Operating Segments and Geographic Data (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Segment Reporting Information [Line Items]
Segment Earnings	$ 4,950	$ 5,253	$ 16,493	$ 18,934
Operating Segments [Member]
Segment Reporting Information [Line Items]
Segment Earnings	5,472	5,828	17,804	20,304
Operating Segments [Member] | Upstream [Member]
Segment Reporting Information [Line Items]
Segment Earnings	5,092	5,139	15,957	16,930
Operating Segments [Member] | Downstream [Member]
Segment Reporting Information [Line Items]
Segment Earnings	380	689	1,847	3,374
Operating Segments [Member] | United States [Member] | Upstream [Member]
Segment Reporting Information [Line Items]
Segment Earnings	1,026	1,122	3,241	3,969
Operating Segments [Member] | United States [Member] | Downstream [Member]
Segment Reporting Information [Line Items]
Segment Earnings	249	456	522	1,717
Operating Segments [Member] | International [Member] | Upstream [Member]
Segment Reporting Information [Line Items]
Segment Earnings	4,066	4,017	12,716	12,961
Operating Segments [Member] | International [Member] | Downstream [Member]
Segment Reporting Information [Line Items]
Segment Earnings	131	233	1,325	1,657
Corporate, Non-Segment [Member] | All Other [Member]
Segment Reporting Information [Line Items]
Interest Income	17	22	56	61
Other	$ (539)	$ (597)	$ (1,367)	$ (1,431)