Industry Segments - Schedule of Industry Segments and Eliminations (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($) segment	Jun. 30, 2019 USD ($)
Segment Information
Number of operating segments | segment			3
Net sales	$ 2,928	$ 4,420	$ 9,541	$ 8,424
Income (loss) from continuing operations before income taxes	(8,184)	941	(10,222)	1,797
Income tax benefit	1,468	(306)	1,493	(531)
Income (loss) from continuing operations	(6,716)	635	(8,729)	1,266
Asset impairments	8,600
Gain on derivative instrument	(76)	0	(661)	0
Goodwill impairment			1,200
Anadarko acquisition-related costs	149	50	297	50
Operating Segments | Oil and Gas
Segment Information
Net sales	2,040	2,718	7,100	5,069
Income (loss) from continuing operations before income taxes	(7,734)	726	(7,498)	1,210
Income tax benefit		0		0
Income (loss) from continuing operations	(7,734)	726	(7,498)	1,210
Asset impairments	6,400		7,000
Gain on derivative instrument			957
Operating Segments | Chemical
Segment Information
Net sales	846	998	1,808	2,057
Income (loss) from continuing operations before income taxes	108	208	294	473
Income tax benefit		0		0
Income (loss) from continuing operations	108	208	294	473
Operating Segments | Midstream And Marketing
Segment Information
Net sales	204	909	994	1,725
Income (loss) from continuing operations before income taxes	(7)	331	(1,294)	610
Income tax benefit		0		0
Income (loss) from continuing operations	(7)	331	(1,294)	610
Goodwill impairment			1,400
Corporate and Eliminations
Segment Information
Net sales	(162)	(205)	(361)	(427)
Income (loss) from continuing operations before income taxes	(551)	(324)	(1,724)	(496)
Income tax benefit	1,468	(306)	1,493	(531)
Income (loss) from continuing operations	917	$ (630)	(231)	$ (1,027)
Anadarko acquisition-related costs	$ 149		297
Loss on interest rate swaps			$ 665