Derivatives (Narrative) (Details) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2013 CAD	Jun. 30, 2013 Swap [Member] gal	Jun. 30, 2013 Swap [Member] Prepaid Expenses And Other Assets [Member] USD ($)	Dec. 31, 2012 Swap [Member] Prepaid Expenses And Other Assets [Member] USD ($)	Jun. 30, 2013 Swap [Member] Accrued Expenses And Other Liabilities [Member] USD ($)	Dec. 31, 2012 Swap [Member] Accrued Expenses And Other Liabilities [Member] USD ($)	Jun. 30, 2013 Swap [Member] Accumulated Other Comprehensive Income [Member] USD ($)	Dec. 31, 2012 Swap [Member] Accumulated Other Comprehensive Income [Member] USD ($)
Derivative [Line Items]
Fixed price swap contract (in gallons)		8,800,000
Amount of forward contracts sold	181
Derivative asset (Less than $1 as of June 30, 2013 and December 31, 2012)			1	1
Derivative liability (Less than $1 as of June 30, 2013 and December 31, 2012)					1	1
Derivative accumulated other comprehensive income (Less than $1 as of June 30, 2013 and December 31, 2012)							$ 1	$ 1