Leases (Narrative) (Details) (USD $)	12 Months Ended								3 Months Ended
	Dec. 31, 2012		Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 Revenue Bonds [Member]	Dec. 31, 2012 Boeing 737-800 NG Aircraft [Member]	Dec. 31, 2010 Boeing 737-800 NG Aircraft [Member]	Dec. 31, 2012 Boeing 777-300 ER Aircraft [Member]	Mar. 31, 2011 Aircraft And Gates [Member]	Dec. 31, 2012 Jet Aircraft [Member]	Dec. 31, 2012 Turboprop Aircraft [Member]	Dec. 31, 2012 Containing Mandatory Tender Provisions [Member] Revenue Bonds [Member]	Dec. 31, 2012 Liabilities Subject to Compromise [Member]	Dec. 31, 2012 Accrued liabilities and other liabilities and deferred credits [Member]
Operating Leased Assets [Line Items]
Capital Leases, Future Minimum Payments, Present Value of Net Minimum Payments	$ 431,000,000	[1]											$ 19,000,000
Deferred Rent Credit													201,000,000	160,000,000
Number of Aircraft Included in Sale-Leaseback Arrangement						26		1
Number of aircraft committed to operating leases										215	9
Number of aircraft committed to capital leases										33
Special Facility Revenue Bond Claims Expected to Be Treated as General Unsecured Claims	1,100,000,000
Number of aircrafts deliveries under sale leaseback transactions						30	36	2
Non Recurring Charges Under Sale Leaseback Transaction									31,000,000
Special facility revenue bonds					486,000,000
Operating lease future payments to repurchase bonds					822,000,000
Operating Leases, rent expense	1,400,000,000		1,600,000,000	1,500,000,000
Number of aircraft operating leased under trusts	19
Operating leases future minimum payments due leased under trusts	98,000,000
Operating Leases, Future Minimum Payments, Due in Two Years	$ 962,000,000											$ 112,000,000

[1] (1)As of December 31, 2012, included in Liabilities Subject to Compromise on the accompanying consolidated balance sheet is approximately $19 million relating to ground capital leases.