permits. Intangible assets are amortized over their useful lives in a manner that reflects the pattern in which the economic benefit of the intangible asset is consumed. Intangible assets are assessed for impairment when a triggering event occurs. See Note 7. Impairment of Long-Lived Assets Long-lived assets, which includes intangible assets and properties, plants and equipment, are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of the assets may not be recoverable. A long-lived asset, or group of assets, is considered to be impaired when the undiscounted net cash flows expected to be generated by the asset are less than its carrying amount. Such estimated future cash flows are highly subjective and are based on numerous assumptions about future operations and market conditions. The impairment recognized is the amount by which the carrying amount exceeds the fair market value of the impaired asset, or group of assets. It is also difficult to precisely estimate fair market value because quoted market prices for our long-lived assets may not be readily available. Therefore, fair market value is generally based on the present values of estimated future cash flows using discount rates commensurate with the risks associated with the assets being reviewed for impairment. See Note 7. Income Taxes Income tax expense (benefit) is determined by applying the provisions of federal and state tax laws to taxable income (loss) during the period. We do business in a number of states with differing laws concerning how income subject to each state's tax structure is measured. These laws, as well as changes in tax legislation, impact what effective tax rate is applied to income generated in each state, and the Company makes estimates of how income will be apportioned among various states based on these factors. Deferred tax asset and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those differences are projected to be recovered or settled. The Company records a valuation allowance against net deferred tax assets if, based upon the available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized. The Company recognizes uncertain tax positions in its financial statements when minimum recognition threshold and measurement attributes are met in accordance with current accounting guidance. See Note 4. Black Lung Benefit Liabilities The Company has obligations related to coal workers’ pneumoconiosis, or black lung, benefits of certain of our former coal miners and their dependents. We adjust our liability each year based upon actuarial calculations of our expected future payments for these benefits, including a provision for incurred but not reported losses. Adjustments are recognized in the period the adjustment occurs as a component of selling, general and administrative expense on the Consolidated Statements of Income. See Note 12. Postretirement Benefit Plan Liabilities The postretirement benefit plans, which are frozen, are unfunded and the accumulated postretirement benefit obligation is fully recognized on the Consolidated Balance Sheets. Actuarial gains (losses) and prior service costs (benefits) which have not yet been recognized in net income are recognized as a credit (charge) to accumulated other comprehensive income (loss). The credit (charge) to accumulated other comprehensive income (loss), which is reflected net of related tax effects, is subsequently recognized in net income when amortized as a component of postretirement benefit plans expense included in interest expense, net on the Consolidated Statements of Income. See Note 9. Asset Retirement Obligations The fair value of a liability for an asset retirement obligation is recognized in the period in which it is incurred if a reasonable estimate of fair value can be made. The associated asset retirement costs are capitalized as part of the carrying amount of the asset and depreciated over its remaining estimated useful life. When the assumptions used to estimate a recorded asset retirement obligation change, a revision is recorded to both the asset retirement obligation and the asset retirement cost capitalized to the extent remaining useful life exists. The Company’s asset retirement obligations primarily relate to costs associated with restoring land to its original state. See Note 8. Leases We determine if an arrangement contains a lease at inception. We recognize right-of-use assets and lease liabilities associated with leases based on the present value of the future minimum lease payments over the lease term at the commencement date. Our leases do not provide an implicit rate of return, therefore, we use our incremental borrowing rate at the inception of the lease to calculate the present value of lease payments. Our incremental borrowing rate is determined through market sources for secured borrowings and approximates the interest rate at which we could borrow on a collateralized basis with similar terms and payments in similar economic environments. Lease terms reflect options to extend or terminate the lease when it is reasonably certain that the option will be exercised. The Company has elected to apply the short-term lease exception for all asset classes, therefore, excluding all leases with a term of less than 12 months from the balance sheet, and will recognize the lease payments in the period they are incurred. Additionally, the Company accounts for lease and non-lease components of an arrangement, such as assets and services, as a single lease component for all asset classes on existing leases. See Note 13. Shipping and Handling Costs Shipping and handling costs are included in cost of products sold and operating expenses on the Consolidated Statements of Income and are generally passed through to our customers. The Company has elected the practical expedient under Accounting Standards Codification (“ASC”) 606, “Revenue from Contracts with Customers,” to account for shipping and handling activities as a promise to fulfill the transfer of coke. See Note 18. Share-Based Compensation We measure the cost of employee services in exchange for equity instrument awards and cash awards based on the grant-date fair value of the award. Cash awards and the performance metrics of equity awards are remeasured on a quarterly basis. The market metrics of equity awards are not remeasured. The total cost is recognized over the requisite service period. Award forfeitures are accounted for as they occur. The costs of equity awards and cash awards are recorded to additional paid-in capital and accrued liabilities, respectively, on the Consolidated Balance Sheets. See Note 15. Fair Value Measurements The Company determines fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. As required, the Company utilizes valuation techniques that maximize the use of observable inputs (levels 1 and 2) and minimize the use of unobservable inputs (level 3) within the fair value hierarchy included in current accounting guidance. Assets and liabilities are classified within the fair value hierarchy based on the lowest level (least observable) input that is significant to the measurement in its entirety. See Note 17. Currency Translation The functional currency of the Company’s Brazilian operations is the Brazilian real. The Company’s Brazil operations translate its assets and liabilities into U.S. dollars at the current exchange rates in effect at the end of the fiscal period. The gains or losses that result from this process are shown as cumulative translation adjustments within accumulated other comprehensive loss in the Consolidated Balance Sheets. The revenue and expense accounts of foreign operations are translated into U.S. dollars at the average exchange rates during the period. Recent Accounting Pronouncements In November 2023, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2023-07, “Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures.” ASU 2023-07 requires disclosure of incremental segment information on an interim and annual basis. This ASU is effective for fiscal years, beginning after December 15, 2023 as well as interim periods beginning after December 31, 2024 and requires retrospective application to all prior periods presented in the financial statements. The Company is currently evaluating the impact of the guidance on the related disclosures. The Company plans to adopt the guidance for the fiscal year ending December 31, 2024. In December 2023, the FASB issued ASU 2023-09, “Income Taxes (Topic 740): Improvement to Income Tax Disclosures.” ASU 2023-09 requires additional disclosures aimed at enhancing the transparency and decision usefulness of income tax disclosures. This ASU is effective for fiscal years beginning after December 15, 2024 on a prospective basis. The Company does not expect this ASU to have a material impact on the Company's disclosures. The Company plans to adopt the guidance for the fiscal year ending December 31, 2025. Labor Concentrations As of December 31, 2023, we have 871 employees in the U.S. Approximately 40 percent of our domestic employees, principally at our cokemaking operations, are represented by the United Steelworkers union under various contracts. Additionally, approximately 3 percent of our domestic employees are represented by the International Union of Operating Engineers. Labor agreements at Kanawha River Terminal (“KRT”), SunCoke Lake Terminal (“Lake Terminal”), and Indiana Harbor were renewed in 2022 and will expire on April 30, 2025, June 30, 2025, and September 1, 2026, respectively. As of December 31, 2023,we have 280 employees at the cokemaking facility in Vitória, Brazil, all of whom are represented by a union under a labor agreement . During 2023, the labor agreement at our Vitória, Brazil facility was renewed for an additional year, and it expires on October 31, 2024.

Customer Concentrations

Customer Concentrations	12 Months Ended
	Dec. 31, 2023
Risks and Uncertainties [Abstract]
Customer Concentrations	3. Customer Concentrations In 2023, the Company sold approximately 3.5 million tons of coke under long-term, take-or-pay contracts to its two primary customers in the U.S.: Cleveland-Cliffs Steel Holding Corporation and Cleveland-Cliffs Steel LLC, subsidiaries of Cleveland-Cliffs Inc. and collectively referred to as “Cliffs Steel,” and United States Steel Corporation (“U.S. Steel”). The tables below show sales to the Company's significant customers: Years Ended December 31, 2023 2022 2021 Sales and other operating revenue Percent of Company sales and other operating revenue Sales and other operating revenue Percent of Company sales and other operating revenue Sales and other operating revenue Percent of Company sales and other operating revenue (Dollars in millions) Cliffs Steel (1) $ 1,349.4 65.4 % $ 1,182.8 60.0 % $ 994.6 68.3 % U.S. Steel (2) $ 300.8 14.6 % $ 284.8 14.4 % $ 210.0 14.4 % (1) Represents revenues included in our Domestic Coke segment. (2) Represents revenues included in our Domestic Coke and Logistics segments.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Income Taxes	4. Income Taxes The components of income before income tax expense are as follows: Years Ended December 31, 2023 2022 2021 (Dollars in millions) Domestic $ 88.8 $ 107.1 $ 50.4 Foreign 9.0 14.6 16.7 Total $ 97.8 $ 121.7 $ 67.1 Income tax expense consisted of the following: Years Ended December 31, 2023 2022 2021 (Dollars in millions) Current tax expense: U.S. federal $ 7.9 $ 4.3 $ 0.8 State 4.7 5.4 3.7 Foreign 3.1 4.8 4.5 Total current tax expense 15.7 14.5 9.0 Deferred tax expense (benefit): U.S. federal 19.7 8.6 11.0 State (1.1) (6.3) (1.7) Total deferred tax expense 18.6 2.3 9.3 Total $ 34.3 $ 16.8 $ 18.3 The reconciliation of income tax expense at the U.S. statutory rate to income tax expense is as follows: Years Ended December 31, 2023 2022 2021 (Dollars in millions) Income tax expense at U.S. statutory rate $ 20.5 21.0 % $ 25.6 21.0 % $ 14.1 21.0 % Increase (reduction) in income taxes resulting from: Income attributable to noncontrolling interests in partnerships (1) (1.3) (1.3) % (0.9) (0.7) % (1.1) (1.7) % State and other income taxes, net of federal income tax effects (2) 3.0 3.1 % (0.9) (0.7) % 1.6 2.4 % Foreign income taxes (3) 3.1 3.1 % 4.8 4.0 % — — % R&D tax credit (4) (0.7) (0.7) % (4.0) (3.4) % — — % Non-deductible equity compensation 2.8 2.9 % 3.0 2.5 % 3.4 4.9 % Return to provision adjustments (1.8) (1.8) % (0.1) (0.1) % (0.1) (0.1) % Change in valuation allowance (3) 8.8 9.0 % (11.0) (9.0) % 0.5 0.8 % Other (0.1) (0.2) % 0.3 0.2 % (0.1) (0.1) % Income tax expense at effective tax rate $ 34.3 35.1 % $ 16.8 13.8 % $ 18.3 27.2 % (1) No income tax expense is reflected in the Consolidated Statements of Income for income attributable to noncontrolling interests in our Indiana Harbor cokemaking facility. (2) State tax rates in 2023 remained in line with the prior year. Lower apportioned state tax rates required the revaluation of certain deferred tax liabilities and resulted in deferred tax benefits of $4.9 million and $1.3 million recorded during 2022 and 2021, respectively. The decrease in apportioned state tax rates in 2022 was partly driven by the dissolution of SunCoke Energy Partners Finance Corp. (3) During 2023, the Company established an $8.4 million valuation allowance, which was a portion of an $11.3 million valuation allowance that was released during 2022 on deferred tax assets attributable to existing foreign tax credit carryforwards. The release of the valuation allowance during 2022 was a result of new regulations published in 2022 by the U.S. Treasury (2022 Foreign Tax Credit (“FTC”) final regulations) that made foreign taxes paid in future years to certain countries, including Brazil, no longer creditable in the U.S. After tax planning in 2022, the Company expected to be able to utilize its existing foreign tax credits carried forward from prior years. During 2023, Brazil enacted new legislation that aligned the Brazil transfer pricing law with the 2022 OECD Guidelines. As a result, the Company has determined that Brazil taxes paid or accrued in 2024 and forward will become creditable under the 2022 final FTC regulations. Due to the change in the Brazilian tax law, the FTCs that are projected to be created will cause $8.4 million of the foreign tax credit carryforward from prior years to not be utilized, resulting in the establishment of the valuation allowance during 2023. Also, during 2023, the IRS issued Notice 2023-55 and 2023-80 that generally allow taxpayers to defer the application of the of the 2022 FTC final regulations until further guidance is issued. Foreign income taxes paid in 2023 reflected the absence of the generation of foreign tax credits for taxes paid in Brazil due to the Company’s election not to defer the application of the 2022 FTC final regulations allowed under the notices. (4) SunCoke conducted an analysis with respect to the Company’s research and development activities, which resulted in a current tax benefit of $0.7 million and a deferred tax benefit of $4.0 million during 2023 and 2022, respectively. The tax effects of temporary differences that comprise the net deferred income tax liability from operations are as follows: December 31, 2023 2022 (Dollars in millions) Deferred tax assets: Retirement benefit liabilities $ 4.1 $ 4.2 Black lung benefit liabilities 13.2 13.2 Share-based compensation 0.6 2.0 Federal tax credit carryforward (1) — 8.7 Foreign tax credit carryforward (2) 8.4 9.2 State net operating loss carryforward, net of federal income tax effects (3) 13.2 12.9 Other liabilities not yet deductible 11.4 12.9 Total deferred tax assets 50.9 63.1 Less: valuation allowance (4) (17.9) (9.2) Deferred tax asset, net 33.0 53.9 Deferred tax liabilities: Properties, plants and equipment (158.3) (155.4) Investment in partnerships (65.1) (70.8) Total deferred tax liabilities (223.4) (226.2) Net deferred tax liability $ (190.4) $ (172.3) (1) Federal tax credit carryforward expires in 2034 through 2043. (2) Foreign tax credit carryforward expires in 2028 through 2032. (3) State net operating loss carryforward, net of federal income tax effects expires in 2033 through 2044. (4) Primarily related to state net operating loss carryforwards and valuation allowance attributable to existing foreign tax credit carryforwards. The Company's consolidated federal income tax returns have been examined by the IRS for all years through the year ended December 31, 2014. Due to the federal tax credit carryforward going back to 2015, SunCoke is currently open to examination by the IRS for tax years ended December 31, 2015 and forward. State and foreign income tax returns are generally subject to examination for a period of three Uncertain Tax Positions During 2023 and 2022, the company recorded expense related to uncertain current and prior year tax positions of $0.1 million and $0.3 million, respectively. At December 31, 2023 and 2022, the balances of unrecognized tax benefits at were $0.4 million and $0.3 million, respectively, that, if recognized, will reduce the effective tax rate on income from continuing operations.

