Disclosures About Segments And Related Information (Schedule Of Long-Lived Assets By Geographic Regions) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Long-lived assets	$ 214,664	$ 199,548	$ 139,116
U.S. [Member]
Long-lived assets	91,146	86,021	37,138
Non-U.S. [Member]
Long-lived assets	123,518	113,527	101,978
Canada [Member]
Long-lived assets	24,458	20,879	15,919
Nigeria [Member]
Long-lived assets	11,806	11,429	11,046
Singapore [Member]
Long-lived assets	9,285	8,610	7,238
Angola [Member]
Long-lived assets	10,395	8,570	7,320
Norway [Member]
Long-lived assets	6,039	6,988	7,251
Australia [Member]
Long-lived assets	9,474	6,570	4,247
United Kingdom [Member]
Long-lived assets	5,008	6,177	7,609
Kazakhstan [Member]
Long-lived assets	$ 7,022	$ 5,938	$ 4,748

Tangible assets that are held by an entity for use in the production or supply of goods and services, for rental to others, or for administrative purposes and that are expected to provide economic benefit for more than one year; net of accumulated depreciation. Examples include land, buildings, machinery and equipment, and other types of furniture and equipment including, but not limited to, office equipment, furniture and fixtures, and computer equipment and software.

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