Derivatives - Cash Flow Hedges (Details) - Bcf	Mar. 31, 2019	Dec. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Natural gas held in storage (in cubic feet)	1	5
Forecast sale of natural gas from storage designated as cash-flow hedges (in cubic feet)		4

This element represents the forecast sales volume of natural gas from storage in billion cubic feet designated as cash flow hedges.

No definition available.

Name:	oxy_DesignatedForecastSaleOfNaturalGasAsCashFlowHedges
Namespace Prefix:	oxy_
Data Type:	num:volumeItemType
Balance Type:	na
Period Type:	instant