Derivative Financial Instruments (Schedule Of NYMEX Contracts And Butane Price Swap Purchase Agreements) (Details)	Mar. 31, 2014 bbl
Fair Value Hedging [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	700,000
Economic Hedges [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	2,200,000
Economic Hedges Futures [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	100,000