Cabot (CBT) 10-Q 6 Feb 25 2025 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Dec. 31, 2024	Feb. 03, 2025
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Dec. 31, 2024
Document Fiscal Year Focus	2025
Document Fiscal Period Focus	Q1
Trading Symbol	CBT
Entity Registrant Name	Cabot Corporation
Entity Central Index Key	0000016040
Entity Current Reporting Status	Yes
Current Fiscal Year End Date	--09-30
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		54,221,492
Entity Shell Company	false
Entity Small Business	false
Entity Emerging Growth Company	false
Entity File Number	1-5667
Entity Tax Identification Number	04-2271897
Entity Address, Address Line One	Two Seaport Lane
Entity Address, Address Line Two	Suite 1400
Entity Address, City or Town	Boston
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02210-2019
City Area Code	617
Local Phone Number	345-0100
Security Exchange Name	NYSE
Title of 12(b) Security	Common Stock, $1 par value per share
Entity Incorporation, State or Country Code	DE
Document Quarterly Report	true
Document Transition Report	false
Entity Interactive Data Current	Yes

Consolidated Statements of Oper

Consolidated Statements of Operations (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Income Statement [Abstract]
Net sales and other operating revenues	$ 955	$ 958
Cost of sales	720	740
Gross profit	235	218
Selling and administrative expenses	66	67
Research and technical expenses	14	15
Income (loss) from operations	155	136
Interest and dividend income	6	9
Interest expense	(18)	(22)
Other income (expense)	1	(29)
Income (loss) from operations before income taxes and equity in earnings of affiliated companies	144	94
(Provision) benefit for income taxes	(41)	(34)
Equity in earnings of affiliated companies, net of tax	1	1
Net income (loss)	104	61
Net income (loss) attributable to noncontrolling interests, net of tax	11	11
Net income (loss) attributable to Cabot Corporation	$ 93	$ 50
Weighted-average common shares outstanding:
Basic	54.3	55.3
Diluted	55	55.8
Earnings (loss) per common share:
Basic	$ 1.69	$ 0.88
Diluted	$ 1.67	$ 0.88

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 104	$ 61
Other comprehensive income (loss), net of tax
Foreign currency translation adjustment, net of tax	(104)	62
Derivatives: net investment hedges
(Gains) losses reclassified to interest expense, net of tax	(1)	(1)
(Gains) losses excluded from effectiveness testing and amortized to interest expense, net of tax	1
Other comprehensive income (loss), net of tax (provision) benefit of $(4), $1	(104)	61
Comprehensive income (loss)		122
Net income (loss) attributable to noncontrolling interests, net of tax	11	11
Foreign currency translation adjustment attributable to noncontrolling interests, net of tax	(7)	4
Comprehensive income (loss) attributable to noncontrolling interests	4	15
Comprehensive income (loss) attributable to Cabot Corporation	$ (4)	$ 107

Consolidated Statements of Co_2

Consolidated Statements of Comprehensive Income (Loss) (Unaudited) (Parenthetical) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Statement of Comprehensive Income [Abstract]
Net of tax (provision) benefit	$ (4)	$ 1

Consolidated Balance Sheets (Un

Consolidated Balance Sheets (Unaudited) - USD ($) $ in Millions	Dec. 31, 2024	Sep. 30, 2024
Current assets:
Cash and cash equivalents	$ 183	$ 223
Accounts and notes receivable, net of reserve for doubtful accounts of $5 and $5	677	733
Inventories:
Raw materials	139	150
Finished goods	331	333
Other	66	69
Total inventories	536	552
Prepaid expenses and other current assets	100	97
Total current assets	1,496	1,605
Property, plant and equipment	4,049	4,082
Accumulated depreciation	(2,493)	(2,548)
Net property, plant and equipment	1,556	1,534
Goodwill	127	133
Equity affiliates	13	23
Intangible assets, net	57	53
Deferred income taxes	211	216
Other assets	182	172
Total assets	3,642	3,736
Current liabilities:
Short-term borrowings	100	45
Accounts payable and accrued liabilities	599	676
Income taxes payable	39	43
Current portion of long-term debt	9	8
Total current liabilities	747	772
Long-term debt	1,089	1,087
Deferred income taxes	39	42
Other liabilities	252	245
Contingencies (Note F)
Preferred stock:
Authorized: 2,000,000 shares of $1 par value, Issued and Outstanding: None and none
Common stock:
Authorized: 200,000,000 shares of $1 par value, Issued: 54,348,447 and 54,430,316 shares, Outstanding: 54,215,426 and 54,297,251 shares	54	54
Less cost of 133,021 and 133,065 shares of common treasury stock	(3)	(3)
Retained earnings	1,772	1,734
Accumulated other comprehensive income (loss)	(457)	(360)
Total Cabot Corporation stockholders' equity	1,366	1,425
Noncontrolling interests	149	165
Total stockholders' equity	1,515	1,590
Total liabilities and stockholders' equity	$ 3,642	$ 3,736

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) (Unaudited) - USD ($) $ in Millions	Dec. 31, 2024	Sep. 30, 2024
Statement of Financial Position [Abstract]
Accounts and notes receivable, reserve for doubtful accounts	$ 5	$ 5
Preferred stock, authorized shares	2,000,000	2,000,000
Preferred stock, par value	$ 1	$ 1
Preferred stock, Issued shares	0	0
Preferred stock, Outstanding shares	0	0
Common stock, authorized shares	200,000,000	200,000,000
Common stock, par value	$ 1	$ 1
Common stock, issued shares	54,348,447	54,430,316
Common stock, outstanding shares	54,215,426	54,297,251
Common treasury stock, shares	133,021	133,065

Consolidated Statements of Cash

Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Cash Flows from Operating Activities:
Net income (loss)	$ 104	$ 61
Adjustments to reconcile net income (loss) to cash provided by operating activities:
Depreciation and amortization	37	41
Deferred tax provision (benefit)		7
Equity in earnings of affiliated companies	(1)	(1)
Share-based compensation	8	6
Other non-cash (income) expense		37
Cash dividends received from equity affiliates	12	1
Changes in assets and liabilities:
Accounts and notes receivable	18	(7)
Inventories	(8)	(19)
Prepaid expenses and other assets	(6)	(2)
Accounts payable and accrued liabilities	(48)	(20)
Income taxes payable	(2)	(10)
Other liabilities	10	11
Cash provided by (used in) operating activities	124	105
Cash Flows from Investing Activities:
Additions to property, plant and equipment	(77)	(54)
Cash paid for asset acquisition	(27)
Cash provided by (used in) investing activities	(104)	(54)
Cash Flows from Financing Activities:
Proceeds from issuance (repayments) of commercial paper, net	55	32
Proceeds from long-term debt	6	0
Repayments of long-term debt	(1)	(1)
Purchases of common stock	(42)	(33)
Proceeds from sales of common stock	2	7
Cash dividends paid to noncontrolling interests	(20)	(12)
Cash dividends paid to common stockholders	(24)	(22)
Cash provided by (used in) financing activities	(24)	(29)
Effects of exchange rate changes on cash	(36)	(16)
Increase (decrease) in cash and cash equivalents	(40)	6
Cash and cash equivalents at beginning of period	223	238
Cash and cash equivalents at end of period	$ 183	$ 244

