Properties, Plant and Equipment (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Properties, Plant and Equipment
Gross Investment at Cost	$ 263,481	[1]	$ 233,432	[1]	$ 207,367	[1]
Net Investment	141,348	[1]	122,608	[1]	104,504	[1]
Additions at Cost	34,015	[1],[2],[3]	32,391	[1],[2],[3]	21,145	[1],[2],[3]
Depreciation Expense	13,413	[1],[4]	12,911	[1],[4]	13,063	[1],[4]
United States [Member]
Properties, Plant and Equipment
Gross Investment at Cost	108,659	[1]	100,185	[1]	87,065	[1]
Net Investment	52,087	[1]	47,056	[1]	36,152	[1]
Additions at Cost	10,124	[1],[2],[3]	16,221	[1],[2],[3]	6,392	[1],[2],[3]
Depreciation Expense	5,085	[1],[4]	4,984	[1],[4]	5,160	[1],[4]
International [Member]
Properties, Plant and Equipment
Gross Investment at Cost	154,822	[1]	133,247	[1]	120,302	[1]
Net Investment	89,261	[1]	75,552	[1]	68,352	[1]
Additions at Cost	23,891	[1],[2],[3]	16,170	[1],[2],[3]	14,753	[1],[2],[3]
Depreciation Expense	8,328	[1],[4]	7,927	[1],[4]	7,903	[1],[4]
Upstream [Member]
Properties, Plant and Equipment
Gross Investment at Cost	227,707	[1]	200,164	[1]	173,101	[1]
Net Investment	123,227	[1]	106,004	[1]	87,665	[1]
Additions at Cost	29,554	[1],[2],[3]	30,126	[1],[2],[3]	19,315	[1],[2],[3]
Depreciation Expense	11,917	[1],[4]	11,460	[1],[4]	11,526	[1],[4]
Upstream [Member] | United States [Member]
Properties, Plant and Equipment
Gross Investment at Cost	81,908	[1]	74,369	[1]	62,523	[1]
Net Investment	37,909	[1]	33,461	[1]	23,277	[1]
Additions at Cost	8,211	[1],[2],[3]	14,404	[1],[2],[3]	4,934	[1],[2],[3]
Depreciation Expense	3,902	[1],[4]	3,870	[1],[4]	4,078	[1],[4]
Upstream [Member] | International [Member]
Properties, Plant and Equipment
Gross Investment at Cost	145,799	[1]	125,795	[1]	110,578	[1]
Net Investment	85,318	[1]	72,543	[1]	64,388	[1]
Additions at Cost	21,343	[1],[2],[3]	15,722	[1],[2],[3]	14,381	[1],[2],[3]
Depreciation Expense	8,015	[1],[4]	7,590	[1],[4]	7,448	[1],[4]
Downstream [Member]
Properties, Plant and Equipment
Gross Investment at Cost	30,782	[1]	28,121	[1]	29,517	[1]
Net Investment	15,263	[1]	13,718	[1]	14,327	[1]
Additions at Cost	4,042	[1],[2],[3]	1,669	[1],[2],[3]	1,560	[1],[2],[3]
Depreciation Expense	1,107	[1],[4]	1,108	[1],[4]	1,192	[1],[4]
Downstream [Member] | United States [Member]
Properties, Plant and Equipment
Gross Investment at Cost	21,792	[1]	20,699	[1]	19,820	[1]
Net Investment	11,333	[1]	10,723	[1]	10,379	[1]
Additions at Cost	1,498	[1],[2],[3]	1,226	[1],[2],[3]	1,199	[1],[2],[3]
Depreciation Expense	799	[1],[4]	776	[1],[4]	741	[1],[4]
Downstream [Member] | International [Member]
Properties, Plant and Equipment
Gross Investment at Cost	8,990	[1]	7,422	[1]	9,697	[1]
Net Investment	3,930	[1]	2,995	[1]	3,948	[1]
Additions at Cost	2,544	[1],[2],[3]	443	[1],[2],[3]	361	[1],[2],[3]
Depreciation Expense	308	[1],[4]	332	[1],[4]	451	[1],[4]
All Other Segments [Member]
Properties, Plant and Equipment
Gross Investment at Cost	4,992	[1],[5]	5,147	[1],[5]	4,749	[1],[5]
Net Investment	2,858	[1],[5]	2,886	[1],[5]	2,512	[1],[5]
Additions at Cost	419	[1],[2],[3],[5]	596	[1],[2],[3],[5]	270	[1],[2],[3],[5]
Depreciation Expense	389	[1],[4],[5]	343	[1],[4],[5]	345	[1],[4],[5]
All Other Segments [Member] | United States [Member]
Properties, Plant and Equipment
Gross Investment at Cost	4,959	[1],[5]	5,117	[1],[5]	4,722	[1],[5]
Net Investment	2,845	[1],[5]	2,872	[1],[5]	2,496	[1],[5]
Additions at Cost	415	[1],[2],[3],[5]	591	[1],[2],[3],[5]	259	[1],[2],[3],[5]
Depreciation Expense	384	[1],[4],[5]	338	[1],[4],[5]	341	[1],[4],[5]
All Other Segments [Member] | International [Member]
Properties, Plant and Equipment
Gross Investment at Cost	33	[1],[5]	30	[1],[5]	27	[1],[5]
Net Investment	13	[1],[5]	14	[1],[5]	16	[1],[5]
Additions at Cost	4	[1],[2],[3],[5]	5	[1],[2],[3],[5]	11	[1],[2],[3],[5]
Depreciation Expense	$ 5	[1],[4],[5]	$ 5	[1],[4],[5]	$ 4	[1],[4],[5]

[1] Other than the United States, Nigeria and Australia, no other country accounted for 10 percent or more of the company’s net properties, plant and equipment (PP&E) in 2012. Nigeria had PP&E of $17,485, $15,601 and $13,896 for 2012, 2011 and 2010, respectively. Australia had $21,770 and $12,423 in 2012 and 2011, respectively.

[2] Net of dry hole expense related to prior years’ expenditures of $80, $45 and $82 in 2012, 2011 and 2010, respectively.

[3] Includes properties acquired with the acquisition of Atlas Energy, Inc., in 2011.

[4] Depreciation expense includes accretion expense of $629, $628 and $513 in 2012, 2011 and 2010, respectively.

[5] Primarily mining operations, power generation businesses, real estate assets and management information systems.