Disclosures About Segments And Related Information (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012		Mar. 31, 2011
Segment Reporting Information [Line Items]
Earnings After Income Tax	$ 9,450		$ 10,650
Sales And Other Operating Revenue	119,189	[1],[2]	109,251	[1],[2]
Upstream United States [Member]
Segment Reporting Information [Line Items]
Earnings After Income Tax	1,010		1,279
Sales And Other Operating Revenue	2,967	[1]	3,286	[1]
Intersegment Revenue	2,492		2,359
Upstream Non-U.S. [Member]
Segment Reporting Information [Line Items]
Earnings After Income Tax	6,792		7,396
Sales And Other Operating Revenue	7,896	[1]	8,878	[1]
Intersegment Revenue	12,170		12,305
Downstream United States [Member]
Segment Reporting Information [Line Items]
Earnings After Income Tax	603		694
Sales And Other Operating Revenue	30,909	[1]	27,537	[1]
Intersegment Revenue	5,510		4,530
Downstream Non-U.S. [Member]
Segment Reporting Information [Line Items]
Earnings After Income Tax	983		405
Sales And Other Operating Revenue	67,018	[1]	59,191	[1]
Intersegment Revenue	17,169		16,501
Chemical United States [Member]
Segment Reporting Information [Line Items]
Earnings After Income Tax	433		669
Sales And Other Operating Revenue	3,927	[1]	3,647	[1]
Intersegment Revenue	3,128		2,816
Chemical Non-U.S. [Member]
Segment Reporting Information [Line Items]
Earnings After Income Tax	268		847
Sales And Other Operating Revenue	6,468	[1]	6,708	[1]
Intersegment Revenue	2,693		2,450
All Other [Member]
Segment Reporting Information [Line Items]
Earnings After Income Tax	(639)		(640)
Sales And Other Operating Revenue	4	[1]	4	[1]
Intersegment Revenue	$ 70		$ 64

[1] Includes sales-based taxes

[2] Sales-based taxes included in sales and other operating revenue for the three months ended March 31, 2012 and 2011, were $8,493 million and $7,916 million, respectively.