Operating Segments and Geographic Data (Details 4) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Segment Reporting Information [Line Items]
Sales and other operating revenues	$ 34,779	$ 42,105	$ 105,291	$ 118,564
Oil and Gas
Segment Reporting Information [Line Items]
Sales and other operating revenues	34,779	42,105	105,291	118,564
Oil and Gas | Operating Segments
Segment Reporting Information [Line Items]
Sales and other operating revenues	42,938	52,339	130,044	142,736
Oil and Gas | All Other
Segment Reporting Information [Line Items]
Sales and other operating revenues	275	270	775	775
Oil and Gas | Total All Other
Segment Reporting Information [Line Items]
Sales and other operating revenues	61	57	187	176
Oil and Gas | United States | Operating Segments
Segment Reporting Information [Line Items]
Sales and other operating revenues	20,096	23,453	59,641	62,301
Oil and Gas | United States | Intersegment Eliminations
Segment Reporting Information [Line Items]
Sales and other operating revenues	(209)	(207)	(576)	(583)
Oil and Gas | United States | All Other
Segment Reporting Information [Line Items]
Sales and other operating revenues	270	264	763	759
Oil and Gas | United States | Intersegment Eliminations
Segment Reporting Information [Line Items]
Sales and other operating revenues	(4,912)	(5,844)	(14,652)	(12,606)
Oil and Gas | International | Operating Segments
Segment Reporting Information [Line Items]
Sales and other operating revenues	22,842	28,886	70,403	80,435
Oil and Gas | International | Intersegment Eliminations
Segment Reporting Information [Line Items]
Sales and other operating revenues	(5)	(6)	(12)	(16)
Oil and Gas | International | All Other
Segment Reporting Information [Line Items]
Sales and other operating revenues	5	6	12	16
Oil and Gas | International | Intersegment Eliminations
Segment Reporting Information [Line Items]
Sales and other operating revenues	(3,247)	(4,390)	(10,101)	(11,566)
Oil and Gas | Upstream
Segment Reporting Information [Line Items]
Sales and other operating revenues	7,508	8,774	23,883	23,353
Oil and Gas | Upstream | Operating Segments
Segment Reporting Information [Line Items]
Sales and other operating revenues	14,209	17,096	44,364	44,253
Oil and Gas | Upstream | United States | Operating Segments
Segment Reporting Information [Line Items]
Sales and other operating revenues	5,602	6,784	17,411	16,405
Oil and Gas | Upstream | United States | Intersegment Eliminations
Segment Reporting Information [Line Items]
Sales and other operating revenues	(3,686)	(4,277)	(11,070)	(10,219)
Oil and Gas | Upstream | International | Operating Segments
Segment Reporting Information [Line Items]
Sales and other operating revenues	8,607	10,312	26,953	27,848
Oil and Gas | Upstream | International | Intersegment Eliminations
Segment Reporting Information [Line Items]
Sales and other operating revenues	(3,015)	(4,045)	(9,411)	(10,681)
Oil and Gas | Downstream
Segment Reporting Information [Line Items]
Sales and other operating revenues	27,210	33,274	81,221	95,035
Oil and Gas | Downstream | Operating Segments
Segment Reporting Information [Line Items]
Sales and other operating revenues	28,454	34,973	84,905	97,708
Oil and Gas | Downstream | United States | Operating Segments
Segment Reporting Information [Line Items]
Sales and other operating revenues	14,224	16,405	41,467	45,137
Oil and Gas | Downstream | United States | Intersegment Eliminations
Segment Reporting Information [Line Items]
Sales and other operating revenues	(1,017)	(1,360)	(3,006)	(1,804)
Oil and Gas | Downstream | International | Operating Segments
Segment Reporting Information [Line Items]
Sales and other operating revenues	14,230	18,568	43,438	52,571
Oil and Gas | Downstream | International | Intersegment Eliminations
Segment Reporting Information [Line Items]
Sales and other operating revenues	$ (227)	$ (339)	$ (678)	$ (869)