Property, Plant and Equipment (Details 2) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013 project	Dec. 31, 2012 project	Dec. 31, 2011 project
Property, Plant and Equipment [Abstract]
Amounts capitalized less than one year after completion of drilling	$ 512	$ 388	$ 482
Amounts capitalized greater than one year after completion of drilling	281	229	222
Total deferred exploratory well costs	793	617	704
Projects that have Exploratory Well Costs that have been Capitalized for Period Greater than One Year, Number of Projects	7	6	5
Increase (Decrease) in Capitalized Exploratory Well Costs that are Pending Determination of Proved Reserves [Roll Forward]
Beginning balance	617	704	657
Additions	746	699	625
Dry well expense	(147)	(111)	(223)
Transfers to development	(414)	(629)	(279)
Dispositions	(9)	(46)	(76)
Ending balance	$ 793	$ 617	$ 704