Operating Segments and Geographic Data (Details 4) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Segment Reporting Information [Line Items]
Sales and other operating revenues	$ 29,705	$ 34,189
Oil and Gas
Segment Reporting Information [Line Items]
Sales and other operating revenues	29,705	34,189
Oil and Gas | Operating Segments
Segment Reporting Information [Line Items]
Sales and other operating revenues	37,050	42,370
Oil and Gas | All Other
Segment Reporting Information [Line Items]
Sales and other operating revenues	212	224
Oil and Gas | Total All Other
Segment Reporting Information [Line Items]
Sales and other operating revenues	65	66
Oil and Gas | United States | Operating Segments
Segment Reporting Information [Line Items]
Sales and other operating revenues	15,862	18,492
Oil and Gas | United States | Intersegment Eliminations
Segment Reporting Information [Line Items]
Sales and other operating revenues	(145)	(156)
Oil and Gas | United States | All Other
Segment Reporting Information [Line Items]
Sales and other operating revenues	210	222
Oil and Gas | United States | Intersegment Eliminations
Segment Reporting Information [Line Items]
Sales and other operating revenues	(4,217)	(4,622)
Oil and Gas | International | Operating Segments
Segment Reporting Information [Line Items]
Sales and other operating revenues	21,188	23,878
Oil and Gas | International | Intersegment Eliminations
Segment Reporting Information [Line Items]
Sales and other operating revenues	(2)	(2)
Oil and Gas | International | All Other
Segment Reporting Information [Line Items]
Sales and other operating revenues	2	2
Oil and Gas | International | Intersegment Eliminations
Segment Reporting Information [Line Items]
Sales and other operating revenues	(3,128)	(3,559)
Oil and Gas | Upstream
Segment Reporting Information [Line Items]
Sales and other operating revenues	8,126	8,440
Oil and Gas | Upstream | Operating Segments
Segment Reporting Information [Line Items]
Sales and other operating revenues	13,479	15,251
Oil and Gas | Upstream | United States | Operating Segments
Segment Reporting Information [Line Items]
Sales and other operating revenues	4,466	5,882
Oil and Gas | Upstream | United States | Intersegment Eliminations
Segment Reporting Information [Line Items]
Sales and other operating revenues	(2,812)	(3,519)
Oil and Gas | Upstream | International | Operating Segments
Segment Reporting Information [Line Items]
Sales and other operating revenues	9,013	9,369
Oil and Gas | Upstream | International | Intersegment Eliminations
Segment Reporting Information [Line Items]
Sales and other operating revenues	(2,541)	(3,292)
Oil and Gas | Downstream
Segment Reporting Information [Line Items]
Sales and other operating revenues	21,514	25,683
Oil and Gas | Downstream | Operating Segments
Segment Reporting Information [Line Items]
Sales and other operating revenues	23,359	26,895
Oil and Gas | Downstream | United States | Operating Segments
Segment Reporting Information [Line Items]
Sales and other operating revenues	11,186	12,388
Oil and Gas | Downstream | United States | Intersegment Eliminations
Segment Reporting Information [Line Items]
Sales and other operating revenues	(1,260)	(947)
Oil and Gas | Downstream | International | Operating Segments
Segment Reporting Information [Line Items]
Sales and other operating revenues	12,173	14,507
Oil and Gas | Downstream | International | Intersegment Eliminations
Segment Reporting Information [Line Items]
Sales and other operating revenues	$ (585)	$ (265)