Cabot (CBT) 10-Q 9 May 22 2022 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Mar. 31, 2022	May 04, 2022
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2022
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q2
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		56,433,688
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, 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		6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021
Income Statement [Abstract]
Net sales and other operating revenues	$ 1,092	$ 842	$ 2,060	$ 1,588
Cost of sales	860	628	1,630	1,181
Gross profit	232	214	430	407
Selling and administrative expenses	74	71	145	132
Research and technical expenses	14	15	27	29
Loss on sale of business and asset impairment charge (Note D)	7		204
Gain on bargain purchase of a business (Note C)	(24)		(24)
Income (loss) from operations	161	128	78	246
Interest and dividend income	4	2	7	4
Interest expense	(11)	(13)	(23)	(25)
Other income (expense)	(7)	1	(8)	(8)
Income (loss) before income taxes and equity in earnings of affiliated companies	147	118	54	217
(Provision) benefit for income taxes	(36)	(34)	(24)	(63)
Equity in earnings of affiliated companies, net of tax	3	1	4	1
Net income (loss)	114	85	34	155
Net income (loss) attributable to noncontrolling interests, net of tax	7	10	16	20
Net income (loss) attributable to Cabot Corporation	$ 107	$ 75	$ 18	$ 135
Weighted-average common shares outstanding:
Basic	56.6	56.6	56.5	56.6
Diluted	57.1	56.7	56.9	56.7
Earnings (loss) per common share:
Basic	$ 1.86	$ 1.31	$ 0.30	$ 2.37
Diluted	$ 1.84	$ 1.30	$ 0.30	$ 2.36

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021
Statement Of Income And Comprehensive Income [Abstract]
Net income (loss)	$ 114	$ 85	$ 34	$ 155
Other comprehensive income (loss), net of tax
Foreign currency translation adjustment, net of tax	46	(76)	18	18
Derivatives: net investment hedges
(Gains) losses reclassified to interest expense, net of tax	(2)	(2)	(3)	(3)
(Gains) losses excluded from effectiveness testing and amortized to interest expense, net of tax	1	1	1	1
Pension and other postretirement benefit liability adjustments, net of tax	1	1	2	4
Other comprehensive income (loss), net of tax of $‒, $‒, $(1), and $(3)	46	(76)	18	20
Comprehensive income (loss)	160	9	52	175
Net income (loss) attributable to noncontrolling interests, net of tax	7	10	16	20
Foreign currency translation adjustment attributable to noncontrolling interests, net of tax	1	(2)	3	5
Comprehensive income (loss) attributable to noncontrolling interests	8	8	19	25
Comprehensive income (loss) attributable to Cabot Corporation	$ 152	$ 1	$ 33	$ 150

Consolidated Statements of Co_2

Consolidated Statements of Comprehensive Income (Loss) (Unaudited) (Parenthetical) - USD ($) $ in Millions	6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Statement Of Income And Comprehensive Income [Abstract]
Net of tax	$ (1)	$ (3)

Consolidated Balance Sheets (Un

Consolidated Balance Sheets (Unaudited) - USD ($) $ in Millions	Mar. 31, 2022	Sep. 30, 2021
Current assets:
Cash and cash equivalents	$ 215	$ 168
Accounts and notes receivable, net of reserve for doubtful accounts of $3 and $4	791	645
Inventories:
Raw materials	193	168
Finished goods	386	300
Other	54	55
Total inventories	633	523
Prepaid expenses and other current assets	139	89
Total current assets	1,778	1,425
Property, plant and equipment, net	1,291	1,376
Goodwill	141	140
Equity affiliates	16	40
Intangible assets, net	70	100
Deferred income taxes	63	53
Other assets	165	172
Total assets	3,524	3,306
Current liabilities:
Short-term borrowings	253	72
Accounts payable and accrued liabilities	737	667
Income taxes payable	44	35
Current portion of long-term debt	373	373
Total current liabilities	1,407	1,147
Long-term debt	711	717
Deferred income taxes	73	73
Other liabilities	267	279
Contingencies (Note G)
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: 56,571,822 and 56,870,237 shares, Outstanding: 56,431,554 and 56,726,818 shares	57	57
Less cost of 140,268 and 143,419 shares of common treasury stock	(4)	(4)
Additional paid-in capital	4	24
Retained earnings	1,135	1,159
Accumulated other comprehensive income (loss)	(274)	(289)
Total Cabot Corporation stockholders' equity	918	947
Noncontrolling interests	148	143
Total stockholders' equity	1,066	1,090
Total liabilities and stockholders' equity	$ 3,524	$ 3,306

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) (Unaudited) - USD ($) $ in Millions	Mar. 31, 2022	Sep. 30, 2021
Statement Of Financial Position [Abstract]
Accounts and notes receivable, reserve for doubtful accounts	$ 3	$ 4
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	56,571,822	56,870,237
Common stock, outstanding shares	56,431,554	56,726,818
Common treasury stock, shares	140,268	143,419

Consolidated Statements of Cash

Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Cash Flows from Operating Activities:
Net income (loss)	$ 34	$ 155
Adjustments to reconcile net income (loss) to cash provided by operating activities:
Depreciation and amortization	75	77
Loss on sale of business and asset impairment charge	204
Gain on bargain purchase of a business	(24)
Deferred tax provision (benefit)	(45)	1
Employee benefit plan settlement		6
Equity in earnings of affiliated companies	(4)	(1)
Non-cash compensation	11	10
Other non-cash (income) expense	8	19
Cash dividends received from equity affiliates		1
Changes in assets and liabilities:
Accounts and notes receivable	(161)	(155)
Inventories	(177)	(80)
Prepaid expenses and other assets	(55)	(8)
Accounts payable and accrued liabilities	84	56
Income taxes payable	10	12
Other liabilities	1	(7)
Cash provided (used) by operating activities	(39)	86
Cash Flows from Investing Activities:
Additions to property, plant and equipment	(71)	(69)
Proceeds from sale of business	79
Cash assumed from acquisition of business	(5)
Other	2	3
Cash provided (used) by investing activities	15	(66)
Cash Flows from Financing Activities:
Proceeds from short-term borrowings	13
Proceeds from issuance (repayments) of commercial paper, net	167	31
Proceeds from long-term debt		100
Repayments of long-term debt	(7)	(117)
Purchases of common stock	(34)	(2)
Proceeds from sales of common stock	3	2
Cash dividends paid to noncontrolling interests	(15)	(1)
Cash dividends paid to common stockholders	(42)	(40)
Cash provided (used) by financing activities	85	(27)
Effects of exchange rate changes on cash	(16)	6
Increase (decrease) in cash, cash equivalents and restricted cash	45	(1)
Cash, cash equivalents and restricted cash at beginning of period	170	151
Cash, cash equivalents and restricted cash at end of period	$ 215	$ 150

Consolidated Statements of Ca_2

Consolidated Statements of Cash Flows (Parenthetical) (Unaudited) $ in Millions	Mar. 31, 2021USD ($)
Cash and cash equivalents	$ 146
Cash, cash equivalents and restricted cash	150
Prepaid Expenses and Other Current Assets
Restricted cash classified within Prepaid expenses and other current assets	$ 4

