| Document and Entity Information | Feb. 13, 2020 |
| Cover [Abstract] | |
| City Area Code | 989 |
| Entity Address, Address Line One | 2211 H.H. Dow Way |
| Entity Address, City or Town | Midland |
| Entity Address, Postal Zip Code | 48674 |
| Entity Address, State or Province | MI |
| Local Phone Number | 636-1000 |
| Entity Registrant Name | Dow Inc. |
| Entity Address, Country | US |
| Entity Incorporation, State or Country Code | DE |
| Amendment Flag | false |
| Entity Central Index Key | 0001751788 |
| Document Type | 8-K |
| Document Period End Date | Feb. 13, 2020 |
| Entity File Number | 001-38646 |
| Entity Tax Identification Number | 30-1128146 |
| 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 $0.01 per share |
| Trading Symbol | DOW |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
