Fair Value Measurements (Details 1) (Derivative Financial Instruments, Assets [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2009
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value Period Start	$ (1,091)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)	1,230
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value Period End	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases, Sales, Issuances, Settlements	1,199
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3	(106)	[1]
Aircraft Fuel and Related Taxes [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	(1,263)
Other (Expense) Income [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	$ 31

[1] During 2009, we implemented systems that better provide for the evaluation of certain inputs against market data. As a result, we reclassified our option contracts to Level 2.