Inventories

Inventories	12 Months Ended
	Dec. 31, 2023
Inventory Disclosure [Abstract]
Inventories	5. Inventories The Company’s inventory consists of metallurgical coal, which is the principal raw material for the Company’s cokemaking operations, coke, which is the finished good sold by the Company to its customers, and materials, supplies and other. These components of inventories, net of lower of cost or net realizable value adjustments of $2.0 million and $2.6 million at December 31, 2023 and 2022, respectively, were as follows: December 31, 2023 2022 (Dollars in millions) Coal $ 107.7 $ 109.4 Coke 17.4 14.3 Materials, supplies and other 57.5 51.5 Total inventories $ 182.6 $ 175.2

Properties, Plants, and Equipme

Properties, Plants, and Equipment	12 Months Ended
	Dec. 31, 2023
Property, Plant and Equipment [Abstract]
Properties, Plants, and Equipment	6. Properties, Plants, and Equipment The components of net properties, plants and equipment were as follows: December 31, 2023 2022 (Dollars in millions) Coke and energy plant, machinery and equipment $ 2,193.9 $ 2,134.9 Logistics plant, machinery and equipment 181.2 176.6 Land and land improvements 110.0 106.8 Construction-in-progress 43.3 40.7 Other 46.3 46.3 Gross investment, at cost 2,574.7 2,505.3 Less: accumulated depreciation (1,383.6) (1,276.0) Total properties, plants and equipment, net $ 1,191.1 $ 1,229.3

Intangible Assets

Intangible Assets	12 Months Ended
	Dec. 31, 2023
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets	7. Intangible Assets Intangible assets, net, include goodwill allocated to our Domestic Coke segment of $3.4 million at both December 31, 2023 and 2022, and other intangibles detailed in the table below, excluding fully amortized intangible assets. There were no changes in the carrying amount of goodwill during the fiscal years ended December 31, 2023 and 2022, respectively. December 31, 2023 December 31, 2022 Weighted - Average Remaining Amortization Years Gross Carrying Amount Accumulated Amortization Net Gross Carrying Amount Accumulated Amortization Net (Dollars in millions) Customer relationships 1 $ 6.7 $ 6.2 $ 0.5 $ 6.7 $ 5.6 $ 1.1 Permits 19 31.7 5.9 25.8 31.7 4.5 27.2 Other 27 1.6 0.2 1.4 1.6 0.1 1.5 Total $ 40.0 $ 12.3 $ 27.7 $ 40.0 $ 10.2 $ 29.8 The permits above represent the environmental and operational permits required to operate a coal export terminal in accordance with the U.S. Environmental Protection Agency (“EPA”) and other regulatory bodies. Intangible assets are amortized over their useful lives in a manner that reflects the pattern in which the economic benefit of the asset is consumed. The permits’ useful lives were estimated to be 27 years at acquisition based on the expected useful life of the significant operating equipment at the facility. We have historical experience of renewing and extending similar arrangements at our other facilities and intend to continue to renew our permits as they come up for renewal for the foreseeable future. The permits were renewed regularly prior to our acquisition of CMT. These permits have an average remaining renewal term of approximate ly 5.4 y ears. Total amortization expense for intangible assets subject to amortization was $2.1 million, $2.0 million and $2.0 million for the years ended December 31, 2023, 2022 and 2021, respectively. Based on the carrying value of finite-lived intangible assets as of December 31, 2023, we estimate amortization expense for each of the next five years and the aggregate amount thereafter as follows: (Dollars in millions) 2024 $ 1.9 2025 1.5 2026 1.5 2027 1.4 2028 1.4 2029-Thereafter 20.0 Total $ 27.7

Asset Retirement Obligations

Asset Retirement Obligations	12 Months Ended
	Dec. 31, 2023
Asset Retirement Obligation [Abstract]
Asset Retirement Obligations	8. Asset Retirement Obligations The Company has asset retirement obligations, primarily in the Domestic Coke segment, related to certain contractual obligations. These contractual obligations mostly relate to costs associated with restoring land to its original state, and may require the retirement and removal of long-lived assets from certain cokemaking properties as well as other reclamation obligations related to our former coal mining business. The Federal Surface Mining Control and Reclamation Act of 1977 and similar state statutes require that mine property be restored in accordance with specified standards and an approved reclamation plan. We do not have any unrecorded asset retirement obligations. The following table provides a reconciliation of changes in the asset retirement obligation from operations during each period: Years ended December 31, 2023 2022 (Dollars in millions) Asset retirement obligation at beginning of year $ 13.8 $ 12.3 Liabilities settled (0.7) — Accretion expense (1) 1.0 0.9 Revisions in estimated cash flows — 0.6 Asset retirement obligation at end of year (2) $ 14.1 $ 13.8 (1) Included in cost of products sold and operating expenses on the Consolidated Statements of Income. (2)

Retirement Benefits Plans

Retirement Benefits Plans	12 Months Ended
	Dec. 31, 2023
Retirement Benefits [Abstract]
Retirement Benefits Plans	9. Retirement Benefits Plans Postretirement Health Care and Life Insurance Plans The Company has plans which provide health care and life insurance benefits for many of its retirees (“postretirement benefit plans”). The postretirement benefit plans are unfunded and the costs are borne by the Company. Effective January 1, 2011, postretirement medical benefits for future retirees were phased out or eliminated for non-mining employees with less than ten years of service. Postretirement benefit plans expense consisted of the following components: Years Ended December 31, 2023 2022 2021 (Dollars in millions) Interest cost on benefit obligations $ 0.9 $ 0.6 $ 0.5 Amortization of: Actuarial losses 0.4 0.7 0.8 Prior service benefit (0.2) (0.2) (0.4) Total expense $ 1.1 $ 1.1 $ 0.9 Postretirement benefit plans expense is determined using actuarial assumptions as of the beginning of the year or using weighted-average assumptions when curtailments, settlements and/or other events require a plan remeasurement. The following assumptions were used to determine postretirement benefit plans expense: December 31, 2023 2022 2021 Discount rate 5.25 % 2.50 % 2.00 % The following amounts were recognized as components of other comprehensive income (loss) before related tax impacts: Years Ended December 31, 2023 2022 2021 (Dollars in millions) Reclassifications to earnings of: Actuarial loss amortization $ 0.4 $ 0.7 $ 0.8 Prior service benefit amortization (0.2) (0.2) (0.4) Retirement benefit plan funded status Actuarial (losses) gains (0.6) 4.0 1.3 $ (0.4) $ 4.5 $ 1.7 The following table sets forth the components of the changes in benefit obligations: Years Ended December 31, 2023 2022 (Dollars in millions) Benefit obligation at beginning of year $ 18.8 $ 24.4 Interest cost 0.9 0.6 Actuarial losses (gains) 0.6 (4.0) Benefits paid (2.2) (2.2) Benefit obligation at end of year (1) $ 18.1 $ 18.8 (1) The current portion of retirement benefit liabilities, which totaled $2.3 million and $2.4 million at December 31, 2023 and 2022, respectively, is classified in accrued liabilities on the Consolidated Balance Sheets. The following table sets forth the cumulative amounts not yet recognized in net income: Years Ended December 31, 2023 2022 (Dollars in millions) Cumulative amounts not yet recognized in net income: Actuarial losses $ 5.4 $ 5.2 Prior service benefits (0.7) (0.8) Accumulated other comprehensive loss (before related tax benefit) $ 4.7 $ 4.4 The expected benefit payments through 2033 for the postretirement benefit plan are as follows: (Dollars in millions) 2024 $ 2.3 2025 2.2 2026 2.0 2027 1.8 2028 1.7 2029 through 2033 $ 6.8 The measurement date for the Company’s postretirement benefit plans is December 31. The following discount rates were used to determine the benefit obligation: December 31, 2023 2022 Discount rate 4.95 % 5.25 % The health care cost trend assumption used at December 31, 2023 to compute the accumulated postretirement benefit obligation for the postretirement benefit plans was 6.75 percent, which is assumed to decline gradually to 5.00 percent in 2031 and to remain at that level thereafter. The health care cost trend assumption used at December 31, 2022 to compute the accumulated postretirement benefit obligation for the postretirement benefit plan was 7.00 percent, which is assumed to decline gradually to 5.00 percent in 2031 and to remain at that level thereafter. Defined Contribution Plans The Company has defined contribution plans which provide retirement benefits for certain of its employees. The Company’s contributions, which are charged against income as incurred, amounted to $7.9 million, $7.9 million and $6.9 million for the years ended December 31, 2023, 2022 and 2021, respectively.

Accrued Liabilities

Accrued Liabilities	12 Months Ended
	Dec. 31, 2023
Balance Sheet Related Disclosures [Abstract]
Accrued Liabilities	10. Accrued Liabilities Accrued liabilities consist of following: December 31, 2023 2022 (Dollars in millions) Accrued benefits $ 26.8 $ 29.7 Current portion of postretirement benefit obligation 2.3 2.4 Other taxes payable 10.4 9.8 Current portion of black lung liability 5.0 5.9 Accrued legal 0.5 4.9 Other 6.7 8.7 Total accrued liabilities $ 51.7 $ 61.4

Debt and Financing Obligations

Debt and Financing Obligations	12 Months Ended
	Dec. 31, 2023
Debt Disclosure [Abstract]
Debt and Financing Obligations	11. Debt and Financing Obligations Total debt and financing obligations consisted of the following: December 31, 2023 2022 (Dollars in millions) 4.875 percent senior notes, due 2029 (“2029 Senior Notes”) $ 500.0 $ 500.0 $350.0 revolving credit facility, due 2026 (“Revolving Facility”) — 35.0 5.346 percent financing obligation, due 2024 — 8.8 Total borrowings $ 500.0 $ 543.8 Debt issuance costs (9.7) (11.6) Total debt and financing obligation $ 490.3 $ 532.2 Less: current portion of long-term debt and financing obligation — 3.3 Total long-term debt and financing obligation $ 490.3 $ 528.9 2029 Senior Notes The 2029 Senior Notes are the senior secured obligations of the Company. Interest on the 2029 Senior Notes is payable semi-annually in cash in arrears on June 30 and December 30 of each year. The Company may redeem some or all of the 2029 Senior Notes at its option, in whole or part, at the dates and amounts set forth in the applicable indenture. The applicable indenture for the 2029 Senior Notes contains covenants that, among other things, limit the Company's ability and, in certain circumstances, the ability of certain of the Company’s subsidiaries to borrow money, create liens on assets, pay dividends or make other distributions on or repurchase or redeem the Company's capital stock, prepay, redeem or repurchase certain debt, make loans and investments, sell assets, incur liens, enter into transactions with affiliates, enter into agreements restricting the ability of subsidiaries to pay dividends and consolidate, merge or sell all or substantially all of the Company's assets. Revolving Facility The proceeds of any borrowings made under the Revolving Facility can be used to finance working capital needs, acquisitions, capital expenditures and for other general corporate purposes. The obligations under the credit agreement are guaranteed by certain of the Company’s subsidiaries and secured by liens on substantially all of the Company’s and the guarantors’ assets pursuant to a guarantee and collateral agreement. As of December 31, 2023, the Revolving Facility had no outstanding balance leaving $350.0 million available. Additionally, the Company has certain letters of credit totaling $21.7 million, which do not reduce the Revolving Facility's available balance. Commitment fees are based on the unused portion of the Revolving Facility at a rate of 0.175 percent. Borrowings under the Revolving Facility bear interest, at SunCoke's option, at a variable rate per annum equal to either (i) an adjusted term secured overnight financing rate (“SOFR”) rate (defined as SOFR for a specified term plus a credit spread adjustment of 10 basis points, subject to a zero percent floor) plus 1.50 percent or (ii) an alternate base rate plus 0.50 percent. The applicable margin is subject to change based on SunCoke's consolidated leverage ratio, as defined in the credit agreement. The weighted-average interest rate for borrowings outstanding under the Revolving Facility was 6.5 percent during 2023. Financing Obligation In December 2020, the Company entered into a sale-leaseback arrangement related to certain coke and logistics equipment, which was accounted for as a financing transaction, resulting in a financing obligation on the Consolidated Balance Sheets. The arrangement had an initial period of 48 months, and an early buyout option after 36 months to purchase the equipment at a fixed rate, which the Company exercised in December 2023. Covenants Under the terms of the Revolving Facility, the Company is subject to a maximum consolidated leverage ratio of 4.50:1.00 and a minimum consolidated interest coverage ratio of 2.50:1.00. The Company's debt agreements contain other covenants and events of default that are customary for similar agreements and may limit our ability to take various actions including our ability to pay a dividend or repurchase our stock. If we fail to perform our obligations under these and other covenants, the lenders' credit commitment could be terminated and any outstanding borrowings, together with accrued interest, under the Revolving Facility could be declared immediately due and payable. The Company has a cross default provision that applies to our indebtedness having a principal amount in excess of $35 million. As of December 31, 2023, the Company was in compliance with all debt covenants. We do not anticipate violation of these covenants nor do we anticipate that any of these covenants will restrict our operations or our ability to obtain additional financing. Maturities As of December 31, 2023, the combined aggregate amount of maturities for long-term borrowings for each of the next five years and thereafter is as follows: (Dollars in millions) 2024 $ — 2025 — 2026 — 2027 — 2028 — 2029-Thereafter 500.0 Total $ 500.0

Commitments and Contingent Liab

Commitments and Contingent Liabilities	12 Months Ended
	Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingent Liabilities	12. Commitments and Contingent Liabilities Legal Matters Between 2005 and 2012, the EPA and the Ohio Environmental Protection Agency (“OEPA”) issued Notices of Violations (“NOVs”), alleging violations of air emission operating permits for our Haverhill and Granite City cokemaking facilities. We worked in a cooperative manner with the EPA, the OEPA and the Illinois Environmental Protection Agency to address the allegations and, in November 2014, entered into a consent decree with these parties in federal district court in the Southern District of Illinois. The consent decree included a civil penalty paid in December 2014, and a commitment to undertake capital projects to improve reliability and enhance environmental performance. Although all projects regarding the consent decree have been completed, the consent decree remains in effect and is being overseen for compliance. Between 2010 and 2016, SunCoke Energy also received certain NOVs, Findings of Violations (“FOVs”), and information requests from the EPA, alleging violations of air operating permit conditions related to our Indiana Harbor cokemaking facility. To reach a settlement of these NOVs and FOVs, a consent decree with the EPA and the Indiana Department of Environmental Management was entered by the federal district court in the Northern District of Indiana during the fourth quarter of 2018. After Indiana Harbor completed all consent decree requirements, the federal district court terminated the consent decree in January 2023. The Company is a party to certain pending and threatened claims, including matters related to commercial disputes, employment claims, personal injury claims, common law tort claims, and environmental claims. Although the ultimate outcome of these claims cannot be ascertained at this time, it is reasonably possible that some portion of these claims could be resolved unfavorably to the Company. Management of the Company believes that any liability which may arise from these claims would likely not have a material adverse impact on our consolidated financial statements. SunCoke's threshold for disclosing material environmental legal proceedings involving a government authority where potential monetary sanctions are involved is $1 million. Black Lung Benefit Liabilities The Company has obligations related to coal workers’ pneumoconiosis, or black lung, to provide benefits to certain of its former coal miners and their dependents. Such benefits are provided for under Title IV of the Federal Coal Mine and Safety Act of 1969 and subsequent amendments, as well as for black lung benefits provided in the states of Virginia, Kentucky and West Virginia pursuant to workers’ compensation legislation. The Patient Protection and Affordable Care Act, which was implemented in 2010 and amended previous legislation related to coal workers’ black lung obligations, provides for the automatic extension of awarded lifetime benefits to surviving spouses and changes the legal criteria used to assess and award claims. We adjust our liability each year based upon actuarial calculations of our expected future payments for these benefits. Our independent actuarial consultants calculate the present value of the estimated black lung liability annually based on actuarial models utilizing our population of former coal miners, historical payout patterns of both the Company and the industry, expected claim filing patterns, expected claimant success rates, actuarial mortality rates, medical costs, death benefits, dependents, discount rates and the current federally mandated payout rates. The estimated liability may be impacted by future changes in the statutory mechanisms, modifications by court decisions and changes in filing patterns by claimants and their advisors, the impact of which cannot be estimated. The following table summarizes discount rates utilized, active claims and the total black lung liabilities. Our independent actuarial consultants calculate the present value of the black lung liability annually in the fourth quarter, unless there are changes in facts and circumstances that could materially alter the amount of the liability. December 31, 2023 2022 (Dollars in millions) Discount rate (1) 4.5 % 4.9 % Active claims 311 332 Total black lung liability, discounted (2) $ 58.2 $ 58.1 Total black lung liability, undiscounted $ 96.0 $ 88.4 (1) The discount rate is determined based on a portfolio of high-quality corporate bonds with maturities that are consistent with the estimated duration of our black lung obligations. A decrease of 25 basis points in the discount rate would have increased black lung expense by $1.4 million in 2023. (2) The current portion of the black lung liability was $5.0 million and $5.9 million at December 31, 2023 and 2022, respectively, and was included in accrued liabilities on the Consolidated Balance Sheets. Expected payments for each of the five succeeding years and the aggregate amount thereafter as of December 31, 2023: (Dollars in millions) 2024 $ 5.0 2025 3.9 2026 4.4 2027 4.0 2028 3.8 2029-Thereafter 74.9 Total $ 96.0 The following table reconciles the expected aggregate undiscounted amount to amounts recognized in the Consolidated Balance Sheets: December 31, 2023 2022 (Dollars in millions) Black lung liability, undiscounted $ 96.0 $ 88.4 Impact of discounting (37.8) (30.3) Black lung liability, discounted $ 58.2 $ 58.1 The following table summarizes the annual black lung payments and expense (benefit): Years Ended December 31, 2023 2022 2021 (Dollars in millions) Payments $ 5.4 $ 5.0 $ 4.4 Expense (benefit) (1) $ 5.5 $ (0.2) $ 3.1 (1) Black lung expense (benefit) incurred in excess of annual accretion of the black lung liability reflects the impact of changes in discount rates, current filing and approval rate assumptions and/or other changes in our actuarial assumptions. On February 1, 2013, SunCoke obtained commercial insurance for black lung claims in excess of a deductible for employees with a last date of employment after that date. Also, during 2013, we were reauthorized to continue to self-insure black lung liabilities incurred prior to February 1, 2013 by the U.S. Department of Labor's Division of Coal Mine Workers' Compensation (“DCMWC”) in exchange for $8.4 million of collateral. In July 2019, the DCMWC required that SunCoke, along with a number of other companies, file an application and supporting documentation for reauthorization to self-insure any legacy black lung obligations incurred prior to February 1, 2013. The Company provided the requested information in the fourth quarter of 2019. The DCMWC subsequently notified the Company in a letter dated February 21, 2020 that the Company was reauthorized to self-insure certain of its black lung obligations; however, the reauthorization is contingent upon the Company providing collateral of $40.4 million to secure certain of its black lung obligations. This proposed collateral requirement is a substantial increase from the $8.4 million in collateral that the Company currently provides to secure these self-insured black lung obligations. The reauthorization process provided the Company with the right to appeal the security determination. SunCoke exercised its right to appeal the DCMWC’s security determination and provided additional information supporting the Company’s position in May 2020 and February 2021. If the Company’s appeal is unsuccessful, the Company may be required to provide additional collateral to receive the self-insurance reauthorization from the DCMWC, which could potentially reduce the Company’s liquidity. Additionally, on January 19, 2023, the Department of Labor issued a new proposed rule that would require self-insured companies to post collateral in the amount of 120 percent of the company's total expected lifetime black lung obligations as determined by the DCMWC. While this new proposed rule is not effective, if finalized, it could potentially reduce the Company's liquidity. We submitted comments on this proposed rule and will continue to monitor any impact to the Company.