Consolidated Statements of Chan

Consolidated Statements of Changes in Stockholders' Equity (Unaudited) - USD ($) shares in Thousands, $ in Millions	Total	Common Stock, Net of Treasury Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Total Cabot Corporation Stockholders' Equity [Member]	Noncontrolling Interests [Member]
Beginning Balance at Sep. 30, 2023	$ 1,407	$ 52	$ 0	$ 1,574	$ (362)	$ 1,264	$ 143
Beginning Balance, Shares at Sep. 30, 2023		55,244
Net income (loss)	61			50		50	11
Total other comprehensive income (loss)	61				57	57	4
Cash dividends paid, Common stock, per share	(22)			(22)		(22)
Cash dividends declared to noncontrolling interests	(12)						(12)
Issuance of stock under equity compensation plans	7		7			7
Issuance of stock under equity compensation plans, Shares		441
Share-based compensation	6		6			6
Purchase and retirement of common stock	(33)		(13)	(20)		(33)
Purchase and retirement of common stock, Shares		(260)
Ending Balance at Dec. 31, 2023	1,475	$ 52		1,582	(305)	1,329	146
Ending Balance, Shares at Dec. 31, 2023		55,425
Beginning Balance at Sep. 30, 2024	1,590	$ 51		1,734	(360)	1,425	165
Beginning Balance, Shares at Sep. 30, 2024		54,297
Net income (loss)	104			93		93	11
Total other comprehensive income (loss)	(104)				(97)	(97)	(7)
Cash dividends paid, Common stock, per share	(24)			(24)		(24)
Cash dividends declared to noncontrolling interests	(20)						(20)
Issuance of stock under equity compensation plans	2		2			2
Issuance of stock under equity compensation plans, Shares		308
Share-based compensation	8		8			8
Purchase and retirement of common stock	(41)		$ (10)	(31)		(41)
Purchase and retirement of common stock, Shares		(390)
Ending Balance at Dec. 31, 2024	$ 1,515	$ 51		$ 1,772	$ (457)	$ 1,366	$ 149
Ending Balance, Shares at Dec. 31, 2024		54,215

Consolidated Statements of Ch_2

Consolidated Statements of Changes in Stockholders' Equity (Unaudited) (Parenthetical) - $ / shares	3 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Statement of Stockholders' Equity [Abstract]
Common stock, cash dividends paid, per share	$ 0.43	$ 0.40

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Pay vs Performance Disclosure
Net Income (Loss)	$ 93	$ 50

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Dec. 31, 2024
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false
Rule 10b5-1 Arrangement Modified	false
Non-Rule 10b5-1 Arrangement Modified	false

Basis of Presentation

Basis of Presentation	3 Months Ended
	Dec. 31, 2024
Accounting Policies [Abstract]
Basis of Presentation	A. Basis of Presentation The consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States (“U.S.”) (“GAAP”) and include the accounts of Cabot Corporation (“Cabot” or the “Company”) and its wholly-owned subsidiaries and majority-owned and controlled U.S. and non-U.S. subsidiaries. Additionally, Cabot considers consolidation of entities over which control is achieved through means other than voting rights. Intercompany transactions have been eliminated in consolidation. The unaudited consolidated financial statements have been prepared in accordance with the requirements of Form 10-Q and consequently do not include all disclosures required by Form 10-K. Additional information may be obtained by referring to Cabot’s Annual Report on Form 10-K for its fiscal year ended September 30, 2024 (the “2024 10-K”). The financial information submitted herewith is unaudited and reflects all adjustments which are, in the opinion of management, necessary to provide a fair statement of the results for the interim periods ended December 31, 2024 and 2023. All such adjustments are of a normal rec urring nature. The results for interim periods are not necessarily indicative of the results to be expected for the fiscal year.

Significant Accounting Policies

Significant Accounting Policies	3 Months Ended
	Dec. 31, 2024
Accounting Policies [Abstract]
Significant Accounting Policies	B. Significant Accounting Policies Full detail on the Company’s significant accounting policies may be obtained by referring to Note A in the 2024 10-K. Argentinian Government Actions The Company’s wholly-owned Argentinian subsidiary operates in a highly inflationary economy and, as a result, the functional currency of the subsidiary is Cabot’s reporting currency, the U.S. dollar. During the three months ended December 31, 2024 and 2023, the Company recorded foreign exchange losses of $ 2 million and $ 40 million, respectively, related to the revaluation of non-functional currency denominated monetary asset and liability balances. Of the $ 40 million of foreign exchange losses in the first quarter of fiscal 2024, $ 33 million related to a single devaluation action in December 2023 by the Argentine government. The Company invests cash in money market funds and recorded investment income of less than $ 1 million and $ 12 million, respectively, for the three months ended December 31, 2024 and 2023. The foreign exchange losses and investment gains are recorded in Other income (expense) in the Consolidated Statement of Operations. Recent Accounting Pronouncements In November 2024, the FASB issued a new standard, Expense Disaggregation Disclosures. The new guidance requires quantitative and qualitative disclosure of certain cost and expense categories in the notes to the financial statements for interim and annual reporting periods. The new standard is effective for the Company's fiscal years and interim periods beginning October 1, 2027, with early adoption permitted. The Company is currently evaluating the timing of adoption and evaluating the impact of the potential adoption of this standard on the Company’s Consolidated Financial Statements. In March 2024, the Securities and Exchange Commission (“SEC”) issued its final rule, The Enhancement and Standardization of Climate-Related Disclosures for Investors that requires the Company to provide certain climate-related information. The rule provides a phased-in compliance period and is effective for fiscal years beginning after December 15, 2024, with early adoption permitted. In April 2024, the SEC voluntarily stayed its rule pending completion of judicial review by the U.S. Court of Appeals for the Eighth Circuit and, therefore, the timing of the effectiveness of these disclosure requirements is uncertain. The Company is currently monitoring the timing of adoption and evaluating the impact of the potential adoption of this standard on the Company’s Consolidated Financial Statements. In December 2023, the FASB issued a new standard, Improvements to Income Tax Disclosures. The new guidance requires additional disclosures primarily related to the income tax rate reconciliation and income taxes paid. The new standard is effective for the Company’s fiscal years and interim periods beginning October 1, 2025. The Company is currently evaluating the impact of the adoption of this standard on the Company’s Consolidated Financial Statements. In November 2023, the FASB issued a new standard, Improvement to Reportable Segment Disclosures. The new guidance requires enhanced disclosure of significant reportable segment expenses. The new standard is effective for the Company’s current fiscal year which began October 1, 2024, and for interim periods beginning October 1, 2025. The Company is currently evaluating the impact of the adoption of this standard on the Company’s Consolidated Financial Statements.

Acquisition

Acquisition	3 Months Ended
	Dec. 31, 2024
Business Combinations [Abstract]
Acquisitions	C. Acquisitions In October 2024, the Company completed the purchase of certain assets and licensed related technology, which the Company expects to use to manufacture certain products for its Battery Materials product line. The Company paid $ 27 million, which was allocated to the identifiable assets on a relative fair value basis, with $ 19 million allocated to property, plant and equipment and $ 8 million to intangible assets.

