XML 113 R48.htm IDEA: XBRL DOCUMENT
v3.19.3

Significant Accounting Policies - Additional Information (Details) shares in Millions | 8 Months Ended | 12 Months Ended
--- | --- | ---
May 12, 2017 shares | Sep. 30, 2019 USD ($) ReportableSegment shares | Sep. 30, 2018 USD ($) shares | Sep. 30, 2017 USD ($) shares | Sep. 30, 2015 USD ($)
Principles of consolidation and basis of presentation [Abstract] |  |  |  |  |  |
Distribution of shares | shares |  | 170.0 |  |  |  |
Sale of Stock, Percentage of Ownership after Transaction |  | 83.00% |  |  |  |
Number of reportable segments | ReportableSegment |  |  | 2 |  |  |
Allowance for doubtful accounts [Abstract] |  |  |  |  |  |
Past due balances reviewed individually (in days) |  |  | 90 days |  |  |
Inventories [Abstract] |  |  |  |  |  |
Inventory replacement cost |  |  | $ 66,000,000 | $ 70,000,000 |  |
Restricted Cash and Investments [Abstract] |  |  |  |  |  |
Litigation Settlement, Amount |  |  |  |  |  | $ 398,000,000
Increase (Decrease) in Restricted Cash |  |  |  |  |  | $ 335,000,000
Restricted Investments, Current |  |  | 24,000,000 | 30,000,000 |  |
Available-for-sale securities, fair value |  |  | $ 334,000,000 | 342,000,000 |  |
New Accounting Pronouncements and Changes in Accounting Principles [Abstract] |  |  |  |  |  |
Cost incurred to obtain contract with customer amortization period of practical expedients |  |  | true |  |  |
Expenses reclassified to other net periodic benefit income |  |  |  |  | $ 4,000,000 |
Recognition of investment gain within net interest and other expense |  |  | $ 7,000,000 |  |  |
Expense Recognition [Abstract] |  |  |  |  |  |
Advertising costs |  |  | 4,000,000 | 4,000,000 | 5,000,000 |
Research and development expense |  |  | $ 66,000,000 | $ 73,000,000 | $ 73,000,000 |
Earnings Per Share [Abstract] |  |  |  |  |  |
Antidilutive securities excluded from calculation of earnings per share | shares |  |  | 1.0 | 0.7 | 1.1 |
ASC 606 [Member] |  |  |  |  |  |
New Accounting Pronouncements and Changes in Accounting Principles [Abstract] |  |  |  |  |  |
Cumulative-effect adjustment to retained earnings |  |  | $ 0 |  |  |
Accumulated other comprehensive income (loss) [Member] |  |  |  |  |  |
New Accounting Pronouncements and Changes in Accounting Principles [Abstract] |  |  |  |  |  |
Unrealized gains on equity securities on reclassification from AOCI to retained earnings | [1],[2] |  | $ 34,000,000 |  |  |
Minimum [Member] |  |  |  |  |  |
Principles of consolidation and basis of presentation [Abstract] |  |  |  |  |  |
Percentage of ownership under equity method |  |  | 20.00% |  |  |
Leases [Abstract] |  |  |  |  |  |
Expected operating lease liabilities |  |  | $ 140,000,000 |  |  |
Minimum [Member] | Trademarks and Trade Names [Member] |  |  |  |  |  |
Goodwill and other intangibles [Abstract] |  |  |  |  |  |
Useful life (in years) |  |  | 3 years |  |  |
Minimum [Member] | Intellectual Property [Member] |  |  |  |  |  |
Goodwill and other intangibles [Abstract] |  |  |  |  |  |
Useful life (in years) |  |  | 5 years |  |  |
Minimum [Member] | Customer and supplier relationships [Member] |  |  |  |  |  |
Goodwill and other intangibles [Abstract] |  |  |  |  |  |
Useful life (in years) |  |  | 3 years |  |  |
Minimum [Member] | Buildings [Member] |  |  |  |  |  |
Property, Plant and Equipment [Abstract] |  |  |  |  |  |
Property, Plant and Equipment, Useful Life |  |  | 12 years |  |  |
Minimum [Member] | Machinery and Equipment [Member] |  |  |  |  |  |
Property, Plant and Equipment [Abstract] |  |  |  |  |  |
Property, Plant and Equipment, Useful Life |  |  | 2 years |  |  |
Maximum [Member] |  |  |  |  |  |
Principles of consolidation and basis of presentation [Abstract] |  |  |  |  |  |
Percentage of ownership under equity method |  |  | 50.00% |  |  |
Leases [Abstract] |  |  |  |  |  |
Expected operating lease liabilities |  |  | $ 180,000,000 |  |  |
Maximum [Member] | Accounting Standards Update 2016-16 [Member] |  |  |  |  |  |
New Accounting Pronouncements and Changes in Accounting Principles [Abstract] |  |  |  |  |  |
Cumulative-effect adjustment, reclassification from other current assets and deferred taxes to retained earnings |  |  | $ 1,000,000 |  |  |
Maximum [Member] | Trademarks and Trade Names [Member] |  |  |  |  |  |
Goodwill and other intangibles [Abstract] |  |  |  |  |  |
Useful life (in years) |  |  | 25 years |  |  |
Maximum [Member] | Intellectual Property [Member] |  |  |  |  |  |
Goodwill and other intangibles [Abstract] |  |  |  |  |  |
Useful life (in years) |  |  | 25 years |  |  |
Maximum [Member] | Customer and supplier relationships [Member] |  |  |  |  |  |
Goodwill and other intangibles [Abstract] |  |  |  |  |  |
Useful life (in years) |  |  | 24 years |  |  |
Maximum [Member] | Buildings [Member] |  |  |  |  |  |
Property, Plant and Equipment [Abstract] |  |  |  |  |  |
Property, Plant and Equipment, Useful Life |  |  | 35 years |  |  |
Maximum [Member] | Machinery and Equipment [Member] |  |  |  |  |  |
Property, Plant and Equipment [Abstract] |  |  |  |  |  |
Property, Plant and Equipment, Useful Life |  |  | 25 years |  |  |
Ashland Limited Liability Company [Member] |  |  |  |  |  |
Principles of consolidation and basis of presentation [Abstract] |  |  |  |  |  |
Ownership Percentage |  |  | 100.00% |  |  |
[1] | At September 30, 2019 and 2018, the accumulated other comprehensive loss of $410 million and $291 million, respectively, was comprised of net unrealized translation losses of $408 million and $328 million, respectively, net unrealized gains on investment securities of zero and $34 million, respectively, and unrecognized prior service costs as a result of certain employee benefit plan amendments of $2 million and unrecognized prior service credits of $3 million, respectively.