Leases

Leases	12 Months Ended
	Dec. 31, 2023
Leases [Abstract]
Leases	13. Leases The Company's operating leases consist primarily of leases for land, office space, equipment, railcars and locomotives. Certain of our long-term leases include one or more options to renew or to terminate, with renewal terms that can extend the lease term from one month to 50 years. The Company's finance leases are immaterial to our consolidated financial statements. The components of lease expense were as follows: Years ended December 31, 2023 2022 (Dollars in millions) Operating leases: Cost of products sold and operating expenses $ 2.3 $ 2.3 Selling, general and administrative expenses 0.5 0.4 $ 2.8 $ 2.7 Short-term leases: Cost of products sold and operating expenses (1)(2) 4.0 5.5 Total lease expense $ 6.8 $ 8.2 (1) Includes expenses for month-to-month equipment leases, which are classified as short-term as the Company is not reasonably certain to renew the lease term beyond one month. (2) Includes variable lease expenses, which are immaterial to the consolidated financial statements. Supplemental balance sheet information related to leases was as follows: Years ended December 31, Financial Statement Classification 2023 2022 (Dollars in millions) Operating ROU assets Deferred charges and other assets $ 11.6 $ 11.3 Operating lease liabilities: Current operating lease liabilities Accrued liabilities $ 2.3 $ 2.0 Noncurrent operating lease liabilities Other deferred credits and liabilities 8.6 8.5 Total operating lease liabilities $ 10.9 $ 10.5 The weighted average remaining lease term and weighted average discount rate were as follows: Years ended December 31, 2023 2022 Weighted average remaining lease term of operating leases 7.1 years 5.9 years Weighted average discount rate of operating leases 4.7 % 4.2 % Supplemental cash flow information related to leases was as follows: Years ended December 31, 2023 2022 (Dollars in millions) Operating cash flow information: Cash paid for amounts included in the measurement of operating lease liabilities $ 2.5 $ 2.4 Non-cash activity: ROU assets obtained in exchange for new operating lease liabilities $ 2.6 $ 0.6 Maturities of operating lease liabilities as of December 31, 2023 are as follows: (Dollars in millions) 2024 $ 2.7 2025 2.6 2026 1.8 2027 1.4 2028 1.4 2029-Thereafter 3.1 Total lease payments 13.0 Less: imputed interest 2.1 Total lease liabilities $ 10.9

Accumulated Other Comprehensive

Accumulated Other Comprehensive Loss	12 Months Ended
	Dec. 31, 2023
Equity [Abstract]
Accumulated Other Comprehensive Loss	14. Accumulated Other Comprehensive Loss The following tables set forth the changes in the balance of accumulated other comprehensive loss, net of tax, by component: Benefit Plans Currency Translation Adjustments Total (Dollars in millions) At December 31, 2021 $ (6.9) $ (9.8) $ (16.7) Other comprehensive income before reclassifications / adjustments 0.4 0.2 0.6 Retirement benefit plans funded status adjustment 3.1 — 3.1 Net current period change in accumulated other comprehensive loss 3.5 0.2 3.7 At December 31, 2022 $ (3.4) $ (9.6) $ (13.0) Other comprehensive income before reclassifications / adjustments 0.1 0.5 0.6 Retirement benefit plans funded status adjustment (0.4) — (0.4) Net current period change in accumulated other comprehensive loss (0.3) 0.5 0.2 At December 31, 2023 $ (3.7) $ (9.1) $ (12.8) The tax benefit associated with the Company's benefit plans as of December 31, 2023 and 2022 was $ 1.0 million in both respective periods. The increase in net income due to reclassification adjustments from accumulated other comprehensive income were as follows (1) : Years Ended December 31, 2023 2022 2021 (Dollars in millions) Amortization of benefit plans to net income: (2) Actuarial loss $ (0.4) $ (0.7) $ (0.8) Prior service benefit 0.2 0.2 0.4 Total before taxes (0.2) (0.5) (0.4) Income tax 0.1 0.1 0.1 Total, net of tax $ (0.1) $ (0.4) $ (0.3) (1) Amounts in parentheses indicate debits to net income. (2)

Share-Based Compensation

Share-Based Compensation	12 Months Ended
	Dec. 31, 2023
Share-Based Payment Arrangement, Noncash Expense [Abstract]
Share-Based Compensation	15. Share-Based Compensation Equity Classified Awards . On May 12, 2022, the Company adopted the SunCoke Energy, Inc. Omnibus Long-Term Incentive Plan (the “Omnibus Plan”). The Omnibus Plan provides for the grant of equity-based awards including stock options and share units, or restricted stock, to the Company’s Board of Directors and certain employees selected for participation in the plan. The total number of shares of common stock authorized for issuance under the Omnibus Plan consists of (i) 2,700,000 new shares, (ii) 2,434,445 shares of common stock reserved for issuance primarily under the previous SunCoke Energy, Inc. Long-Term Performance Enhancement Plan (“SunCoke LTPEP”), which all equity based awards were issued under prior to the effective date of May 12, 2022, and (iii) any shares of common stock subject to awards granted under the SunCoke LTPEP that were outstanding on the effective date and that, on or after such date, are not issued or delivered to a participant. As of the effective date, new awards will no longer be granted under the SunCoke LTPEP. Awards previously granted under the SunCoke LTPEP, and described in further detail below, were not modified or impacted by the adoption of the Omnibus Plan. Stock Options Stock options granted by the Company vest in three equal annual installments beginning one year from the date of grant, and expire ten years from the date of grant. The Company calculates the value of each employee stock option, estimated on the date of grant, using the Black-Scholes option pricing model. There were no stock options granted by the Company during the years ended December 31, 2023, 2022 and 2021. The following table summarizes information with respect to common stock option awards outstanding as of December 31, 2023 and stock option activity during the fiscal year then ended: Number of Weighted Weighted Average Remaining Contractual Term (years) Aggregate Outstanding at December 31, 2022 1,520,210 $ 15.06 2.7 0.2 Exercised (21,887) $ 4.01 Expired (298,667) $ 16.52 Outstanding and Exercisable December 31, 2023 1,199,656 $ 14.89 2.3 0.5 Intrinsic value for stock options is defined as the difference between the current market value of our common stock and the exercise price of the stock options. Total intrinsic value of stock options exercised in 2023, 2022 and 2021 was $0.1 million, $0.2 million, and $0.3 million, respectively. Restricted Stock Units Settled in Shares The Company issues restricted stock units (“RSUs”) to be settled in shares of the Company's common stock to certain employees and members of the Board of Directors. The Company granted the following RSUs during the years ended December 31, 2023, 2022 and 2021: Number of RSUs Weighted Average Grant-Date Fair Value per Unit Grant Date Fair Value (Dollars in millions) 2023 grants 352,646 $ 8.97 $ 3.2 2022 grants 346,600 $ 7.62 $ 2.6 2021 grants 463,476 $ 6.72 $ 3.1 The RSUs granted to employees vest and become payable in three annual installments beginning one year from the date of grant. RSUs granted to the Company's Board of Directors vest upon grant, but are issued upon termination of board service. The following table summarizes information with respect to RSUs outstanding as of December 31, 2023 and RSU activity during the fiscal year then ended: Number of Weighted Nonvested at December 31, 2022 670,978 $ 7.08 Granted 352,646 $ 8.97 Vested (308,354) $ 6.83 Nonvested at December 31, 2023 715,270 $ 8.12 Total grant date fair value of RSUs vested was $2.1 million, $1.7 million and $1.2 million during 2023, 2022 and 2021, respectively. Performance Share Units The Company grants performance share units (“PSUs”), which represent the right to receive shares of the Company's common stock, contingent upon the attainment of Company performance and market goals and continued employment. The Company granted the following PSUs during the years ended December 31, 2023, 2022 and 2021: Number of PSUs Weighted Average Grant Date Fair Value per Unit Grant Date Fair Value (Dollars in millions) 2023 grant (1) 147,232 $ 9.84 $ 1.4 2022 grant (1) 154,860 $ 8.40 $ 1.3 2021 grant (1) 177,176 $ 7.60 $ 1.3 (1) The service period for the 2023, 2022, and 2021 PSUs ends on December 31, 2025, 2024 and 2023, and the awards will vest during the first quarter of 2026, 2025 and 2024, respectively. The service period for certain retiree eligible participants is accelerated. The PSU grants were split 50/50 between the Company's three-year cumulative Adjusted EBITDA performance measure and the Company's three-year average pre-tax return on capital (“ROIC”) performance measure for its coke and logistics businesses and unallocated corporate expenses. The number of PSUs ultimately awarded will be determined by the Adjusted EBITDA and ROIC performance versus targets and the Company's three-year total shareholder return (“TSR”) as compared to the TSR of the companies making up the NASDAQ U.S. Benchmark Iron & Steel Index (“TSR Modifier”). The TSR Modifier can impact the payout (between 80 percent and 120 percent of the 2023 and 2022 awards, and between 75 percent and 125 percent of the 2021 awards) of the Company's final performance measure results. The 2023 and 2022 awards may vest between 25 percent and 200 percent of the original units granted and the 2021 awards may vest between zero and 250 percent. The fair value of the PSUs granted is based on the closing price of our common stock on the date of grant as well as a Monte Carlo simulation for the valuation of the TSR Modifier. The following table summarizes information with respect to unearned PSUs outstanding as of December 31, 2023 and PSU activity during the fiscal year then ended: Number of Weighted Nonvested at December 31, 2022 498,746 $ 7.21 Granted 147,232 $ 9.84 Performance adjustments 161,091 $ 6.70 Vested (354,244) $ 6.70 Nonvested at December 31, 2023 452,825 $ 7.50 Liability Classified Awards Restricted Stock Units Settled in Cash During the years ended December 31, 2023, 2022 and 2021, the Company issued 216,547, 250,615 and 230,056 restricted stock units to be settled in cash (“Cash RSUs”), respectively, which vest in three annual installments beginning one year from the grant date. The weighted average grant date fair value of the Cash RSUs granted during the years ended December 31, 2023, 2022 and 2021, was $9.24, $7.56 and $6.68, respectively, and was based on the closing price of our common stock on the day of grant. The Cash RSU liability at December 31, 2023 was adjusted based on the closing price of our common stock on December 31, 2023 of $10.74 per share. The Cash RSU liability was $2.8 million at December 31, 2023 and was $2.4 million at December 31, 2022. Cash Incentive Award The Company also granted share-based compensation to eligible participants under the SunCoke Energy, Inc. Long-Term Cash Incentive Plan (“SunCoke LTCIP”), which became effective January 1, 2016. The SunCoke LTCIP is designed to provide for performance-based, cash-settled awards. All awards vest immediately upon a change in control and a qualifying termination of employment as defined by the SunCoke LTCIP. As of May 12, 2022, performance-based, cash settled awards will be granted under the new Omnibus Plan. The awards previously granted under the SunCoke LTCIP were not modified or impacted by the adoption of the Omnibus Plan. The cash incentive award liability is included in accrued liabilities and other deferred credits and liabilities on the Consolidated Balance Sheets. The Company issued a grant date fair value award of $2.2 million, $2.0 million and $2.1 million during the years ended December 31, 2023, 2022 and 2021, respectively, for which the service periods end on December 31, 2025, 2024 and 2023, respectively, and the awards will vests during the first quarter of 2026, 2025 and 2024, respectively. The service period for certain retiree eligible participants is accelerated. The 2023, 2022 and 2021 awards are split 50/50 between the Adjusted EBITDA and ROIC metrics, consistent with the PSU awards, but is not impacted by the TSR modifier. See above for details. The cash incentive award liability at December 31, 2023 was adjusted based on the Company's three-year cumulative Adjusted EBITDA performance and adjusted average pre-tax return on capital for the Company's coke and logistics businesses and unallocated corporate expenses. The cash incentive award liability was $8.1 million at December 31, 2023 and $8.7 million at December 31, 2022. Summary of Share-Based Compensation Expense Below is a summary of the compensation expense, unrecognized compensation costs, the period for which the unrecognized compensation cost is expected to be recognized over for each award: Years Ended December 31, 2023 2022 2021 2023 2022 2021 December 31, 2023 Compensation Expense (1) Net of tax Unrecognized Compensation Cost Weighted Average Remaining Recognition Period (Dollars in millions) (Dollars in millions) (Years) Equity Awards: Stock Options $ — $ — $ 0.1 $ — $ — $ 0.1 $ — — RSUs 2.5 2.5 2.3 2.0 1.9 1.8 $ 0.6 1.6 PSUs 1.9 3.9 3.4 1.4 3.0 2.6 $ 0.7 1.6 Total equity awards $ 4.4 $ 6.4 $ 5.8 $ 3.4 $ 4.9 $ 4.5 Liability Awards: Cash RSUs $ 2.6 $ 2.1 $ 1.7 $ 2.0 $ 1.6 $ 1.3 $ 1.5 1.7 Cash incentive award 2.7 5.1 3.4 2.0 3.9 2.6 $ 1.5 1.6 Total liability awards $ 5.3 $ 7.2 $ 5.1 $ 4.0 $ 5.5 $ 3.9 (1) Compensation expense is recognized by the Company in selling, general and administrative expenses on the Consolidated Statements of Income.