Goodwill and Intangible Assets

Goodwill and Intangible Assets	3 Months Ended
	Dec. 31, 2024
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	. Goodwill and Intangible Assets The carrying amount of goodwill attributable to each reportable segment and the changes in those balances during the three months ended December 31, 2024 are as follows: Reinforcement Performance Total (In millions) Balance at September 30, 2024 $ 48 $ 85 $ 133 Foreign currency impact ( 2 ) ( 4 ) ( 6 ) Balance at December 31, 2024 $ 46 $ 81 $ 127 The following table provides information regarding the Company’s intangible assets: December 31, 2024 September 30, 2024 Gross Accumulated Net Gross Accumulated Net (In millions) Intangible assets with finite lives Developed technologies (1) $ 40 $ ( 12 ) $ 28 $ 34 $ ( 12 ) $ 22 Trademarks 2 ( 1 ) 1 2 ( 1 ) 1 Customer relationships 58 ( 30 ) 28 60 ( 30 ) 30 Total intangible assets $ 100 $ ( 43 ) $ 57 $ 96 $ ( 43 ) $ 53 (1) Included within Developed technologies as of December 31, 2024 is $ 8 million of intangible assets acquired during the first quarter of fiscal 2025 as discussed in Note C above. Intangible assets are amortized over their estimated useful lives, which range betwee n ten and twenty-five years , with a weighted average amortization period of approximately sixteen years . Amortiza tion expense was $ 2 million and $ 1 million, respectively, for the three months ended December 31, 2024 and 2023. Amortization expense is included in Cost of sales, Selling and administrative expenses and Research and technical expenses in the Consolidated Statements of Operations. Total amortization expense is estimated to be approximately $ 6 million each year for the next five fiscal years.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income (Loss) ("AOCI")	3 Months Ended
	Dec. 31, 2024
Stockholders' Equity Note [Abstract]
Accumulated Other Comprehensive Income (Loss) ("AOCI")	E. Accumulated Other Comprehensive Income (Loss) (“AOCI”) Comprehensive income combines net income (loss) and other comprehensive income items, which are reported as components of stockholders’ equity in the accompanying Consolidated Balance Sheets. Changes in each component of AOCI, net of tax, were as follows: Currency Pension and Other Total (In millions) Balance at September 30, 2024, attributable to Cabot Corporation $ ( 342 ) $ ( 18 ) $ ( 360 ) Other comprehensive income (loss) before reclassifications ( 104 ) — ( 104 ) Amounts reclassified from AOCI — — — Less: Other comprehensive income (loss) attributable to ( 7 ) — ( 7 ) Balance at December 31, 2024, attributable to Cabot Corporation $ ( 439 ) $ ( 18 ) $ ( 457 ) Currency Pension and Other Total (In millions) Balance at September 30, 2023, attributable to Cabot Corporation $ ( 353 ) $ ( 9 ) $ ( 362 ) Other comprehensive income (loss) before reclassifications 62 — 62 Amounts reclassified from AOCI ( 1 ) — ( 1 ) Less: Other comprehensive income (loss) attributable to 4 — 4 Balance at December 31, 2023, attributable to Cabot Corporation $ ( 296 ) $ ( 9 ) $ ( 305 ) For both three months ended December 31, 2024 and 2023, the Company reclassified $ 1 million of gain associated with net investment hedges and $ 1 million and nil , respectively, of losses excluded from net investment hedges effectiveness testing out of AOCI and into interest expense on the Consolidated Statements of Operations.

Contingencies

Contingencies	3 Months Ended
	Dec. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
Contingencies	F. Contingencies Respirator Liabilities Cabot has exposure in connection with a safety respiratory products business that a subsidiary acquired from American Optical Corporation (“AO”) in an April 1990 asset purchase transaction. The subsidiary manufactured respirators under the AO brand and disposed of that business in July 1995. In connection with its acquisition of the business, the subsidiary agreed, in certain circumstances, to assume a portion of AO’s liabilities, including costs of legal fees together with amounts paid in settlements and judgments, allocable to AO respiratory products used prior to the 1990 purchase by the Cabot subsidiary. In exchange for the subsidiary’s assumption of certain of AO’s respirator liabilities, AO agreed to provide to the subsidiary the benefits of: (i) AO’s insurance coverage for the period prior to the 1990 acquisition and (ii) a former owner’s indemnity of AO holding it harmless from any liability allocable to AO respiratory products used prior to May 1982. As more fully described in the 2024 10-K, the respirator liabilities generally involve claims for personal injury, including asbestosis, silicosis and coal worker’s pneumoconiosis, allegedly resulting from the use of respirators that are alleged to have been negligently designed and/or labeled. At no time did this respiratory product line represent a significant portion of the respirator market. In addition to Cabot’s subsidiary, other parties are responsible for significant portions of the costs of these respirator liabilities (as defined in the 2024 10-K, the “Payor Group”). Cabot has a reserve to cover its expected share of liabilities for pending and future respirator liability claims, which is included in Other liabilities and Accounts payable and accrued liabilities on the Consolidated Balance Sheets. The Company expects these liabilities to be incurred over a number of years. The reserve balance was $ 34 million and $ 35 million at December 31, 2024 and September 30, 2024, respectively. The Company’s current estimate of the cost of its share of pending and future respirator liability claims is based on facts and circumstances existing at this time, including the number and nature of the remaining claims. Developments that could affect the Company’s estimate include, but are not limited to, (i) significant changes in the number of future claims, (ii) changes in the rate of dismissals without payment of pending claims, (iii) significant changes in the average cost of resolving claims, including potential settlements of groups of claims, (iv) significant changes in the legal costs of defending these claims, (v) changes in the nature of claims received or changes in our assessment of the viability of these claims, (vi) trial and appellate outcomes, (vii) changes in the law and procedure applicable to these claims, (viii) the financial viability of the parties that contribute to the payment of respirator claims, (ix) exhaustion or changes in the recoverability of the insurance coverage maintained by certain members of the Payor Group, or a change in the availability of the indemnity provided by a former owner of AO, (x) changes in the allocation of costs among the various parties paying legal and settlement costs, and (xi) a determination that the assumptions that were used to estimate Cabot’s share of liability are no longer reasonable. The Company cannot determine the impact of these potential developments on its current estimate of its share of liability for existing and future claims. Because reserves are limited to amounts that are probable and estimable as of a relevant measurement date, and there is inherent difficulty in projecting the impact of potential developments on Cabot’s share of liability for these existing and future claims, it is reasonably possible that the liabilities for existing and future claims could change in the near term and that change could be material. Other Matters The Company has various other lawsuits, claims and contingent liabilities arising in the ordinary course of its business and with respect to its divested businesses. The Company does not believe that any of these matters will have a material adverse effect on its financial position; however, litigation is inherently unpredictable. Cabot could incur judgments, enter into settlements or revise its expectations regarding the outcome of certain matters, and such developments could have a material impact on its results of operations in the period in which the amounts are accrued or its cash flows in the period in which the amounts are paid.

Income Tax

Income Tax	3 Months Ended
	Dec. 31, 2024
Income Tax Disclosure [Abstract]
Income Tax	G. Income Tax Effective Tax Rate Three Months Ended December 31 2024 2023 (Dollars in millions) (Provision) benefit for income taxes $ ( 41 ) $ ( 34 ) Effective tax rate 28 % 36 % For the three months ended December 31, 2024 and 2023, the provision for income taxes included a net discrete tax expense of $ 2 million and $ 7 million, respectively. Income tax in Interim Periods The Company records its tax provision or benefit on an interim basis using an estimated annual effective tax rate. This rate is applied to the current period ordinary income or loss to determine the income tax provision or benefit allocated to the interim period. The income tax effects of unusual or infrequent items are excluded from the estimated annual effective tax rate and are recognized in the impacted interim period. Losses from jurisdictions for which no benefit can be recognized are excluded from the overall computations of the estimated annual effective tax rate and a separate estimated annual effective tax rate is computed and applied to ordinary income or loss in the loss jurisdiction. Valuation allowances are provided against the future tax benefits that arise from the deferred tax assets in jurisdictions for which the Company expects that no benefit can be recognized. The estimated annual effective tax rate may be significantly impacted by nondeductible expenses and the Company’s projected earnings mix by tax jurisdiction. Adjustments to the estimated annual effective income tax rate are recognized in the period when such estimates are revised. Uncertainties Cabot and certain subsidiaries are under audit in a number of jurisdictions. In addition, certain statutes of limitations are scheduled to expire in the near future. It is reasonably possible that a change in the unrecognized tax benefits may also occur within the next twelve months related to the settlement of one or more of these audits or the lapse of applicable statutes of limitations. However, an estimated range of the impact on the unrecognized tax benefits cannot be quantified at this time. Cabot files U.S. federal and state and non-U.S. income tax returns in jurisdictions with varying statutes of limitations. The 2021 through 2023 tax years generally remain subject to examination by the IRS and various tax years from 2021 through 2023 remain subject to examination by the respective state tax authorities. In foreign jurisdictions, various tax years from 2006 through 2024 remain subject to examination by their respective tax authorities. During the three month periods ended December 31, 2024 and 2023, Cabot released uncertain tax positions of $ 2 million and $ 1 million, respectively, due to the expiration of statutes of limitations in various jurisdictions.

