Represents the amount of costs that were previously allocated to the Composites segment and Marl facility but have been reclassified to the Unallocated and Other Segment.

No definition available.

+ Details

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Namespace Prefix:	ash_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of consideration received or receivable for the disposal of assets and liabilities, including discontinued operation.

+ References

No definition available.

+ Details

Name:	us-gaap_DisposalGroupIncludingDiscontinuedOperationConsideration
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- 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

No definition available.

+ Details

Name:	us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The cash inflow associated with the amount received from the sale of a portion of the company's business, for example a segment, division, branch or other business, during the period.

+ 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
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3179-108585

+ Details

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Namespace Prefix:	us-gaap_
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Period Type:	duration

- Details

Name:	us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis=ash_CompositesSegmentAndIntermediatesAndSolventsFacilityMember
Namespace Prefix:
Data Type:	na
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- Details

Name:	srt_CounterpartyNameAxis=ash_INEOSEnterprisesMember
Namespace Prefix:
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Balance Type:
Period Type:

Divestitures - Additional Information (Details) - USD ($) $ in Millions		3 Months Ended
	Nov. 15, 2018	Dec. 31, 2018	Dec. 31, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Stranded divestitures costs		$ 12	$ 12
Composites Segment and the Intermediates and Solvents Facility [Member] \| INEOS Enterprises [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Transaction value in sale of business	$ 1,100
Expected net proceeds from sale of business	$ 1,000