Operating Segments and Geographic Data (Details 3) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Segment Reporting Information [Line Items]
Income Tax Expense	$ 19,996	$ 20,626	$ 12,919
Upstream [Member]
Segment Reporting Information [Line Items]
Income Tax Expense	19,374	20,444	12,765
Upstream [Member] | United States [Member]
Segment Reporting Information [Line Items]
Income Tax Expense	2,820	3,701	2,285
Upstream [Member] | International [Member]
Segment Reporting Information [Line Items]
Income Tax Expense	16,554	16,743	10,480
Downstream [Member]
Segment Reporting Information [Line Items]
Income Tax Expense	1,638	1,201	1,142
Downstream [Member] | United States [Member]
Segment Reporting Information [Line Items]
Income Tax Expense	1,051	785	680
Downstream [Member] | International [Member]
Segment Reporting Information [Line Items]
Income Tax Expense	587	416	462
All Other Segments [Member]
Segment Reporting Information [Line Items]
Income Tax Expense	$ (1,016)	$ (1,019)	$ (988)