Earnings Per Share

Earnings Per Share	3 Months Ended
	Dec. 31, 2024
Earnings Per Share [Abstract]
Earnings Per Share	H. Earnings Per Share The following tables summarize the components of the basic and diluted earnings (loss) per common share (“EPS”) computations: Three Months Ended December 31 2024 2023 (In millions, except per share amounts) Basic EPS: Net income (loss) attributable to Cabot $ 93 $ 50 Less: Dividends and dividend equivalents — — Less: Undistributed earnings allocated to (1) 1 1 Earnings (loss) allocated to common $ 92 $ 49 Weighted average common shares and 55.2 56.4 Less: Participating securities (1) 0.9 1.1 Adjusted weighted average common 54.3 55.3 Earnings (loss) per common share - basic: $ 1.69 $ 0.88 Diluted EPS: Earnings (loss) allocated to common $ 92 $ 49 Plus: Earnings allocated to 1 1 Less: Adjusted earnings allocated to (2) 1 1 Earnings (loss) allocated to common $ 92 $ 49 Adjusted weighted average common 54.3 55.3 Effect of dilutive securities: Common shares issuable (3) 0.7 0.5 Adjusted weighted average common 55.0 55.8 Earnings (loss) per common share - diluted: $ 1.67 $ 0.88 (1) Participating securities consist of shares underlying unvested time-based restricted stock units (the "TSUs"), earned and unvested performance-based restricted stock units (the "PSUs", and referred to in this note collectively with the TSUs as the "RSUs"), stock units accounted for under the Supplemental 401(k) Plan portion of the Company’s Deferred Compensation and Supplemental Retirement Plan, and stock units and phantom stock units accounted for under the Company’s Non-Employee Directors’ Deferral Plan. The holders of RSUs are entitled to receive dividend equivalents, payable in cash, to the extent dividends are paid on the outstanding shares of Common Stock, and equal in value to the dividends that would have been paid in respect of the Common Stock underlying the RSU. The accounts of holders of stock units and phantom stock units are credited with dividend equivalents, which are payable, in stock or cash, as the case may be, with the distribution of account balances. Undistributed earnings are the earnings which remain after dividends declared during the period are assumed to be distributed to the common and participating stockholders. Undistributed earnings are allocated to common and participating stockholders on the same basis as dividend distributions. The calculation of undistributed earnings is as follows: Three Months Ended December 31 2024 2023 (In millions) Calculation of undistributed earnings (loss): Net income (loss) attributable to Cabot Corporation $ 93 $ 50 Less: Dividends declared on common stock 24 22 Less: Dividends declared on participating — — Undistributed earnings (loss) $ 69 $ 28 Allocation of undistributed earnings (loss): Undistributed earnings (loss) allocated to $ 68 $ 27 Undistributed earnings allocated to 1 1 Undistributed earnings (loss) $ 69 $ 28 (2) Undistributed earnings are adjusted for the assumed distribution of dividends to the dilutive securities, which are described in (3) below, and then reallocated to participating securities. (3) Represents incremental shares of common stock from the assumed exercise of stock options issued under Cabot’s equity incentive plans. For the three months ended December 31, 2024 and 2023, 63,807 and 330,331 incremental shares of common stock, respectively, were excluded from the calculation of diluted earnings per share because the inclusion of these shares would have been antidilutive.

Financial Instruments and Fair

Financial Instruments and Fair Value Measurements	3 Months Ended
	Dec. 31, 2024
Fair Value Disclosures [Abstract]
Financial Instruments and Fair Value Measurements	I. Financial Instruments and Fair Value Measurements The FASB authoritative guidance on fair value measurements defines fair value, provides a framework for measuring fair value, and requires certain disclosures about fair value measurements. The required disclosures focus on the inputs used to measure fair value. The guidance establishes the following hierarchy for categorizing these inputs: Level 1 — Quoted market prices in active markets for identical assets or liabilities Level 2 — Significant other observable inputs (e.g., quoted prices for similar items in active markets, quoted prices for identical or similar items in markets that are not active, inputs other than quoted prices that are observable such as interest rate and yield curves, and market-corroborated inputs) Level 3 — Significant unobservable inputs There were no transfers of financial assets or liabilities measured at fair value between Level 1 and Level 2 and there were no Level 3 investments during the first three months of either fiscal 2025 or 2024. At December 31, 2024 and September 30, 2024, the fair values of cash and cash equivalents, accounts and notes receivable, accounts payable and accrued liabilities, and short-term borrowings and variable rate debt approximated their carrying values due to the short-term nature of these instruments. Cash and cash equivalents are classified as Level 1 within the fair value hierarchy. At December 31, 2024 and September 30, 2024, Cabot had derivatives relating to foreign currency risks, including a net investment hedge and forward foreign currency contracts, carried at fair value. At December 31, 2024 and September 30, 2024, the fair value of the net investment hedge was an asset of $ 17 million and $ 1 million, respectively, and was included in Prepaid expenses and other current assets and Other Assets on the Consolidated Balance sheets. At December 31, 2024 and September 30, 2024, the fair value of the forward currency contracts was a net asset of less than $ 1 million and an asset of less than $ 1 million, respectively, and was included in Prepaid expenses and other current assets and Accounts payable and accrued liabilities on the Consolidated Balance Sheets. These derivatives are classified as Level 2 instruments within the fair value hierarchy as the fair value determination was based on observable inputs. At both December 31, 2024 and September 30, 2024, the fair value of guaranteed investment contracts included in Other assets on the Consolidated Balance Sheets was $ 8 million . Guaranteed investment contracts were classified as Level 2 instruments within the fair value hierarchy as the fair value determination was based on other observable inputs. The carrying value and fair value of the long-term fixed rate debt w ere $ 1.08 billion and $ 1.06 billion, res pectively, as of December 31, 2024 , and $ 1.08 billion and $ 1.08 billion, respectively, as of September 30, 2024. The fair values of Cabot’s fixed rate long-term debt are estimated based on comparable quoted market prices at the respective period ends. The carrying amounts of Cabot’s floating rate long-term debt and finance and operating lease obligations approximate their fair values. All such measurements are based on observable inputs and are classified as Level 2 within the fair value hierarchy. The valuation technique used is the discounted cash flow model.

Supplier Financing Programs

Supplier Financing Programs	3 Months Ended
	Dec. 31, 2024
Payables and Accruals [Abstract]
Supplier Financing Programs	J. Supplier Financing Programs The Company maintains supply chain finance agreements with third-party financial institutions. These agreements allow the Company’s participating suppliers to sell their receivables to such third-party financial institutions to receive payment earlier than the negotiated commercial terms between the supplier and the Company. Such sales are at the sole discretion of the supplier, and on terms and conditions that are negotiated between the supplier and the respective financial institution. The terms and conditions of the supplier invoice, including payment terms and amounts due, are not impacted by a supplier’s participation in the program. Pursuant to the supply chain finance agreements, the Company has agreed to pay financial institutions on the original due date of the applicable invoice. There are no guarantees associated with these programs. The Company's outstanding payment obligations to financial institutions related to supplier financing programs were $ 14 million and $ 16 million as of December 31, 2024 and September 30, 2024, respectively, and are included within Accounts payable and accrued liabilities on the Consolidated Balance Sheets.

