Properties, Plant and Equipment (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Properties, Plant and Equipment
Properties, plant and equipment, at cost	$ 233,432	$ 207,367	$ 188,288
Properties, plant and equipment, net	122,608	104,504	96,468
Total property plant and equipment, additions at cost	32,391	21,145	17,008
Depreciation, depletion and amortization	12,911	13,063	12,110
Total depreciation expenses	12,911	13,063	12,110
United States [Member]
Properties, Plant and Equipment
Properties, plant and equipment, at cost	100,185	87,065	81,859
Properties, plant and equipment, net	47,056	36,152	34,853
Total property plant and equipment, additions at cost	16,221	6,392	5,746
Depreciation, depletion and amortization	4,984	5,160	4,983
International [Member]
Properties, Plant and Equipment
Properties, plant and equipment, at cost	133,247	120,302	106,429
Properties, plant and equipment, net	75,552	68,352	61,615
Total property plant and equipment, additions at cost	16,170	14,753	11,262
Depreciation, depletion and amortization	7,927	7,903	7,127
Upstream [Member]
Properties, Plant and Equipment
Properties, plant and equipment, at cost	200,164	173,101	154,885
Properties, plant and equipment, net	106,004	87,665	79,723
Total property plant and equipment, additions at cost	30,126	19,315	14,231
Depreciation, depletion and amortization	11,460	11,526	10,661
Upstream [Member] | United States [Member]
Properties, Plant and Equipment
Properties, plant and equipment, at cost	74,369	62,523	58,328
Properties, plant and equipment, net	33,461	23,277	22,273
Total property plant and equipment, additions at cost	14,404	4,934	3,518
Depreciation, depletion and amortization	3,870	4,078	3,992
Upstream [Member] | International [Member]
Properties, Plant and Equipment
Properties, plant and equipment, at cost	125,795	110,578	96,557
Properties, plant and equipment, net	72,543	64,388	57,450
Total property plant and equipment, additions at cost	15,722	14,381	10,803
Depreciation, depletion and amortization	7,590	7,448	6,669
Downstream [Member]
Properties, Plant and Equipment
Properties, plant and equipment, at cost	28,121	29,517	28,814
Properties, plant and equipment, net	13,718	14,327	14,186
Total property plant and equipment, additions at cost	1,669	1,560	2,330
Depreciation, depletion and amortization	1,108	1,192	1,120
Downstream [Member] | United States [Member]
Properties, Plant and Equipment
Properties, plant and equipment, at cost	20,699	19,820	18,962
Properties, plant and equipment, net	10,723	10,379	10,032
Total property plant and equipment, additions at cost	1,226	1,199	1,874
Depreciation, depletion and amortization	776	741	666
Downstream [Member] | International [Member]
Properties, Plant and Equipment
Properties, plant and equipment, at cost	7,422	9,697	9,852
Properties, plant and equipment, net	2,995	3,948	4,154
Total property plant and equipment, additions at cost	443	361	456
Depreciation, depletion and amortization	332	451	454
All Other Segments [Member]
Properties, Plant and Equipment
Properties, plant and equipment, at cost	5,147	4,749	4,589
Properties, plant and equipment, net	2,886	2,512	2,559
Total property plant and equipment, additions at cost	596	270	357
Depreciation, depletion and amortization	343	345	329
All Other Segments [Member] | United States [Member]
Properties, Plant and Equipment
Properties, plant and equipment, at cost	5,117	4,722	4,569
Properties, plant and equipment, net	2,872	2,496	2,548
Total property plant and equipment, additions at cost	591	259	354
Depreciation, depletion and amortization	338	341	325
All Other Segments [Member] | International [Member]
Properties, Plant and Equipment
Properties, plant and equipment, at cost	30	27	20
Properties, plant and equipment, net	14	16	11
Total property plant and equipment, additions at cost	5	11	3
Depreciation, depletion and amortization	$ 5	$ 4	$ 4