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, 2020	$ 814	$ 53		$ 989	$ (351)	$ 691	$ 123
Beginning Balance, Shares at Sep. 30, 2020		56,467
Net income (loss)	70			60		60	10
Total other comprehensive income (loss)	96				89	89	7
Cash dividends paid, Common stock, per share	(20)			(20)		(20)
Cash dividends declared to noncontrolling interests	(1)						(1)
Issuance of stock under equity compensation plans	1		$ 1			1
Issuance of stock under equity compensation plans, Shares		192
Amortization of share-based compensation	4		4			4
Purchase and retirement of common stock	(2)		(2)			(2)
Purchase and retirement of common stock, Shares		(53)
Amount reclassified to retained earnings in excess of additional paid in capital			(3)	3
Ending Balance at Dec. 31, 2020	962	$ 53		1,032	(262)	823	139
Ending Balance, Shares at Dec. 31, 2020		56,606
Beginning Balance at Sep. 30, 2020	814	$ 53		989	(351)	691	123
Beginning Balance, Shares at Sep. 30, 2020		56,467
Net income (loss)	155
Total other comprehensive income (loss)	20
Ending Balance at Mar. 31, 2021	947	$ 53		1,094	(336)	811	136
Ending Balance, Shares at Mar. 31, 2021		56,622
Beginning Balance at Dec. 31, 2020	962	$ 53		1,032	(262)	823	139
Beginning Balance, Shares at Dec. 31, 2020		56,606
Net income (loss)	85			75		75	10
Total other comprehensive income (loss)	(76)				(74)	(74)	(2)
Cash dividends paid, Common stock, per share	(20)			(20)		(20)
Cash dividends declared to noncontrolling interests	(11)						(11)
Issuance of stock under equity compensation plans	1		1			1
Issuance of stock under equity compensation plans, Shares		17
Amortization of share-based compensation	6		6			6
Purchase and retirement of common stock, Shares		(1)
Amount reclassified to retained earnings in excess of additional paid in capital			(7)	7
Ending Balance at Mar. 31, 2021	947	$ 53		1,094	(336)	811	136
Ending Balance, Shares at Mar. 31, 2021		56,622
Beginning Balance at Sep. 30, 2021	1,090	$ 53	24	1,159	(289)	947	143
Beginning Balance, Shares at Sep. 30, 2021		56,727
Net income (loss)	(80)			(89)		(89)	9
Total other comprehensive income (loss)	(28)				(30)	(30)	2
Cash dividends paid, Common stock, per share	(21)			(21)		(21)
Issuance of stock under equity compensation plans, Shares		202
Amortization of share-based compensation	6		6			6
Purchase and retirement of common stock	(19)		(19)			(19)
Purchase and retirement of common stock, Shares		(349)
Ending Balance at Dec. 31, 2021	948	$ 53	11	1,049	(319)	794	154
Ending Balance, Shares at Dec. 31, 2021		56,580
Beginning Balance at Sep. 30, 2021	1,090	$ 53	24	1,159	(289)	947	143
Beginning Balance, Shares at Sep. 30, 2021		56,727
Net income (loss)	34
Total other comprehensive income (loss)	18
Ending Balance at Mar. 31, 2022	1,066	$ 53	4	1,135	(274)	918	148
Ending Balance, Shares at Mar. 31, 2022		56,431
Beginning Balance at Dec. 31, 2021	948	$ 53	11	1,049	(319)	794	154
Beginning Balance, Shares at Dec. 31, 2021		56,580
Net income (loss)	114			107		107	7
Total other comprehensive income (loss)	46				45	45	1
Cash dividends paid, Common stock, per share	(21)			(21)		(21)
Cash dividends declared to noncontrolling interests	(14)						(14)
Issuance of stock under equity compensation plans	3		3			3
Issuance of stock under equity compensation plans, Shares		72
Amortization of share-based compensation	5		5			5
Purchase and retirement of common stock	(15)		(15)			(15)
Purchase and retirement of common stock, Shares		(221)
Ending Balance at Mar. 31, 2022	$ 1,066	$ 53	$ 4	$ 1,135	$ (274)	$ 918	$ 148
Ending Balance, Shares at Mar. 31, 2022		56,431

Consolidated Statements of Ch_2

Consolidated Statements of Changes in Stockholders' Equity (Unaudited) (Parenthetical) - $ / shares	3 Months Ended
	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021	Dec. 31, 2020
Statement Of Stockholders Equity [Abstract]
Common stock, cash dividends paid, per share	$ 0.37	$ 0.37	$ 0.35	$ 0.35

Basis of Presentation

Basis of Presentation	6 Months Ended
	Mar. 31, 2022
Accounting Policies [Abstract]
Basis of Presentation	A. Basis of Presentation The consolidated financial statements have been prepared in conformity with accounting policies generally accepted in the United States (“U.S.”) 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, 2021 (“2021 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 March 31, 2022 and 2021. All such adjustments are of a normal recurring nature. The results for interim periods are not necessarily indicative of the results to be expected for the fiscal year. As discussed in Note C, on February 28, 2022, the Company acquired Tokai Carbon (Tianjin) Co. (“Tokai Carbon”). The results of operations and cash flows of Tokai Carbon are included in the Company’s consolidated financial statements from the date of acquisition. As discussed in Note D, on March 1, 2022, the Company completed the sale of its Purification Solutions business to an affiliate of funds advised by One Equity Partners (“OEP”). The sale of the Purification Solutions business did not meet the criteria to be reported as a discontinued operation as it did not constitute a significant strategic business shift for the Company, and has no major effect on operations. Therefore, prior periods’ consolidated financial statements and disclosures have not been retroactively restated to reflect the impact of the sale of the Purification Solutions business .

Significant Accounting Policies

Significant Accounting Policies	6 Months Ended
	Mar. 31, 2022
Accounting Policies [Abstract]
Significant Accounting Policies	B. Significant Accounting Policies Recently Adopted Accounting Standards In December 2019, the FASB issued a new standard Simplifying the Accounting for Income Taxes. The new guidance simplifies the accounting for income taxes by removing several exceptions in the current standard and adding guidance that reduces complexity in certain areas. The new standard is effective for fiscal years beginning after December 15, 2020. The Company adopted this standard on October 1, 2021. The adoption of this standard did not materially impact the Company’s consolidated financial statements. Recent Accounting Pronouncements In March 2020, the FASB issued a new standard on Reference Rate Reform, which provides temporary optional expedients and exceptions to the existing guidance on contract modifications and hedge accounting to ease the financial reporting burdens related to the expected market transition from the London Interbank Offered Rate ("LIBOR") and other interbank offered rates to alternative reference rates. The standard was effective upon issuance and may generally be applied through December 31, 2022 to any new or amended contracts, hedging relationships, and other transactions that reference LIBOR. The Company is currently evaluating the timing of adoption and the impact of the adoption of this standard on its consolidated financial statements.

Acquisition

Acquisition	6 Months Ended
	Mar. 31, 2022
Business Combinations [Abstract]
Acquisition	C. Acquisition Tokai Carbon (Tianjin) Co. On February 28, 2022, the Company purchased 100% of the registered capital of Tokai Carbon, a carbon black manufacturing facility, from Tokai Carbon Group for a net purchase price of $9 million, consisting of cash consideration payable of $14 million, including customary post-closing adjustments, and net of $5 million of cash acquired. The provisional estimates of the fair value of assets and liabilities acquired as of February 28, 2022 are set forth below along with the calculation of the Gain on bargain purchase of a business based on the cash consideration payable. (In millions) Fair value of asset acquired Cash $ 5 Accounts and notes receivable 5 Inventories 11 Prepaid expenses and other current assets 7 Property, plant and equipment 12 Amounts attributable to assets acquired 40 Fair value of liabilities assumed Accounts payable and accrued liabilities (2 ) Amounts attributable to liabilities assumed (2 ) Total identifiable net assets 38 Cash consideration payable 14 Gain on bargain purchase of a business $ 24 The excess of the fair value of the net assets over the purchase price was recorded as a gain of $24 million for the period ended March 31, 2022. The Gain on bargain purchase of a business arose primarily due to necessary equipment upgrades that will be required after the purchase to continue to utilize the existing assets. The payment of $14 million of cash consideration for the acquisition is expected to occur in the third quarter of fiscal 2022 and at March 31, 2022, was included in Accounts payable and accrued liabilities in the Consolidated Balances Sheets.

Divestiture

Divestiture	6 Months Ended
	Mar. 31, 2022
Discontinued Operations And Disposal Groups [Abstract]
Divestiture	D. Divestitures Sale of Purification Solutions Business On March 1, 2022, the Company completed the sale of its Purification Solutions business, a reporting segment of the Company, to OEP for total expected cash proceeds of approximately $90 million, net of $7 million cash transferred. Upon completion of the sale, the Company received net cash proceeds of $79 million and recorded a receivable for $11 million, which are subject to customary post-closing adjustments. The $11 million receivable is included in Accounts and notes receivable on the Consolidated Balance Sheet at March 31, 2022. The Company expects to settle this receivable by the end of fiscal 2022. The Company recognized a pre-tax loss on sale of the Purification Solutions business of $7 million in the second quarter of fiscal 2022 and $197 million pre-tax impairment charge in the first quarter of fiscal 2022. The total after-tax loss on sale and impairment charge was $167 million for the six months ended March 31, 2022 . Sale of Marshall Mine In September 2020, the Company entered into an agreement to sell its lignite mine located in Marshall, Texas to ADA Carbon Solutions, LLC (“ADACS”) for a nominal amount. As part of the transaction, the Company agreed to fund a portion of the costs ADACS expects to incur to close the mine. Additionally, in conjunction with the sale of the mine, the Business entered into a long-term supply agreement with ADACS, a producer of lignite-based activated carbon, which included an agreement for the Company to fund certain capital expenditures. These liabilities totaled $11 million, which the Company settled in full with ADACS during the second quarter of fiscal 2022 in connection with the sale of the Business.

