Industry Segments (Details) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2017 USD ($) segment	Sep. 30, 2016 USD ($) segment
Segment Information
Number of operating segments \| segment			3	3
Net sales	$ 2,999	$ 2,648	$ 9,016	$ 7,302
Pre-tax operating profit (loss)	275	(268)	1,262	(1,063)
Income taxes	(85)	30	(448)	329
Discontinued operations, net		(3)		432
Net income (loss)	190	(241)	814	(302)
Pre-tax gain on sale of oil and gas properties	86	60	598	198
Oil and Gas
Segment Information
Loss from contract termination		160		160
Oil and Gas \| Non-strategic acreage in Midland Basin Counties
Segment Information
Pre-tax gain on sale of oil and gas properties	81		81
Oil and Gas \| Domestic oil and gas assets
Segment Information
Pre-tax gain on sale of oil and gas properties			510
Oil and Gas \| Libya operations
Segment Information
Impairment charges		112		112
Oil and Gas \| South Texas Eagle Ford non-operated properties
Segment Information
Pre-tax gain on sale of properties		59		59
Oil and Gas \| Piceance basin
Segment Information
Pre-tax gain on sale of properties				121
Chemical \| Occidental Tower in Dallas
Segment Information
Pre-tax gain on sale of properties				57
Chemical \| Texas and non-core specialty business
Segment Information
Pre-tax gain on sale of properties				31
Midstream and Marketing \| Equity investment
Segment Information
Non-cash fair value gain			94
Operating segments \| Oil and Gas
Segment Information
Net sales	1,865	1,660	5,607	4,560
Pre-tax operating profit (loss)	220	(51)	1,067	(653)
Net income (loss)	220	(51)	1,067	(653)
Operating segments \| Chemical
Segment Information
Net sales	1,071	988	3,295	2,786
Pre-tax operating profit (loss)	200	117	600	419
Net income (loss)	200	117	600	419
Operating segments \| Midstream and Marketing
Segment Information
Net sales	266	202	747	476
Pre-tax operating profit (loss)	4	(180)	76	(333)
Net income (loss)	4	(180)	76	(333)
Corporate and Eliminations
Segment Information
Net sales	(203)	(202)	(633)	(520)
Pre-tax operating profit (loss)	(149)	(154)	(481)	(496)
Income taxes	(85)	30	(448)	329
Discontinued operations, net		(3)		432
Net income (loss)	$ (234)	$ (127)	$ (929)	$ 265

For each line item in the statement of financial position, the amounts of gains and losses from fair value changes included in earnings.

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