Disclosures About Segments And Related Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Segment Reporting Information [Line Items]
Earnings (Loss) after income tax	$ (680)	$ 3,170	$ (2,370)	$ 8,650
Sales and other operating revenue	45,425	63,422	132,836	192,559
Upstream United States [Member]
Segment Reporting Information [Line Items]
Earnings (Loss) after income tax	(681)	37	(2,582)	468
Sales and other operating revenue	1,422	1,941	4,280	7,228
Intersegment Revenue	2,348	2,876	5,999	7,828
Upstream Non-U.S. [Member]
Segment Reporting Information [Line Items]
Earnings (Loss) after income tax	298	2,131	1,084	7,837
Sales and other operating revenue	2,015	3,069	6,604	10,582
Intersegment Revenue	5,132	7,383	14,371	22,888
Downstream United States [Member]
Segment Reporting Information [Line Items]
Earnings (Loss) after income tax	(136)	673	(338)	822
Sales and other operating revenue	12,267	18,358	35,854	52,721
Intersegment Revenue	2,812	5,439	8,820	16,942
Downstream Non-U.S. [Member]
Segment Reporting Information [Line Items]
Earnings (Loss) after income tax	(95)	557	472	603
Sales and other operating revenue	23,862	33,391	69,468	100,994
Intersegment Revenue	3,334	5,826	11,210	18,563
Chemical United States [Member]
Segment Reporting Information [Line Items]
Earnings (Loss) after income tax	357	53	816	208
Sales and other operating revenue	2,162	2,412	6,028	7,421
Intersegment Revenue	1,480	1,489	4,466	5,947
Chemical Non-U.S. [Member]
Segment Reporting Information [Line Items]
Earnings (Loss) after income tax	304	188	456	739
Sales and other operating revenue	3,684	4,241	10,574	13,583
Intersegment Revenue	895	1,413	2,866	4,543
Corporate And Financing [Member]
Segment Reporting Information [Line Items]
Earnings (Loss) after income tax	(727)	(469)	(2,278)	(2,027)
Sales and other operating revenue	13	10	28	30
Intersegment Revenue	$ 55	$ 60	$ 166	$ 168