Goodwill and Intangible Assets

Goodwill and Intangible Assets	6 Months Ended
	Mar. 31, 2022
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	E. Goodwill and Intangible Assets The carrying amount of goodwill attributable to each reportable segment with goodwill balances and the changes in those balances during the six months ended March 31, 2022 are as follows: Reinforcement Materials Performance Chemicals Total (In millions) Balance at September 30, 2021 $ 48 $ 92 $ 140 Foreign currency impact — 1 1 Balance at March 31, 2022 $ 48 $ 93 $ 141 The following table provides information regarding the Company’s intangible assets: March 31, 2022 September 30, 2021 Gross Carrying Value Accumulated Amortization Net Intangible Assets Gross Carrying Value Accumulated Amortization Net Intangible Assets (In millions) Intangible assets with finite lives Developed technologies $ 36 $ (7 ) $ 29 $ 62 $ (12 ) $ 50 Trademarks 3 (1 ) 2 11 (1 ) 10 Customer relationships 61 (22 ) 39 60 (20 ) 40 Total intangible assets $ 100 $ (30 ) $ 70 $ 133 $ (33 ) $ 100 Intangible assets are amortized over their estimated useful lives, which range between ten and twenty-five years, with a weighted average amortization period of approximately seventeen years. Amortization expense was $1 million and $2 million for the three months ended March 31, 2022 and 2021, respectively, and $3 million and $4 million for the six months ended March 31, 2022 and 2021, respectively. 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")	6 Months Ended
	Mar. 31, 2022
Stockholders Equity Note [Abstract]
Accumulated Other Comprehensive Income (Loss) ("AOCI")	F. 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 Translation Adjustment Pension and Other Postretirement Benefit Liability Adjustments Total (In millions) Balance at September 30, 2021, attributable to Cabot Corporation $ (265 ) $ (24 ) $ (289 ) Other comprehensive income (loss) before reclassifications (28 ) 1 (27 ) Amounts reclassified from AOCI (1 ) — (1 ) Less: Other comprehensive income (loss) attributable to noncontrolling interests 2 — 2 Balance at December 31, 2021, attributable to Cabot Corporation (296 ) (23 ) (319 ) Other comprehensive income (loss) before reclassifications 12 1 13 Amounts reclassified from AOCI 33 — 33 Less: Other comprehensive income (loss) attributable to noncontrolling interests 1 — 1 Balance at March 31, 2022, attributable to Cabot Corporation $ (252 ) $ (22 ) $ (274 ) The amounts reclassified out of AOCI and into the Consolidated Statements of Operations in each of the three and six months ended March 31, 2022 and 2021 were as follows: Affected Line Item in the Consolidated Three Months Ended March 31 Six Months Ended March 31 Statements of Operations 2022 2021 2022 2021 (In millions) Derivatives: net investment hedges (Gains) losses reclassified to interest expense Interest expense $ (2 ) $ (2 ) $ (3 ) $ (3 ) (Gains) losses excluded from effectiveness testing and amortized to interest expense Interest expense 1 1 1 1 Release of currency translation adjustment Loss on sale of business and asset impairment charge 33 — 33 — Pension and other postretirement Release of actuarial losses and prior service cost (credit) Loss on sale of business and asset impairment charge 1 — 1 — Amortization of actuarial losses and prior service cost (credit) Net Periodic Benefit Cost — — — 1 Settlement charge Net Periodic Benefit Cost — — — 6 Total before tax $ 33 $ (1 ) $ 32 $ 5

Contingencies

Contingencies	6 Months Ended
	Mar. 31, 2022
Commitments And Contingencies Disclosure [Abstract]
Contingencies	G. 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 2021 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 2021 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 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.

Insurance Recoveries

Insurance Recoveries	6 Months Ended
	Mar. 31, 2022
Insurance Recovery [Abstract]
Insurance Recoveries	H. Insurance Recoveries Pepinster, Belgium In July 2021, the Company’s Specialty Compounds manufacturing and research and development facility in Pepinster, Belgium experienced significant flooding. Full production was temporarily halted and has resumed in the second quarter of fiscal 2022. During fiscal 2021, the Company recorded expenses of $17 million for clean-up costs, inventory, and fixed asset impairments and simultaneously recognized a fully offsetting loss recovery from expected insurance proceeds. For the three and six months ended March 31, 2022, the Company recorded additional expenses of $1 million and $6 million, respectively, for clean-up costs, inventory, and fixed asset impairments and simultaneously recognized a fully offsetting loss recovery from expected insurance proceeds as the Company expects insurance proceeds in excess of the total incurred costs and policy deductibles. The flood-related expenses and loss recoveries are both included within Cost of sales in the Consolidated Statements of Operations for the three and six months ended March 31, 2022. During fiscal 2021, the Company received insurance proceeds of $8 million. For the three and six months ended March 31, 2022, the Company received additional insurance proceeds of $2 million and $7 million, respectively. In the six months ended March 31, 2022, this amount included $1 million in Cash provided by investing activities and $6 million in Cash provided by operating activities in the Consolidated Statements of Cash Flows. At March 31, 2022 and September 30, 2021, the receivable for insurance recoveries was $8 million and $9 million, respectively, and is included in Accounts and notes receivable on the Consolidated Balance Sheet.

Income Tax

Income Tax	6 Months Ended
	Mar. 31, 2022
Income Tax Disclosure [Abstract]
Income Tax	I. Income Tax Effective Tax Rate Three Months Ended March 31 Six Months Ended March 31 2022 2021 2022 2021 (Dollars in millions) (Provision) benefit for income taxes $ (36 ) $ (34 ) $ (24 ) $ (63 ) Effective tax rate 24 % 29 % 44 % 29 % For the three and six months ended March 31, 2022, the (Provision) benefit for income taxes included a net discrete tax expense of $1 million and a net discrete tax benefit of $36 million, respectively, Cabot generated a U.S. tax benefit of $183 million from the tax loss related to the divestiture of the Purification Solutions business. This benefit was fully offset with a valuation allowance. 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 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 Ca bot 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 2018 through 2020 tax years generally remain subject to examination by the IRS and various tax years from 2005 through 2020 remain subject to examination by the respective state tax authorities. In significant non-U.S. jurisdictions, various tax years from 2005 through 2021 remain subject to examination by their respective tax authorities. During the three and six months ended March 31, 2022, Cabot released uncertain tax positions of $1 million and $2 million, respectively, due to the expiration of statutes of limitations in various jurisdictions. During the three and six months ended March 31, 2021, Cabot released uncertain tax positions of less than $1 million and $1 million, respectively, due to the expiration of statutes of limitations in various jurisdictions.

