Operating Segments and Geographic Data - Segment Sales and Operating Revenues (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Total Sales and Other Operating Revenues	[1]	$ 139,865	$ 158,902
Oil and Gas
Segment Reporting Information [Line Items]
Total Sales and Other Operating Revenues		139,865	158,902	$ 134,674
Oil and Gas | Operating Segments
Segment Reporting Information [Line Items]
Total Sales and Other Operating Revenues		172,995	191,228	157,505
Oil and Gas | Corporate And Eliminations [Member]
Segment Reporting Information [Line Items]
Total Sales and Other Operating Revenues		246	236	209
Oil and Gas | Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Total Sales and Other Operating Revenues		1,084	1,044	1,048
Oil and Gas | United States | Operating Segments
Segment Reporting Information [Line Items]
Total Sales and Other Operating Revenues		79,693	83,289	67,404
Oil and Gas | United States | Intersegment
Segment Reporting Information [Line Items]
Total Sales and Other Operating Revenues		(818)	(786)	(814)
Oil and Gas | United States | Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Total Sales and Other Operating Revenues		1,064	1,022	1,022
Oil and Gas | United States | Intersegment Elimination
Segment Reporting Information [Line Items]
Total Sales and Other Operating Revenues		(19,686)	(17,493)	(10,169)
Oil and Gas | International | Operating Segments
Segment Reporting Information [Line Items]
Total Sales and Other Operating Revenues		93,302	107,939	90,101
Oil and Gas | International | Intersegment
Segment Reporting Information [Line Items]
Total Sales and Other Operating Revenues		(20)	(22)	(25)
Oil and Gas | International | Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Total Sales and Other Operating Revenues		20	22	26
Oil and Gas | International | Intersegment Elimination
Segment Reporting Information [Line Items]
Total Sales and Other Operating Revenues		(13,444)	(14,833)	(12,662)
Oil and Gas | Upstream
Segment Reporting Information [Line Items]
Total Sales and Other Operating Revenues		31,707	33,069	21,110
Oil and Gas | Upstream | Operating Segments
Segment Reporting Information [Line Items]
Total Sales and Other Operating Revenues		58,986	60,713	41,922
Oil and Gas | Upstream | United States | Operating Segments
Segment Reporting Information [Line Items]
Total Sales and Other Operating Revenues		23,358	22,891	13,242
Oil and Gas | Upstream | United States | Intersegment
Segment Reporting Information [Line Items]
Total Sales and Other Operating Revenues		(14,944)	(13,965)	(9,341)
Oil and Gas | Upstream | International | Operating Segments
Segment Reporting Information [Line Items]
Total Sales and Other Operating Revenues		35,628	37,822	28,680
Oil and Gas | Upstream | International | Intersegment
Segment Reporting Information [Line Items]
Total Sales and Other Operating Revenues		(12,335)	(13,679)	(11,471)
Oil and Gas | Downstream
Segment Reporting Information [Line Items]
Total Sales and Other Operating Revenues		107,912	125,597	113,355
Oil and Gas | Downstream | Operating Segments
Segment Reporting Information [Line Items]
Total Sales and Other Operating Revenues		112,925	129,471	114,535
Oil and Gas | Downstream | United States | Operating Segments
Segment Reporting Information [Line Items]
Total Sales and Other Operating Revenues		55,271	59,376	53,140
Oil and Gas | Downstream | United States | Intersegment
Segment Reporting Information [Line Items]
Total Sales and Other Operating Revenues		(3,924)	(2,742)	(14)
Oil and Gas | Downstream | International | Operating Segments
Segment Reporting Information [Line Items]
Total Sales and Other Operating Revenues		57,654	70,095	61,395
Oil and Gas | Downstream | International | Intersegment
Segment Reporting Information [Line Items]
Total Sales and Other Operating Revenues		$ (1,089)	$ (1,132)	$ (1,166)

[1] 2017 include excise, value-added and similar taxes of $7,189, collected on behalf of third parties. Beginning in 2018, these taxes are netted in "Taxes other than on income" in accordance with Accounting Standards Update (ASU) 2014-09. Refer to Note 24, "Revenue" beginning on page 89.