| Document and Entity Information | Dec. 07, 2020 |
| Entity Listings [Line Items] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Dec. 7, 2020 |
| Entity Registrant Name | OCCIDENTAL PETROLEUM CORP /DE/ |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 1-09210 |
| Entity Tax Identification Number | 95-4035997 |
| Entity Address, Address Line One | 5 GREENWAY PLAZA, 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 | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0000797468 |
| Common Stock [Member] | |
| Entity Listings [Line Items] | |
| Title of 12(b) Security | Common Stock, $0.20 par value |
| Trading Symbol | OXY |
| Security Exchange Name | NYSE |
| Warrants to Purchase Common Stock, par value $0.20 [Member] | |
| Entity Listings [Line Items] | |
| Title of 12(b) Security | Warrants to Purchase Common Stock, par value $0.20 |
| Trading Symbol | OXY WS |
| Security Exchange Name | NYSE |
