Operating Segments and Geographic Data (Details 2) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Segment Reporting Information [Line Items]
Sales and Other Operating Revenues	[1]		$ 32,877		$ 64,401
Includes excise, value-added and similar taxes			1,771		3,448
Oil and Gas
Segment Reporting Information [Line Items]
Sales and Other Operating Revenues		$ 40,491	32,877	$ 76,459	64,401
Oil and Gas | Operating Segments
Segment Reporting Information [Line Items]
Sales and Other Operating Revenues		47,957	38,296	90,397	75,302
Oil and Gas | All Other
Segment Reporting Information [Line Items]
Sales and Other Operating Revenues		275	286	505	526
Oil and Gas | Total All Other
Segment Reporting Information [Line Items]
Sales and Other Operating Revenues		58	48	119	100
Oil and Gas | United States | Operating Segments
Segment Reporting Information [Line Items]
Sales and Other Operating Revenues		21,002	16,735	38,848	32,642
Oil and Gas | United States | Intersegment Eliminations
Segment Reporting Information [Line Items]
Sales and Other Operating Revenues		(210)	(231)	(376)	(414)
Oil and Gas | United States | All Other
Segment Reporting Information [Line Items]
Sales and Other Operating Revenues		268	278	495	513
Oil and Gas | United States | Intersegment Eliminations
Segment Reporting Information [Line Items]
Sales and Other Operating Revenues		(3,836)	(2,432)	(6,762)	(4,859)
Oil and Gas | International | Operating Segments
Segment Reporting Information [Line Items]
Sales and Other Operating Revenues		26,955	21,561	51,549	42,660
Oil and Gas | International | Intersegment Eliminations
Segment Reporting Information [Line Items]
Sales and Other Operating Revenues		(7)	(7)	(10)	(12)
Oil and Gas | International | All Other
Segment Reporting Information [Line Items]
Sales and Other Operating Revenues		7	8	10	13
Oil and Gas | International | Intersegment Eliminations
Segment Reporting Information [Line Items]
Sales and Other Operating Revenues		(3,630)	(2,987)	(7,176)	(6,042)
Oil and Gas | Upstream
Segment Reporting Information [Line Items]
Sales and Other Operating Revenues		7,318	5,081	14,579	9,941
Oil and Gas | Upstream | Operating Segments
Segment Reporting Information [Line Items]
Sales and Other Operating Revenues		13,924	9,987	27,157	19,808
Oil and Gas | Upstream | United States | Operating Segments
Segment Reporting Information [Line Items]
Sales and Other Operating Revenues		5,044	3,135	9,621	6,375
Oil and Gas | Upstream | United States | Intersegment Eliminations
Segment Reporting Information [Line Items]
Sales and Other Operating Revenues		(3,185)	(2,198)	(5,942)	(4,439)
Oil and Gas | Upstream | International | Operating Segments
Segment Reporting Information [Line Items]
Sales and Other Operating Revenues		8,880	6,852	17,536	13,433
Oil and Gas | Upstream | International | Intersegment Eliminations
Segment Reporting Information [Line Items]
Sales and Other Operating Revenues		(3,421)	(2,708)	(6,636)	(5,428)
Oil and Gas | Downstream
Segment Reporting Information [Line Items]
Sales and Other Operating Revenues		33,115	27,748	61,761	54,360
Oil and Gas | Downstream | Operating Segments
Segment Reporting Information [Line Items]
Sales and Other Operating Revenues		33,758	28,023	62,735	54,968
Oil and Gas | Downstream | United States | Operating Segments
Segment Reporting Information [Line Items]
Sales and Other Operating Revenues		15,690	13,322	28,732	25,754
Oil and Gas | Downstream | United States | Intersegment Eliminations
Segment Reporting Information [Line Items]
Sales and Other Operating Revenues		(441)	(3)	(444)	(6)
Oil and Gas | Downstream | International | Operating Segments
Segment Reporting Information [Line Items]
Sales and Other Operating Revenues		18,068	14,701	34,003	29,214
Oil and Gas | Downstream | International | Intersegment Eliminations
Segment Reporting Information [Line Items]
Sales and Other Operating Revenues		$ (202)	$ (272)	$ (530)	$ (602)

[1] The three-month and six-month comparative periods ended June 30, 2017, include excise, value-added and similar taxes of $1,771 million and $3,448 million, respectively, collected on behalf of third parties. Beginning in 2018, these taxes are netted in "Taxes other than on income" in accordance with ASU 2014-09. Refer to Note 17, "Revenue" beginning on page 24.