Financial Information by Segmen

Financial Information by Segment	3 Months Ended
	Dec. 31, 2024
Segment Reporting [Abstract]
Financial Information by Segment	K. Financial Information by Segment The Company identifies a product line as an operating segment if: i) it engages in business activities from which it may earn revenues and incur expenses; ii) its operating results are regularly reviewed by the Chief Operating Decision Maker (“CODM”), who is Cabot’s President and Chief Executive Officer, to make decisions about resources to be allocated to the segment and assess its performance; and iii) it has available discrete financial information. The CODM reviews financial information at the operating segment level to allocate resources and to assess the operating results and financial performance for each operating segment. Operating segments are aggregated into a reportable segment if the operating segments are determined to have similar economic characteristics and if the operating segments are similar in the following areas: i) nature of products and services; ii) nature of production processes; iii) type or class of customer for their products and services; iv) methods used to distribute the products or provide services; and v) if applicable, the nature of the regulatory environment. The Company has two reportable segments: Reinforcement Materials and Performance Chemicals. The Reinforcement Materials segment combines the reinforcing carbons and engineered elastomer composites product lines. The Performance Chemicals segment aggregates the specialty carbons, specialty compounds, fumed metal oxides, battery materials, inkjet colorants and aerogel product lines. Income (loss) before income taxes (“Segment EBIT”) is presented for each reportable segment in the table below. Segment EBIT excludes Interest expense, General unallocated income (expense), Unallocated corporate costs and Certain items, meaning items management does not consider representative of on-going operating segment results. In addition, Segment EBIT includes Equity in earnings of affiliated companies, net of tax, Net income attributable to noncontrolling interests, net of tax, and discounting charges for certain Notes receivable. Financial information by reportable segment is as follows: Reinforcement Performance Segment Unallocated (1) Consolidated (In millions) Three Months Ended December 31, 2024 Revenues from external customers (2) $ 611 $ 311 $ 922 $ 33 $ 955 Income (loss) before income taxes (3) $ 130 $ 45 $ 175 $ ( 31 ) $ 144 Three Months Ended December 31, 2023 Revenues from external customers (2) $ 641 $ 285 $ 926 $ 32 $ 958 Income (loss) before income taxes (3) $ 129 $ 34 $ 163 $ ( 69 ) $ 94 (1) Unallocated and Other includes certain items and eliminations necessary to reflect management’s reporting of operating segment results. These items are reflective of the segment reporting presented to the CODM. (2) Consolidated Total Revenues from external customers reconciles to Net sales and other operating revenues on the Consolidated Statements of Operations. Revenues from external customers that are categorized as Unallocated and Other reflects external shipping and handling fees, the impact of unearned revenue, and discounting charges for certain Notes receivable. Details are provided in the table below: Three Months Ended December 31 2024 2023 (In millions) Shipping and handling fees $ 28 $ 30 Other 5 2 Total $ 33 $ 32 (3) Consolidated Total Income (loss) before income taxes reconciles to Income (loss) before income taxes and equity in earnings of affiliated companies on the Consolidated Statements of Operations. Income (loss) before income taxes that are categorized as Unallocated and Other includes: Three Months Ended December 31 2024 2023 (In millions) Interest expense $ ( 18 ) $ ( 22 ) Certain items (a) Legal and environmental matters and reserves ( 5 ) — Argentina controlled currency devaluation and other losses (Note B) — ( 33 ) Global restructuring activities — ( 9 ) Other certain items ( 1 ) — Total certain items ( 6 ) ( 42 ) Unallocated corporate costs (b) ( 13 ) ( 17 ) General unallocated income (expense) (c) 7 13 Less: Equity in earnings of affiliated companies, net (d) 1 1 Total $ ( 31 ) $ ( 69 ) (a) Certain items are items of expense and income that management does not consider representative of the Company’s fundamental on-going segment results and they are, therefore, excluded from Segment EBIT. (b) Unallocated corporate costs are costs that are not controlled by the segments and primarily benefit corporate interests. (c) General unallocated income (expense) consists of gains (losses) arising from foreign currency transactions, net of other foreign currency risk management activities, Interest and dividend income, the profit or loss related to the corporate adjustment for unearned revenue and unrealized holding gains (losses) for investments. This does not include items of income or expense that are separately treated as Certain items. (d) Equity in earnings of affiliated companies, net of tax, is included in Segment EBIT and is removed in Unallocated and other to reconcile to Income (loss) from operations before income taxes and equity in earnings from affiliated companies. The Company’s segments operate globally. In addition to presenting Revenue from external customers by reportable segment, the following tables further disaggregate Revenues from external customers by geographic region. Three Months Ended December 31, 2024 Reinforcement Performance Consolidated Total (In millions) Americas $ 244 $ 90 $ 334 Asia Pacific 247 144 391 Europe, Middle East and Africa 120 77 197 Segment revenues from external customers 611 311 922 Unallocated and other 33 Net sales and other operating revenues $ 955 Three Months Ended December 31, 2023 Reinforcement Performance Consolidated Total (In millions) Americas $ 254 $ 88 $ 342 Asia Pacific 260 120 380 Europe, Middle East and Africa 127 77 204 Segment revenues from external customers 641 285 926 Unallocated and other 32 Net sales and other operating revenues $ 958

Significant Accounting Polici_2

Significant Accounting Policies (Policies)	3 Months Ended
	Dec. 31, 2024
Accounting Policies [Abstract]
Recent Accounting Pronouncements	Recent Accounting Pronouncements In November 2024, the FASB issued a new standard, Expense Disaggregation Disclosures. The new guidance requires quantitative and qualitative disclosure of certain cost and expense categories in the notes to the financial statements for interim and annual reporting periods. The new standard is effective for the Company's fiscal years and interim periods beginning October 1, 2027, with early adoption permitted. The Company is currently evaluating the timing of adoption and evaluating the impact of the potential adoption of this standard on the Company’s Consolidated Financial Statements. In March 2024, the Securities and Exchange Commission (“SEC”) issued its final rule, The Enhancement and Standardization of Climate-Related Disclosures for Investors that requires the Company to provide certain climate-related information. The rule provides a phased-in compliance period and is effective for fiscal years beginning after December 15, 2024, with early adoption permitted. In April 2024, the SEC voluntarily stayed its rule pending completion of judicial review by the U.S. Court of Appeals for the Eighth Circuit and, therefore, the timing of the effectiveness of these disclosure requirements is uncertain. The Company is currently monitoring the timing of adoption and evaluating the impact of the potential adoption of this standard on the Company’s Consolidated Financial Statements. In December 2023, the FASB issued a new standard, Improvements to Income Tax Disclosures. The new guidance requires additional disclosures primarily related to the income tax rate reconciliation and income taxes paid. The new standard is effective for the Company’s fiscal years and interim periods beginning October 1, 2025. The Company is currently evaluating the impact of the adoption of this standard on the Company’s Consolidated Financial Statements. In November 2023, the FASB issued a new standard, Improvement to Reportable Segment Disclosures. The new guidance requires enhanced disclosure of significant reportable segment expenses. The new standard is effective for the Company’s current fiscal year which began October 1, 2024, and for interim periods beginning October 1, 2025. The Company is currently evaluating the impact of the adoption of this standard on the Company’s Consolidated Financial Statements.

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	3 Months Ended
	Dec. 31, 2024
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Changes in Balances	The carrying amount of goodwill attributable to each reportable segment and the changes in those balances during the three months ended December 31, 2024 are as follows: Reinforcement Performance Total (In millions) Balance at September 30, 2024 $ 48 $ 85 $ 133 Foreign currency impact ( 2 ) ( 4 ) ( 6 ) Balance at December 31, 2024 $ 46 $ 81 $ 127
Schedule of Intangible Assets	The following table provides information regarding the Company’s intangible assets: December 31, 2024 September 30, 2024 Gross Accumulated Net Gross Accumulated Net (In millions) Intangible assets with finite lives Developed technologies (1) $ 40 $ ( 12 ) $ 28 $ 34 $ ( 12 ) $ 22 Trademarks 2 ( 1 ) 1 2 ( 1 ) 1 Customer relationships 58 ( 30 ) 28 60 ( 30 ) 30 Total intangible assets $ 100 $ ( 43 ) $ 57 $ 96 $ ( 43 ) $ 53 (1) Included within Developed technologies as of December 31, 2024 is $ 8 million of intangible assets acquired during the first quarter of fiscal 2025 as discussed in Note C above.

