XML 83 R66.htm IDEA: XBRL DOCUMENT
v3.23.3

Derivatives - Additional Information (Detail) - USD ($) | 12 Months Ended
--- | ---
Sep. 30, 2023 | Sep. 30, 2022 | Sep. 30, 2021
Derivative [Line Items] |  |  |
Significant concentration of credit risk associated with our derivative instruments | $ 0 | $ 0 |
Maximum [Member] |  |  |
Derivative [Line Items] |  |  |
Fair value of derivative instruments not designated as hedges, liability | 1,000,000 | 1,000,000 |
Net Investment Hedge [Member] | Cross Currency Swaps [Member] |  |  |
Derivative [Line Items] |  |  |
Net cash interest received | 4,000,000 | 4,000,000 | $ 3,000,000
Fair value of swaps, net asset | 12,000,000 | 29,000,000 |
Cumulative gain related to swaps | $ 15,000,000 | $ 32,000,000 |
Net Investment Hedge [Member] | Cross Currency Swaps [Member] | Fixed Rate Debt [Member] |  |  |
Derivative [Line Items] |  |  |
Derivative Instruments Frequency of Cash Settlements | semi-annually |  |

X
- Definition Accumulated other comprehensive income (loss) cumulative changes in net gain (loss) from net investment hedges net of tax. + References No definition available. + Details
Name: | cbt_AccumulatedOtherComprehensiveIncomeLossCumulativeChangesInNetGainLossFromNetInvestmentHedgesNetOfTax
Namespace Prefix: | cbt_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Concentration risk credit risk value. + References No definition available. + Details
Name: | cbt_ConcentrationRiskCreditRiskValue
Namespace Prefix: | cbt_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Derivative instruments frequency of cash settlements. + References No definition available. + Details
Name: | cbt_DerivativeInstrumentsFrequencyOfCashSettlements
Namespace Prefix: | cbt_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The amount of cash received during the period on settlement of a hedge. + References No definition available. + Details
Name: | us-gaap_DerivativeCashReceivedOnHedge
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Fair value as of the balance sheet date of derivative instrument not designated as hedging instrument and classified as a liability. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4B -Subparagraph (c)(2) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480434/815-10-50-4B + Details
Name: | us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsLiabilityAtFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 815 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (f) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480237/815-40-50-5 + Details
Name: | us-gaap_DerivativeLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Fair value of all derivative assets designated as hedges of net investment in foreign operations. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4B -Subparagraph (c)(1) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480434/815-10-50-4B + Details
Name: | us-gaap_NetInvestmentHedgeDerivativeAssetsAtFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis=us-gaap_NetInvestmentHedgingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=us-gaap_CrossCurrencyInterestRateContractMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=cbt_FixedRateDebtMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |