Financial Derivative Instruments (Details 2)																9 Months Ended	12 Months Ended	9 Months Ended
	May 31, 2013 Enhanced Equipment Trust Certificates (EETC) USD ($) item	Sep. 30, 2013 Derivatives designated as hedging instruments Interest rate derivatives USD ($)	Sep. 30, 2013 Derivatives designated as hedging instruments Interest rate derivatives Prepaid expenses and other USD ($)	Sep. 30, 2013 Derivatives designated as hedging instruments Interest rate derivatives Long-term prepayments and other USD ($)	Sep. 30, 2013 Derivatives designated as hedging instruments Foreign currency derivatives Prepaid expenses and other USD ($)	Sep. 30, 2013 Derivatives designated as hedging instruments Foreign currency derivatives Other liabilities and deferred credits USD ($)	Sep. 30, 2013 Derivatives designated as hedging instruments Foreign currency derivatives Japanese yen Prepaid expenses and other JPY (¥)	Sep. 30, 2013 Derivatives designated as hedging instruments Foreign currency derivatives Japanese yen Other liabilities and deferred credits JPY (¥)	Sep. 30, 2013 Derivatives designated as hedging instruments Foreign currency derivatives Korean Won Prepaid expenses and other KRW	Sep. 30, 2013 Derivatives designated as hedging instruments Foreign currency derivatives Australian dollar Prepaid expenses and other AUD	Sep. 30, 2013 Derivatives designated as hedging instruments Foreign currency derivatives Australian dollar Other liabilities and deferred credits AUD	Sep. 30, 2013 Derivatives designated as hedging instruments Foreign currency derivatives New Zealand Dollars Prepaid expenses and other NZD	Sep. 30, 2013 Derivatives not designated as hedging instruments Foreign currency derivatives Prepaid expenses and other USD ($)	Sep. 30, 2013 Derivatives not designated as hedging instruments Foreign currency derivatives Japanese yen Prepaid expenses and other JPY (¥)	Sep. 30, 2013 Derivatives not designated as hedging instruments Foreign currency derivatives Australian dollar Prepaid expenses and other AUD	Sep. 30, 2013 Derivatives not designated as hedging instruments Fuel derivative contracts Prepaid expenses and other USD ($) gal	Dec. 31, 2012 Derivatives not designated as hedging instruments Fuel derivative contracts Prepaid expenses and other USD ($) gal	Sep. 30, 2013 Derivatives not designated as hedging instruments Fuel derivative contracts Long-term prepayments and other USD ($) gal	Sep. 30, 2013 Derivatives not designated as hedging instruments Negative arbitrage derivative USD ($)	Sep. 30, 2013 Derivatives not designated as hedging instruments Negative arbitrage derivative Other accrued liabilities USD ($)	Sep. 30, 2013 Derivatives not designated as hedging instruments Negative arbitrage derivative Other liabilities and deferred credits USD ($)
Fair Value of Derivatives
Number of pass-through trusts	2
Aggregate principal amount issued	$ 444,500,000
Notional Amount		67,000,000					12,036,740,000	1,713,861,000	9,144,358,000	71,051,000	13,204,000	8,689,000		6,180,000	58,000				444,540,000
Notional Amount																91,350,000	126,924,000	9,240,000
Gross fair value of assets, current			82,000		4,372,000								426,000			5,573,000	13,094,000
Gross fair value of assets, noncurrent				375,000		58,000												1,144,000
Gross fair value of liabilities, current					(2,204,000)								(274,000)			(589,000)	(397,000)			(12,250,000)
Gross fair value of liabilities, noncurrent						(197,000)												(147,000)			(615,000)
Net derivative position			$ 82,000	$ 375,000	$ 2,168,000	$ (139,000)							$ 152,000			$ 4,984,000	$ 12,697,000	$ 997,000		$ (12,250,000)	$ (615,000)