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Income (Loss) ("AOCI") (Tables)	3 Months Ended
	Dec. 31, 2024
Equity [Abstract]
Changes in Each Component of AOCI, Net of Tax	Changes in each component of AOCI, net of tax, were as follows: Currency Pension and Other Total (In millions) Balance at September 30, 2024, attributable to Cabot Corporation $ ( 342 ) $ ( 18 ) $ ( 360 ) Other comprehensive income (loss) before reclassifications ( 104 ) — ( 104 ) Amounts reclassified from AOCI — — — Less: Other comprehensive income (loss) attributable to ( 7 ) — ( 7 ) Balance at December 31, 2024, attributable to Cabot Corporation $ ( 439 ) $ ( 18 ) $ ( 457 ) Currency Pension and Other Total (In millions) Balance at September 30, 2023, attributable to Cabot Corporation $ ( 353 ) $ ( 9 ) $ ( 362 ) Other comprehensive income (loss) before reclassifications 62 — 62 Amounts reclassified from AOCI ( 1 ) — ( 1 ) Less: Other comprehensive income (loss) attributable to 4 — 4 Balance at December 31, 2023, attributable to Cabot Corporation $ ( 296 ) $ ( 9 ) $ ( 305 )

Income Tax (Tables)

Income Tax (Tables)	3 Months Ended
	Dec. 31, 2024
Income Tax Disclosure [Abstract]
Effective Tax Rate	Effective Tax Rate Three Months Ended December 31 2024 2023 (Dollars in millions) (Provision) benefit for income taxes $ ( 41 ) $ ( 34 ) Effective tax rate 28 % 36 %

Earnings Per Share (Tables)

Earnings Per Share (Tables)	3 Months Ended
	Dec. 31, 2024
Earnings Per Share [Abstract]
Components of Basic and Diluted Earnings (Loss) Per Common Share (EPS)	The following tables summarize the components of the basic and diluted earnings (loss) per common share (“EPS”) computations: Three Months Ended December 31 2024 2023 (In millions, except per share amounts) Basic EPS: Net income (loss) attributable to Cabot $ 93 $ 50 Less: Dividends and dividend equivalents — — Less: Undistributed earnings allocated to (1) 1 1 Earnings (loss) allocated to common $ 92 $ 49 Weighted average common shares and 55.2 56.4 Less: Participating securities (1) 0.9 1.1 Adjusted weighted average common 54.3 55.3 Earnings (loss) per common share - basic: $ 1.69 $ 0.88 Diluted EPS: Earnings (loss) allocated to common $ 92 $ 49 Plus: Earnings allocated to 1 1 Less: Adjusted earnings allocated to (2) 1 1 Earnings (loss) allocated to common $ 92 $ 49 Adjusted weighted average common 54.3 55.3 Effect of dilutive securities: Common shares issuable (3) 0.7 0.5 Adjusted weighted average common 55.0 55.8 Earnings (loss) per common share - diluted: $ 1.67 $ 0.88 (1) Participating securities consist of shares underlying unvested time-based restricted stock units (the "TSUs"), earned and unvested performance-based restricted stock units (the "PSUs", and referred to in this note collectively with the TSUs as the "RSUs"), stock units accounted for under the Supplemental 401(k) Plan portion of the Company’s Deferred Compensation and Supplemental Retirement Plan, and stock units and phantom stock units accounted for under the Company’s Non-Employee Directors’ Deferral Plan. The holders of RSUs are entitled to receive dividend equivalents, payable in cash, to the extent dividends are paid on the outstanding shares of Common Stock, and equal in value to the dividends that would have been paid in respect of the Common Stock underlying the RSU. The accounts of holders of stock units and phantom stock units are credited with dividend equivalents, which are payable, in stock or cash, as the case may be, with the distribution of account balances.
Calculation of Undistributed Earnings	Undistributed earnings are the earnings which remain after dividends declared during the period are assumed to be distributed to the common and participating stockholders. Undistributed earnings are allocated to common and participating stockholders on the same basis as dividend distributions. The calculation of undistributed earnings is as follows: Three Months Ended December 31 2024 2023 (In millions) Calculation of undistributed earnings (loss): Net income (loss) attributable to Cabot Corporation $ 93 $ 50 Less: Dividends declared on common stock 24 22 Less: Dividends declared on participating — — Undistributed earnings (loss) $ 69 $ 28 Allocation of undistributed earnings (loss): Undistributed earnings (loss) allocated to $ 68 $ 27 Undistributed earnings allocated to 1 1 Undistributed earnings (loss) $ 69 $ 28 (2) Undistributed earnings are adjusted for the assumed distribution of dividends to the dilutive securities, which are described in (3) below, and then reallocated to participating securities. (3) Represents incremental shares of common stock from the assumed exercise of stock options issued under Cabot’s equity incentive plans. For the three months ended December 31, 2024 and 2023, 63,807 and 330,331 incremental shares of common stock, respectively, were excluded from the calculation of diluted earnings per share because the inclusion of these shares would have been antidilutive.

Financial Information by Segm_2

Financial Information by Segment (Tables)	3 Months Ended
	Dec. 31, 2024
Segment Reporting [Abstract]
Financial Information by Reportable Segment	Financial information by reportable segment is as follows: Reinforcement Performance Segment Unallocated (1) Consolidated (In millions) Three Months Ended December 31, 2024 Revenues from external customers (2) $ 611 $ 311 $ 922 $ 33 $ 955 Income (loss) before income taxes (3) $ 130 $ 45 $ 175 $ ( 31 ) $ 144 Three Months Ended December 31, 2023 Revenues from external customers (2) $ 641 $ 285 $ 926 $ 32 $ 958 Income (loss) before income taxes (3) $ 129 $ 34 $ 163 $ ( 69 ) $ 94 (1) Unallocated and Other includes certain items and eliminations necessary to reflect management’s reporting of operating segment results. These items are reflective of the segment reporting presented to the CODM. (2) Consolidated Total Revenues from external customers reconciles to Net sales and other operating revenues on the Consolidated Statements of Operations. Revenues from external customers that are categorized as Unallocated and Other reflects external shipping and handling fees, the impact of unearned revenue, and discounting charges for certain Notes receivable. Details are provided in the table below: Three Months Ended December 31 2024 2023 (In millions) Shipping and handling fees $ 28 $ 30 Other 5 2 Total $ 33 $ 32 (3) Consolidated Total Income (loss) before income taxes reconciles to Income (loss) before income taxes and equity in earnings of affiliated companies on the Consolidated Statements of Operations. Income (loss) before income taxes that are categorized as Unallocated and Other includes: Three Months Ended December 31 2024 2023 (In millions) Interest expense $ ( 18 ) $ ( 22 ) Certain items (a) Legal and environmental matters and reserves ( 5 ) — Argentina controlled currency devaluation and other losses (Note B) — ( 33 ) Global restructuring activities — ( 9 ) Other certain items ( 1 ) — Total certain items ( 6 ) ( 42 ) Unallocated corporate costs (b) ( 13 ) ( 17 ) General unallocated income (expense) (c) 7 13 Less: Equity in earnings of affiliated companies, net (d) 1 1 Total $ ( 31 ) $ ( 69 ) (a) Certain items are items of expense and income that management does not consider representative of the Company’s fundamental on-going segment results and they are, therefore, excluded from Segment EBIT. (b) Unallocated corporate costs are costs that are not controlled by the segments and primarily benefit corporate interests. (c) General unallocated income (expense) consists of gains (losses) arising from foreign currency transactions, net of other foreign currency risk management activities, Interest and dividend income, the profit or loss related to the corporate adjustment for unearned revenue and unrealized holding gains (losses) for investments. This does not include items of income or expense that are separately treated as Certain items. (d) Equity in earnings of affiliated companies, net of tax, is included in Segment EBIT and is removed in Unallocated and other to reconcile to Income (loss) from operations before income taxes and equity in earnings from affiliated companies.
Revenues from External Customers by Geographic Region	The Company’s segments operate globally. In addition to presenting Revenue from external customers by reportable segment, the following tables further disaggregate Revenues from external customers by geographic region. Three Months Ended December 31, 2024 Reinforcement Performance Consolidated Total (In millions) Americas $ 244 $ 90 $ 334 Asia Pacific 247 144 391 Europe, Middle East and Africa 120 77 197 Segment revenues from external customers 611 311 922 Unallocated and other 33 Net sales and other operating revenues $ 955 Three Months Ended December 31, 2023 Reinforcement Performance Consolidated Total (In millions) Americas $ 254 $ 88 $ 342 Asia Pacific 260 120 380 Europe, Middle East and Africa 127 77 204 Segment revenues from external customers 641 285 926 Unallocated and other 32 Net sales and other operating revenues $ 958

