DOMESTIC AND FOREIGN INCOME TAXES (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Domestic and foreign components of income from continuing operations before domestic and foreign income taxes
Income from continuing operations before income taxes, Domestic	$ (5,810.0)	$ (732.0)	$ 3,399.0
Income from continuing operations before income taxes, Foreign	(3,666.0)	2,273.0	4,747.0
Income from continuing operations before income taxes, Total	(9,476.0)	1,541.0	8,146.0
Provisions (credits) for domestic and foreign income taxes on continuing operations
Current United States Federal tax expense (benefit)	(810.0)	870.0	113.0
Current State and Local tax expense (benefit)	(31.0)	81.0	17.0
Current Foreign tax expense (benefit)	883.0	1,912.0	2,170.0
Current Total tax expense (benefit)	42.0	2,863.0	2,300.0
Deferred United States Federal tax expense (benefit)	(1,146.0)	(1,037.0)	883.0
Deferred State and Local tax expense (benefit)	(83.0)	(71.0)	48.0
Deferred Foreign tax expense (benefit)	(143.0)	(70.0)	(17.0)
Deferred Total tax expense (benefit)	(1,372.0)	(1,178.0)	914.0
United States Federal Total tax expense (benefit)	(1,956.0)	(167.0)	996.0
State and Local Total tax expense (benefit)	(114.0)	10.0	65.0
Foreign Total tax expense (benefit)	740.0	1,842.0	2,153.0
Total tax expense (benefit)	$ (1,330.0)	$ 1,685.0	$ 3,214.0
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)	35.00%	35.00%	35.00%
Effect of spin-off of California Resources	(1.00%)	12.00%
Operations outside the United States (as a percent)	(21.00%)	65.00%	5.00%
State income taxes, net of federal benefit (as a percent)	1.00%	1.00%	1.00%
Other (as a percent)		(4.00%)	(1.00%)
Worldwide effective tax rate (as a percent)	14.00%	109.00%	40.00%
Deferred Tax Assets and Liabilities
Deferred Tax Assets, environmental reserves	$ 136.0	$ 123.0
Deferred Tax Assets, postretirement benefit accruals	346.0	379.0
Deferred Tax Assets, deferred compensation and benefits	179.0	208.0
Deferred Tax Assets, asset retirement obligations	372.0	307.0
Deferred Tax Assets, foreign tax credit carryforwards	2,034.0	1,765.0
Deferred tax Assets, federal benefit of state income taxes	11.0	85.0
Deferred Tax Assets, all other	677.0	274.0
Deferred Tax Assets, subtotal	3,755.0	3,141.0
Deferred Tax Assets, valuation allowance	(1,834.0)	(1,744.0)
Deferred Tax Assets, total deferred taxes	1,921.0	1,397.0
Deferred Tax Liabilities, property, plant and equipment differences	3,232.0	4,081.0
Deferred Tax Liabilities, equity investments, partnerships and foreign subsidiaries	12.0
Deferred Tax Liabilities, all other		221.0
Deferred Tax Liabilities, Gross	3,244.0	4,302.0
Deferred Tax Liabilities, total deferred taxes	3,244.0	4,302.0
Deferred tax assets, current		110.0
Unremitted earnings of certain consolidated foreign subsidiaries	9,900.0
Deferred tax liability not recognized, indefinitely reinvested foreign earnings	115.0
Discontinued operations income tax charges (benefits)	1.0	454.0	$ 550.0
Credit to additional paid-in capital, excess tax benefit from the exercise of certain stock-based compensation awards	0.0	4.0	6.0
Unrecognized tax benefits included in deferred credits and other liabilities - other that would affect effective tax rate	22.0
Reconciliation of unrecognized tax benefits
Balance, at beginning of period	61.0	61.0
Reductions based on tax positions related to prior years and settlements	(39.0)
Balance, at end of period	$ 22.0	$ 61.0	$ 61.0