Property, Plant and Equipment (Details 2) (USD $) In Millions	9 Months Ended
	Sep. 30, 2011
Total Deferred Exploratory Well Costs [Abstract]
Amounts capitalized greater than one year after completion of drilling	$ 390
Increase decrease in capitalized exploratory well costs greater than one year [Line Items]
Change in exploratory well costs capitalized greater than one year	67
Norway Project [Member]
Increase decrease in capitalized exploratory well costs greater than one year [Line Items]
Change in exploratory well costs capitalized greater than one year	(26)
Innsbruckprospect [Member]
Increase decrease in capitalized exploratory well costs greater than one year [Line Items]
Change in exploratory well costs capitalized greater than one year	$ 88