Significant Accounting Polici_3

Significant Accounting Policies - Additional Information (Detail) - Other Income (Expense) [Member] - USD ($)	3 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Significant Accounting Policies [Line Items]
Foreign exchange losses	$ (40,000,000)
Maximum [Member]
Significant Accounting Policies [Line Items]
Investment income (loss)	1,000,000	$ 12,000,000
Revaluation of Non-functional Currency [Member]
Significant Accounting Policies [Line Items]
Foreign exchange losses	$ (2,000,000)	(40,000,000)
Single Devaluation Action [Member]
Significant Accounting Policies [Line Items]
Foreign exchange losses		$ (33,000,000)

Acquisitions - Additional Infor

Acquisitions - Additional Information (Detail) - Certain Assets and Licensed Related Technology [Member] $ in Millions	1 Months Ended
	Oct. 31, 2024 USD ($)
Business Acquisition [Line Items]
Business acquisition, purchase price allocated to identifiable assets on relative fair value basis	$ 27
Business acquisition, purchase price allocation, property, plants and equipment	19
Business acquisition, purchase price allocation, intangible assets	$ 8

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets - Schedule of Changes in Balances (Detail) $ in Millions	3 Months Ended
	Dec. 31, 2024 USD ($)
Goodwill And Intangible Assets [Line Items]
Beginning balance	$ 133
Foreign currency impact	(6)
Ending balance	127
Reinforcement Materials [Member]
Goodwill And Intangible Assets [Line Items]
Beginning balance	48
Foreign currency impact	(2)
Ending balance	46
Performance Chemicals [Member]
Goodwill And Intangible Assets [Line Items]
Beginning balance	85
Foreign currency impact	(4)
Ending balance	$ 81

Goodwill and Intangible Asset_3

Goodwill and Intangible Assets - Schedule of Intangible Assets (Detail) - USD ($) $ in Millions	Dec. 31, 2024	Sep. 30, 2024
Finite Lived Intangible Assets [Line Items]
Gross Carrying Value, finite lives	$ 100	$ 96
Accumulated Amortization	(43)	(43)
Net Intangible Assets, finite lives	57	53
Developed Technologies [Member]
Finite Lived Intangible Assets [Line Items]
Gross Carrying Value, finite lives	40	34
Accumulated Amortization	(12)	(12)
Net Intangible Assets, finite lives	28	22
Trademarks [Member]
Finite Lived Intangible Assets [Line Items]
Gross Carrying Value, finite lives	2	2
Accumulated Amortization	(1)	(1)
Net Intangible Assets, finite lives	1	1
Customer Relationships [Member]
Finite Lived Intangible Assets [Line Items]
Gross Carrying Value, finite lives	58	60
Accumulated Amortization	(30)	(30)
Net Intangible Assets, finite lives	$ 28	$ 30

Goodwill and Intangible Asset_4

Goodwill and Intangible Assets - Schedule of Intangible Assets (Parenthetical) (Detail) $ in Millions	3 Months Ended
	Dec. 31, 2024 USD ($)
Developed Technologies [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets acquired	$ 8

Goodwill and Intangible Asset_5

Goodwill and Intangible Assets - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Goodwill And Intangible Assets [Line Items]
Amortization expense estimated for year one	$ 6
Amortization expense estimated for year two	6
Amortization expense estimated for year three	6
Amortization expense estimated for year four	6
Amortization expense estimated for year five	6
Cost of Sales, Selling and Administrative Expenses and Research and Technical Expenses [Member]
Goodwill And Intangible Assets [Line Items]
Amortization of intangible assets	$ 2	$ 1
Minimum [Member]
Goodwill And Intangible Assets [Line Items]
Useful life of intangible assets	10 years
Maximum [Member]
Goodwill And Intangible Assets [Line Items]
Useful life of intangible assets	25 years
Weighted Average [Member]
Goodwill And Intangible Assets [Line Items]
Useful life of intangible assets	16 years

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Income (Loss) ("AOCI") - Changes in Each Component of AOCI, Net of Tax (Detail) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	$ 1,590	$ 1,407
Ending Balance	1,515	1,475
Currency Translation Adjustment [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(342)	(353)
Other comprehensive income (loss) before reclassifications	(104)	62
Amounts reclassified from AOCI		(1)
Less: Other comprehensive income (loss) attributable to noncontrolling interests	(7)	4
Ending Balance	(439)	(296)
Pension and Other Post-retirement Benefit Liability Adjustments [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(18)	(9)
Ending Balance	(18)	(9)
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(360)	(362)
Other comprehensive income (loss) before reclassifications	(104)	62
Amounts reclassified from AOCI		(1)
Less: Other comprehensive income (loss) attributable to noncontrolling interests	(7)	4
Ending Balance	$ (457)	$ (305)

Accumulated Other Comprehensi_4

Accumulated Other Comprehensive Income (Loss) ("AOCI") - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Equity [Abstract]
Gain associated with the net investment hedge out of AOCI	$ 1	$ 1
Losses excluded from net investment hedges effectiveness testing out of AOCI	$ 1	$ 0

Contingencies - Additional Info

Contingencies - Additional Information (Detail) - USD ($) $ in Millions	Dec. 31, 2024	Sep. 30, 2024
Respirator Liabilities [Member]
Loss Contingencies [Line Items]
Respirator reserve	$ 34	$ 35

Income Tax - Effective Tax Rate

Income Tax - Effective Tax Rate (Detail) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Income Tax Disclosure [Abstract]
(Provision) benefit for income taxes	$ (41)	$ (34)
Effective tax rate	28%	36%

Income Tax - Additional Informa

Income Tax - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Income Taxes [Line Items]
Net discrete tax expense	$ 2	$ 7
Uncertain tax positions from expirations of statute of limitations	$ 2	$ 1
United States Internal Revenue Service (IRS) [Member]
Income Taxes [Line Items]
Tax years remain subject to examination	2021 2022 2023
State Tax Authorities [Member]
Income Taxes [Line Items]
Tax years remain subject to examination	2021 2022 2023
Foreign Jurisdictions [Member]
Income Taxes [Line Items]
Tax years remain subject to examination	2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024

