Operating Segments and Geographic Data (Details 1) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012		Dec. 31, 2011
Segment Assets
Goodwill	$ 4,640		$ 4,642
Total Assets	232,982		209,474
United States [Member]
Segment Assets
Total Assets	72,641		68,114
International [Member]
Segment Assets
Total Assets	155,701		136,718
Upstream [Member]
Segment Assets
Goodwill	4,640		4,642
Total Assets	162,337		140,290
Upstream [Member] | United States [Member]
Segment Assets
Total Assets	41,891		37,108
Upstream [Member] | International [Member]
Segment Assets
Total Assets	115,806		98,540
Downstream [Member]
Segment Assets
Total Assets	43,047		42,699
Downstream [Member] | United States [Member]
Segment Assets
Total Assets	23,023		22,182
Downstream [Member] | International [Member]
Segment Assets
Total Assets	20,024		20,517
Reportable Segment [Member]
Segment Assets
Total Assets	205,384		182,989
All Other Segments [Member]
Segment Assets
Total Assets	27,598	[1]	26,485	[1]
All Other Segments [Member] | United States [Member]
Segment Assets
Total Assets	7,727	[1]	8,824	[1]
All Other Segments [Member] | International [Member]
Segment Assets
Total Assets	$ 19,871	[1]	$ 17,661	[1]

[1] “All Other” assets consist primarily of worldwide cash, cash equivalents, time deposits and marketable securities, real estate, energy services, information systems, mining operations, power generation businesses, alternative fuels, technology companies, and assets of the corporate administrative functions.