Earnings Per Share

Earnings Per Share	12 Months Ended
	Dec. 31, 2023
Earnings Per Share [Abstract]
Earnings Per Share	16. Earnings Per Share Basic earnings per share (“EPS”) has been computed by dividing net income available to SunCoke Energy, Inc. by the weighted average number of shares outstanding during the period. Except where the result would be anti-dilutive, diluted earnings per share has been computed to give effect to share-based compensation awards using the treasury stock method. The following table sets forth the reconciliation of the weighted-average number of common shares used to compute basic earnings per share to those used to compute diluted EPS: Years Ended December 31, 2023 2022 2021 (Shares in millions) Weighted-average number of common shares outstanding-basic 84.7 83.8 83.0 Add: effect of dilutive share-based compensation awards 0.2 0.8 0.7 Weighted-average number of shares-diluted 84.9 84.6 83.7 The following table shows stock options, restricted stock units, and performance stock units that are excluded from the computation of diluted earnings per share as the shares would have been anti-dilutive: Years Ended December 31, 2023 2022 2021 (Shares in millions) Stock options 1.2 1.6 2.5 Total 1.2 1.6 2.5

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2023
Fair Value Disclosures [Abstract]
Fair Value Measurements	17. Fair Value Measurements The Company measures certain financial and non-financial assets and liabilities at fair value on a recurring basis. Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in the principal or most advantageous market in an orderly transaction between market participants on the measurement date. Fair value disclosures are reflected in a three-level hierarchy, maximizing the use of observable inputs and minimizing the use of unobservable inputs. The valuation hierarchy is based upon the transparency of inputs to the valuation of an asset or liability on the measurement date. The three levels are defined as follows: • Level 1—inputs to the valuation methodology are quoted prices (unadjusted) for an identical asset or liability in an active market. • Level 2—inputs to the valuation methodology include quoted prices for a similar asset or liability in an active market or model-derived valuations in which all significant inputs are observable for substantially the full term of the asset or liability. • Level 3—inputs to the valuation methodology are unobservable and significant to the fair value measurement of the asset or liability. Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis Cash and Cash Equivalents Certain assets and liabilities are measured at fair value on a recurring basis. The Company’s cash and cash equivalents were measured at fair value at December 31, 2023 and December 31, 2022 based on quoted prices in active markets for identical assets. These inputs are classified as Level 1 within the valuation hierarchy. Certain Financial Assets and Liabilities not Measured at Fair Value At December 31, 2023 and 2022, the fair value of the Company’s long-term debt was estimated to be $450.2 million and $471.9 million, respectively, compared to a carrying amount of $500.0 million and $543.8 million, respectively. These fair values were estimated by management based upon estimates of debt pricing provided by financial institutions which are considered Level 2 inputs.

Revenue from Contracts with Cus

Revenue from Contracts with Customers	12 Months Ended
	Dec. 31, 2023
Revenue from Contract with Customer [Abstract]
Revenue from Contracts with Customers	18. Revenue from Contracts with Customers Cokemaking Our blast furnace coke sales are largely made pursuant to long-term, take-or-pay agreements. These agreements require us to produce and deliver the contracted volumes of coke and require our customers to purchase such volumes of coke up to a specified tonnage or pay the contract price for any tonnage they elect not to take. As of December 31, 2023, our coke sales agreements have approximately 22.0 million tons of unsatisfied or partially unsatisfied performance obligations, which are expected to be delivered over a weighted average remaining contract term of approximately ten years. Our coke sales prices include an operating cost component, a coal cost component and a return of capital component. Operating costs under four of our coke sales agreements are fixed subject to an annual adjustment based on an inflation index. Under our other three coke sales agreements, operating costs are passed through to the respective customers subject to an annually negotiated budget, in some cases subject to a cap annually adjusted for inflation, and we share any difference in costs from the budgeted amounts with our customers. Our coke sales agreements contain pass-through provisions for coal and coal procurement costs, subject to meeting contractual coal-to-coke yields. To the extent that the actual coal-to-coke yields are less than the contractual standard, we are responsible for the cost of the excess coal used in the cokemaking process. Conversely, to the extent our actual coal-to-coke yields are higher than the contractual standard, we realize gains. The reimbursement of pass-through operating and coal costs from these coke sales agreements are considered to be variable consideration components included in the cokemaking sales price. The return of capital component for each ton of coke sold to the customer is determined at the time the coke sales agreement is signed and is effective for the term of each sales agreement. This component of our coke sales prices is intended to provide an adequate return on invested capital and may differ based on investment levels and other considerations. The actual return on invested capital at any facility is also impacted by favorable or unfavorable performance on pass-through cost items. Revenues are recognized when performance obligations to our customers are satisfied in an amount that reflects the consideration that we expect to receive in exchange for the coke. We also sell non-contracted blast furnace coke tons into the North American spot coke and export coke markets, utilizing capacity in excess of that reserved for our long-term, take-or-pay agreements. These non-contracted blast coke sales are generally sold on a spot basis at the current market price, and do not contain the same provisions as our long-term, take-or-pay agreements discussed above. While the revenues in our Domestic Coke segment are primarily tied to blast furnace coke sales made under long-term, take-or-pay agreements, we also produce and sell foundry coke out of our Jewell cokemaking facility. Foundry coke sales are generally made under annual agreements with our customers for an agreed upon price and do not contain take-or-pay volume commitments. Logistics In our logistics business, handling and/or mixing services are provided to steel, coke (including some of our domestic cokemaking facilities), electric utility, coal producing and other manufacturing based customers. Materials are transported in numerous ways, including rail, truck, barge or ship. We do not take possession of materials handled, but rather act as intermediaries between our customers and end users, deriving our revenues from services provided on a per ton basis. The handling and mixing services consist primarily of two performance obligations, unloading and loading of materials. Revenues are recognized when the customer receives the benefits of the services provided, in an amount that reflects the consideration that we will receive in exchange for those services. Estimated take-or-pay revenue of approximately $27.4 million from all of our multi-year logistics contracts is expected to be recognized over the next three years for unsatisfied or partially unsatisfied performance obligations as of December 31, 2023. Energy Our cokemaking ovens utilize efficient, modern heat recovery technology designed to combust the coal’s volatile components liberated during the cokemaking process and use the resulting heat to create steam or electricity for sale. Our Middletown facility and the second phase of our Haverhill facility, or Haverhill II, have cogeneration plants that generate electricity, which is either sold into the regional power market or to customers pursuant to energy sales agreements. Our Granite City facility and the first phase of our Haverhill facility, or Haverhill I, have steam generation facilities, which produce steam for sale to customers pursuant to steam supply and purchase agreements. The energy provided under these arrangements results in transfer of control over time. Revenues are recognized over time as energy is delivered to our customers, in an amount based on the terms of each arrangement. Energy generated at our remaining facilities is either used internally or provided, at minimal cost, to energy suppliers. Operating and Licensing Fees Operating and licensing fees are made pursuant to long-term contracts with ArcelorMittal Brazil, where we operate a Brazilian cokemaking facility. The licensing fees are based upon the level of production required by our customer. Operating fees include the full pass-through of the operating costs of the Brazilian facility as well as a per ton fee based on the level of production required by our customer. Revenues are recognized over time as our customers receive and consume the benefits in an amount that corresponds directly with the value provided to the customer to date. Disaggregated Sales and Other Operating Revenue The following table provides disaggregated sales and other operating revenue by product or service, excluding intersegment revenues: Years Ended December 31, 2023 2022 2021 (Dollars in millions) Sales and other operating revenue: Cokemaking $ 1,898.5 $ 1,791.3 $ 1,293.6 Energy 47.3 61.5 56.1 Logistics 73.1 76.7 64.3 Operating and licensing fees 35.2 38.0 36.6 Other 9.1 5.0 5.4 Sales and other operating revenue $ 2,063.2 $ 1,972.5 $ 1,456.0 See Note 3 Customer Concentrations for further detail on operating revenue.

Business Segment Information

Business Segment Information	12 Months Ended
	Dec. 31, 2023
Segment Reporting [Abstract]
Business Segment Information	19. Business Segment Information The Company reports its business through three reportable segments: Domestic Coke, Brazil Coke and Logistics. The Domestic Coke segment includes the Jewell, Indiana Harbor, Haverhill, Granite City and Middletown cokemaking facilities. Each of these facilities produces coke, and all facilities except Jewell recover waste heat, which is converted to steam or electricity. The Brazil Coke segment includes the licensing and operating fees payable to us under long-term contracts with ArcelorMittal Brazil, under which we operate a cokemaking facility located in Vitória, Brazil through January 2028. Logistics operations are comprised of CMT, KRT, and Lake Terminal, which provides services to our Indiana Harbor cokemaking facility. Handling and mixing results are presented in the Logistics segment. The Company elected to combine Dismal River Terminal (“DRT”) operations into the Jewell cokemaking operations in the Domestic Coke segment beginning January 1, 2023. The DRT results were included in the Logistics segment in 2022 and are not recast. Corporate expenses that can be identified with a segment have been included in determining segment results. The remainder is included in Corporate and Other, which is not a reporting segment, but which also includes activity from our legacy coal mining business. Segment assets are those assets utilized within a specific segment. The following table includes Adjusted EBITDA reportable segments, as defined below, which is a measure of segment profit or loss reported to the chief operating decision maker for purposes of allocating resources to the segments and assessing their performance: Years Ended December 31, 2023 2022 2021 (Dollars in millions) Sales and other operating revenue: Domestic Coke $ 1,954.0 $ 1,856.9 $ 1,354.5 Brazil Coke 35.2 38.0 36.6 Logistics 74.0 77.6 64.9 Logistics intersegment sales 22.1 28.9 27.1 Elimination of intersegment sales (22.1) (28.9) (27.1) Total sales and other operating revenue $ 2,063.2 $ 1,972.5 $ 1,456.0 Adjusted EBITDA reportable segments: Domestic Coke $ 247.8 $ 263.4 $ 243.4 Brazil Coke 9.1 14.5 17.2 Logistics 44.3 49.7 43.5 Total Adjusted EBITDA reportable segments $ 301.2 $ 327.6 $ 304.1 Depreciation and amortization expense: Domestic Coke $ 129.4 $ 126.8 $ 119.0 Brazil Coke 0.3 0.2 0.4 Logistics 12.8 14.5 13.3 Total reportable segments $ 142.5 $ 141.5 $ 132.7 Corporate and Other 0.3 1.0 1.2 Total depreciation and amortization expense $ 142.8 $ 142.5 $ 133.9 Capital expenditures: Domestic Coke $ 103.2 $ 70.3 $ 83.1 Brazil Coke 0.4 0.1 0.3 Logistics 5.1 4.5 14.7 Total reportable segments $ 108.7 $ 74.9 $ 98.1 Corporate and Other 0.5 0.6 0.5 Total capital expenditures $ 109.2 $ 75.5 $ 98.6 The following table sets forth the Company’s segment assets: December 31, 2023 2022 (Dollars in millions) Segment assets: Domestic Coke $ 1,405.5 $ 1,422.6 Brazil Coke 11.9 15.7 Logistics (1) 158.4 193.5 Total reportable segments $ 1,575.8 $ 1,631.8 Corporate and Other 84.6 22.8 Total assets $ 1,660.4 $ 1,654.6 (1) Logistics segment assets included $21.7 million of DRT assets as of December 31, 2022, which are included in the Domestic Coke segment in 2023. The Company evaluates the performance of its segments based on segment Adjusted EBITDA reportable segments, which is defined as earnings before interest, taxes, depreciation and amortization, adjusted for any impairments, restructuring costs, gains or losses on extinguishment of debt, transaction costs, and/or corporate/other expenses (“Adjusted EBITDA reportable segments”). Management believes Adjusted EBITDA reportable segments is an important measure in assessing operating performance. Additionally, other companies may calculate Adjusted EBITDA reportable segments differently than we do, limiting its usefulness as a comparative measure. Reconciliation of Adjusted EBITDA Reportable Segments to Net Income Below is a reconciliation of Adjusted EBITDA reportable segments to net income, which is its most directly comparable financial measure calculated and presented in accordance with GAAP: Years Ended December 31, 2023 2022 2021 (Dollars in millions) Net income $ 63.5 $ 104.9 $ 48.8 Add: Depreciation and amortization expense 142.8 142.5 133.9 Interest expense, net 27.3 32.0 42.5 Loss on extinguishment of debt — — 31.9 Income tax expense 34.3 16.8 18.3 Transaction costs (1) 0.9 1.5 — Corporate and Other 32.4 29.9 28.7 Adjusted EBITDA reportable segments $ 301.2 $ 327.6 $ 304.1 (1) Costs incurred as part of the granulated pig iron project with U.S. Steel.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Consolidation and Basis of Presentation	Consolidation and Basis of Presentation
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 amounts reported in the consolidated financial statements and accompanying notes. Actual amounts could differ from these estimates.
Revenue Recognition	Revenue Recognition
Cash Equivalents	Cash Equivalents
Inventories	Inventories
Properties, Plants and Equipment	Properties, Plants and Equipment Plants and equipment are depreciated on a straight-line basis over their estimated useful lives. Coke and energy plant, machinery and equipment are generally depreciated over 20 to 30 years. Logistics plant, machinery and equipment are
Intangible Assets	Intangible Assets
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets
Income Taxes	Income Taxes
Black Lung Benefit Liabilities	Black Lung Benefit Liabilities
Postretirement Benefit Plan Liabilities	Postretirement Benefit Plan Liabilities
Asset Retirement Obligations	Asset Retirement Obligations The fair value of a liability for an asset retirement obligation is recognized in the period in which it is incurred if a reasonable estimate of fair value can be made. The associated asset retirement costs are capitalized as part of the carrying
Leases	Leases
Shipping and Handling Costs	Shipping and Handling Costs
Share-Based Compensation	Share-Based Compensation
Fair Value Measurements	Fair Value Measurements
Currency Translation	Currency Translation
Recent Accounting Pronouncements	Recent Accounting Pronouncements In November 2023, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2023-07, “Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures.” ASU 2023-07 requires disclosure of incremental segment information on an interim and annual basis. This ASU is effective for fiscal years, beginning after December 15, 2023 as well as interim periods beginning after December 31, 2024 and requires retrospective application to all prior periods presented in the financial statements. The Company is currently evaluating the impact of the guidance on the related disclosures. The Company plans to adopt the guidance for the fiscal year ending December 31, 2024. In December 2023, the FASB issued ASU 2023-09, “Income Taxes (Topic 740): Improvement to Income Tax Disclosures.” ASU 2023-09 requires additional disclosures aimed at enhancing the transparency and decision usefulness of income tax disclosures. This ASU is effective for fiscal years beginning after December 15, 2024 on a prospective basis. The Company does not expect this ASU to have a material impact on the Company's disclosures. The Company plans to adopt the guidance for the fiscal year ending December 31, 2025.

Customer Concentrations (Tables

Customer Concentrations (Tables)	12 Months Ended
	Dec. 31, 2023
Risks and Uncertainties [Abstract]
Schedules of Concentration of Risk, by Risk Factor	The tables below show sales to the Company's significant customers: Years Ended December 31, 2023 2022 2021 Sales and other operating revenue Percent of Company sales and other operating revenue Sales and other operating revenue Percent of Company sales and other operating revenue Sales and other operating revenue Percent of Company sales and other operating revenue (Dollars in millions) Cliffs Steel (1) $ 1,349.4 65.4 % $ 1,182.8 60.0 % $ 994.6 68.3 % U.S. Steel (2) $ 300.8 14.6 % $ 284.8 14.4 % $ 210.0 14.4 % (1) Represents revenues included in our Domestic Coke segment. (2) Represents revenues included in our Domestic Coke and Logistics segments.

