Litigation (Details) (USD $)		0 Months Ended	1 Months Ended		6 Months Ended					0 Months Ended
	Jun. 30, 2013 MTBE [Member] Pending Litigation [Member] LegalMatter	Aug. 03, 2012 Ecuador [Member] Pending Litigation [Member]	Sep. 30, 2010 Ecuador [Member] Pending Litigation [Member]	Aug. 31, 2010 Ecuador [Member] Pending Litigation [Member]	Jun. 30, 2013 Ecuador [Member] Pending Litigation [Member] LegalMatter	Nov. 06, 2012 Ecuador [Member] Pending Litigation [Member]	Jan. 03, 2012 Ecuador [Member] Pending Litigation [Member]	Feb. 14, 2011 Ecuador [Member] Pending Litigation [Member]	Dec. 31, 2008 Ecuador [Member] Pending Litigation [Member]	Jul. 02, 2013 Embargo Order [Member] Ecuador [Member] Subsequent Event [Member]	Jun. 30, 2013 Declatory Relief Claim [Member] Ecuador [Member] Pending Litigation [Member] LegalMatter	Jun. 30, 2013 Discovery Stay On Claims [Member] Ecuador [Member] Pending Litigation [Member] LegalMatter
Loss Contingencies [Line Items]
Pending lawsuits and claims (in number of claims)	9				9						1	8
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
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								$ 96,000,000
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%