Operating Segments and Geographic Data (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Segment Reporting Information [Line Items]
Segment Earnings	$ 5,365	$ 7,210	$ 11,543	$ 13,681
Operating Segments [Member]
Segment Reporting Information [Line Items]
Segment Earnings	5,715	7,501	12,332	14,476
Operating Segments [Member] | Upstream [Member]
Segment Reporting Information [Line Items]
Segment Earnings	4,949	5,620	10,865	11,791
Operating Segments [Member] | Downstream [Member]
Segment Reporting Information [Line Items]
Segment Earnings	766	1,881	1,467	2,685
Operating Segments [Member] | United States [Member] | Upstream [Member]
Segment Reporting Information [Line Items]
Segment Earnings	1,083	1,318	2,215	2,847
Operating Segments [Member] | United States [Member] | Downstream [Member]
Segment Reporting Information [Line Items]
Segment Earnings	138	802	273	1,261
Operating Segments [Member] | International [Member] | Upstream [Member]
Segment Reporting Information [Line Items]
Segment Earnings	3,866	4,302	8,650	8,944
Operating Segments [Member] | International [Member] | Downstream [Member]
Segment Reporting Information [Line Items]
Segment Earnings	628	1,079	1,194	1,424
Corporate, Non-Segment [Member] | All Other [Member]
Segment Reporting Information [Line Items]
Interest Income	18	19	39	39
Other	$ (368)	$ (310)	$ (828)	$ (834)