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Components of Income (Loss) Before Income Tax Expense (Benefit)	The components of income before income tax expense are as follows: Years Ended December 31, 2023 2022 2021 (Dollars in millions) Domestic $ 88.8 $ 107.1 $ 50.4 Foreign 9.0 14.6 16.7 Total $ 97.8 $ 121.7 $ 67.1
Components of Income Tax Expense (Benefit)	Income tax expense consisted of the following: Years Ended December 31, 2023 2022 2021 (Dollars in millions) Current tax expense: U.S. federal $ 7.9 $ 4.3 $ 0.8 State 4.7 5.4 3.7 Foreign 3.1 4.8 4.5 Total current tax expense 15.7 14.5 9.0 Deferred tax expense (benefit): U.S. federal 19.7 8.6 11.0 State (1.1) (6.3) (1.7) Total deferred tax expense 18.6 2.3 9.3 Total $ 34.3 $ 16.8 $ 18.3
Reconciliation of Income Tax Expense (Benefit)	The reconciliation of income tax expense at the U.S. statutory rate to income tax expense is as follows: Years Ended December 31, 2023 2022 2021 (Dollars in millions) Income tax expense at U.S. statutory rate $ 20.5 21.0 % $ 25.6 21.0 % $ 14.1 21.0 % Increase (reduction) in income taxes resulting from: Income attributable to noncontrolling interests in partnerships (1) (1.3) (1.3) % (0.9) (0.7) % (1.1) (1.7) % State and other income taxes, net of federal income tax effects (2) 3.0 3.1 % (0.9) (0.7) % 1.6 2.4 % Foreign income taxes (3) 3.1 3.1 % 4.8 4.0 % — — % R&D tax credit (4) (0.7) (0.7) % (4.0) (3.4) % — — % Non-deductible equity compensation 2.8 2.9 % 3.0 2.5 % 3.4 4.9 % Return to provision adjustments (1.8) (1.8) % (0.1) (0.1) % (0.1) (0.1) % Change in valuation allowance (3) 8.8 9.0 % (11.0) (9.0) % 0.5 0.8 % Other (0.1) (0.2) % 0.3 0.2 % (0.1) (0.1) % Income tax expense at effective tax rate $ 34.3 35.1 % $ 16.8 13.8 % $ 18.3 27.2 % (1) No income tax expense is reflected in the Consolidated Statements of Income for income attributable to noncontrolling interests in our Indiana Harbor cokemaking facility. (2) State tax rates in 2023 remained in line with the prior year. Lower apportioned state tax rates required the revaluation of certain deferred tax liabilities and resulted in deferred tax benefits of $4.9 million and $1.3 million recorded during 2022 and 2021, respectively. The decrease in apportioned state tax rates in 2022 was partly driven by the dissolution of SunCoke Energy Partners Finance Corp. (3) During 2023, the Company established an $8.4 million valuation allowance, which was a portion of an $11.3 million valuation allowance that was released during 2022 on deferred tax assets attributable to existing foreign tax credit carryforwards. The release of the valuation allowance during 2022 was a result of new regulations published in 2022 by the U.S. Treasury (2022 Foreign Tax Credit (“FTC”) final regulations) that made foreign taxes paid in future years to certain countries, including Brazil, no longer creditable in the U.S. After tax planning in 2022, the Company expected to be able to utilize its existing foreign tax credits carried forward from prior years. During 2023, Brazil enacted new legislation that aligned the Brazil transfer pricing law with the 2022 OECD Guidelines. As a result, the Company has determined that Brazil taxes paid or accrued in 2024 and forward will become creditable under the 2022 final FTC regulations. Due to the change in the Brazilian tax law, the FTCs that are projected to be created will cause $8.4 million of the foreign tax credit carryforward from prior years to not be utilized, resulting in the establishment of the valuation allowance during 2023. Also, during 2023, the IRS issued Notice 2023-55 and 2023-80 that generally allow taxpayers to defer the application of the of the 2022 FTC final regulations until further guidance is issued. Foreign income taxes paid in 2023 reflected the absence of the generation of foreign tax credits for taxes paid in Brazil due to the Company’s election not to defer the application of the 2022 FTC final regulations allowed under the notices. (4) SunCoke conducted an analysis with respect to the Company’s research and development activities, which resulted in a current tax benefit of $0.7 million and a deferred tax benefit of $4.0 million during 2023 and 2022, respectively.
Tax Effects of Temporary Differences that Comprise the Net Deferred Income Tax Liability	The tax effects of temporary differences that comprise the net deferred income tax liability from operations are as follows: December 31, 2023 2022 (Dollars in millions) Deferred tax assets: Retirement benefit liabilities $ 4.1 $ 4.2 Black lung benefit liabilities 13.2 13.2 Share-based compensation 0.6 2.0 Federal tax credit carryforward (1) — 8.7 Foreign tax credit carryforward (2) 8.4 9.2 State net operating loss carryforward, net of federal income tax effects (3) 13.2 12.9 Other liabilities not yet deductible 11.4 12.9 Total deferred tax assets 50.9 63.1 Less: valuation allowance (4) (17.9) (9.2) Deferred tax asset, net 33.0 53.9 Deferred tax liabilities: Properties, plants and equipment (158.3) (155.4) Investment in partnerships (65.1) (70.8) Total deferred tax liabilities (223.4) (226.2) Net deferred tax liability $ (190.4) $ (172.3) (1) Federal tax credit carryforward expires in 2034 through 2043. (2) Foreign tax credit carryforward expires in 2028 through 2032. (3) State net operating loss carryforward, net of federal income tax effects expires in 2033 through 2044. (4) Primarily related to state net operating loss carryforwards and valuation allowance attributable to existing foreign tax credit carryforwards.

Inventories (Tables)

Inventories (Tables)	12 Months Ended
	Dec. 31, 2023
Inventory Disclosure [Abstract]
Schedule of Components of Inventories	These components of inventories, net of lower of cost or net realizable value adjustments of $2.0 million and $2.6 million at December 31, 2023 and 2022, respectively, were as follows: December 31, 2023 2022 (Dollars in millions) Coal $ 107.7 $ 109.4 Coke 17.4 14.3 Materials, supplies and other 57.5 51.5 Total inventories $ 182.6 $ 175.2

Properties, Plants and Equipmen

Properties, Plants and Equipment (Tables)	12 Months Ended
	Dec. 31, 2023
Property, Plant and Equipment [Abstract]
Schedule of Components of Net Properties, Plants and Equipment	The components of net properties, plants and equipment were as follows: December 31, 2023 2022 (Dollars in millions) Coke and energy plant, machinery and equipment $ 2,193.9 $ 2,134.9 Logistics plant, machinery and equipment 181.2 176.6 Land and land improvements 110.0 106.8 Construction-in-progress 43.3 40.7 Other 46.3 46.3 Gross investment, at cost 2,574.7 2,505.3 Less: accumulated depreciation (1,383.6) (1,276.0) Total properties, plants and equipment, net $ 1,191.1 $ 1,229.3

Intangible Assets (Tables)

Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2023
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Finite-Lived Intangible Assets	Intangible assets, net, include goodwill allocated to our Domestic Coke segment of $3.4 million at both December 31, 2023 and 2022, and other intangibles detailed in the table below, excluding fully amortized intangible assets. There were no changes in the carrying amount of goodwill during the fiscal years ended December 31, 2023 and 2022, respectively. December 31, 2023 December 31, 2022 Weighted - Average Remaining Amortization Years Gross Carrying Amount Accumulated Amortization Net Gross Carrying Amount Accumulated Amortization Net (Dollars in millions) Customer relationships 1 $ 6.7 $ 6.2 $ 0.5 $ 6.7 $ 5.6 $ 1.1 Permits 19 31.7 5.9 25.8 31.7 4.5 27.2 Other 27 1.6 0.2 1.4 1.6 0.1 1.5 Total $ 40.0 $ 12.3 $ 27.7 $ 40.0 $ 10.2 $ 29.8
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense	Based on the carrying value of finite-lived intangible assets as of December 31, 2023, we estimate amortization expense for each of the next five years and the aggregate amount thereafter as follows: (Dollars in millions) 2024 $ 1.9 2025 1.5 2026 1.5 2027 1.4 2028 1.4 2029-Thereafter 20.0 Total $ 27.7

Asset Retirement Obligations (T

Asset Retirement Obligations (Tables)	12 Months Ended
	Dec. 31, 2023
Asset Retirement Obligation [Abstract]
Reconciliation of Changes in the Asset Retirement Obligation	The following table provides a reconciliation of changes in the asset retirement obligation from operations during each period: Years ended December 31, 2023 2022 (Dollars in millions) Asset retirement obligation at beginning of year $ 13.8 $ 12.3 Liabilities settled (0.7) — Accretion expense (1) 1.0 0.9 Revisions in estimated cash flows — 0.6 Asset retirement obligation at end of year (2) $ 14.1 $ 13.8 (1) Included in cost of products sold and operating expenses on the Consolidated Statements of Income. (2)

Retirement Benefits Plans (Tabl

Retirement Benefits Plans (Tables)	12 Months Ended
	Dec. 31, 2023
Retirement Benefits [Abstract]
Postretirement Benefit Plans Expense	Postretirement benefit plans expense consisted of the following components: Years Ended December 31, 2023 2022 2021 (Dollars in millions) Interest cost on benefit obligations $ 0.9 $ 0.6 $ 0.5 Amortization of: Actuarial losses 0.4 0.7 0.8 Prior service benefit (0.2) (0.2) (0.4) Total expense $ 1.1 $ 1.1 $ 0.9
Discount Rates Used to Determine Benefit Obligations For the Plans	The following assumptions were used to determine postretirement benefit plans expense: December 31, 2023 2022 2021 Discount rate 5.25 % 2.50 % 2.00 % December 31, 2023 2022 Discount rate 4.95 % 5.25 %
Recognized Components of Other Comprehensive Income (Loss)	The following amounts were recognized as components of other comprehensive income (loss) before related tax impacts: Years Ended December 31, 2023 2022 2021 (Dollars in millions) Reclassifications to earnings of: Actuarial loss amortization $ 0.4 $ 0.7 $ 0.8 Prior service benefit amortization (0.2) (0.2) (0.4) Retirement benefit plan funded status Actuarial (losses) gains (0.6) 4.0 1.3 $ (0.4) $ 4.5 $ 1.7
Components of Changes in Benefit Obligations and Fair Value of Plan Assets	The following table sets forth the components of the changes in benefit obligations: Years Ended December 31, 2023 2022 (Dollars in millions) Benefit obligation at beginning of year $ 18.8 $ 24.4 Interest cost 0.9 0.6 Actuarial losses (gains) 0.6 (4.0) Benefits paid (2.2) (2.2) Benefit obligation at end of year (1) $ 18.1 $ 18.8 (1) The current portion of retirement benefit liabilities, which totaled $2.3 million and $2.4 million at December 31, 2023 and 2022, respectively, is classified in accrued liabilities on the Consolidated Balance Sheets.
Cumulative Amounts Not Recognized	The following table sets forth the cumulative amounts not yet recognized in net income: Years Ended December 31, 2023 2022 (Dollars in millions) Cumulative amounts not yet recognized in net income: Actuarial losses $ 5.4 $ 5.2 Prior service benefits (0.7) (0.8) Accumulated other comprehensive loss (before related tax benefit) $ 4.7 $ 4.4
Expected Benefit Payments	The expected benefit payments through 2033 for the postretirement benefit plan are as follows: (Dollars in millions) 2024 $ 2.3 2025 2.2 2026 2.0 2027 1.8 2028 1.7 2029 through 2033 $ 6.8

Accrued Liabilities (Tables)

Accrued Liabilities (Tables)	12 Months Ended
	Dec. 31, 2023
Balance Sheet Related Disclosures [Abstract]
Schedule of Accrued Liabilities	Accrued liabilities consist of following: December 31, 2023 2022 (Dollars in millions) Accrued benefits $ 26.8 $ 29.7 Current portion of postretirement benefit obligation 2.3 2.4 Other taxes payable 10.4 9.8 Current portion of black lung liability 5.0 5.9 Accrued legal 0.5 4.9 Other 6.7 8.7 Total accrued liabilities $ 51.7 $ 61.4

Debt and Financing Obligations

Debt and Financing Obligations (Tables)	12 Months Ended
	Dec. 31, 2023
Debt Disclosure [Abstract]
Schedule of Total Debt and Financing Obligation	Total debt and financing obligations consisted of the following: December 31, 2023 2022 (Dollars in millions) 4.875 percent senior notes, due 2029 (“2029 Senior Notes”) $ 500.0 $ 500.0 $350.0 revolving credit facility, due 2026 (“Revolving Facility”) — 35.0 5.346 percent financing obligation, due 2024 — 8.8 Total borrowings $ 500.0 $ 543.8 Debt issuance costs (9.7) (11.6) Total debt and financing obligation $ 490.3 $ 532.2 Less: current portion of long-term debt and financing obligation — 3.3 Total long-term debt and financing obligation $ 490.3 $ 528.9
Schedule of Maturities of Long-Term Debt	As of December 31, 2023, the combined aggregate amount of maturities for long-term borrowings for each of the next five years and thereafter is as follows: (Dollars in millions) 2024 $ — 2025 — 2026 — 2027 — 2028 — 2029-Thereafter 500.0 Total $ 500.0

Commitments and Contingent Li_2

Commitments and Contingent Liabilities (Tables)	12 Months Ended
	Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Schedule of Benefit Liabilities	The following table summarizes discount rates utilized, active claims and the total black lung liabilities. Our independent actuarial consultants calculate the present value of the black lung liability annually in the fourth quarter, unless there are changes in facts and circumstances that could materially alter the amount of the liability. December 31, 2023 2022 (Dollars in millions) Discount rate (1) 4.5 % 4.9 % Active claims 311 332 Total black lung liability, discounted (2) $ 58.2 $ 58.1 Total black lung liability, undiscounted $ 96.0 $ 88.4 (1) The discount rate is determined based on a portfolio of high-quality corporate bonds with maturities that are consistent with the estimated duration of our black lung obligations. A decrease of 25 basis points in the discount rate would have increased black lung expense by $1.4 million in 2023. (2) The current portion of the black lung liability was $5.0 million and $5.9 million at December 31, 2023 and 2022, respectively, and was included in accrued liabilities on the Consolidated Balance Sheets. The following table reconciles the expected aggregate undiscounted amount to amounts recognized in the Consolidated Balance Sheets: December 31, 2023 2022 (Dollars in millions) Black lung liability, undiscounted $ 96.0 $ 88.4 Impact of discounting (37.8) (30.3) Black lung liability, discounted $ 58.2 $ 58.1 The following table summarizes the annual black lung payments and expense (benefit): Years Ended December 31, 2023 2022 2021 (Dollars in millions) Payments $ 5.4 $ 5.0 $ 4.4 Expense (benefit) (1) $ 5.5 $ (0.2) $ 3.1
Schedule of Other Commitments	Expected payments for each of the five succeeding years and the aggregate amount thereafter as of December 31, 2023: (Dollars in millions) 2024 $ 5.0 2025 3.9 2026 4.4 2027 4.0 2028 3.8 2029-Thereafter 74.9 Total $ 96.0

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2023
Leases [Abstract]
Lease Expense and Weighted Average Remaining Lease Term and Weighted Average Discount Rate	The components of lease expense were as follows: Years ended December 31, 2023 2022 (Dollars in millions) Operating leases: Cost of products sold and operating expenses $ 2.3 $ 2.3 Selling, general and administrative expenses 0.5 0.4 $ 2.8 $ 2.7 Short-term leases: Cost of products sold and operating expenses (1)(2) 4.0 5.5 Total lease expense $ 6.8 $ 8.2 (1) Includes expenses for month-to-month equipment leases, which are classified as short-term as the Company is not reasonably certain to renew the lease term beyond one month. (2) Includes variable lease expenses, which are immaterial to the consolidated financial statements. The weighted average remaining lease term and weighted average discount rate were as follows: Years ended December 31, 2023 2022 Weighted average remaining lease term of operating leases 7.1 years 5.9 years Weighted average discount rate of operating leases 4.7 % 4.2 %
Supplemental Balance Sheet and Cash Flow Information	Supplemental balance sheet information related to leases was as follows: Years ended December 31, Financial Statement Classification 2023 2022 (Dollars in millions) Operating ROU assets Deferred charges and other assets $ 11.6 $ 11.3 Operating lease liabilities: Current operating lease liabilities Accrued liabilities $ 2.3 $ 2.0 Noncurrent operating lease liabilities Other deferred credits and liabilities 8.6 8.5 Total operating lease liabilities $ 10.9 $ 10.5 Supplemental cash flow information related to leases was as follows: Years ended December 31, 2023 2022 (Dollars in millions) Operating cash flow information: Cash paid for amounts included in the measurement of operating lease liabilities $ 2.5 $ 2.4 Non-cash activity: ROU assets obtained in exchange for new operating lease liabilities $ 2.6 $ 0.6
Lease Maturity, Operating Lease	Maturities of operating lease liabilities as of December 31, 2023 are as follows: (Dollars in millions) 2024 $ 2.7 2025 2.6 2026 1.8 2027 1.4 2028 1.4 2029-Thereafter 3.1 Total lease payments 13.0 Less: imputed interest 2.1 Total lease liabilities $ 10.9

