Derivatives - Cash-Flow Hedges (Details) ft³ in Billions	Dec. 31, 2017 ft³
Derivatives
Natural gas held in storage (in cubic feet)	7
Forecast sale of natural gas from storage designated as cash-flow hedges (in cubic feet)	7

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