Earnings Per Share

Earnings Per Share	6 Months Ended
	Mar. 31, 2022
Earnings Per Share [Abstract]
Earnings Per Share	J. Earnings Per Share The following tables summarize the components of the basic and diluted earnings (loss) per common share (“EPS”) computations: Three Months Ended March 31 Six Months Ended March 31 2022 2021 2022 2021 (In millions, except per share amounts) Basic EPS: Net income (loss) attributable to Cabot Corporation $ 107 $ 75 $ 18 $ 135 Less: Dividends and dividend equivalents to participating securities 1 — 1 — Less: Undistributed earnings allocated to participating securities ( 1) 1 1 — 1 Earnings (loss) allocated to common shareholders (numerator) $ 105 $ 74 $ 17 $ 134 Weighted average common shares and participating securities outstanding 57.5 57.4 57.4 57.3 Less: Participating securities ( 1) 0.9 0.8 0.9 0.7 Adjusted weighted average common shares (denominator) 56.6 56.6 56.5 56.6 Earnings (loss) per common share - basic: $ 1.86 $ 1.31 $ 0.30 $ 2.37 Diluted EPS: Earnings (loss) allocated to common shareholders $ 105 $ 74 $ 17 $ 134 Plus: Earnings allocated to participating securities 2 1 1 1 Less: Adjusted earnings allocated to participating securities ( 2) 2 1 1 1 Earnings (loss) allocated to common shareholders (numerator) $ 105 $ 74 $ 17 $ 134 Adjusted weighted average common shares outstanding 56.6 56.6 56.5 56.6 Effect of dilutive securities: Common shares issuable ( 3) 0.5 0.1 0.4 0.1 Adjusted weighted average common shares (denominator) 57.1 56.7 56.9 56.7 Earnings (loss) per common share - diluted: $ 1.84 $ 1.30 $ 0.30 $ 2.36 (1) Participating securities consist of shares underlying all outstanding and achieved performance-based restricted stock units and all unvested time-based restricted stock units. The holders of these units are entitled to receive dividend equivalents payable in cash to the extent dividends are paid on the Company’s outstanding common stock and equal in value to the dividends that would have been paid in respect of the shares underlying such units. Undistributed earnings are the earnings which remain after dividends declared during the period are assumed to be distributed to the common and participating shareholders. Undistributed earnings are allocated to common and participating shareholders on the same basis as dividend distributions. The calculation of undistributed earnings is as follows: Three Months Ended March 31 Six Months Ended March 31 2022 2021 2022 2021 (In millions) Calculation of undistributed earnings (loss): Net income (loss) attributable to Cabot Corporation $ 107 $ 75 $ 18 $ 135 Less: Dividends declared on common stock 21 20 42 40 Less: Dividends declared on participating securities 1 — 1 — Undistributed earnings (loss) $ 85 $ 55 $ (25 ) $ 95 Allocation of undistributed earnings (loss): Undistributed earnings (loss) allocated to common shareholders $ 84 $ 54 $ (25 ) $ 94 Undistributed earnings allocated to participating shareholders 1 1 — 1 Undistributed earnings (loss) $ 85 $ 55 $ (25 ) $ 95 (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 (i) assumed exercise of stock options issued under Cabot’s equity incentive plans; and (ii) assumed issuance of shares to employees pursuant to the Company’s Deferred Compensation and Supplemental Retirement Plan. For the three and six months ended March 31, 2022, 242,031 and 356,476 incremental shares of common stock were excluded from the calculation of diluted earnings per share because the inclusion of these shares would have been antidilutive. For the three and six months ended March 31, 2021, 1,120,460 and 1,377,609 incremental shares of common stock 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	6 Months Ended
	Mar. 31, 2022
Fair Value Disclosures [Abstract]
Financial Instruments and Fair Value Measurements	K. 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 six months of either fiscal 2022 or 2021. At March 31, 2022 and September 30, 2021, Cabot had derivatives relating to foreign currency risks, including a net investment hedge and forward foreign currency contracts, carried at fair value. At March 31, 2022, the fair value of these derivatives was a net liability of $2 million and was included in Prepaid expenses and other current assets, Accounts payable and accrued liabilities, and Other liabilities on the Consolidated Balance Sheets. At September 30, 2021, the fair value of these derivatives was a net asset of $3 million and was included in Prepaid expenses and other current assets, Accounts payable and accrued liabilities, and Other assets 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 each of March 31, 2022 and September 31, 2021, the fair value of guaranteed investment contracts included in Other assets on the Consolidated Balance Sheets was $10 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. At March 31, 2022 and September 30, 2021, 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. The carrying value and fair value of the long-term fixed rate debt were $1.06 billion and $1.07 billion, respectively, as of March 31, 2022, and $1.06 billion and $1.13 billion, respectively, as of September 30, 2021. 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.

Financial Information by Segmen

Financial Information by Segment	6 Months Ended
	Mar. 31, 2022
Segment Reporting [Abstract]
Financial Information by Segment	L. 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 consisting of Reinforcement Materials and Performance Chemicals. The Company’s former Purification Solutions segment was a separate reporting segment prior to divestiture in the second quarter of fiscal 2022. The Reinforcement Materials segment combines the reinforcing carbons and engineered elastomer composites product lines. The Performance Chemicals segment combines the specialty carbons, fumed metal oxides, battery materials and aerogel product lines into the Performance Additives business, and combines the specialty compounds and inkjet colorants product lines into the Formulated Solutions business. These businesses are similar in terms of economic characteristics, nature of products, processes, customer class and product distribution methods, and therefore have been aggregated into one reportable segment. The net sales from each of these businesses for the three and six months ended March 31, 2022 and 2021 were as follows: Three Months Ended March 31 Six Months Ended March 31 2022 2021 2022 2021 (In millions) Performance Additives $ 266 $ 203 $ 493 $ 387 Formulated Solutions 94 91 169 174 Total Performance Chemicals $ 360 $ 294 $ 662 $ 561 The Purification Solutions segment consisted of the Company’s activated carbon business. 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, the full operating results of a contractual joint venture in Purification Solutions, royalties, 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 Materials Performance Chemicals Purification Solutions Segment Total Unallocated and Other ( 1) Consolidated Total (In millions) Three Months Ended March 31, 2022 Revenues from external customers ( 2) $ 627 $ 360 $ 36 $ 1,023 $ 69 $ 1,092 Income (loss) before income taxes ( 3) $ 101 $ 70 $ — $ 171 $ (24 ) $ 147 Three Months Ended March 31, 2021 Revenues from external customers ( 2) $ 434 $ 294 $ 63 $ 791 $ 51 $ 842 Income (loss) before income taxes ( 3) $ 89 $ 58 $ 2 $ 149 $ (31 ) $ 118 Six Months Ended March 31, 2022 Revenues from external customers ( 2) $ 1,168 $ 662 $ 97 $ 1,927 $ 133 $ 2,060 Income (loss) before income taxes ( 3) $ 186 $ 122 $ — $ 308 $ (254 ) $ 54 Six Months Ended March 31, 2021 Revenues from external customers ( 2) $ 809 $ 561 $ 122 $ 1,492 $ 96 $ 1,588 Income (loss) before income taxes ( 3) $ 177 $ 112 $ — $ 289 $ (72 ) $ 217 ( 1 ) ( 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 royalties, external shipping and handling fees, the impact of unearned revenue, the removal of 100% of the sales of an equity method affiliate, discounting charges for certain Notes receivable, and by-product revenue. Details are provided in the table below: Three Months Ended March 31 Six Months Ended March 31 2022 2021 2022 2021 (In millions) Shipping and handling fees $ 41 $ 38 $ 80 $ 71 By-product sales 33 18 61 35 Other (5 ) (5 ) (8 ) (10 ) Total $ 69 $ 51 $ 133 $ 96 ( 3 ) Consolidated Total Income (loss) before income taxes Three Months Ended March 31 Six Months Ended March 31 2022 2021 2022 2021 (In millions) Interest expense $ (11 ) $ (13 ) $ (23 ) $ (25 ) Certain items (a) Gain on bargain purchase of a business (Note C) 24 — 24 — Loss on sale of business and asset impairment charge (Note D) (7 ) — (204 ) — Legal and environmental matters and reserves (7 ) — (8 ) — Divestiture related charges (1 ) — (5 ) — Acquisition and integration-related charges (2 ) (1 ) (3 ) (2 ) Global restructuring activities — (1 ) (2 ) (4 ) Employee benefit plan settlement and other charges — 1 — (5 ) Other — — 1 (1 ) Total certain items, pre-tax 7 (1 ) (197 ) (12 ) Unallocated corporate costs (b) (16 ) (16 ) (30 ) (29 ) General unallocated income (expense) (c) (1 ) — — (5 ) Less: Equity in earnings of affiliated companies, net of tax (d) 3 1 4 1 Total $ (24 ) $ (31 ) $ (254 ) $ (72 ) (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, the impact of including the full operating results of a contractual joint venture in Purification Solutions Segment EBIT and unrealized holding gains (losses) for equity securities. (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 March 31, 2022 Reinforcement Materials Performance Chemicals Purification Solutions Consolidated Total (In millions) Americas $ 252 $ 110 $ 16 $ 378 Asia Pacific 245 138 6 389 Europe, Middle East and Africa 130 112 14 256 Segment revenues from external customers 627 360 36 1,023 Unallocated and other 69 Net sales and other operating revenues $ 1,092 Three Months Ended March 31, 2021 Reinforcement Materials Performance Chemicals Purification Solutions Consolidated Total (In millions) Americas $ 163 $ 78 $ 26 $ 267 Asia Pacific 185 122 9 316 Europe, Middle East and Africa 86 94 28 208 Segment revenues from external customers 434 294 63 791 Unallocated and other 51 Net sales and other operating revenues $ 842 Six Months Ended March 31, 2022 Reinforcement Materials Performance Chemicals Purification Solutions Consolidated Total (In millions) Americas $ 458 $ 200 $ 43 $ 701 Asia Pacific 485 274 14 773 Europe, Middle East and Africa 225 188 40 453 Segment revenues from external customers 1,168 662 97 1,927 Unallocated and other 133 Net sales and other operating revenues $ 2,060 Six Months Ended March 31, 2021 Reinforcement Materials Performance Chemicals Purification Solutions Consolidated Total (In millions) Americas $ 312 $ 147 $ 51 $ 510 Asia Pacific 340 240 18 598 Europe, Middle East and Africa 157 174 53 384 Segment revenues from external customers 809 561 122 1,492 Unallocated and other 96 Net sales and other operating revenues $ 1,588

