Financial Instruments And Risk Management (Narrative) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Number of barrels of jet fuel derivative contracts outstanding	16,000,000		16,000,000
Fuel derivative maturity in months	12		12
Derivatives, Fair Value [Line Items]
Collateral Already Posted, Aggregate Fair Value	$ 2		$ 2
Derivative Instruments, Gain (Loss) Recognized in Income, Net	9	31	10	268
Price Risk Cash Flow Hedge Derivative, at Fair Value, Net	97		97		80
Derivative Instruments, Gain (Loss) Reclassification from Accumulated OCI to Income, Estimate of Time to Transfer			12
Derivative Instruments, Gain (Loss) Reclassification from Accumulated OCI to Income, Estimated Net Amount to be Transferred			$ (47)