RETIREMENT AND POSTRETIREMENT BENEFIT PLANS - DEFINED BENEFIT PLANS (Details)	Dec. 31, 2018 employee
Domestic
DEFINED BENEFIT PLANS
Number of employees accruing benefits under defined benefit plans	400
Foreign
DEFINED BENEFIT PLANS
Number of employees accruing benefits under defined benefit plans	1,000

This element represents the number of employees currently accruing benefits under defined benefit plans.

No definition available.

Name:	oxy_DefinedBenefitPlanNumberOfParticipatingEmployees
Namespace Prefix:	oxy_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant