Cover Page - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2021	Jan. 31, 2022	Jun. 30, 2021
Entity Information [Line Items]
Document Type	10-K
Document Annual Report	true
Document Transition Report	false
Document Period End Date	Dec. 31, 2021
Current Fiscal Year End Date	--12-31
Entity File Number	1-9210
Entity Registrant Name	Occidental Petroleum Corporation
Entity Incorporation, State or Country Code	DE
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
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 29.2
Entity Common Stock, Shares Outstanding		934,063,989
Documents Incorporated by Reference	Portions of the registrant’s definitive Proxy Statement, relating to its 2022 Annual Meeting of Stockholders, are incorporated by reference into Part III of this Form 10-K.
Entity Central Index Key	0000797468
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY
Amendment Flag	false
Common Stock, $0.20 par value
Entity Information [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, $0.20 par value
Entity Information [Line Items]
Title of 12(b) Security	Warrants to Purchase Common Stock, $0.20 par value
Trading Symbol	OXY WS
Security Exchange Name	NYSE