Operating Segments and Geographic Data (Details 4) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Segment Reporting Information [Line Items]
Sales and other operating revenues	$ 36,323	$ 40,491	$ 70,512	$ 76,459
Oil and Gas
Segment Reporting Information [Line Items]
Sales and other operating revenues	36,323	40,491	70,512	76,459
Oil and Gas | Operating Segments
Segment Reporting Information [Line Items]
Sales and other operating revenues	44,736	47,957	87,106	90,397
Oil and Gas | All Other
Segment Reporting Information [Line Items]
Sales and other operating revenues	276	275	500	505
Oil and Gas | Total All Other
Segment Reporting Information [Line Items]
Sales and other operating revenues	60	58	126	119
Oil and Gas | United States | Operating Segments
Segment Reporting Information [Line Items]
Sales and other operating revenues	21,053	21,002	39,545	38,848
Oil and Gas | United States | Intersegment Eliminations
Segment Reporting Information [Line Items]
Sales and other operating revenues	(211)	(210)	(367)	(376)
Oil and Gas | United States | All Other
Segment Reporting Information [Line Items]
Sales and other operating revenues	271	268	493	495
Oil and Gas | United States | Intersegment Eliminations
Segment Reporting Information [Line Items]
Sales and other operating revenues	(5,118)	(3,836)	(9,740)	(6,762)
Oil and Gas | International | Operating Segments
Segment Reporting Information [Line Items]
Sales and other operating revenues	23,683	26,955	47,561	51,549
Oil and Gas | International | Intersegment Eliminations
Segment Reporting Information [Line Items]
Sales and other operating revenues	(5)	(7)	(7)	(10)
Oil and Gas | International | All Other
Segment Reporting Information [Line Items]
Sales and other operating revenues	5	7	7	10
Oil and Gas | International | Intersegment Eliminations
Segment Reporting Information [Line Items]
Sales and other operating revenues	(3,295)	(3,630)	(6,854)	(7,176)
Oil and Gas | Upstream
Segment Reporting Information [Line Items]
Sales and other operating revenues	7,935	7,318	16,375	14,579
Oil and Gas | Upstream | Operating Segments
Segment Reporting Information [Line Items]
Sales and other operating revenues	14,904	13,924	30,155	27,157
Oil and Gas | Upstream | United States | Operating Segments
Segment Reporting Information [Line Items]
Sales and other operating revenues	5,927	5,044	11,809	9,621
Oil and Gas | Upstream | United States | Intersegment Eliminations
Segment Reporting Information [Line Items]
Sales and other operating revenues	(3,865)	(3,185)	(7,384)	(5,942)
Oil and Gas | Upstream | International | Operating Segments
Segment Reporting Information [Line Items]
Sales and other operating revenues	8,977	8,880	18,346	17,536
Oil and Gas | Upstream | International | Intersegment Eliminations
Segment Reporting Information [Line Items]
Sales and other operating revenues	(3,104)	(3,421)	(6,396)	(6,636)
Oil and Gas | Downstream
Segment Reporting Information [Line Items]
Sales and other operating revenues	28,328	33,115	54,011	61,761
Oil and Gas | Downstream | Operating Segments
Segment Reporting Information [Line Items]
Sales and other operating revenues	29,556	33,758	56,451	62,735
Oil and Gas | Downstream | United States | Operating Segments
Segment Reporting Information [Line Items]
Sales and other operating revenues	14,855	15,690	27,243	28,732
Oil and Gas | Downstream | United States | Intersegment Eliminations
Segment Reporting Information [Line Items]
Sales and other operating revenues	(1,042)	(441)	(1,989)	(444)
Oil and Gas | Downstream | International | Operating Segments
Segment Reporting Information [Line Items]
Sales and other operating revenues	14,701	18,068	29,208	34,003
Oil and Gas | Downstream | International | Intersegment Eliminations
Segment Reporting Information [Line Items]
Sales and other operating revenues	$ (186)	$ (202)	$ (451)	$ (530)