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Loss (Tables)	12 Months Ended
	Dec. 31, 2023
Equity [Abstract]
Components of Accumulated Other Comprehensive Loss	The following tables set forth the changes in the balance of accumulated other comprehensive loss, net of tax, by component: Benefit Plans Currency Translation Adjustments Total (Dollars in millions) At December 31, 2021 $ (6.9) $ (9.8) $ (16.7) Other comprehensive income before reclassifications / adjustments 0.4 0.2 0.6 Retirement benefit plans funded status adjustment 3.1 — 3.1 Net current period change in accumulated other comprehensive loss 3.5 0.2 3.7 At December 31, 2022 $ (3.4) $ (9.6) $ (13.0) Other comprehensive income before reclassifications / adjustments 0.1 0.5 0.6 Retirement benefit plans funded status adjustment (0.4) — (0.4) Net current period change in accumulated other comprehensive loss (0.3) 0.5 0.2 At December 31, 2023 $ (3.7) $ (9.1) $ (12.8)
Impact of Net Income of Reclassification Adjustments	The increase in net income due to reclassification adjustments from accumulated other comprehensive income were as follows (1) : Years Ended December 31, 2023 2022 2021 (Dollars in millions) Amortization of benefit plans to net income: (2) Actuarial loss $ (0.4) $ (0.7) $ (0.8) Prior service benefit 0.2 0.2 0.4 Total before taxes (0.2) (0.5) (0.4) Income tax 0.1 0.1 0.1 Total, net of tax $ (0.1) $ (0.4) $ (0.3) (1) Amounts in parentheses indicate debits to net income. (2)

Share-Based Compensation (Table

Share-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2023
Share-Based Payment Arrangement, Noncash Expense [Abstract]
Summary of Information with respect to Common Stock Option Awards and Performance Share Units	The following table summarizes information with respect to common stock option awards outstanding as of December 31, 2023 and stock option activity during the fiscal year then ended: Number of Weighted Weighted Average Remaining Contractual Term (years) Aggregate Outstanding at December 31, 2022 1,520,210 $ 15.06 2.7 0.2 Exercised (21,887) $ 4.01 Expired (298,667) $ 16.52 Outstanding and Exercisable December 31, 2023 1,199,656 $ 14.89 2.3 0.5 The Company granted the following PSUs during the years ended December 31, 2023, 2022 and 2021: Number of PSUs Weighted Average Grant Date Fair Value per Unit Grant Date Fair Value (Dollars in millions) 2023 grant (1) 147,232 $ 9.84 $ 1.4 2022 grant (1) 154,860 $ 8.40 $ 1.3 2021 grant (1) 177,176 $ 7.60 $ 1.3 (1) The service period for the 2023, 2022, and 2021 PSUs ends on December 31, 2025, 2024 and 2023, and the awards will vest during the first quarter of 2026, 2025 and 2024, respectively. The service period for certain retiree eligible participants is accelerated.
Summary of Information with Respect to RSUs	The Company granted the following RSUs during the years ended December 31, 2023, 2022 and 2021: Number of RSUs Weighted Average Grant-Date Fair Value per Unit Grant Date Fair Value (Dollars in millions) 2023 grants 352,646 $ 8.97 $ 3.2 2022 grants 346,600 $ 7.62 $ 2.6 2021 grants 463,476 $ 6.72 $ 3.1 The following table summarizes information with respect to RSUs outstanding as of December 31, 2023 and RSU activity during the fiscal year then ended: Number of Weighted Nonvested at December 31, 2022 670,978 $ 7.08 Granted 352,646 $ 8.97 Vested (308,354) $ 6.83 Nonvested at December 31, 2023 715,270 $ 8.12
Summary of Information with Respect to PSUs	The following table summarizes information with respect to unearned PSUs outstanding as of December 31, 2023 and PSU activity during the fiscal year then ended: Number of Weighted Nonvested at December 31, 2022 498,746 $ 7.21 Granted 147,232 $ 9.84 Performance adjustments 161,091 $ 6.70 Vested (354,244) $ 6.70 Nonvested at December 31, 2023 452,825 $ 7.50
Schedule of Unrecognized Compensation Cost	Below is a summary of the compensation expense, unrecognized compensation costs, the period for which the unrecognized compensation cost is expected to be recognized over for each award: Years Ended December 31, 2023 2022 2021 2023 2022 2021 December 31, 2023 Compensation Expense (1) Net of tax Unrecognized Compensation Cost Weighted Average Remaining Recognition Period (Dollars in millions) (Dollars in millions) (Years) Equity Awards: Stock Options $ — $ — $ 0.1 $ — $ — $ 0.1 $ — — RSUs 2.5 2.5 2.3 2.0 1.9 1.8 $ 0.6 1.6 PSUs 1.9 3.9 3.4 1.4 3.0 2.6 $ 0.7 1.6 Total equity awards $ 4.4 $ 6.4 $ 5.8 $ 3.4 $ 4.9 $ 4.5 Liability Awards: Cash RSUs $ 2.6 $ 2.1 $ 1.7 $ 2.0 $ 1.6 $ 1.3 $ 1.5 1.7 Cash incentive award 2.7 5.1 3.4 2.0 3.9 2.6 $ 1.5 1.6 Total liability awards $ 5.3 $ 7.2 $ 5.1 $ 4.0 $ 5.5 $ 3.9 (1) Compensation expense is recognized by the Company in selling, general and administrative expenses on the Consolidated Statements of Income.

Earnings Per Share (Tables)

Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2023
Earnings Per Share [Abstract]
Schedule of Reconciliation of Weighted-Average Number of Common Shares Used to Compute Basic EPS to Those Used to Compute Diluted EPS	The following table sets forth the reconciliation of the weighted-average number of common shares used to compute basic earnings per share to those used to compute diluted EPS: Years Ended December 31, 2023 2022 2021 (Shares in millions) Weighted-average number of common shares outstanding-basic 84.7 83.8 83.0 Add: effect of dilutive share-based compensation awards 0.2 0.8 0.7 Weighted-average number of shares-diluted 84.9 84.6 83.7
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share	The following table shows stock options, restricted stock units, and performance stock units that are excluded from the computation of diluted earnings per share as the shares would have been anti-dilutive: Years Ended December 31, 2023 2022 2021 (Shares in millions) Stock options 1.2 1.6 2.5 Total 1.2 1.6 2.5

Revenue from Contracts with C_2

Revenue from Contracts with Customers (Tables)	12 Months Ended
	Dec. 31, 2023
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue	The following table provides disaggregated sales and other operating revenue by product or service, excluding intersegment revenues: Years Ended December 31, 2023 2022 2021 (Dollars in millions) Sales and other operating revenue: Cokemaking $ 1,898.5 $ 1,791.3 $ 1,293.6 Energy 47.3 61.5 56.1 Logistics 73.1 76.7 64.3 Operating and licensing fees 35.2 38.0 36.6 Other 9.1 5.0 5.4 Sales and other operating revenue $ 2,063.2 $ 1,972.5 $ 1,456.0

Business Segment Information (T

Business Segment Information (Tables)	12 Months Ended
	Dec. 31, 2023
Segment Reporting [Abstract]
Schedule of Business Segment Information	The following table includes Adjusted EBITDA reportable segments, as defined below, which is a measure of segment profit or loss reported to the chief operating decision maker for purposes of allocating resources to the segments and assessing their performance: Years Ended December 31, 2023 2022 2021 (Dollars in millions) Sales and other operating revenue: Domestic Coke $ 1,954.0 $ 1,856.9 $ 1,354.5 Brazil Coke 35.2 38.0 36.6 Logistics 74.0 77.6 64.9 Logistics intersegment sales 22.1 28.9 27.1 Elimination of intersegment sales (22.1) (28.9) (27.1) Total sales and other operating revenue $ 2,063.2 $ 1,972.5 $ 1,456.0 Adjusted EBITDA reportable segments: Domestic Coke $ 247.8 $ 263.4 $ 243.4 Brazil Coke 9.1 14.5 17.2 Logistics 44.3 49.7 43.5 Total Adjusted EBITDA reportable segments $ 301.2 $ 327.6 $ 304.1 Depreciation and amortization expense: Domestic Coke $ 129.4 $ 126.8 $ 119.0 Brazil Coke 0.3 0.2 0.4 Logistics 12.8 14.5 13.3 Total reportable segments $ 142.5 $ 141.5 $ 132.7 Corporate and Other 0.3 1.0 1.2 Total depreciation and amortization expense $ 142.8 $ 142.5 $ 133.9 Capital expenditures: Domestic Coke $ 103.2 $ 70.3 $ 83.1 Brazil Coke 0.4 0.1 0.3 Logistics 5.1 4.5 14.7 Total reportable segments $ 108.7 $ 74.9 $ 98.1 Corporate and Other 0.5 0.6 0.5 Total capital expenditures $ 109.2 $ 75.5 $ 98.6 The following table sets forth the Company’s segment assets: December 31, 2023 2022 (Dollars in millions) Segment assets: Domestic Coke $ 1,405.5 $ 1,422.6 Brazil Coke 11.9 15.7 Logistics (1) 158.4 193.5 Total reportable segments $ 1,575.8 $ 1,631.8 Corporate and Other 84.6 22.8 Total assets $ 1,660.4 $ 1,654.6 (1)
Schedule of Reconciliation of Adjusted EBITDA (Unaudited) to Net Income	Below is a reconciliation of Adjusted EBITDA reportable segments to net income, which is its most directly comparable financial measure calculated and presented in accordance with GAAP: Years Ended December 31, 2023 2022 2021 (Dollars in millions) Net income $ 63.5 $ 104.9 $ 48.8 Add: Depreciation and amortization expense 142.8 142.5 133.9 Interest expense, net 27.3 32.0 42.5 Loss on extinguishment of debt — — 31.9 Income tax expense 34.3 16.8 18.3 Transaction costs (1) 0.9 1.5 — Corporate and Other 32.4 29.9 28.7 Adjusted EBITDA reportable segments $ 301.2 $ 327.6 $ 304.1 (1) Costs incurred as part of the granulated pig iron project with U.S. Steel.

General and Basis of Presenta_2

General and Basis of Presentation (Details) T in Millions	12 Months Ended
	Dec. 31, 2023 facility T
Results of Operations for Oil and Gas Producing Activities, by Geographic Area [Line Items]
Coke production experience, more than	60 years
Indiana Harbor
Results of Operations for Oil and Gas Producing Activities, by Geographic Area [Line Items]
Ownership percentage (as a percent)	14.80%
United States
Results of Operations for Oil and Gas Producing Activities, by Geographic Area [Line Items]
Number of facilities | facility	5
Cokemaking capacity (in tons)	4.2
Brazil
Results of Operations for Oil and Gas Producing Activities, by Geographic Area [Line Items]
Number of facilities | facility	1
Cokemaking capacity (in tons)	1.7
Gulf Coast, East Coast, Great Lakes, and International Ports
Results of Operations for Oil and Gas Producing Activities, by Geographic Area [Line Items]
Coal handling capacity (in tons), more than	40
Coal storage capacity (in tons)	3

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Details) $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($) employee	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Property, Plant and Equipment
Accrued capital expenditures | $	$ 8.7	$ 15.6	$ 9.6
United States
Labor Concentrations
Number of employees	871
Percent of employees represented by United Steelworkers union	40%
Percent of employees represented by International Union of Operating Engineers	3%
Brazil
Labor Concentrations
Number of employees	280
Coke and energy plant, machinery and equipment | Minimum
Property, Plant and Equipment
Useful life	20 years
Coke and energy plant, machinery and equipment | Maximum
Property, Plant and Equipment
Useful life	30 years
Logistics plant, machinery and equipment | Minimum
Property, Plant and Equipment
Useful life	15 years
Logistics plant, machinery and equipment | Maximum
Property, Plant and Equipment
Useful life	30 years

Customer Concentrations (Narrat

Customer Concentrations (Narrative) (Details) T in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($) customer T	Dec. 31, 2022 USD ($)
Concentration Risk [Line Items]
Number of primary customers | customer	2
Customer Concentration Risk
Concentration Risk [Line Items]
Quantity of coke sold to three primary customers (in tons) | T	3.5
Customer Concentration Risk | Cliffs Steel and U.S. Steel | Accounts Receivable
Concentration Risk [Line Items]
Concentration risk, percentage	50%	39%
Customer Concentration Risk | Cliffs Steel | Accounts Receivable
Concentration Risk [Line Items]
Accounts receivable net	$ 35.7	$ 33.5
Customer Concentration Risk | U.S. Steel | Accounts Receivable
Concentration Risk [Line Items]
Accounts receivable net	$ 7.9	$ 7.1

Customer Concentrations (Sales

Customer Concentrations (Sales and Receivables to Significant Customers) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Concentration Risk [Line Items]
Sales and other operating revenue	$ 2,063.2	$ 1,972.5	$ 1,456
Cliffs Steel | Sales Revenue, Net | Customer Concentration Risk
Concentration Risk [Line Items]
Sales and other operating revenue	$ 1,349.4	$ 1,182.8	$ 994.6
Percent of Company sales and other operating revenue	65.40%	60%	68.30%
U.S. Steel | Sales Revenue, Net | Customer Concentration Risk
Concentration Risk [Line Items]
Sales and other operating revenue	$ 300.8	$ 284.8	$ 210
Percent of Company sales and other operating revenue	14.60%	14.40%	14.40%

Income Taxes (Components of Inc

Income Taxes (Components of Income From Operations) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Domestic	$ 88.8	$ 107.1	$ 50.4
Foreign	9	14.6	16.7
Income before income tax expense	$ 97.8	$ 121.7	$ 67.1

Income Taxes (Components of I_2

Income Taxes (Components of Income Tax Expense) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Current tax expense:
U.S. federal	$ 7.9	$ 4.3	$ 0.8
State	4.7	5.4	3.7
Foreign	3.1	4.8	4.5
Total current tax expense	15.7	14.5	9
Deferred tax expense (benefit):
U.S. federal	19.7	8.6	11
State	(1.1)	(6.3)	(1.7)
Total deferred tax expense	18.6	2.3	9.3
Total	$ 34.3	$ 16.8	$ 18.3

Income Taxes (Reconciliation of

Income Taxes (Reconciliation of Income Tax Expense to US Statutory Rate) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Reconciliation of income tax expense
Income tax expense at U.S. statutory rate	$ 20,500,000	$ 25,600,000	$ 14,100,000
Income tax expense attributable to noncontrolling interests	(1,300,000)	(900,000)	(1,100,000)
State and other income taxes, net of federal income tax effects	3,000,000	(900,000)	1,600,000
Foreign income taxes	3,100,000	4,800,000	0
R&D tax credit	(700,000)	(4,000,000)	0
Non-deductible equity compensation	2,800,000	3,000,000	3,400,000
Return to provision adjustments	(1,800,000)	(100,000)	(100,000)
Change in valuation allowance	8,800,000	(11,000,000)	500,000
Other	(100,000)	300,000	(100,000)
Total	$ 34,300,000	$ 16,800,000	$ 18,300,000
Reconciliation of income tax expense (as a percent)
Income tax expense at U.S. statutory rate	21%	21%	21%
Income attributable to noncontrolling interests in partnerships	(1.30%)	(0.70%)	(1.70%)
State and other income taxes, net of federal income tax effects	3.10%	(0.70%)	2.40%
Foreign income taxes	3.10%	4%	0%
R&D tax credit	(0.70%)	(3.40%)	0%
Non-deductible equity compensation	2.90%	2.50%	4.90%
Return to provision adjustments	(1.80%)	(0.10%)	(0.10%)
Change in valuation allowance	9%	(9.00%)	0.80%
Other	(0.20%)	0.20%	(0.10%)
Income tax expense at effective tax rate	35.10%	13.80%	27.20%
Valuation Allowance [Line Items]
Income tax expense attributable to noncontrolling interests	$ 1,300,000	$ 900,000	$ 1,100,000
Impact of change in tax laws		4,900,000	1,300,000
Impact of research and development tax credits	700,000	4,000,000	$ 0
Indiana Harbor
Reconciliation of income tax expense
Income tax expense attributable to noncontrolling interests	0
Valuation Allowance [Line Items]
Income tax expense attributable to noncontrolling interests	0
Foreign Tax Credit Carryforward
Valuation Allowance [Line Items]
Valuation allowance, increase (decrease)	$ 8,400,000	$ (11,300,000)

