Financial Instruments and Concentrations of Risk (Details 2)	12 Months Ended
	Dec. 31, 2013 bbl	Dec. 31, 2012 bbl
Sales [Member]
Derivative, Nonmonetary Notional Amount, Volume	2,595,000	1,743,000
Purchases [Member]
Derivative, Nonmonetary Notional Amount, Volume	2,575,000	1,636,000