Derivatives (Narrative) (Details) In Millions, unless otherwise specified	3 Months Ended	9 Months Ended
	Sep. 30, 2013 CAD	Sep. 30, 2013 CAD	Sep. 30, 2013 Swap [Member] gal	Sep. 30, 2013 Swap [Member] Prepaid Expenses And Other Assets [Member] USD ($)	Dec. 31, 2012 Swap [Member] Prepaid Expenses And Other Assets [Member] USD ($)	Sep. 30, 2013 Swap [Member] Accrued Expenses And Other Liabilities [Member] USD ($)	Dec. 31, 2012 Swap [Member] Accrued Expenses And Other Liabilities [Member] USD ($)	Sep. 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)			7,300,000
Amount of forward contracts sold	155	336
Derivative asset (Less than $1 as of September 30, 2013 and December 31, 2012)				1	1
Derivative liability (Less than $1 as of September 30, 2013 and December 31, 2012)						1	1
Derivative accumulated other comprehensive income (Less than $1 as of September 30, 2013 and December 31, 2012)								$ 1	$ 1