Accounting for Suspended Exploratory Wells (Details 1) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013 Well Project		Dec. 31, 2012 Project		Dec. 31, 2011 Project
Projects with Exploratory Well Costs Capitalized for More than One Year [Line Items]
Capitalized exploratory well costs that have been capitalized for period greater than one year	$ 2,604		$ 2,180		$ 1,877
Total number of exploratory wells that have been capitalized for period greater than one year	191
Number of projects	51	[1]	46	[1]	47	[1]
1997-2001 [Member]
Projects with Exploratory Well Costs Capitalized for More than One Year [Line Items]
Capitalized exploratory well costs that have been capitalized for period greater than one year	120
Aging of exploratory well costs capitalized for more than one year based on drilling completion date of individual wells 1997 to 2000 number of wells	28
2002-2006 [Member]
Projects with Exploratory Well Costs Capitalized for More than One Year [Line Items]
Capitalized exploratory well costs that have been capitalized for period greater than one year	531
Aging of exploratory well costs capitalized for more than one year based on drilling completion date of individual wells 2001 to 2005 number of wells	46
2007-2011 [Member]
Projects with Exploratory Well Costs Capitalized for More than One Year [Line Items]
Capitalized exploratory well costs that have been capitalized for period greater than one year	1,953
Aging of exploratory well costs capitalized for more than one year based on drilling completion date of individual wells 2006 to 2010 number of wells	117
1999 [Member]
Projects with Exploratory Well Costs Capitalized for More than One Year [Line Items]
Capitalized exploratory well costs that have been capitalized for period greater than one year	8
Number of projects	1
2003-2007 [Member]
Projects with Exploratory Well Costs Capitalized for More than One Year [Line Items]
Capitalized exploratory well costs that have been capitalized for period greater than one year	347
Number of projects	10
2008-2012 [Member]
Projects with Exploratory Well Costs Capitalized for More than One Year [Line Items]
Capitalized exploratory well costs that have been capitalized for period greater than one year	$ 2,249
Number of projects	40

[1] Certain projects have multiple wells or fields or both.