Significant Accounting Polici_2

Significant Accounting Policies (Policies)	6 Months Ended
	Mar. 31, 2022
Accounting Policies [Abstract]
Recently Adopted Accounting Standards	Recently Adopted Accounting Standards In December 2019, the FASB issued a new standard Simplifying the Accounting for Income Taxes. The new guidance simplifies the accounting for income taxes by removing several exceptions in the current standard and adding guidance that reduces complexity in certain areas. The new standard is effective for fiscal years beginning after December 15, 2020. The Company adopted this standard on October 1, 2021. The adoption of this standard did not materially impact the Company’s consolidated financial statements.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In March 2020, the FASB issued a new standard on Reference Rate Reform, which provides temporary optional expedients and exceptions to the existing guidance on contract modifications and hedge accounting to ease the financial reporting burdens related to the expected market transition from the London Interbank Offered Rate ("LIBOR") and other interbank offered rates to alternative reference rates. The standard was effective upon issuance and may generally be applied through December 31, 2022 to any new or amended contracts, hedging relationships, and other transactions that reference LIBOR. The Company is currently evaluating the timing of adoption and the impact of the adoption of this standard on its consolidated financial statements.

Acquisition (Tables)

Acquisition (Tables)	6 Months Ended
	Mar. 31, 2022
Business Combinations [Abstract]
Schedule of Estimates of Fair Value of Assets and Liabilities Acquired	The provisional estimates of the fair value of assets and liabilities acquired as of February 28, 2022 are set forth below along with the calculation of the Gain on bargain purchase of a business based on the cash consideration payable. (In millions) Fair value of asset acquired Cash $ 5 Accounts and notes receivable 5 Inventories 11 Prepaid expenses and other current assets 7 Property, plant and equipment 12 Amounts attributable to assets acquired 40 Fair value of liabilities assumed Accounts payable and accrued liabilities (2 ) Amounts attributable to liabilities assumed (2 ) Total identifiable net assets 38 Cash consideration payable 14 Gain on bargain purchase of a business $ 24

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	6 Months Ended
	Mar. 31, 2022
Goodwill And Intangible Assets Disclosure [Abstract]
Schedule of Goodwill Balances	The carrying amount of goodwill attributable to each reportable segment with goodwill balances and the changes in those balances during the six months ended March 31, 2022 are as follows: Reinforcement Materials Performance Chemicals Total (In millions) Balance at September 30, 2021 $ 48 $ 92 $ 140 Foreign currency impact — 1 1 Balance at March 31, 2022 $ 48 $ 93 $ 141
Schedule of Intangible Assets	The following table provides information regarding the Company’s intangible assets: March 31, 2022 September 30, 2021 Gross Carrying Value Accumulated Amortization Net Intangible Assets Gross Carrying Value Accumulated Amortization Net Intangible Assets (In millions) Intangible assets with finite lives Developed technologies $ 36 $ (7 ) $ 29 $ 62 $ (12 ) $ 50 Trademarks 3 (1 ) 2 11 (1 ) 10 Customer relationships 61 (22 ) 39 60 (20 ) 40 Total intangible assets $ 100 $ (30 ) $ 70 $ 133 $ (33 ) $ 100

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Income (Loss) ("AOCI") (Tables)	6 Months Ended
	Mar. 31, 2022
Equity [Abstract]
Changes in Each Component of AOCI, Net of Tax	Changes in each component of AOCI, net of tax, were as follows: Currency Translation Adjustment Pension and Other Postretirement Benefit Liability Adjustments Total (In millions) Balance at September 30, 2021, attributable to Cabot Corporation $ (265 ) $ (24 ) $ (289 ) Other comprehensive income (loss) before reclassifications (28 ) 1 (27 ) Amounts reclassified from AOCI (1 ) — (1 ) Less: Other comprehensive income (loss) attributable to noncontrolling interests 2 — 2 Balance at December 31, 2021, attributable to Cabot Corporation (296 ) (23 ) (319 ) Other comprehensive income (loss) before reclassifications 12 1 13 Amounts reclassified from AOCI 33 — 33 Less: Other comprehensive income (loss) attributable to noncontrolling interests 1 — 1 Balance at March 31, 2022, attributable to Cabot Corporation $ (252 ) $ (22 ) $ (274 )
Amounts Reclassified Out of AOCI	The amounts reclassified out of AOCI and into the Consolidated Statements of Operations in each of the three and six months ended March 31, 2022 and 2021 were as follows: Affected Line Item in the Consolidated Three Months Ended March 31 Six Months Ended March 31 Statements of Operations 2022 2021 2022 2021 (In millions) Derivatives: net investment hedges (Gains) losses reclassified to interest expense Interest expense $ (2 ) $ (2 ) $ (3 ) $ (3 ) (Gains) losses excluded from effectiveness testing and amortized to interest expense Interest expense 1 1 1 1 Release of currency translation adjustment Loss on sale of business and asset impairment charge 33 — 33 — Pension and other postretirement Release of actuarial losses and prior service cost (credit) Loss on sale of business and asset impairment charge 1 — 1 — Amortization of actuarial losses and prior service cost (credit) Net Periodic Benefit Cost — — — 1 Settlement charge Net Periodic Benefit Cost — — — 6 Total before tax $ 33 $ (1 ) $ 32 $ 5

Income Tax (Tables)

Income Tax (Tables)	6 Months Ended
	Mar. 31, 2022
Income Tax Disclosure [Abstract]
Effective Tax Rate	Effective Tax Rate Three Months Ended March 31 Six Months Ended March 31 2022 2021 2022 2021 (Dollars in millions) (Provision) benefit for income taxes $ (36 ) $ (34 ) $ (24 ) $ (63 ) Effective tax rate 24 % 29 % 44 % 29 %

Earnings Per Share (Tables)

