Derivatives (Schedule Of Outstanding Derivatives Entered Into Hedge Inventory Or Fixed Price Purchase Commitments) (Details) (Not Designated As Hedging Instrument [Member], USD $)	Dec. 31, 2011
Selling Contracts [Member] | Crude Oil Futures [Member]
Derivative [Line Items]
Weighted average contract price per bbl	$ 96.16
Contract volumes (1,000 bbls)	$ 169
Selling Contracts [Member] | Heating Oil Futures [Member]
Derivative [Line Items]
Weighted average contract price per gal	$ 2.86
Contract volumes (1,000 bbls)	178
Selling Contracts [Member] | RBOB Gasoline Futures [Member]
Derivative [Line Items]
Weighted average contract price per gal	$ 2.66
Contract volumes (1,000 bbls)	15
Selling Contracts [Member] | Fuel Oil Futures [Member]
Derivative [Line Items]
Weighted average contract price per bbl	$ 93.73
Contract volumes (1,000 bbls)	489
Selling Contracts [Member] | Crude Oil Options [Member]
Derivative [Line Items]
Weighted average contract price per mmBtu	$ 2.05
Contract volumes (1,000 bbls)	355
Selling Contracts [Member] | Heating Oil Options [Member]
Derivative [Line Items]
Weighted average contract price per mmBtu	$ 0.09
Contract volumes (1,000 bbls)	30
Buying Contracts [Member] | Crude Oil Futures [Member]
Derivative [Line Items]
Weighted average contract price per bbl	$ 98.83
Contract volumes (1,000 bbls)	90
Buying Contracts [Member] | Heating Oil Futures [Member]
Derivative [Line Items]
Weighted average contract price per gal	$ 2.83
Contract volumes (1,000 bbls)	60
Buying Contracts [Member] | RBOB Gasoline Futures [Member]
Derivative [Line Items]
Weighted average contract price per gal
Contract volumes (1,000 bbls)
Buying Contracts [Member] | Fuel Oil Futures [Member]
Derivative [Line Items]
Weighted average contract price per bbl
Contract volumes (1,000 bbls)
Buying Contracts [Member] | Crude Oil Options [Member]
Derivative [Line Items]
Weighted average contract price per mmBtu	$ 0.56
Contract volumes (1,000 bbls)	75
Buying Contracts [Member] | Heating Oil Options [Member]
Derivative [Line Items]
Weighted average contract price per mmBtu
Contract volumes (1,000 bbls)