Quarterly Financial Data (Unaudited) (Details 1) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011
Quarterly Financial Information, Quarterly Charges and Credits, Amount Affecting Comparability	$ (231)	$ 279	$ (754)	$ 163	$ 46	$ (216)	$ (168)	$ 2
Employee Severance [Member]
Quarterly Financial Information, Quarterly Charges and Credits, Amount Affecting Comparability	0	(66)	(171)	0	(52)	(3)	(80)	0
Facilities and Fleet [Member]
Quarterly Financial Information, Quarterly Charges and Credits, Amount Affecting Comparability	(122)	(122)	(22)	(27)	(29)	0	(64)	(7)
Gain on slot exchange and divestiture [Member]
Quarterly Financial Information, Quarterly Charges and Credits, Amount Affecting Comparability	0	39	0	39	43	0	0	0
Impairment of Intangible Assets [Member]
Quarterly Financial Information, Quarterly Charges and Credits, Amount Affecting Comparability					(50)	0	0	0
Loss on extingushment of debt [Member]
Quarterly Financial Information, Quarterly Charges and Credits, Amount Affecting Comparability	(106)	(12)	0	0	(30)	(5)	(13)	(20)
Gain (Loss) on Derivatives [Member]
Quarterly Financial Information, Quarterly Charges and Credits, Amount Affecting Comparability	$ (3)	$ 440	$ (561)	$ 151	$ 164	$ (208)	$ (11)	$ 29