Segment Information (Details) (USD $) In Millions	3 Months Ended	9 Months Ended
Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Revenues:
Customer revenues	$ 3,633	$ 2,839	$ 10,969	$ 8,287
Intersegment revenues	6	20	47	49
Related parties	16	15	45	41
Segment revenues, total	3,655	2,874	11,061	8,377
Elimination of intersegment revenues	(6)	(20)	(47)	(49)
Total revenues	3,649	2,854	11,014	8,328
Segment income (loss)	477	569	1,950	1,494
Income from equity method investments, segment	123	102	360	270
Depreciation, depletion and amortization, segment	509	520	1,685	1,349
Income tax provision (benefit), segment	940	602	2,227	1,782
Capital expenditures, segment	721	778	2,339	2,475
Exploration and Production Segment [Member]
Revenues:
Customer revenues	3,190	2,605	9,696	7,622
Intersegment revenues	6	20	47	49
Related parties	16	15	45	41
Segment revenues, total	3,212	2,640	9,788	7,712
Elimination of intersegment revenues	(6)	(20)	(47)	(49)
Total revenues	3,206	2,620	9,741	7,663
Segment income (loss)	330	510	1,599	1,444
Income from equity method investments, segment	63	51	187	128
Depreciation, depletion and amortization, segment	454	491	1,541	1,279
Income tax provision (benefit), segment	890	579	2,101	1,741
Capital expenditures, segment	684	586	2,101	1,774
Oil Sands Mining Segment [Member]
Revenues:
Customer revenues	427	196	1,180	567
Segment revenues, total	427	196	1,180	567
Total revenues	427	196	1,180	567
Segment income (loss)	92	18	193	(59)
Depreciation, depletion and amortization, segment	55	28	141	67
Income tax provision (benefit), segment	31	2	64	(15)
Capital expenditures, segment	36	191	236	699
Integrated Gas Segment [Member]
Revenues:
Customer revenues	16	38	93	98
Segment revenues, total	16	38	93	98
Total revenues	16	38	93	98
Segment income (loss)	55	41	158	109
Income from equity method investments, segment	60	51	173	142
Depreciation, depletion and amortization, segment		1	3	3
Income tax provision (benefit), segment	19	21	62	56
Capital expenditures, segment	$ 1	$ 1	$ 2	$ 2

Revenues arising from transactions between (a) a parent company and its subsidiaries; (b) subsidiaries of a common parent; (c) an entity and trusts for the benefit of employees, such as pension and profit-sharing trusts that are managed by or under the trusteeship of the entity's' management; (d) an entity and its principal, owners, management, or members of their immediate families; and (e) affiliates.

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-Paragraph 2

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Total revenue from sale of goods and services rendered during the reporting period, in the normal course of business, reduced by sales returns and allowances, and sales discounts.

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Amount of depreciation, depletion, and amortization expense for the reportable segment. Must be disclosed if the amount (a) is included in the measure of segment profit or loss reviewed by the chief operating decision maker or (b) is otherwise regularly provided to the chief operating decision maker, even if not included in that measure of segment profit or loss

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Total expenditures for additions to long-lived assets other than financial instruments, long-term customer relationships of a financial institution, mortgage and other servicing rights, deferred policy acquisition costs, and deferred tax assets of the reportable segment. Must be disclosed if the amount (a) is included in the determination of segment assets reviewed by the chief operating decision maker or (b) is otherwise regularly provided to the chief operating decision maker, even if not included in the determination of segment assets.

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Amount of income tax expense or benefit attributed to the reportable segment. Must be disclosed if the amount (a) is included in the measure of segment profit or loss reviewed by the chief operating decision maker or (b) is otherwise regularly provided to the chief operating decision maker, even if not included in that measure of segment profit or loss

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Amount of revenue from transactions with other operating segments of the same entity. Must be disclosed if the amount (a) is included in the measure of segment profit or loss reviewed by the chief operating decision maker or (b) is otherwise regularly provided to the chief operating decision maker, even if not included in that measure of segment profit or loss

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Amount of total revenue for the reportable segment, including revenue from external customers, transactions with other operating segments of the same entity, and (gross) interest revenue. All considered to be "operating revenue" for purposes of the taxonomy.

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Amount of revenue from external customers for the reportable segment. Must be disclosed if the amounts (a) is included in the measure of segment profit or loss reviewed by the chief operating decision maker or (b) is otherwise regularly provided to the chief operating decision maker, even if not included in that measure of segment profit or loss

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