Income Taxes (Components of Net

Income Taxes (Components of Net Deferred Tax Liability) (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Deferred tax assets:
Retirement benefit liabilities	$ 4.1	$ 4.2
Black lung benefit liabilities	13.2	13.2
Share-based compensation	0.6	2
Federal tax credit carryforward	0	8.7
Foreign tax credit carryforward	8.4	9.2
State net operating loss carryforward, net of federal income tax effects	13.2	12.9
Other liabilities not yet deductible	11.4	12.9
Total deferred tax assets	50.9	63.1
Less valuation allowance	(17.9)	(9.2)
Deferred tax asset, net	33	53.9
Deferred tax liabilities:
Properties, plants and equipment	(158.3)	(155.4)
Investment in partnerships	(65.1)	(70.8)
Total deferred tax liabilities	(223.4)	(226.2)
Net deferred tax liability	$ (190.4)	$ (172.3)

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
State and foreign income tax returns subject to examination period (in years)	3 years
State and foreign income tax returns subject to examination period maximum (in years)	5 years
Period amended federal returns remain subject to examination	1 year
Unrecognized tax benefits, decrease resulting from prior period tax positions	$ 100,000	$ 300,000
Unrecognized tax benefits	400,000	300,000
Uncertain tax positions	0		$ 0
Interest and penalties	$ 0	$ 0	$ 0

Inventories (Details)

Inventories (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Inventory Disclosure [Abstract]
Coal	$ 107.7	$ 109.4
Coke	17.4	14.3
Materials, supplies and other	57.5	51.5
Total inventories	182.6	175.2
Inventory adjustments	$ 2	$ 2.6

Properties, Plants, and Equip_2

Properties, Plants, and Equipment (Components) (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Line Items]
Gross investment, at cost	$ 2,574.7	$ 2,505.3
Less: accumulated depreciation	(1,383.6)	(1,276)
Total properties, plants and equipment, net	1,191.1	1,229.3
Coke and energy plant, machinery and equipment
Property, Plant and Equipment [Line Items]
Gross investment, at cost	2,193.9	2,134.9
Logistics plant, machinery and equipment
Property, Plant and Equipment [Line Items]
Gross investment, at cost	181.2	176.6
Land and land improvements
Property, Plant and Equipment [Line Items]
Gross investment, at cost	110	106.8
Construction-in-progress
Property, Plant and Equipment [Line Items]
Gross investment, at cost	43.3	40.7
Other
Property, Plant and Equipment [Line Items]
Gross investment, at cost	$ 46.3	$ 46.3

Intangible Assets ( Narrative)

Intangible Assets ( Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Finite-Lived Intangible Assets [Line Items]
Change in goodwill balance	$ 0	$ 0
Total amortization expense of intangible assets	$ 2,100,000	2,000,000	$ 2,000,000
Permits
Finite-Lived Intangible Assets [Line Items]
Useful life	19 years
Convent Marine Terminal | Permits
Finite-Lived Intangible Assets [Line Items]
Useful life	27 years
Average remaining renewal term	5 years 4 months 24 days
Domestic Coke | Operating Segments
Finite-Lived Intangible Assets [Line Items]
Intangible assets, net	$ 3,400,000	$ 3,400,000

Intangible Assets (Gross and Ne

Intangible Assets (Gross and Net Intangible Assets) (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 40	$ 40
Accumulated Amortization	12.3	10.2
Total	$ 27.7	29.8
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Weighted - Average Remaining Amortization Years	1 year
Gross Carrying Amount	$ 6.7	6.7
Accumulated Amortization	6.2	5.6
Total	$ 0.5	1.1
Permits
Finite-Lived Intangible Assets [Line Items]
Weighted - Average Remaining Amortization Years	19 years
Gross Carrying Amount	$ 31.7	31.7
Accumulated Amortization	5.9	4.5
Total	$ 25.8	27.2
Other
Finite-Lived Intangible Assets [Line Items]
Weighted - Average Remaining Amortization Years	27 years
Gross Carrying Amount	$ 1.6	1.6
Accumulated Amortization	0.2	0.1
Total	$ 1.4	$ 1.5

Intangible Assets (Schedule of

Intangible Assets (Schedule of Future Amortization Expense) (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Goodwill and Intangible Assets Disclosure [Abstract]
2024	$ 1.9
2025	1.5
2026	1.5
2027	1.4
2028	1.4
2029-Thereafter	20
Total	$ 27.7	$ 29.8

Asset Retirement Obligations (D

Asset Retirement Obligations (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning Balance	$ 13,800,000	$ 12,300,000
Liabilities settled	(700,000)	0
Accretion expense	1,000,000	900,000
Revisions in estimated cash flows	0	600,000
Ending Balance	14,100,000	13,800,000
Current portion of asset retirement obligation liabilities	$ 0	$ 400,000

Retirement Benefits Plans (Narr

Retirement Benefits Plans (Narrative) (Details) - USD ($) $ in Millions		12 Months Ended
	Jan. 01, 2011	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plan Disclosure [Line Items]
Company's pretax income and the aggregate compensation levels of participating employees		$ 7.9	$ 7.9	$ 6.9
Postretirement benefit plans
Defined Benefit Plan Disclosure [Line Items]
Years of service, less than	10 years
Health care cost trend assumption increased health care cost trend rates (as a percent)		6.75%	7%
Health care cost trend assumption increased health care cost trend rates (as a percent)		5%	5%

Retirement Benefits Plans (Post

Retirement Benefits Plans (Postretirement Benefit Plans (Benefit) Expense Components) (Details) - Postretirement benefit plans - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plan Disclosure [Line Items]
Interest cost on benefit obligations	$ 0.9	$ 0.6	$ 0.5
Amortization of:
Actuarial losses	0.4	0.7	0.8
Prior service benefit	(0.2)	(0.2)	(0.4)
Total expense	$ 1.1	$ 1.1	$ 0.9

Retirement Benefits Plans (Assu

Retirement Benefits Plans (Assumptions Used to Determine Defined Benefit Plan and Postretirement Benefit Plans Expense (Benefit) (Details)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Postretirement benefit plans
Defined Benefit Plan Disclosure [Line Items]
Discount rate	5.25%	2.50%	2%

Retirement Benefits Plans (Amou

Retirement Benefits Plans (Amounts Recognized as Components of Other Comprehensive (Loss) Income) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Reclassifications to earnings of:
Prior service benefit amortization	$ (0.1)	$ (0.4)	$ (0.3)
Retirement benefit plan funded status adjustments:
Actuarial (losses) gains	0.4	(3.1)	(1)
Total	(0.1)	(0.4)	(0.3)
Postretirement benefit plans
Reclassifications to earnings of:
Actuarial loss amortization	0.4	0.7	0.8
Prior service benefit amortization	(0.2)	(0.2)	(0.4)
Retirement benefit plan funded status adjustments:
Actuarial (losses) gains	(0.6)	4	1.3
Total	$ (0.4)	$ 4.5	$ 1.7

Retirement Benefits Plans (Comp

Retirement Benefits Plans (Components of the Changes in Benefit Obligations and Fair Value of Plan Assets) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Current portion of retirement liabilities classified in accrued liabilities	$ 2.3	$ 2.4
Postretirement benefit plans
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation at beginning of year	18.8	24.4
Interest cost	0.9	0.6	$ 0.5
Actuarial losses (gains)	0.6	(4)
Benefits paid	(2.2)	(2.2)
Benefit obligations at end of year	$ 18.1	$ 18.8	$ 24.4

Retirement Benefits Plans (Cumu

Retirement Benefits Plans (Cumulative Amounts Not Yet Recognized in Net Income) (Details) - Postretirement benefit plans - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Cumulative amounts not yet recognized in net income:
Actuarial losses	$ 5.4	$ 5.2
Prior service benefits	(0.7)	(0.8)
Accumulated other comprehensive loss (before related tax benefit)	$ 4.7	$ 4.4

Retirement Benefits Plans (Expe

Retirement Benefits Plans (Expected Benefit Payments) (Details) - Postretirement benefit plans $ in Millions	Dec. 31, 2023 USD ($)
Regulatory Liabilities [Line Items]
2024	$ 2.3
2025	2.2
2026	2
2027	1.8
2028	1.7
2029 through 2033	$ 6.8

Retirement Benefits Plans (Disc

Retirement Benefits Plans (Discount Rate) (Details)	Dec. 31, 2023	Dec. 31, 2022
Postretirement benefit plans
Defined Benefit Plan Disclosure [Line Items]
Discount rate (as a percent)	4.95%	5.25%

Accrued Liabilities (Details)

Accrued Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Balance Sheet Related Disclosures [Abstract]
Accrued benefits	$ 26.8	$ 29.7
Current portion of postretirement benefit obligation	2.3	2.4
Other taxes payable	10.4	9.8
Current portion of black lung liability	5	5.9
Accrued legal	0.5	4.9
Other	6.7	8.7
Total accrued liabilities	$ 51.7	$ 61.4

Debt and Financing Obligation_2

Debt and Financing Obligations (Schedule of Total Debt and Financing Obligation) (Details) - USD ($)	Dec. 31, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Total borrowings	$ 500,000,000	$ 543,800,000
Debt issuance costs	(9,700,000)	(11,600,000)
Total debt and financing obligation	490,300,000	532,200,000
Less: current portion of long-term debt and financing obligation	0	3,300,000
Total long-term debt and financing obligation	$ 490,300,000	528,900,000
4.875 percent senior notes, due 2029 (“2029 Senior Notes”) | Senior notes
Debt Instrument [Line Items]
Interest rate on senior notes (as a percent)	4.875%
Total borrowings	$ 500,000,000	500,000,000
$350.0 revolving credit facility, due 2026 (“Revolving Facility”) | Line of Credit | Revolving credit facility
Debt Instrument [Line Items]
Principal amount of term loan	350,000,000
Total borrowings	$ 0	35,000,000
5.346 percent financing obligation, due 2024 | Financing Obligation
Debt Instrument [Line Items]
Interest rate on senior notes (as a percent)	5.346%
Total borrowings	$ 0	$ 8,800,000

Debt and Financing Obligation_3

Debt and Financing Obligations (Revolving Facility) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Outstanding balance	$ 500	$ 543.8
Revolving credit facility | Line of Credit | SunCoke Revolving Credit Facility, Due 2024
Debt Instrument [Line Items]
Remaining borrowing capacity	$ 350
Unused capacity commitment fee	0.175%
The weighted-average interest rate for borrowings outstanding under credit agreement (as a percent)	6.50%
Revolving credit facility | Line of Credit | SunCoke Revolving Credit Facility, Due 2024 | SOFR
Debt Instrument [Line Items]
Basis spread on variable rate	0.10%
Revolving credit facility | Line of Credit | SunCoke Revolving Credit Facility, Due 2024 | Secured Overnight Financing Rate (SOFR) Floor
Debt Instrument [Line Items]
Basis spread on variable rate	0%
Revolving credit facility | Line of Credit | SunCoke Revolving Credit Facility, Due 2024 | Adjusted Secured Overnight Financing Rate (SOFR)
Debt Instrument [Line Items]
Basis spread on variable rate	1.50%
Revolving credit facility | Line of Credit | SunCoke Revolving Credit Facility, Due 2024 | Adjusted Base Rate
Debt Instrument [Line Items]
Basis spread on variable rate	0.50%
Letter of Credit | Line of Credit | SunCoke Revolving Credit Facility, Due 2024
Debt Instrument [Line Items]
Outstanding balance	$ 21.7

Debt and Financing Obligation_4

Debt and Financing Obligations (Financing Obligation) (Details) - Integral Equipment and Mobile Equipment - Domestic Coke and Coal Logistics	12 Months Ended
	Dec. 31, 2023
Sale Leaseback Transaction [Line Items]
Initial lease period	48 months
Buyout option period	36 months

Debt and Financing Obligation_5

Debt and Financing Obligations (Covenants) (Details) - Credit Agreement and Partner Revolver	Dec. 31, 2023 USD ($)
Line of Credit Facility [Line Items]
Maximum consolidated leverage ratio	4.50
Minimum consolidated interest coverage ratio	2.50
SunCoke Energy Partners, L.P.
Line of Credit Facility [Line Items]
Cross default covenant threshold	$ 35,000,000

Debt and Financing Obligation_6

Debt and Financing Obligations (Schedule of Long-Term Debt Maturity) (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Debt Disclosure [Abstract]
2024	$ 0
2025	0
2026	0
2027	0
2028	0
2029-Thereafter	500
Total	$ 500	$ 543.8

Commitments and Contingent Li_3

Commitments and Contingent Liabilities (Narrative) (Details) - USD ($) $ in Millions		12 Months Ended
	Feb. 21, 2020	Dec. 31, 2013	Dec. 31, 2023
Loss Contingencies [Line Items]
Threshold for disclosing material environmental legal proceedings			$ 1
Uninsured Risk
Loss Contingencies [Line Items]
Loss contingency accrual, payments	$ 40.4	$ 8.4

Commitments and Contingent Li_4

Commitments and Contingent Liabilities (Schedule of Black Lung Benefit Liabilities) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($) claim	Dec. 31, 2022 USD ($) claim
Loss Contingencies [Line Items]
Current portion of black lung liability	$ 5	$ 5.9
Black Lung Benefit
Loss Contingencies [Line Items]
Discount rate	4.50%	4.90%
Active claims | claim	311	332
Total black lung liabilities, discounted	$ 58.2	$ 58.1
Total black lung liabilities, undiscounted	96	$ 88.4
Increase in black lung expense	1.4
Current portion of black lung liability	$ 5

Commitments and Contingent Li_5

Commitments and Contingent Liabilities (Schedule of Expected Payments for Black Lung Benefit Liabilities) (Details) - Black Lung Benefit $ in Millions	Dec. 31, 2023 USD ($)
Other Commitments [Line Items]
2024	$ 5
2025	3.9
2026	4.4
2027	4
2028	3.8
2029-Thereafter	74.9
Total	$ 96

Commitments and Contingent Li_6

Commitments and Contingent Liabilities (Schedule of Expected Aggregate Undiscounted Amount to Amounts Recognized) (Details) - Black Lung Benefit - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Loss Contingencies [Line Items]
Black lung liability, undiscounted	$ 96	$ 88.4
Impact of discounting	(37.8)	(30.3)
Black lung liability, discounted	$ 58.2	$ 58.1

Commitments and Contingent Li_7

Commitments and Contingent Liabilities (Schedule of Annual Black Lung Payments and (Benefit) Expense) (Details) - Black Lung Benefit - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Loss Contingencies [Line Items]
Loss contingency accrual, payments	$ 5.4	$ 5	$ 4.4
Expense (benefit)	$ 5.5	$ (0.2)	$ 3.1

Leases - Narrative (Details)

Leases - Narrative (Details)	Dec. 31, 2023 option
Lessee, Lease, Description [Line Items]
Number of options to renew	1
Minimum
Lessee, Lease, Description [Line Items]
Option to extend, operating lease	1 month
Maximum
Lessee, Lease, Description [Line Items]
Option to extend, operating lease	50 years

Leases - Lease Expense (Details

Leases - Lease Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Operating leases:
Operating lease cost	$ 2.8	$ 2.7
Short-term leases:
Total lease expense	6.8	8.2
Cost of products sold and operating expenses
Operating leases:
Operating lease cost	2.3	2.3
Short-term leases:
Cost of products sold and operating expenses	4	5.5
Selling, general and administrative expenses
Operating leases:
Operating lease cost	$ 0.5	$ 0.4

