Financial Instruments And Risk Management (Effect Of Derivative Instruments On Statements Of Operations) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012
Derivative Instruments, Gain (Loss) [Line Items]
Derivative instruments, gain (loss) recognized in income, net	$ (25)	[1]	$ (10)	[1]	$ (2)	[1]	$ 10	[1]
Amount of gain (loss) recognized in income, ineffectiveness	36	[2]	2	[2]	25	[2]	(3)	[2]
Fuel Derivative Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative instruments, gain (loss) reclassified from accumulated OCI into income, effective portion, net	$ (11)	[3]	$ (12)	[3]	$ (23)	[3]	$ 13	[3]

[1] Includes the effective and ineffective portion of hedge gain (loss)

[2] Includes the ineffective portion of hedge gain (loss)

[3] Includes the effective portion of hedge gain (loss)