Litigation (Details) (USD $)	36 Months Ended	0 Months Ended		1 Months Ended		3 Months Ended	0 Months Ended
	Dec. 31, 1993 breach	Aug. 03, 2012	Feb. 14, 2011	Sep. 30, 2010	Aug. 31, 2010	Mar. 31, 2015 LegalMatter	Jul. 02, 2013	Nov. 13, 2013	Nov. 06, 2012	Jan. 03, 2012	Dec. 31, 2008
Loss Contingencies [Line Items]
Number of contract breaches	7
MTBE [Member] | Pending Litigation [Member]
Loss Contingencies [Line Items]
Pending lawsuits and claims (in number of claims)						7
Ecuador [Member] | Pending Litigation [Member]
Loss Contingencies [Line Items]
Pending lawsuits and claims (in number of claims)						9
Conducted remediation program (in years)						3 years
Remediation program						$ 40,000,000
Financial compensation for purported damages on mining engineer's report											18,900,000,000
Assessment for purported unjust enrichment on mining engineer's report											8,400,000,000
Court order requiring the parties to provide their positions on damages within (in days)					45 days
Approximate damages on plaintiffs' submission, Minimum				16,000,000,000
Approximate damages on plaintiffs' submission, Maximum				76,000,000,000
Approximate unjust enrichment on plaintiffs' submission, Minimum				5,000,000,000
Approximate unjust enrichment on plaintiffs' submission, Maximum				38,000,000,000
Amount assessed in damages			8,600,000,000					9,500,000,000
Amount assessed for plaintiffs representatives			900,000,000
Additional amount assessed in punitive damages			8,600,000,000
Public apology date within judgment/clarification ruling (in days)			15 days
Proposed additional payment for plaintiff attorney fees as percentage of judgment										0.10%
Litigation settlement, amount		19,100,000,000
Percentage of payments withheld by third parties due to freeze order									40.00%
Percentage of funds wIthheld by banks due to freeze order									40.00%
Embargo Order [Member] | Ecuador [Member]
Loss Contingencies [Line Items]
Litigation settlement, amount							$ 96,000,000
Declatory Relief Claim [Member] | Ecuador [Member] | Pending Litigation [Member]
Loss Contingencies [Line Items]
Pending lawsuits and claims (in number of claims)						1
Discovery Stay On Claims [Member] | Ecuador [Member] | Pending Litigation [Member]
Loss Contingencies [Line Items]
Pending lawsuits and claims (in number of claims)						8