Environmental Liabilities and Expenditures (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2011 Y segment Cubicfeet site
Environmental Liabilities and Expenditures
Environmental remediation reserves, current, included in accrued liabilities	$ (78)
Environmental remediation reserves, noncurrent, included in deferred credits and other liabilities - other	(277)
Environmental remediation reserves.
Number of Sites	169
Environmental remediation reserves	355
Environmental reserves, exceeding $ ten million	10
Environmental reserves, exceeding $ ten million, number of sites	10
Environmental reserves, range between zero to $ one million site category, number of sites	120
Environmental reserves, range between zero to $ one million site category, lower limit	0
Environmental reserves, range between zero to $ one million site category, upper limit	1
Period of expending first half of environmental reserves (in years)	4
Period of expending second half of environmental reserves	Ten or more years
Environmental remediation additional loss range	380
NPL sites
Environmental remediation reserves.
Number of Sites	38
Environmental remediation reserves	59
Third-party sites
Environmental remediation reserves.
Number of Sites	81
Environmental remediation reserves	94
Occidental-operated sites
Environmental remediation reserves.
Number of Sites	21
Environmental remediation reserves	111
Closed or non-operated Occidental sites
Environmental remediation reserves.
Number of Sites	29
Environmental remediation reserves	$ 91