Earnings Per Share (Tables)	6 Months Ended
	Mar. 31, 2022
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 March 31 Six Months Ended March 31 2022 2021 2022 2021 (In millions, except per share amounts) Basic EPS: Net income (loss) attributable to Cabot Corporation $ 107 $ 75 $ 18 $ 135 Less: Dividends and dividend equivalents to participating securities 1 — 1 — Less: Undistributed earnings allocated to participating securities ( 1) 1 1 — 1 Earnings (loss) allocated to common shareholders (numerator) $ 105 $ 74 $ 17 $ 134 Weighted average common shares and participating securities outstanding 57.5 57.4 57.4 57.3 Less: Participating securities ( 1) 0.9 0.8 0.9 0.7 Adjusted weighted average common shares (denominator) 56.6 56.6 56.5 56.6 Earnings (loss) per common share - basic: $ 1.86 $ 1.31 $ 0.30 $ 2.37 Diluted EPS: Earnings (loss) allocated to common shareholders $ 105 $ 74 $ 17 $ 134 Plus: Earnings allocated to participating securities 2 1 1 1 Less: Adjusted earnings allocated to participating securities ( 2) 2 1 1 1 Earnings (loss) allocated to common shareholders (numerator) $ 105 $ 74 $ 17 $ 134 Adjusted weighted average common shares outstanding 56.6 56.6 56.5 56.6 Effect of dilutive securities: Common shares issuable ( 3) 0.5 0.1 0.4 0.1 Adjusted weighted average common shares (denominator) 57.1 56.7 56.9 56.7 Earnings (loss) per common share - diluted: $ 1.84 $ 1.30 $ 0.30 $ 2.36 (1) Participating securities consist of shares underlying all outstanding and achieved performance-based restricted stock units and all unvested time-based restricted stock units. The holders of these units are entitled to receive dividend equivalents payable in cash to the extent dividends are paid on the Company’s outstanding common stock and equal in value to the dividends that would have been paid in respect of the shares underlying such units.
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 shareholders. Undistributed earnings are allocated to common and participating shareholders on the same basis as dividend distributions. The calculation of undistributed earnings is as follows: Three Months Ended March 31 Six Months Ended March 31 2022 2021 2022 2021 (In millions) Calculation of undistributed earnings (loss): Net income (loss) attributable to Cabot Corporation $ 107 $ 75 $ 18 $ 135 Less: Dividends declared on common stock 21 20 42 40 Less: Dividends declared on participating securities 1 — 1 — Undistributed earnings (loss) $ 85 $ 55 $ (25 ) $ 95 Allocation of undistributed earnings (loss): Undistributed earnings (loss) allocated to common shareholders $ 84 $ 54 $ (25 ) $ 94 Undistributed earnings allocated to participating shareholders 1 1 — 1 Undistributed earnings (loss) $ 85 $ 55 $ (25 ) $ 95 (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 (i) assumed exercise of stock options issued under Cabot’s equity incentive plans; and (ii) assumed issuance of shares to employees pursuant to the Company’s Deferred Compensation and Supplemental Retirement Plan. For the three and six months ended March 31, 2022, 242,031 and 356,476 incremental shares of common stock were excluded from the calculation of diluted earnings per share because the inclusion of these shares would have been antidilutive. For the three and six months ended March 31, 2021, 1,120,460 and 1,377,609 incremental shares of common stock 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)	6 Months Ended
	Mar. 31, 2022
Segment Reporting [Abstract]
Schedule of Performance Segment	The net sales from each of these businesses for the three and six months ended March 31, 2022 and 2021 were as follows: Three Months Ended March 31 Six Months Ended March 31 2022 2021 2022 2021 (In millions) Performance Additives $ 266 $ 203 $ 493 $ 387 Formulated Solutions 94 91 169 174 Total Performance Chemicals $ 360 $ 294 $ 662 $ 561
Financial Information by Reportable Segment	Financial information by reportable segment is as follows: Reinforcement Materials Performance Chemicals Purification Solutions Segment Total Unallocated and Other ( 1) Consolidated Total (In millions) Three Months Ended March 31, 2022 Revenues from external customers ( 2) $ 627 $ 360 $ 36 $ 1,023 $ 69 $ 1,092 Income (loss) before income taxes ( 3) $ 101 $ 70 $ — $ 171 $ (24 ) $ 147 Three Months Ended March 31, 2021 Revenues from external customers ( 2) $ 434 $ 294 $ 63 $ 791 $ 51 $ 842 Income (loss) before income taxes ( 3) $ 89 $ 58 $ 2 $ 149 $ (31 ) $ 118 Six Months Ended March 31, 2022 Revenues from external customers ( 2) $ 1,168 $ 662 $ 97 $ 1,927 $ 133 $ 2,060 Income (loss) before income taxes ( 3) $ 186 $ 122 $ — $ 308 $ (254 ) $ 54 Six Months Ended March 31, 2021 Revenues from external customers ( 2) $ 809 $ 561 $ 122 $ 1,492 $ 96 $ 1,588 Income (loss) before income taxes ( 3) $ 177 $ 112 $ — $ 289 $ (72 ) $ 217 ( 1 ) ( 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 royalties, external shipping and handling fees, the impact of unearned revenue, the removal of 100% of the sales of an equity method affiliate, discounting charges for certain Notes receivable, and by-product revenue. Details are provided in the table below: Three Months Ended March 31 Six Months Ended March 31 2022 2021 2022 2021 (In millions) Shipping and handling fees $ 41 $ 38 $ 80 $ 71 By-product sales 33 18 61 35 Other (5 ) (5 ) (8 ) (10 ) Total $ 69 $ 51 $ 133 $ 96 ( 3 ) Consolidated Total Income (loss) before income taxes Three Months Ended March 31 Six Months Ended March 31 2022 2021 2022 2021 (In millions) Interest expense $ (11 ) $ (13 ) $ (23 ) $ (25 ) Certain items (a) Gain on bargain purchase of a business (Note C) 24 — 24 — Loss on sale of business and asset impairment charge (Note D) (7 ) — (204 ) — Legal and environmental matters and reserves (7 ) — (8 ) — Divestiture related charges (1 ) — (5 ) — Acquisition and integration-related charges (2 ) (1 ) (3 ) (2 ) Global restructuring activities — (1 ) (2 ) (4 ) Employee benefit plan settlement and other charges — 1 — (5 ) Other — — 1 (1 ) Total certain items, pre-tax 7 (1 ) (197 ) (12 ) Unallocated corporate costs (b) (16 ) (16 ) (30 ) (29 ) General unallocated income (expense) (c) (1 ) — — (5 ) Less: Equity in earnings of affiliated companies, net of tax (d) 3 1 4 1 Total $ (24 ) $ (31 ) $ (254 ) $ (72 ) (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, the impact of including the full operating results of a contractual joint venture in Purification Solutions Segment EBIT and unrealized holding gains (losses) for equity securities. (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 March 31, 2022 Reinforcement Materials Performance Chemicals Purification Solutions Consolidated Total (In millions) Americas $ 252 $ 110 $ 16 $ 378 Asia Pacific 245 138 6 389 Europe, Middle East and Africa 130 112 14 256 Segment revenues from external customers 627 360 36 1,023 Unallocated and other 69 Net sales and other operating revenues $ 1,092 Three Months Ended March 31, 2021 Reinforcement Materials Performance Chemicals Purification Solutions Consolidated Total (In millions) Americas $ 163 $ 78 $ 26 $ 267 Asia Pacific 185 122 9 316 Europe, Middle East and Africa 86 94 28 208 Segment revenues from external customers 434 294 63 791 Unallocated and other 51 Net sales and other operating revenues $ 842 Six Months Ended March 31, 2022 Reinforcement Materials Performance Chemicals Purification Solutions Consolidated Total (In millions) Americas $ 458 $ 200 $ 43 $ 701 Asia Pacific 485 274 14 773 Europe, Middle East and Africa 225 188 40 453 Segment revenues from external customers 1,168 662 97 1,927 Unallocated and other 133 Net sales and other operating revenues $ 2,060 Six Months Ended March 31, 2021 Reinforcement Materials Performance Chemicals Purification Solutions Consolidated Total (In millions) Americas $ 312 $ 147 $ 51 $ 510 Asia Pacific 340 240 18 598 Europe, Middle East and Africa 157 174 53 384 Segment revenues from external customers 809 561 122 1,492 Unallocated and other 96 Net sales and other operating revenues $ 1,588

Acquisition - Additional Inform

Acquisition - Additional Information (Detail) - USD ($) $ in Millions	Feb. 28, 2022	Jun. 30, 2022	Mar. 31, 2022	Mar. 31, 2022
Business Acquisition [Line Items]
Cash assumed from acquisition of business				$ (5)
Gain on bargain purchase of a business				24
Accounts Payable and Accrued Liabilities [Member]
Business Acquisition [Line Items]
Gain on bargain purchase of a business				$ 24
Tokai Carbon Group(Tianjin) Co. [Member]
Business Acquisition [Line Items]
Business acquisition, ownership percentage	100.00%
Business acquisition, purchase price	$ 9
Business acquisition, cash consideration	14		$ 14
Cash assumed from acquisition of business	5
Gain on bargain purchase of a business	$ 24
Tokai Carbon Group(Tianjin) Co. [Member] | Scenario Forecast [Member]
Business Acquisition [Line Items]
Business acquisition, cash consideration		$ 14

Acquisition - Schedule of Estim

Acquisition - Schedule of Estimates of Fair Value of Assets and Liabilities Acquired (Detail) - USD ($) $ in Millions	Feb. 28, 2022	Mar. 31, 2022	Mar. 31, 2022
Fair value of liabilities assumed
Gain on bargain purchase of a business			$ 24
Tokai Carbon Group(Tianjin) Co. [Member]
Fair value of asset acquired
Cash	$ 5
Accounts and notes receivable	5
Inventories	11
Prepaid expenses and other current assets	7
Property, plant and equipment	12
Amounts attributable to assets acquired	40
Fair value of liabilities assumed
Accounts payable and accrued liabilities	(2)
Amounts attributable to liabilities assumed	(2)
Total identifiable net assets	38
Business acquisition, cash consideration	14	$ 14
Gain on bargain purchase of a business	$ 24

