DOMESTIC AND FOREIGN INCOME TAXES (Details) - USD ($) $ in Millions		12 Months Ended
	Jan. 01, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 22, 2017
Domestic and foreign components of income from continuing operations before domestic and foreign income taxes
Income from continuing operations before income taxes, Domestic		$ (609)	$ (2,698)	$ (5,810)
Income from continuing operations before income taxes, Foreign		1,937	1,034	(3,666)
Pre-tax operating profit (loss)		1,328	(1,664)	(9,476)
Provisions (credits) for domestic and foreign income taxes on continuing operations
Current United States Federal tax expense (benefit)		(81)	(784)	(810)
Current State and Local tax expense (benefit)		11	9	(31)
Current Foreign tax expense (benefit)		806	630	883
Current Total tax expense (benefit)		736	(145)	42
Deferred United States Federal tax expense (benefit)		(856)	(504)	(1,146)
Deferred State and Local tax expense (benefit)		23	(19)	(83)
Deferred Foreign tax expense (benefit)		114	6	(143)
Deferred Total tax expense (benefit)		(719)	(517)	(1,372)
United States Federal Total tax expense (benefit)		(937)	(1,288)	(1,956)
State and Local Total tax expense (benefit)		34	(10)	(114)
Foreign Total tax expense (benefit)		920	636	740
Total tax expense (benefit)		$ 17	$ (662)	$ (1,330)
Reconciliation of the United States federal statutory income tax rate to Occidental's worldwide effective tax rate on income from continuing operations
United States federal statutory tax rate (as a percent)	21.00%	35.00%	35.00%	35.00%
Other than temporary loss on available for sale investment in California Resources stock (as a percent)			(2.00%)	(1.00%)
Enhanced oil recovery credit (as a percent)		(9.00%)	5.00%
Tax benefit due to write off of exploration blocks (as a percent)			14.00%
Change in federal income tax rate		(44.00%)
Tax expense due to reversal of indefinite reinvestment assertion		7.00%
Operations outside the United States (as a percent)		12.00%	(14.00%)	(21.00%)
State income taxes, net of federal benefit (as a percent)		2.00%		1.00%
Other (as a percent)		(2.00%)	2.00%
Worldwide effective tax rate (as a percent)		1.00%	40.00%	14.00%
Tax Cuts and Jobs Act (TCJA)
Estimate of state tax associated with mandatory deemed repatriation					$ 10
Deferred Tax Assets and Liabilities
Deferred Tax Assets, environmental reserves		$ 191	$ 314
Deferred Tax Assets, postretirement benefit accruals		145	342
Deferred Tax Assets, deferred compensation and benefits		151	222
Deferred Tax Assets, asset retirement obligations		228	406
Deferred Tax Assets, foreign tax credit carryforwards		2,750	2,046
Deferred Tax Assets, Corporate alternative minimum tax credit carryforwards			226
Deferred Tax Assets, General business credit carryforwards		407	186
Deferred Tax Assets, Net operating loss carryforward		437
Deferred Tax Assets, federal benefit of state income taxes		10	8
Deferred Tax Assets, all other		146	370
Deferred Tax Assets, subtotal		4,465	4,120
Deferred Tax Assets, valuation allowance		(2,640)	(1,849)
Deferred Tax Assets, total deferred taxes		1,825	2,271
Deferred Tax Liabilities, property, plant and equipment differences		2,272	3,345
Deferred Tax Liabilities, equity investments, partnerships and foreign subsidiaries		134	58
Deferred Tax Liabilities, total deferred taxes		2,406	3,403
State operating loss carryforwards		35
Federal operating loss carryforwards that expire in 2037		402
Deferred Tax Assets, General business credit carryforwards, expire between 2033 and 2037		407
Deferred foreign tax liability due to reversal of indefinite re-investment assertion		99
Discontinued operations income tax charges (benefits)			249	$ 1
Unrecognized tax benefits included in deferred credits and other liabilities - other that would affect effective tax rate		22
Reconciliation of unrecognized tax benefits
Balance, at beginning of period	$ 22	22	22	61
Reductions based on tax positions related to prior years and settlements				(39)
Balance, at end of period		22	22	$ 22
State
Deferred Tax Assets and Liabilities
Valuation allowance on net operating loss carryforwards		4
Other current assets
Deferred Tax Assets and Liabilities
Income tax receivables		76	$ 761
Non-current receivables
Deferred Tax Assets and Liabilities
Deferred Tax Assets, Corporate alternative minimum tax credit carryforwards		221
General business credits
Deferred Tax Assets and Liabilities
Addition of general business credits to credit carryforward balance		$ 221
Forecast
Tax Cuts and Jobs Act (TCJA)
Threshold for qualifying for income of a U.S.-owned foreign corporation (net of allowed deduction) under the TCJA	10.00%