Leases - Supplemental Balance S

Leases - Supplemental Balance Sheet Information (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Leases [Abstract]
Operating ROU assets, extensible list	Deferred charges and other assets	Deferred charges and other assets
Operating lease liability, current, extensible list	Accrued liabilities	Accrued liabilities
Operating lease liability, noncurrent, extensible list	Other deferred credits and liabilities	Other deferred credits and liabilities
Operating ROU assets	$ 11.6	$ 11.3
Current operating lease liabilities	2.3	2
Noncurrent operating lease liabilities	8.6	8.5
Total operating lease liabilities	$ 10.9	$ 10.5

Leases - Weighted Average (Deta

Leases - Weighted Average (Details)	Dec. 31, 2023	Dec. 31, 2022
Leases [Abstract]
Weighted average remaining lease term of operating leases	7 years 1 month 6 days	5 years 10 months 24 days
Weighted average discount rate of operating leases	4.70%	4.20%

Leases - Supplemental Cash Flow

Leases - Supplemental Cash Flow Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Operating cash flow information:
Cash paid for amounts included in the measurement of operating lease liabilities	$ 2.5	$ 2.4
ROU assets obtained in exchange for new operating lease liabilities	$ 2.6	$ 0.6

Leases - Maturities (Details)

Leases - Maturities (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Operating Leases
2024	$ 2.7
2025	2.6
2026	1.8
2027	1.4
2028	1.4
2029-Thereafter	3.1
Total lease payments	13
Less: imputed interest	2.1
Total lease liabilities	$ 10.9	$ 10.5

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Loss (Components of Accumulated Other Comprehensive Loss) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 622.7	$ 535.4	$ 500.9
Other comprehensive income before reclassifications / adjustments	0.6	0.6
Retirement benefit plans funded status adjustment	(0.4)	3.1	1
Net current period change in accumulated other comprehensive loss	0.2	3.7
Ending balance	645.5	622.7	535.4
Accumulated Other Comprehensive Loss
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(13)	(16.7)	(17.1)
Retirement benefit plans funded status adjustment	(0.4)	3.1	1
Ending balance	(12.8)	(13)	(16.7)
Benefit Plans
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(3.4)	(6.9)
Other comprehensive income before reclassifications / adjustments	0.1	0.4
Retirement benefit plans funded status adjustment	(0.4)	3.1
Net current period change in accumulated other comprehensive loss	(0.3)	3.5
Ending balance	(3.7)	(3.4)	(6.9)
Tax (benefit) expense associated with benefit plans	1	1
Currency Translation Adjustments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(9.6)	(9.8)
Other comprehensive income before reclassifications / adjustments	0.5	0.2
Retirement benefit plans funded status adjustment	0	0
Net current period change in accumulated other comprehensive loss	0.5	0.2
Ending balance	$ (9.1)	$ (9.6)	$ (9.8)

Accumulated Other Comprehensi_4

Accumulated Other Comprehensive Loss (Reclassification Adjustments From AOCI) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amortization of benefit plans to net income	$ (0.2)	$ (0.5)	$ (0.4)
Income tax	0.1	0.1	0.1
Benefit Plans
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total, net of tax	(0.1)	(0.4)	(0.3)
Actuarial loss
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amortization of benefit plans to net income	(0.4)	(0.7)	(0.8)
Prior service benefit
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amortization of benefit plans to net income	$ 0.2	$ 0.2	$ 0.4

Share-Based Compensation (Equit

Share-Based Compensation (Equity Classified Awards Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($) installment shares	Dec. 31, 2022 USD ($) shares	Dec. 31, 2021 USD ($) shares	May 12, 2022 shares
Omnibus Long-Term Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares of common stock authorized (in shares)				2,700,000
Number of shares of common stock reserved (in shares)				2,434,445
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total intrinsic value of stock options exercised | $	$ 0.1	$ 0.2	$ 0.3
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of annual installment in which stock option exercisable | installment	3
Period from grant date for annual installment (in years)	1 year
Total fair value of non-option award units vested | $	$ 2.1	$ 1.7	$ 1.2
SunCoke LTPEP | Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of annual installment in which stock option exercisable | installment	3
Period from grant date for annual installment (in years)	1 year
Expiration period	10 years
Number of shares granted (in shares)	0	0	0
SunCoke LTPEP | Performance stock units | ROIC Portion
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percent of award allocation	50%
Measurement period	3 years
SunCoke LTPEP | Performance stock units | TSR Portion
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Measurement period	3 years
SunCoke LTPEP | Performance stock units | TSR Portion | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payout percentage	80%	80%	75%
Percentage adjustment of award determined by pre-tax return on capital (as a percent)	25%	25%	0%
SunCoke LTPEP | Performance stock units | TSR Portion | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payout percentage	120%	120%	125%
Percentage adjustment of award determined by pre-tax return on capital (as a percent)	200%	200%	250%

Share-Based Compensation (Summa

Share-Based Compensation (Summary of Stock Option Activity) (Details) - Stock Options - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Number of Options (in shares)
Outstanding at the beginning of period (in shares)	1,520,210
Exercised (in shares)	(21,887)
Expired (in shares)	(298,667)
Outstanding at end of period (in shares)	1,199,656	1,520,210
Weighted Average Exercise Price (in dollars per share)
Outstanding at beginning of period (in dollars per share)	$ 15.06
Exercised (in dollars per share)	4.01
Expired (in dollars per share)	16.52
Outstanding at end of period (in dollars per share)	$ 14.89	$ 15.06
Weighted Average Remaining Contractual Term (years)
Weighted average remaining contractual term (in years)	2 years 3 months 18 days	2 years 8 months 12 days
Aggregate Intrinsic Value (millions)
Aggregate intrinsic value	$ 0.5	$ 0.2

Share-Based Compensation (Restr

Share-Based Compensation (Restricted Stock Units and Performance Share Units Granted) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted (in shares)	352,646	346,600	463,476
Weighted Average Grant-Date Fair Value (in dollars per share)	$ 8.97	$ 7.62	$ 6.72
Grant Date Fair Value	$ 3.2	$ 2.6	$ 3.1
Performance stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted (in shares)	147,232	154,860	177,176
Weighted Average Grant-Date Fair Value (in dollars per share)	$ 9.84	$ 8.40	$ 7.60
Grant Date Fair Value	$ 1.4	$ 1.3	$ 1.3

Share-Based Compensation (Sum_2

Share-Based Compensation (Summary of RSUs and PSUs Outstanding) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Restricted stock units
Number of Units
Outstanding at beginning of period (in shares)	670,978
Granted (in shares)	352,646	346,600	463,476
Vested (in shares)	(308,354)
Outstanding at end of period (in shares)	715,270	670,978
Weighted Average Grant- Date Fair Value (in dollars per share)
Outstanding at beginning of period (in dollars per share)	$ 7.08
Granted (in dollars per share)	8.97	$ 7.62	$ 6.72
Vested (in dollars per share)	6.83
Outstanding at end of period (in dollars per share)	$ 8.12	$ 7.08
Performance stock units
Number of Units
Outstanding at beginning of period (in shares)	498,746
Granted (in shares)	147,232	154,860	177,176
Performance adjustments (in shares)	161,091
Vested (in shares)	(354,244)
Outstanding at end of period (in shares)	452,825	498,746
Weighted Average Grant- Date Fair Value (in dollars per share)
Outstanding at beginning of period (in dollars per share)	$ 7.21
Granted (in dollars per share)	9.84	$ 8.40	$ 7.60
Performance adjustments (in dollars per share)	6.70
Vested (in dollars per share)	6.70
Outstanding at end of period (in dollars per share)	$ 7.50	$ 7.21

Share-Based Compensation (Liabi

Share-Based Compensation (Liability Classified Awards Narrative) (Details) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($) installment $ / shares shares	Dec. 31, 2022 USD ($) $ / shares shares	Dec. 31, 2021 USD ($) $ / shares shares
Restricted Stock Units Settled in Cash
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted (in shares) | shares	216,547	250,615	230,056
Number of annual installment in which stock option exercisable | installment	3
Period from grant date for annual installment (in years)	1 year
Granted (in dollars per share) | $ / shares	$ 9.24	$ 7.56	$ 6.68
Closing price (in dollars per share) | $ / shares	$ 10.74
Deferred compensation	$ 2.8	$ 2.4
Cash Incentive Award | Suncoke LTCIP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Deferred compensation	8.1	8.7
Grant date fair value award	$ 2.2	$ 2	$ 2.1
Percent of award allocation	50%	50%	50%
Measurement period	3 years

Share-Based Compensation (Compe

Share-Based Compensation (Compensation Expense and Unrecognized Compensation Costs) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized Compensation Cost	$ 0
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized Compensation Cost	$ 0.6
Weighted Average Remaining Recognition Period	1 year 7 months 6 days
Performance stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized Compensation Cost	$ 0.7
Weighted Average Remaining Recognition Period	1 year 7 months 6 days
Restricted Stock Units Settled in Cash
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized Compensation Cost	$ 1.5
Weighted Average Remaining Recognition Period	1 year 8 months 12 days
Cash Incentive Award
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized Compensation Cost	$ 1.5
Weighted Average Remaining Recognition Period	1 year 7 months 6 days
Selling, General and Administrative Expenses | Equity Classified Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	$ 4.4	$ 6.4	$ 5.8
Net of tax	3.4	4.9	4.5
Selling, General and Administrative Expenses | Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	0	0	0.1
Net of tax	0	0	0.1
Selling, General and Administrative Expenses | Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	2.5	2.5	2.3
Net of tax	2	1.9	1.8
Selling, General and Administrative Expenses | Performance stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	1.9	3.9	3.4
Net of tax	1.4	3	2.6
Selling, General and Administrative Expenses | Liability Classified Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	5.3	7.2	5.1
Net of tax	4	5.5	3.9
Selling, General and Administrative Expenses | Restricted Stock Units Settled in Cash
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	2.6	2.1	1.7
Net of tax	2	1.6	1.3
Selling, General and Administrative Expenses | Cash Incentive Award
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	2.7	5.1	3.4
Net of tax	$ 2	$ 3.9	$ 2.6

Share-Based Compensation (Sum_3

Share-Based Compensation (Summary of Share-Based Compensation Expense Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Director
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Compensation expense	$ 0.7	$ 0.3	$ 0.3

Earnings Per Share (Computation

Earnings Per Share (Computation of EPS) (Details) - shares shares in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Earnings Per Share [Abstract]
Weighted-average number of common shares outstanding-basic (in shares)	84.7	83.8	83
Add: effect of dilutive share-based compensation awards (in shares)	0.2	0.8	0.7
Weighted-average number of shares-diluted (in shares)	84.9	84.6	83.7

Earnings Per Share (Antidilutiv

Earnings Per Share (Antidilutive Shares Excluded From EPS Calculation) (Details) - shares shares in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential dilutive effect excluded from the computation of diluted weighted-average shares outstanding (in shares)	1.2	1.6	2.5
Stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential dilutive effect excluded from the computation of diluted weighted-average shares outstanding (in shares)	1.2	1.6	2.5

Fair Value Measurements (Detail

Fair Value Measurements (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Fair Value Disclosures [Abstract]
Fair value of long-term debt	$ 450.2	$ 471.9
Outstanding balance	$ 500	$ 543.8

Revenue from Contracts with C_3

Revenue from Contracts with Customers (Narrative) (Details) T in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($) agreement performance_obligation T
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Number of coke sales agreements with fixed operating costs	4
Number of coke sales agreements with operating costs passed through to customers	3
Number of performance obligations in handling and mixing services | performance_obligation	2
Cokemaking
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Unsatisfied performance obligation (in tons) | T	22
Average remaining term	10 years
Logistics
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Average remaining term	3 years
Performance obligation amount | $	$ 27.4

Revenue from Contracts with C_4

Revenue from Contracts with Customers (Disaggregated Sales and Other Operating Revenue) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Disaggregation of Revenue [Line Items]
Sales and other operating revenue	$ 2,063.2	$ 1,972.5	$ 1,456
Cokemaking
Disaggregation of Revenue [Line Items]
Sales and other operating revenue	1,898.5	1,791.3	1,293.6
Energy
Disaggregation of Revenue [Line Items]
Sales and other operating revenue	47.3	61.5	56.1
Logistics
Disaggregation of Revenue [Line Items]
Sales and other operating revenue	73.1	76.7	64.3
Operating and licensing fees
Disaggregation of Revenue [Line Items]
Sales and other operating revenue	35.2	38	36.6
Other
Disaggregation of Revenue [Line Items]
Sales and other operating revenue	$ 9.1	$ 5	$ 5.4

Business Segment Information (N

Business Segment Information (Narrative) (Details)	12 Months Ended
	Dec. 31, 2023 segment
Segment Reporting [Abstract]
Number of reportable segments	3

Business Segment Information (S

Business Segment Information (Segment Profit or Loss) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Segment Reporting Information [Line Items]
Sales and other operating revenue	$ 2,063.2	$ 1,972.5	$ 1,456
Adjusted EBITDA reportable segments:	301.2	327.6	304.1
Depreciation and amortization expense:	142.8	142.5	133.9
Capital expenditures:	109.2	75.5	98.6
Operating Segments
Segment Reporting Information [Line Items]
Depreciation and amortization expense:	142.5	141.5	132.7
Capital expenditures:	108.7	74.9	98.1
Operating Segments | Domestic Coke
Segment Reporting Information [Line Items]
Sales and other operating revenue	1,954	1,856.9	1,354.5
Adjusted EBITDA reportable segments:	247.8	263.4	243.4
Depreciation and amortization expense:	129.4	126.8	119
Capital expenditures:	103.2	70.3	83.1
Operating Segments | Brazil Coke
Segment Reporting Information [Line Items]
Sales and other operating revenue	35.2	38	36.6
Adjusted EBITDA reportable segments:	9.1	14.5	17.2
Depreciation and amortization expense:	0.3	0.2	0.4
Capital expenditures:	0.4	0.1	0.3
Operating Segments | Logistics
Segment Reporting Information [Line Items]
Sales and other operating revenue	74	77.6	64.9
Adjusted EBITDA reportable segments:	44.3	49.7	43.5
Depreciation and amortization expense:	12.8	14.5	13.3
Capital expenditures:	5.1	4.5	14.7
Intersegment sales
Segment Reporting Information [Line Items]
Sales and other operating revenue	(22.1)	(28.9)	(27.1)
Intersegment sales | Logistics
Segment Reporting Information [Line Items]
Sales and other operating revenue	22.1	28.9	27.1
Corporate and Other
Segment Reporting Information [Line Items]
Depreciation and amortization expense:	0.3	1	1.2
Capital expenditures:	$ 0.5	$ 0.6	$ 0.5

Business Segment Information _2

Business Segment Information (Segment Assets) (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Segment Reporting Information [Line Items]
Total assets	$ 1,660.4	$ 1,654.6
Operating Segments
Segment Reporting Information [Line Items]
Total assets	1,575.8	1,631.8
Operating Segments | Domestic Coke
Segment Reporting Information [Line Items]
Total assets	1,405.5	1,422.6
Operating Segments | Brazil Coke
Segment Reporting Information [Line Items]
Total assets	11.9	15.7
Operating Segments | Logistics
Segment Reporting Information [Line Items]
Total assets	158.4	193.5
Operating Segments | Logistics | Dismal River Terminal ("DRT")
Segment Reporting Information [Line Items]
Total assets		21.7
Corporate and Other
Segment Reporting Information [Line Items]
Total assets	$ 84.6	$ 22.8

Business Segment Information (A

Business Segment Information (Adjusted EBITDA) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Segment Reporting [Abstract]
Net income	$ 63.5	$ 104.9	$ 48.8
Add:
Depreciation and amortization expense	142.8	142.5	133.9
Interest expense, net	27.3	32	42.5
Loss on extinguishment of debt	0	0	31.9
Income tax expense	34.3	16.8	18.3
Transaction costs	0.9	1.5	0
Corporate and Other	32.4	29.9	28.7
Adjusted EBITDA reportable segments	$ 301.2	$ 327.6	$ 304.1