The charge against earnings resulting from the aggregate write down of all assets from their carrying value to their fair value.

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Exploration expenses (including prospecting) related to oil and gas producing entities and would be included in operating expenses of that entity. Costs incurred in identifying areas that may warrant examination and in examining specific areas that are considered to have prospects of containing oil and gas reserves, including costs of drilling exploratory wells and exploratory-type stratigraphic test wells. Exploration costs may be incurred both before acquiring the related property (sometimes referred to in part as prospecting costs) and after acquiring the property. Principal types of exploration costs, which include depreciation and applicable operating costs of support equipment and facilities and other costs of exploration activities, are: (i) Costs of topographical, geographical and geophysical studies, rights of access to properties to conduct those studies, and salaries and other expenses of geologists, geophysical crews, and others conducting those studies. Collectively, these are sometimes referred to as geological and geophysical or "G&G" costs. (ii) Costs of carrying and retaining undeveloped properties, such as delay rentals, ad valorem taxes on properties, legal costs for title defense, and the maintenance of land and lease records. (iii) Dry hole contributions and bottom hole contributions. (iv) Costs of drilling and equipping exploratory wells. (v) Costs of drilling exploratory-type stratigraphic test wells.

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Impairments (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Impairment charges by segment, before-tax
Asset Impairment Charges	$ 529	$ 680	$ 321
Exploration expenses	1,232	1,500	1,038
Alaska [Member]
Impairment charges by segment, before-tax
Asset Impairment Charges	3	3	2
Lower 48 and Latin America [Member]
Impairment charges by segment, before-tax
Asset Impairment Charges	2	192	71
Canada [Member]
Impairment charges by segment, before-tax
Asset Impairment Charges	216	262	253
Europe [Member]
Impairment charges by segment, before-tax
Asset Impairment Charges	301	211	(37)
Asia Pacific and Middle East [Member]
Impairment charges by segment, before-tax
Asset Impairment Charges	3	4
Corporate [Member]
Impairment charges by segment, before-tax
Asset Impairment Charges	4	8	32
McKenzie Gas Project [Member]
Impairment charges by segment, before-tax
Asset Impairment Charges		213
Exploration expenses		481
L48, Latin American And Canada [Member]
Impairment charges by segment, before-tax
Asset Impairment Charges			$ 289