Environmental Liabilities and Expenditures (Details) $ in Millions	1 Months Ended	3 Months Ended	6 Months Ended	9 Months Ended
	Mar. 31, 2016 mi	Sep. 30, 2016 USD ($)	Jun. 30, 2019 USD ($) category	Sep. 30, 2019 USD ($) site	Dec. 31, 2018 USD ($)
Environmental remediation reserves
Number of Sites | site				185
Environmental remediation reserves, current, included in accrued liabilities			$ 149
Environmental remediation reserves, non-current, included in deferred credits and other liabilities - other			$ 905	$ 905	$ 762
Number of non-NPL sites categories | category			3
Reserve Balance				$ 1,054
Environmental reserves, exceeding $ ten million, threshold value			$ 10
Environmental reserves, exceeding $ ten million, number of sites | site				19
Environmental reserves, range between zero to $ one million site category, number of sites | site				112
Expected expend funds of environmental reserves (as a percent)				40.00%
Minimum period of expending second half of environmental reserves			10 years
Environmental remediation additional loss range				$ 1,200
Low end of range
Environmental remediation reserves
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
Period of expending first half of environmental reserves			4 years
NPL sites
Environmental remediation reserves
Number of Sites | site				34
Reserve Balance				$ 452
Third-party sites
Environmental remediation reserves
Number of Sites | site				66
Reserve Balance				$ 223
Occidental-operated sites
Environmental remediation reserves
Number of Sites | site				14
Reserve Balance				$ 110
Closed or non-operated Occidental sites
Environmental remediation reserves
Number of Sites | site				29
Reserve Balance				$ 127
Environmental sites assumed from the Merger
Environmental remediation reserves
Number of Sites | site				42
Reserve Balance				$ 142
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
Anadarko
Environmental remediation reserves
Number of Sites | site				42