Derivative Instruments (Narrative) (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2013
Foreign Currency Derivatives [Member]
Derivative [Line Items]
Notional amounts of foreign currency derivatives	$ 240.0
Refined Oil Products [Member] | Commodity Derivative Contracts [Member]
Derivative [Line Items]
Outstanding derivative swap contracts	$ 31.4
Minimum [Member] | Foreign Currency Derivatives [Member]
Derivative [Line Items]
Derivative maturities	July 2013
Minimum [Member] | Commodity Derivative Contracts [Member]
Derivative [Line Items]
Derivative maturities	July 2013
Maximum [Member] | Foreign Currency Derivatives [Member]
Derivative [Line Items]
Derivative maturities	March 2014
Maximum [Member] | Commodity Derivative Contracts [Member]
Derivative [Line Items]
Derivative maturities	November 2013