Environmental Liabilities and Expenditures (Details)	1 Months Ended	3 Months Ended
	Mar. 31, 2016 mi	Mar. 31, 2020 USD ($) site	Mar. 31, 2017 USD ($)	Dec. 31, 2019 USD ($)
Environmental remediation reserves
Number of Sites | site		177
Environmental remediation reserves, current, included in accrued liabilities		$ 1,177,000,000
Environmental remediation reserves, non-current, included in deferred credits and other liabilities - other		1,017,000,000		$ 1,035,000,000
Environmental reserves, exceeding $ ten million, threshold value		$ 10,000,000
Environmental reserves, exceeding $ ten million, number of sites | site		19
Environmental reserves, range between zero to $ one million site category, number of sites | site		101
Expected expend funds of environmental reserves (as a percent)		45.00%
Environmental remediation additional loss range		$ 1,100,000,000
Low end of range
Environmental remediation reserves
Environmental reserves, range between zero to $ one million site category		$ 0
Period of expending first half of environmental reserves		3 years
High end of range
Environmental remediation reserves
Environmental reserves, range between zero to $ one million site category		$ 1,000,000
Period of expending first half of environmental reserves		4 years
NPL sites
Environmental remediation reserves
Number of Sites | site		37
Environmental remediation reserves, current, included in accrued liabilities		$ 459,000,000
Third-party sites
Environmental remediation reserves
Number of Sites | site		73
Environmental remediation reserves, current, included in accrued liabilities		$ 301,000,000
Occidental-operated sites
Environmental remediation reserves
Number of Sites | site		17
Environmental remediation reserves, current, included in accrued liabilities		$ 152,000,000
Closed or non-operated Occidental sites
Environmental remediation reserves
Number of Sites | site		50
Environmental remediation reserves, current, included in accrued liabilities		$ 265,000,000
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			$ 165,000,000
Accrued liabilities
Environmental remediation reserves
Environmental remediation reserves, current, included in accrued liabilities		160,000,000
Deferred credits and other liabilities - other
Environmental remediation reserves
Environmental remediation reserves, non-current, included in deferred credits and other liabilities - other		$ 1,000,000,000.0