[2] | Represents the cumulative-effect adjustment related to the adoption of the new guidance related to the accounting for equity securities and the tax effects of intercompany transfers during fiscal 2019. See note A for more information

X
- Definition Allowance For Doubtful Accounts Abstract. + References No definition available. + Details
Name: | ash_AllowanceForDoubtfulAccountsAbstract
Namespace Prefix: | ash_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Expected operating lease liabilities. + References No definition available. + Details
Name: | ash_ExpectedOperatingLeaseLiabilities
Namespace Prefix: | ash_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Expense Recognition Abstract. + References No definition available. + Details
Name: | ash_ExpenseRecognitionAbstract
Namespace Prefix: | ash_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Expenses reclassfied to other defined benefit plan net periodic benefit income. + References No definition available. + Details
Name: | ash_ExpensesReclassfiedToOtherDefinedBenefitPlanNetPeriodicBenefitIncome
Namespace Prefix: | ash_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Number of days past due accounts receivables are reviewed individually for collectibility. + References No definition available. + Details
Name: | ash_PastDueBalancesReviewedIndividually
Namespace Prefix: | ash_
Data Type: | us-types:durationStringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Principles of consolidation and basis of presentation [Abstract]. + References No definition available. + Details
Name: | ash_PrinciplesOfConsolidationAndBasisOfPresentationAbstract
Namespace Prefix: | ash_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Sale of interest in subsidiary, shares. + References No definition available. + Details
Name: | ash_SaleOfInterestInSubsidiaryShares
Namespace Prefix: | ash_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount charged to advertising expense for the period, which are expenses incurred with the objective of increasing revenue for a specified brand, product or product line. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 720 -SubTopic 35 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6420018&loc=d3e36677-107848 + Details
Name: | us-gaap_AdvertisingExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 260 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257 + Details
Name: | us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 30 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=118942338&loc=SL82898722-210454 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=118954083&loc=d3e26610-111562 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (aa) -URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27161-111563 + Details
Name: | us-gaap_AvailableForSaleSecuritiesDebtSecurities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of the cumulative effect on retained earnings net of related income tax effect. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 250 -SubTopic 10 -Section 50 -Paragraph 9 -URI http://asc.fasb.org/extlink&oid=109234566&loc=d3e22663-107794 + Details
Name: | us-gaap_CumulativeEffectOnRetainedEarningsNetOfTax1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_EarningsPerShareAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 323 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=114001798&loc=d3e33918-111571 + Details
Name: | us-gaap_EquityMethodInvestmentOwnershipPercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References No definition available. + Details
Name: | us-gaap_FiniteLivedIntangibleAssetUsefulLife
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition The net cash inflow or outflow for the increase (decrease) associated with funds that are not available for withdrawal or use (such as funds held in escrow) and are associated with underlying transactions that are classified as investing activities. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 12 -URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3179-108585 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 13 -URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3213-108585 + Details
Name: | us-gaap_IncreaseDecreaseInRestrictedCash
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_IntangibleAssetsNetIncludingGoodwillAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_InventoryDisclosureAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The amount of LIFO (last in first out) inventory present at the reporting date when inventory is also valued using different valuation methods. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6361739&loc=d3e7789-107766 + Details
Name: | us-gaap_LIFOInventoryAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_LeasesAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount awarded from other party in judgment or settlement of litigation. + References No definition available. + Details
Name: | us-gaap_LitigationSettlementAmountAwardedFromOtherParty
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The parent entity's interest in net assets of the subsidiary, expressed as a percentage. + References No definition available. + Details
Name: | us-gaap_MinorityInterestOwnershipPercentageByParent
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Amount of cumulative effect of the change in accounting principle or new accounting pronouncement on retained earnings or other components of equity or net assets in the statement of financial position as of the beginning of the earliest period presented. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 250 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (b)(3) -URI http://asc.fasb.org/extlink&oid=109234566&loc=d3e22499-107794 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 250 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=109234566&loc=d3e22583-107794 + Details