Divestitures - Additional Infor

Divestitures - Additional Information (Detail) - USD ($) $ in Millions	Mar. 01, 2022	Mar. 31, 2022	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2022	Sep. 30, 2021
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Proceeds from sale of business					$ 79
Accounts and notes receivable		$ 791	$ 791		791	$ 645
Impairment charge			7		204
Purification Solutions [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Proceeds from sale of business		79
Proceeds from divestiture of cash transferred		11
Accounts and notes receivable		11	11		11
Pre-tax loss on sale			7
Impairment charge				$ 197
Impairment charge after tax					167
Purification Solutions [Member] | One Equity Partners [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Proceeds from sale of business	$ 90
Proceeds from divestiture of cash transferred	$ 7
Marshall Mine | ADA Carbon Solutions, LLC [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Accounts payable and accrued liabilities		$ 11	$ 11		$ 11

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets - Schedule of Goodwill Balances (Detail) $ in Millions	6 Months Ended
	Mar. 31, 2022USD ($)
Goodwill And Intangible Assets [Line Items]
Beginning balance	$ 140
Foreign currency impact	1
Ending balance	141
Reinforcement Materials [Member]
Goodwill And Intangible Assets [Line Items]
Beginning balance	48
Ending balance	48
Performance Chemicals [Member]
Goodwill And Intangible Assets [Line Items]
Beginning balance	92
Foreign currency impact	1
Ending balance	$ 93

Goodwill and Intangible Asset_3

Goodwill and Intangible Assets - Schedule of Intangible Assets (Detail) - USD ($) $ in Millions	Mar. 31, 2022	Sep. 30, 2021
Finite Lived Intangible Assets [Line Items]
Gross Carrying Value, finite lives	$ 100	$ 133
Accumulated Amortization	(30)	(33)
Net Intangible Assets, finite lives	70	100
Developed Technologies [Member]
Finite Lived Intangible Assets [Line Items]
Gross Carrying Value, finite lives	36	62
Accumulated Amortization	(7)	(12)
Net Intangible Assets, finite lives	29	50
Trademarks [Member]
Finite Lived Intangible Assets [Line Items]
Gross Carrying Value, finite lives	3	11
Accumulated Amortization	(1)	(1)
Net Intangible Assets, finite lives	2	10
Customer Relationships [Member]
Finite Lived Intangible Assets [Line Items]
Gross Carrying Value, finite lives	61	60
Accumulated Amortization	(22)	(20)
Net Intangible Assets, finite lives	$ 39	$ 40

Goodwill and Intangible Asset_4

Goodwill and Intangible Assets - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021
Goodwill And Intangible Assets [Line Items]
Amortization expense estimated for year one	$ 6		$ 6
Amortization expense estimated for year two	6		6
Amortization expense estimated for year three	6		6
Amortization expense estimated for year four	6		6
Amortization expense estimated for year five	6		6
Cost of Sales, Selling and Administrative Expenses and Research and Technical Expenses [Member]
Goodwill And Intangible Assets [Line Items]
Amortization of intangible assets	$ 1	$ 2	$ 3	$ 4
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			17 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
	Mar. 31, 2022	Dec. 31, 2021
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	$ 948	$ 1,090
Ending Balance	1,066	948
Currency Translation Adjustment [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(296)	(265)
Other comprehensive income (loss) before reclassifications	12	(28)
Amounts reclassified from AOCI	33	(1)
Less: Other comprehensive income (loss) attributable to noncontrolling interests	1	2
Ending Balance	(252)	(296)
Pension and Other Postretirement Benefit Liability Adjustments [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(23)	(24)
Other comprehensive income (loss) before reclassifications	1	1
Ending Balance	(22)	(23)
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(319)	(289)
Other comprehensive income (loss) before reclassifications	13	(27)
Amounts reclassified from AOCI	33	(1)
Less: Other comprehensive income (loss) attributable to noncontrolling interests	1	2
Ending Balance	$ (274)	$ (319)

Accumulated Other Comprehensi_4

Accumulated Other Comprehensive Income (Loss) ("AOCI") - Amounts Reclassified Out of AOCI (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021
(Gains) Losses Reclassified to Interest Expense [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total before tax	$ (2)	$ (2)	$ (3)	$ (3)
(Gains) Losses Excluded from Effectiveness Testing and Amortized to Interest Expense [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total before tax	1	1	1	1
Release of Currency Translation Adjustment [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total before tax	33		33
Release of Actuarial Losses and Prior Service Cost (Credit) [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total before tax	1		1
Amortization of Actuarial Losses and Prior Service Cost (Credit) [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total before tax				1
Settlement Charge [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total before tax				6
Accumulated Other Comprehensive Income (Loss) [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total before tax	$ 33	$ (1)	$ 32	$ 5

Contingencies - Additional Info

Contingencies - Additional Information (Detail) - USD ($) $ in Millions	Mar. 31, 2022	Sep. 30, 2021
Respirator Liabilities [Member]
Loss Contingencies [Line Items]
Respirator reserve	$ 42	$ 44

Insurance Recoveries - Addition

Insurance Recoveries - Additional Information (Detail) - Pepinster, Belgium [Member] - Flood [Member] - USD ($) $ in Millions	1 Months Ended	3 Months Ended	6 Months Ended	12 Months Ended
	Jul. 31, 2021	Mar. 31, 2022	Mar. 31, 2022	Sep. 30, 2021
Business Interruption Loss [Line Items]
Flood-related expenses	$ 17	$ 1	$ 6
Insurance proceeds		2	7	$ 8
Cash provided by investing activities			1
Cash provided by operating activities			6
Insurance settlements receivable		$ 8	$ 8	$ 9

Income Tax - Effective Tax Rate

Income Tax - Effective Tax Rate (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021
Income Tax Disclosure [Abstract]
(Provision) benefit for income taxes	$ (36)	$ (34)	$ (24)	$ (63)
Effective tax rate	24.00%	29.00%	44.00%	29.00%

Income Tax - Additional Informa

Income Tax - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021
Income Taxes [Line Items]
Net discrete tax (benefits) expense related to tax settlements	$ 1	$ (1)	$ (36)	$ 1
Uncertain tax positions from expirations of statute of limitations	1		$ 2	$ 1
United States Internal Revenue Service (IRS) [Member] | Earliest Tax Year [Member]
Income Taxes [Line Items]
Tax years remain subject to examination			2018
United States Internal Revenue Service (IRS) [Member] | Latest Tax Year [Member]
Income Taxes [Line Items]
Tax years remain subject to examination			2020
State Tax Authorities [Member] | Earliest Tax Year [Member]
Income Taxes [Line Items]
Tax years remain subject to examination			2005
State Tax Authorities [Member] | Latest Tax Year [Member]
Income Taxes [Line Items]
Tax years remain subject to examination			2020
Non-U.S. Jurisdictions [Member] | Earliest Tax Year [Member]
Income Taxes [Line Items]
Tax years remain subject to examination			2005
Non-U.S. Jurisdictions [Member] | Latest Tax Year [Member]
Income Taxes [Line Items]
Tax years remain subject to examination			2021
Maximum [Member]
Income Taxes [Line Items]
Uncertain tax positions from expirations of statute of limitations		$ 1
Purification Solutions [Member]
Income Taxes [Line Items]
Net discrete tax (benefits) expense related to tax settlements	$ 36
Income tax benefit from tax loss related to divestiture			$ 183

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		6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021
Basic EPS:
Net income (loss) attributable to Cabot Corporation	$ 107	$ 75	$ 18	$ 135
Less: Dividends and dividend equivalents to participating securities	1		1
Less: Undistributed earnings allocated to participating securities	1	1		1
Earnings (loss) allocated to common shareholders (numerator)	$ 105	$ 74	$ 17	$ 134
Weighted average common shares and participating securities outstanding	57.5	57.4	57.4	57.3
Less: Participating securities	0.9	0.8	0.9	0.7
Adjusted weighted average common shares (denominator)	56.6	56.6	56.5	56.6
Earnings (loss) per common share - basic:	$ 1.86	$ 1.31	$ 0.30	$ 2.37
Diluted EPS:
Earnings (loss) allocated to common shareholders	$ 105	$ 74	$ 17	$ 134
Plus: Earnings allocated to participating securities	2	1	1	1
Less: Adjusted earnings allocated to participating securities	2	1	1	1
Earnings (loss) allocated to common shareholders (numerator)	$ 105	$ 74	$ 17	$ 134
Adjusted weighted average common shares outstanding	56.6	56.6	56.5	56.6
Common shares issuable	0.5	0.1	0.4	0.1
Adjusted weighted average common shares (denominator)	57.1	56.7	56.9	56.7
Earnings (loss) per common share - diluted:	$ 1.84	$ 1.30	$ 0.30	$ 2.36

