Operating Segments and Geographic Data (Details 3) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Segment income tax expense
Income Tax Expense	$ 20,626	$ 12,919	$ 7,965
Upstream [Member]
Segment income tax expense
Income Tax Expense	20,444	12,765	8,702
Upstream [Member] | United States [Member]
Segment income tax expense
Income Tax Expense	3,701	2,285	1,251
Upstream [Member] | International [Member]
Segment income tax expense
Income Tax Expense	16,743	10,480	7,451
Downstream [Member]
Segment income tax expense
Income Tax Expense	1,201	1,142	380
Downstream [Member] | United States [Member]
Segment income tax expense
Income Tax Expense	785	680	(83)
Downstream [Member] | International [Member]
Segment income tax expense
Income Tax Expense	416	462	463
All Other Segments [Member]
Segment income tax expense
Income Tax Expense	$ (1,019)	$ (988)	$ (1,117)