| Document And Entity Information | Apr. 30, 2024 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Apr. 30, 2024 |
| Entity Registrant Name | ASHLAND INC. |
| Entity Central Index Key | 0001674862 |
| Entity Emerging Growth Company | false |
| Entity File Number | 333-211719 |
| Entity Incorporation, State or Country Code | DE |
| Entity Tax Identification Number | 81-2587835 |
| Entity Address, Address Line One | 8145 Blazer Drive |
| Entity Address, City or Town | Wilmington |
| Entity Address, State or Province | DE |
| Entity Address, Postal Zip Code | 19808 |
| City Area Code | 302 |
| Local Phone Number | 995-3000 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, par value $.01 per share |
| Trading Symbol | ASH |
| Security Exchange Name | NYSE |