Earnings Per Share - Calculatio

Earnings Per Share - Calculation of Undistributed Earnings (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021
Earnings Per Share [Abstract]
Net income (loss) attributable to Cabot Corporation	$ 107	$ 75	$ 18	$ 135
Less: Dividends declared on common stock	21	20	42	40
Less: Dividends declared on participating securities	1		1
Undistributed earnings (loss)	85	55	(25)	95
Undistributed earnings (loss) allocated to common shareholders	84	54	$ (25)	94
Undistributed earnings allocated to participating shareholders	$ 1	$ 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		6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021
Earnings Per Share [Abstract]
Antidilutive securities excluded from computation of earnings per share	242,031	1,120,460	356,476	1,377,609

Financial Instruments and Fai_2

Financial Instruments and Fair Value Measurements - Additional Information (Detail) - USD ($)	6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Sep. 30, 2021
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
Fair value of long-term debt	1,070,000,000		$ 1,130,000,000
Fixed Rate Debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying value of long-term debt	1,060,000,000		1,060,000,000
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	10,000,000		10,000,000
Significant Observable Inputs (Level 2) [Member] | Foreign Currency Risks [Member] | Prepaid Expenses and Other Current Assets Accounts Payable and Accrued Liabilities and Other Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets (liabilities), at fair Value, net	$ 2,000,000
Significant Observable Inputs (Level 2) [Member] | Foreign Currency Risks [Member] | Prepaid Expenses and Other Current Assets Accounts Payable and Accrued Liabilities and Other Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets (liabilities), at fair Value, net			$ 3,000,000

Financial Information by Segm_3

Financial Information by Segment - Additional Information (Detail) - Segment	3 Months Ended	6 Months Ended
	Mar. 31, 2022	Mar. 31, 2022
Segment Reporting Information [Line Items]
Number of business reportable segments	2
Performance Chemicals [Member]
Segment Reporting Information [Line Items]
Number of business reportable segments		1

Financial Information by Segm_4

Financial Information by Segment - Schedule of Performance Segment (Detail) - Performance Chemicals [Member] - Operating Segments [Member] - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021
Segment Reporting Information [Line Items]
Net sales	$ 360	$ 294	$ 662	$ 561
Performance Additives [Member]
Segment Reporting Information [Line Items]
Net sales	266	203	493	387
Formulated Solutions [Member]
Segment Reporting Information [Line Items]
Net sales	$ 94	$ 91	$ 169	$ 174

Financial Information by Segm_5

Financial Information by Segment - Financial Information by Reportable Segment (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021
Segment Reporting Information [Line Items]
Revenues from external customers	$ 1,092	$ 842	$ 2,060	$ 1,588
Income (loss) before income taxes	147	118	54	217
Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues from external customers	1,023	791	1,927	1,492
Income (loss) before income taxes	171	149	308	289
Unallocated and Other [Member]
Segment Reporting Information [Line Items]
Revenues from external customers	69	51	133	96
Income (loss) before income taxes	(24)	(31)	(254)	(72)
Reinforcement Materials [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues from external customers	627	434	1,168	809
Income (loss) before income taxes	101	89	186	177
Performance Chemicals [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues from external customers	360	294	662	561
Income (loss) before income taxes	70	58	122	112
Purification Solutions [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues from external customers	$ 36	63	$ 97	$ 122
Income (loss) before income taxes		$ 2

Financial Information by Segm_6

Financial Information by Segment - Financial Information by Reportable Segment (Parenthetical) (Detail)	3 Months Ended		6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021
Segment Reporting [Abstract]
Percentage of sale of an equity method affiliate	100.00%	100.00%	100.00%	100.00%

Financial Information by Segm_7

Financial Information by Segment - Sales of Equity Method Affiliate and Discounting Charges for Certain Notes Receivable, by-product Revenue and Indirect Tax Settlement Credits (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021
Segment Reporting Information [Line Items]
Revenues from external customers	$ 1,092	$ 842	$ 2,060	$ 1,588
Unallocated and Other [Member]
Segment Reporting Information [Line Items]
Revenues from external customers	69	51	133	96
Unallocated and Other [Member] | Shipping and Handling Costs [Member]
Segment Reporting Information [Line Items]
Revenues from external customers	41	38	80	71
Unallocated and Other [Member] | By-product Sales [Member]
Segment Reporting Information [Line Items]
Revenues from external customers	33	18	61	35
Unallocated and Other [Member] | Other [Member]
Segment Reporting Information [Line Items]
Revenues from external customers	$ (5)	$ (5)	$ (8)	$ (10)

Financial Information by Segm_8

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		6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021
Segment Reporting Information [Line Items]
Interest expense	$ (11)	$ (13)	$ (23)	$ (25)
Gain on bargain purchase of a business (Note C)	24		24
Loss on sale of business and asset impairment charge (Note D)	7		204
Unallocated and Other [Member]
Segment Reporting Information [Line Items]
Interest expense	(11)	(13)	(23)	(25)
Unallocated corporate costs	(16)	(16)	(30)	(29)
General unallocated income (expense)	(1)			(5)
Less: Equity in earnings of affiliated companies, net of tax	3	1	4	1
Income from continuing operations before income taxes and equity in earnings of affiliated companies	(24)	(31)	(254)	(72)
Certain Items [Member]
Segment Reporting Information [Line Items]
Gain on bargain purchase of a business (Note C)	24		24
Loss on sale of business and asset impairment charge (Note D)	(7)		(204)
Legal and environmental matters and reserves	(7)		(8)
Divestiture related charges	(1)		(5)
Acquisition and integration-related charges	(2)	(1)	(3)	(2)
Global restructuring activities		(1)	(2)	(4)
Employee benefit plan settlement and other charges		1		(5)
Other			1	(1)
Total certain items, pre-tax	$ 7	$ (1)	$ (197)	$ (12)

Financial Information by Segm_9

Financial Information by Segment - Revenue from External Customers by Geographic Region (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021
Segment Reporting Information [Line Items]
Net sales and other operating revenues	$ 1,092	$ 842	$ 2,060	$ 1,588
Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales and other operating revenues	1,023	791	1,927	1,492
Unallocated and Other [Member]
Segment Reporting Information [Line Items]
Net sales and other operating revenues	69	51	133	96
Americas [Member]
Segment Reporting Information [Line Items]
Net sales and other operating revenues	378	267	701	510
Asia Pacific [Member]
Segment Reporting Information [Line Items]
Net sales and other operating revenues	389	316	773	598
Europe, Middle East and Africa [Member]
Segment Reporting Information [Line Items]
Net sales and other operating revenues	256	208	453	384
Reinforcement Materials [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales and other operating revenues	627	434	1,168	809
Reinforcement Materials [Member] | Americas [Member]
Segment Reporting Information [Line Items]
Net sales and other operating revenues	252	163	458	312
Reinforcement Materials [Member] | Asia Pacific [Member]
Segment Reporting Information [Line Items]
Net sales and other operating revenues	245	185	485	340
Reinforcement Materials [Member] | Europe, Middle East and Africa [Member]
Segment Reporting Information [Line Items]
Net sales and other operating revenues	130	86	225	157
Performance Chemicals [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales and other operating revenues	360	294	662	561
Performance Chemicals [Member] | Americas [Member]
Segment Reporting Information [Line Items]
Net sales and other operating revenues	110	78	200	147
Performance Chemicals [Member] | Asia Pacific [Member]
Segment Reporting Information [Line Items]
Net sales and other operating revenues	138	122	274	240
Performance Chemicals [Member] | Europe, Middle East and Africa [Member]
Segment Reporting Information [Line Items]
Net sales and other operating revenues	112	94	188	174
Purification Solutions [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales and other operating revenues	36	63	97	122
Purification Solutions [Member] | Americas [Member]
Segment Reporting Information [Line Items]
Net sales and other operating revenues	16	26	43	51
Purification Solutions [Member] | Asia Pacific [Member]
Segment Reporting Information [Line Items]
Net sales and other operating revenues	6	9	14	18
Purification Solutions [Member] | Europe, Middle East and Africa [Member]
Segment Reporting Information [Line Items]
Net sales and other operating revenues	$ 14	$ 28	$ 40	$ 53