Derivative Financial Instruments (Schedule Of Forward Purchase And Sales Contracts) (Details) (Forward Contracts [Member], USD $) In Millions, unless otherwise specified	Mar. 31, 2012
Forward Contracts [Member]
Derivative [Line Items]
Forward purchase contracts, Amount	$ 55.3
Forward purchase contracts, Barrels	600,000
Forward sales contracts, Amount	$ 44.4
Forward sales contracts, Barrels	300,000