| Document and Entity Information | Aug. 05, 2019 |
| Document and Entity Information [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Aug. 5, 2019 |
| Entity Registrant Name | Occidental Petroleum Corp |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 001-09210 |
| Entity Tax Identification Number | 95-4035997 |
| Entity Address, Address Line One | 5 Greenway Plaza |
| Entity Address, Address Line Two | Suite 110 |
| Entity Address, City or Town | Houston |
| Entity Address, State or Province | TX |
| Entity Address, Postal Zip Code | 77046 |
| City Area Code | 713 |
| Local Phone Number | 215-7000 |
| Written Communications | true |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock |
| Trading Symbol | OXY |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0000797468 |
