Segment Information (Details 5) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Segment Reporting, Asset Reconciling Item
Assets	$ 116,433	$ 113,452	$ 109,022
Unallocated amounts:
Deferred tax assets	10,916	10,503
Plant, other property and equipment	13,883	14,096
Pension assets	2,843	3,068
Total segments
Segment Reporting, Asset Reconciling Item
Assets	91,557	89,292	81,714
Elimination of internal transactions
Segment Reporting, Asset Reconciling Item
Assets	(5,407)	(5,515)	(5,481)
Unallocated to segments
Unallocated amounts:
Cash and marketable securities	10,575	10,113	12,688
Notes and accounts receivable	3,526	3,762	3,928
Deferred tax assets	4,865	4,494	5,545
Plant, other property and equipment	2,918	3,067	2,971
Pension assets	2,837	3,060	2,994
Other	$ 5,562	$ 5,178	$ 4,665

Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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Cash includes currency on hand as well as demand deposits with banks or financial institutions. It also includes other kinds of accounts that have the general characteristics of demand deposits in that the customer may deposit additional funds at any time and effectively may withdraw funds at any time without prior notice or penalty. Cash equivalents, excluding items classified as marketable securities, include short-term, highly liquid Investments that are both readily convertible to known amounts of cash, and so near their maturity that they present minimal risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three years ago does not become a cash equivalent when its remaining maturity is three months. Short-term investments, exclusive of cash equivalents, generally consist of marketable securities intended to be sold within one year (or the normal operating cycle if longer) and may include trading securities, available-for-sale securities, or held-to-maturity securities (if maturing within one year), as applicable.

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- Definition

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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