Earnings Per Share - Components

Earnings Per Share - Components of Basic and Diluted Earnings (Loss) Per Common Share (EPS) (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Basic EPS:
Net income (loss) attributable to Cabot Corporation	$ 93	$ 50
Less: Undistributed earnings allocated to participating securities	1	1
Earnings (loss) allocated to common stockholders (numerator)	$ 92	$ 49
Weighted average common shares and participating securities outstanding	55.2	56.4
Less: Participating securities	0.9	1.1
Adjusted weighted average common shares (denominator)	54.3	55.3
Earnings (loss) per common share - basic:	$ 1.69	$ 0.88
Diluted EPS:
Earnings (loss) allocated to common stockholders	$ 92	$ 49
Plus: Earnings allocated to participating securities	1	1
Less: Adjusted earnings allocated to participating securities	1	1
Earnings (loss) allocated to common stockholders (numerator)	$ 92	$ 49
Adjusted weighted average common shares outstanding	54.3	55.3
Common shares issuable	0.7	0.5
Adjusted weighted average common shares (denominator)	55	55.8
Earnings (loss) per common share - diluted:	$ 1.67	$ 0.88

Earnings Per Share - Calculatio

Earnings Per Share - Calculation of Undistributed Earnings (Detail) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Earnings Per Share [Abstract]
Net income (loss) attributable to Cabot Corporation	$ 93	$ 50
Less: Dividends declared on common stock	24	22
Undistributed earnings (loss)	69	28
Undistributed earnings (loss) allocated to common shareholders	68	27
Undistributed earnings allocated to participating shareholders	$ 1	$ 1

Earnings Per Share - Componen_2

Earnings Per Share - Components of Basic and Diluted Earnings (Loss) Per Common Share (EPS) (Parenthetical) (Detail) - shares	3 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Earnings Per Share [Abstract]
Antidilutive securities excluded from computation of earnings per share	63,807	330,331

Financial Instruments and Fai_2

Financial Instruments and Fair Value Measurements - Additional Information (Detail) - USD ($)	3 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Sep. 30, 2024
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, liabilities, Level 2 to Level 1 transfers, amount	$ 0	$ 0
Fair value, assets, Level 2 to Level 1 transfers, amount	0	0
Fair value, liabilities, Level 1 to Level 2 transfers, amount	0	0
Fair value, assets, Level 1 to Level 2 transfers, amount	0	0
Fair value, assets, transfers into Level 3, amount	0	0
Fair value, assets, transfers out of Level 3, amount	0	0
Fair value, liabilities, transfers into Level 3, amount	0	0
Fair value, liabilities, transfers out of Level 3, amount	0	$ 0
Fixed Rate Debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying value of long-term debt	1,080,000,000		$ 1,080,000,000
Fair value of long-term debt	1,060,000,000		1,080,000,000
Significant Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other assets in the Consolidated Balance Sheets	8,000,000		8,000,000
Significant Observable Inputs (Level 2) [Member] | Net Investment Hedge [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other assets in the Consolidated Balance Sheets	17,000,000		1,000,000
Significant Observable Inputs (Level 2) [Member] | Forward Currency Contracts [Member] | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other assets in the Consolidated Balance Sheets	$ 1,000,000		$ 1,000,000

Supplier Financing Programs - A

Supplier Financing Programs - Additional Information (Details) - USD ($) $ in Millions	Dec. 31, 2024	Sep. 30, 2024
Supplier Finance Program [Line Items]
Outstanding payment obligations to financial institutions related to supplier financing programs	$ 14	$ 16
Supplier Finance Program, Obligation, Current, Statement of Financial Position [Extensible Enumeration]	Accounts Payable and Accrued Liabilities, Current	Accounts Payable and Accrued Liabilities, Current

Financial Information by Segm_3

Financial Information by Segment - Additional Information (Detail)	3 Months Ended
	Dec. 31, 2024 Segment
Segment Reporting Information [Line Items]
Number of business reportable segments	2

Financial Information by Segm_4

Financial Information by Segment - Financial Information by Reportable Segment (Detail) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Segment Reporting Information [Line Items]
Revenues from external customers	$ 955	$ 958
Income (loss) before income taxes	144	94
Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues from external customers	922	926
Income (loss) before income taxes	175	163
Unallocated and Other [Member]
Segment Reporting Information [Line Items]
Revenues from external customers	33	32
Income (loss) before income taxes	(31)	(69)
Reinforcement Materials [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues from external customers	611	641
Income (loss) before income taxes	130	129
Performance Chemicals [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues from external customers	311	285
Income (loss) before income taxes	$ 45	$ 34

Financial Information by Segm_5

Financial Information by Segment - Revenues From External Customers That are Categorized as Unallocated and Other Reflects Royalties, External Shipping and Handling Fees, The Impact of Unearned Revenue, Discounting Charges For Certain Notes Receivable, and Other By-product Revenue (Detail) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Segment Reporting Information [Line Items]
Revenues from external customers	$ 955	$ 958
Unallocated and Other [Member]
Segment Reporting Information [Line Items]
Revenues from external customers	33	32
Unallocated and Other [Member] | Shipping and Handling Costs [Member]
Segment Reporting Information [Line Items]
Revenues from external customers	28	30
Unallocated and Other [Member] | Other [Member]
Segment Reporting Information [Line Items]
Revenues from external customers	$ 5	$ 2

Financial Information by Segm_6

Financial Information by Segment - Schedule of Income (Loss) from Continuing Operations before Income Taxes and Equity in Earnings of Affiliated Companies for Unallocated and Other (Detail) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Segment Reporting Information [Line Items]
Interest expense	$ (18)	$ (22)
Less: Equity in earnings of affiliated companies, net of tax	1	1
Unallocated and Other [Member]
Segment Reporting Information [Line Items]
Interest expense	(18)	(22)
Unallocated corporate costs	(13)	(17)
General unallocated income (expense)	7	13
Less: Equity in earnings of affiliated companies, net of tax	1	1
Income from continuing operations before income taxes and equity in earnings of affiliated companies	(31)	(69)
Certain Items [Member]
Segment Reporting Information [Line Items]
Legal and environmental matters and reserves	(5)
Global restructuring activities		(9)
Other certain items	(1)
Total certain items	$ (6)	(42)
Certain Items [Member] | Argentina [Member]
Segment Reporting Information [Line Items]
Controlled currency devaluation and other losses		$ (33)

Financial Information by Segm_7

Financial Information by Segment - Revenue from External Customers by Geographic Region (Detail) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Segment Reporting Information [Line Items]
Net sales and other operating revenues	$ 955	$ 958
Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales and other operating revenues	922	926
Unallocated and Other [Member]
Segment Reporting Information [Line Items]
Net sales and other operating revenues	33	32
Americas [Member]
Segment Reporting Information [Line Items]
Net sales and other operating revenues	334	342
Asia Pacific [Member]
Segment Reporting Information [Line Items]
Net sales and other operating revenues	391	380
Europe, Middle East and Africa [Member]
Segment Reporting Information [Line Items]
Net sales and other operating revenues	197	204
Reinforcement Materials [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales and other operating revenues	611	641
Reinforcement Materials [Member] | Americas [Member]
Segment Reporting Information [Line Items]
Net sales and other operating revenues	244	254
Reinforcement Materials [Member] | Asia Pacific [Member]
Segment Reporting Information [Line Items]
Net sales and other operating revenues	247	260
Reinforcement Materials [Member] | Europe, Middle East and Africa [Member]
Segment Reporting Information [Line Items]
Net sales and other operating revenues	120	127
Performance Chemicals [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales and other operating revenues	311	285
Performance Chemicals [Member] | Americas [Member]
Segment Reporting Information [Line Items]
Net sales and other operating revenues	90	88
Performance Chemicals [Member] | Asia Pacific [Member]
Segment Reporting Information [Line Items]
Net sales and other operating revenues	144	120
Performance Chemicals [Member] | Europe, Middle East and Africa [Member]
Segment Reporting Information [Line Items]
Net sales and other operating revenues	$ 77	$ 77