ENVIRONMENTAL LIABILITIES AND EXPENDITURES (Details) $ in Millions	1 Months Ended	3 Months Ended	12 Months Ended
	Mar. 31, 2016 mi	Sep. 30, 2016 USD ($)	Dec. 31, 2016 USD ($) site	Dec. 31, 2015 USD ($) site	Dec. 31, 2014 USD ($) site
Environmental remediation reserves
Number of Sites | site			147	149	145
Environmental remediation reserves, current, included in accrued liabilities			$ 131	$ 70	$ 79
Environmental remediation reserves, noncurrent, included in deferred credits and other liabilities - other			739	316	255
Reserve Balance			870	386	334
Environmental reserves, exceeding $ ten million, threshold value			$ 10
Environmental reserves, exceeding $ ten million, number of sites | site			16
Environmental reserves, range between zero to $ one million site category, number of sites | site			88
Minimum period of expending second half of environmental reserves			10 years
Environmental remediation additional loss range			$ 1,000
Environmental costs, including certain estimates by segment
Operating Expenses			151	180	194
Capital Expenditures			73	167	189
Low end of range
Environmental remediation reserves
Environmental reserves, range between zero to $ one million site category			$ 0
Period of expending 40 percent of environmental reserves			3 years
High end of range
Environmental remediation reserves
Environmental reserves, range between zero to $ one million site category			$ 1
Period of expending 40 percent of environmental reserves			4 years
Oil and Gas
Environmental costs, including certain estimates by segment
Operating Expenses			$ 65	93	103
Capital Expenditures			43	122	143
Chemical
Environmental costs, including certain estimates by segment
Operating Expenses			75	74	80
Capital Expenditures			25	41	35
Midstream, Marketing and Other
Environmental costs, including certain estimates by segment
Operating Expenses			11	13	11
Capital Expenditures			5	4	11
Corporate
Environmental costs, including certain estimates by segment
Remediation Expenses			$ 61	$ 117	$ 79
Lower Passaic River
Environmental remediation reserves
Stretch of Lower Passaic river requiring remedial actions | mi	8.3
Stretch of Lower Passaic river not covered by remedial actions | mi	9
Clean-up estimated cost		$ 165
NPL sites
Environmental remediation reserves
Number of Sites | site			33	34	30
Reserve Balance			$ 461	$ 27	$ 23
Number of sites with significant environmental remediation reserves | site			3
Percentage of environmental reserves accounted for by associated sites			95.00%
Number of sites indemnified by third party | site			17
Third-party sites
Environmental remediation reserves
Number of Sites | site			68	66	67
Reserve Balance			$ 163	$ 128	$ 101
Number of sites with significant environmental remediation reserves | site			4
Percentage of environmental reserves accounted for by associated sites			53.00%
Number of sites indemnified by third party | site			9
Number of sites not indemnified by third party | site				68
Occidental-operated sites
Environmental remediation reserves
Number of Sites | site			17	18	17
Reserve Balance			$ 106	$ 107	$ 107
Number of sites with significant environmental remediation reserves | site			3
Percentage of environmental reserves accounted for by associated sites			48.00%
Closed or non-operated Occidental sites
Environmental remediation reserves
Number of Sites | site			29	31	31
Reserve Balance			$ 140	$ 124	$ 103
Number of sites with significant environmental remediation reserves | site			6
Percentage of environmental reserves accounted for by associated sites			69.00%