Segment Information (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Segment Reporting Information [Line Items]
Sales and other operating revenues	$ 8,736		$ 9,246		$ 9,237
Marketing revenues	2,110		2,079		2,729
Total revenues	10,846		11,325		11,966
Income from equity method investments	424		423		370
Net gain (loss) on disposal of assets and other income	(12)		35		150
Production expenses	2,246		2,156		2,079
Marketing costs	2,105		2,076		2,734
Exploration expenses	793		891		685
Depreciation, depletion and amortization	2,861		2,500		2,008
Impairments	132		96		371
Other expenses	1,116	[1]	1,048	[1]	1,040	[1]
Taxes other than income	406		345		243
Net interest and other	238		278		222
Provision for income taxes	392		1,462		2,248
Segment income/Income from continuing operations	969		931		856
Property, Plant and Equipment, Additions	5,495	[2]	4,449	[2]	4,526	[2]
North America Exploration and Production [Member]
Segment Reporting Information [Line Items]
Sales and other operating revenues	5,770		5,068		3,944
Marketing revenues	1,839		1,797		2,451
Total revenues	7,609		6,865		6,395
Income from equity method investments	0		0		2
Net gain (loss) on disposal of assets and other income	23		12		11
Production expenses	891		797		706
Marketing costs	1,836		1,796		2,444
Exploration expenses	608		725		588
Depreciation, depletion and amortization	2,342		1,927		1,428
Impairments	23		41		11
Other expenses	473	[1]	420	[1]	400	[1]
Taxes other than income	385		318		226
Net interest and other	0		0		0
Provision for income taxes	381		324		223
Segment income/Income from continuing operations	693		529		382
Property, Plant and Equipment, Additions	4,698	[2]	3,649	[2]	3,988	[2]
International Exploration and Production [Member]
Segment Reporting Information [Line Items]
Sales and other operating revenues	1,410		2,654		3,719
Marketing revenues	219		264		248
Total revenues	1,629		2,918		3,967
Income from equity method investments	424		427		368
Net gain (loss) on disposal of assets and other income	57		50		21
Production expenses	386		359		377
Marketing costs	217		262		259
Exploration expenses	185		166		97
Depreciation, depletion and amortization	269		331		318
Impairments	0		0		0
Other expenses	197	[1]	161	[1]	116	[1]
Taxes other than income	0		0		0
Net interest and other	0		0		0
Provision for income taxes	288		1,358		2,294
Segment income/Income from continuing operations	568		758		895
Property, Plant and Equipment, Additions	534	[2]	456	[2]	235	[2]
Oil Sands Mining Segment [Member]
Segment Reporting Information [Line Items]
Sales and other operating revenues	1,556		1,576		1,521
Marketing revenues	52		18		30
Total revenues	1,608		1,594		1,551
Income from equity method investments	0		0		0
Net gain (loss) on disposal of assets and other income	4		5		4
Production expenses	969		1,000		996
Marketing costs	52		18		31
Exploration expenses	0		0		0
Depreciation, depletion and amortization	206		218		217
Impairments	0		0		0
Other expenses	54	[1]	66	[1]	60	[1]
Taxes other than income	20		22		22
Net interest and other	0		0		0
Provision for income taxes	76		69		58
Segment income/Income from continuing operations	235		206		171
Property, Plant and Equipment, Additions	212	[2]	286	[2]	188	[2]
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Sales and other operating revenues	0		(52)	[3]	53	[4]
Marketing revenues	0		0		0
Total revenues	0		(52)		53
Income from equity method investments	0		(4)	[5]	0
Net gain (loss) on disposal of assets and other income	(96)	[6]	(32)	[7]	114	[8]
Production expenses	0		0		0
Marketing costs	0		0		0
Exploration expenses	0		0		0
Depreciation, depletion and amortization	44		24		45
Impairments	109	[9]	55	[9]	360	[9]
Other expenses	392	[1],[10]	401	[1],[11]	464	[1],[11]
Taxes other than income	1		5		(5)
Net interest and other	238		278		222
Provision for income taxes	(353)		(289)		(327)
Segment income/Income from continuing operations	(527)		(562)		(592)
Property, Plant and Equipment, Additions	51	[2]	58	[2]	115	[2]
United States Pension Plan of US Entity [Member]
Segment Reporting Information [Line Items]
Net settlement loss	$ 99	[12]	$ 45	[12]	$ 45	[12]

[1] Includes other operating expenses and general and administrative expenses.

[2] Includes accruals.

[3] Unrealized loss on crude oil derivative instruments (see Note 15).

[4] Unrealized gain on crude oil derivative instruments (see Note 15).

[5] EGHoldings impairment (see Note 14).

[6] Primarily related to the sale of non-core acreage from our North America E&P segment (see Note 5).

[7] Related to the disposal of assets from our North America E&P segment (see Note 5).

[8] Related to the disposal of assets from our North America E&P and International E&P segments (see Note 5).

[9] Proved property impairments (see Note 14).

[10] Includes pension settlement loss of $99 million (see Note 19).

[11] Includes pension settlement loss of $45 million (see Note 19).

[12] Settlement losses are recorded when lump sum payments from a plan in a period exceed the plan’s total service and interest costs for the period. Such settlements occurred in one or more of our U.S. pension plans in all periods presented.