Segment Information (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Segment Reporting Information [Line Items]
Sales and other operating revenues, including related party	$ 3,119	$ 3,405	$ 9,978	$ 9,324
Marketing revenues	668	631	1,597	2,237
Segment income	669	578	1,724	1,620
Income from equity method investments	114	122	309	260
Depreciation, depletion and amortization	720	625	2,205	1,779
Income tax provision (benefit)	787	1,279	2,890	3,231
North America Exploration and Production [Member]
Segment Reporting Information [Line Items]
Sales and other operating revenues, including related party	1,321	993	3,820	2,738
Marketing revenues	607	548	1,391	2,019
Segment revenues	1,928	1,541	5,211	4,757
Segment income	242	107	404	281
Income from equity method investments	0	1	0	2
Depreciation, depletion and amortization	490	360	1,458	964
Income tax provision (benefit)	143	66	242	166
Capital expenditures	831	1,045	2,705	2,887
International Exploration and Production [Member]
Segment Reporting Information [Line Items]
Sales and other operating revenues, including related party	1,396	1,907	5,015	5,383
Marketing revenues	58	73	194	193
Segment revenues	1,454	1,980	5,209	5,576
Segment income	321	405	1,156	1,185
Income from equity method investments	114	121	309	258
Depreciation, depletion and amortization	179	194	575	622
Income tax provision (benefit)	714	1,219	2,860	3,260
Capital expenditures	254	229	720	569
Oil Sands Mining Segment [Member]
Segment Reporting Information [Line Items]
Sales and other operating revenues, including related party	463	460	1,204	1,158
Marketing revenues	3	10	12	25
Segment revenues	466	470	1,216	1,183
Segment income	106	66	164	154
Income from equity method investments	0	0	0	0
Depreciation, depletion and amortization	54	60	154	159
Income tax provision (benefit)	35	20	55	50
Capital expenditures	65	41	207	136
Total All Segments [Member]
Segment Reporting Information [Line Items]
Sales and other operating revenues, including related party	3,180	3,360	10,039	9,279
Marketing revenues	668	631	1,597	2,237
Segment revenues	3,848	3,991	11,636	11,516
Unrealized loss on crude oil derivative instruments	(61)	45	(61)	45
Segment reporting revenue from external customers	3,787	4,036	11,575	11,561
Segment income	669	578	1,724	1,620
Income from equity method investments	114	122	309	260
Depreciation, depletion and amortization	723	614	2,187	1,745
Income tax provision (benefit)	892	1,305	3,157	3,476
Capital expenditures	$ 1,150	$ 1,315	$ 3,632	$ 3,592