Property, Plant and Equipment Property, Plant and Equipment (Details 2) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014
Total Deferred Exploratory Well Costs [Abstract]
Amounts capitalized greater than one year after completion of drilling	$ 153
Capitalized Exploratory Well Cost, Period Increase (Decrease)	(128)
Angola Assets [Member]
Total Deferred Exploratory Well Costs [Abstract]
Capitalized Exploratory Well Cost, Period Increase (Decrease)	(153)
ShenandoahGoM [Member]
Total Deferred Exploratory Well Costs [Abstract]
Capitalized Exploratory Well Cost, Period Increase (Decrease)	51
BoylaNorway [Member]
Total Deferred Exploratory Well Costs [Abstract]
Capitalized Exploratory Well Cost, Period Increase (Decrease)	$ (26)