Name: | us-gaap_NewAccountingPronouncementOrChangeInAccountingPrincipleCumulativeEffectOfChangeOnEquityOrNetAssets1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Represents the quantification of the effect of adopting the new accounting standard or change in accounting principle expected by the entity to have a significant effect on the entity's financial statements. + References No definition available. + Details
Name: | us-gaap_NewAccountingPronouncementOrChangeInAccountingPrincipleEffectOfAdoptionQuantification
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_NewAccountingPronouncementsAndChangesInAccountingPrinciplesAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements. + References No definition available. + Details
Name: | us-gaap_NumberOfReportableSegments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_PropertyPlantAndEquipmentAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment. + References No definition available. + Details
Name: | us-gaap_PropertyPlantAndEquipmentUsefulLife
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition The net realized gains or losses on investments during the period, not including gains or losses on securities separately or otherwise categorized as trading, available-for-sale, or held-to-maturity. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 220 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-04.3(a)) -URI http://asc.fasb.org/extlink&oid=116637232&loc=SL114874131-224263 + Details
Name: | us-gaap_RealizedInvestmentGainsLosses
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The aggregate costs incurred (1) in a planned search or critical investigation aimed at discovery of new knowledge with the hope that such knowledge will be useful in developing a new product or service, a new process or technique, or in bringing about a significant improvement to an existing product or process; or (2) to translate research findings or other knowledge into a plan or design for a new product or process or for a significant improvement to an existing product or process whether intended for sale or the entity's use, during the reporting period charged to research and development projects, including the costs of developing computer software up to the point in time of achieving technological feasibility, and costs allocated in accounting for a business combination to in-process projects deemed to have no alternative future use. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 985 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6501960&loc=d3e128462-111756 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 730 -SubTopic 10 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6420194&loc=d3e21568-108373 + Details
Name: | us-gaap_ResearchAndDevelopmentExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_RestrictedCashAndInvestmentsAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The current cash, cash equivalents and investments that are restricted as to withdrawal or usage. Restrictions may include legally restricted deposits held as compensating balances against short-term borrowing arrangements, contracts entered into with others, or entity statements of intention with regard to particular deposits; however, time deposits and short-term certificates of deposit are not generally included in legally restricted deposits. Excludes compensating balance arrangements that are not agreements which legally restrict the use of cash amounts shown on the balance sheet. Includes current cash equivalents and investments that are similarly restricted as to withdrawal, usage or disposal. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.1) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_RestrictedCashAndInvestmentsCurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Indicates (true false) whether practical expedient was elected to recognize incremental cost of obtaining contract as expense when incurred if amortization period would have been one year or less. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 340 -SubTopic 40 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=68051541&loc=SL51790836-203054 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 606 -SubTopic 10 -Section 50 -Paragraph 22 -URI http://asc.fasb.org/extlink&oid=118956577&loc=SL49130569-203045 + Details
Name: | us-gaap_RevenuePracticalExpedientIncrementalCostOfObtainingContract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:booleanItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of subsidiary's or equity investee's stock owned by parent company after stock transaction. + References No definition available. + Details
Name: | us-gaap_SaleOfStockPercentageOfOwnershipAfterTransaction
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_AdjustmentsForNewAccountingPronouncementsAxis=us-gaap_AccountingStandardsUpdate201409Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementEquityComponentsAxis=us-gaap_AccumulatedOtherComprehensiveIncomeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

X
- Details
Name: | us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=us-gaap_TrademarksAndTradeNamesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=us-gaap_IntellectualPropertyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=us-gaap_CustomerRelationshipsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_BuildingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_MachineryAndEquipmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

X
- Details
Name: | us-gaap_AdjustmentsForNewAccountingPronouncementsAxis=us-gaap_AccountingStandardsUpdate201616Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_OwnershipAxis=ash_AshlandLimitedLiabilityCompanyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |