SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - DERIVATIVE INSTRUMENTS (Details)	12 Months Ended
Dec. 31, 2017
Low end of range
DERIVATIVE INSTRUMENTS
Range used to determine if derivative instrument is effective	80.00%
High end of range
DERIVATIVE INSTRUMENTS
Range used to determine if derivative instrument is effective	125.00%

The percentage used to determine if a hedge is effective and qualifies for hedge accounting.

No definition available.

Name:	oxy_DerivativeInstrumentsHedgeEffectiveness
Namespace Prefix:	oxy_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration