Schedule of Gains (Losses) on Derivative Instruments (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2012 Designated as Hedging Instrument Cash Flow Hedging	Dec. 31, 2011 Designated as Hedging Instrument Cash Flow Hedging	Dec. 31, 2012 Not Designated as Hedging Instrument	Dec. 31, 2010 Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in AOCI on Derivatives (Effective Portion)	$ (51)	$ 163
Gain (Loss) Reclassified from AOCI into Income (Fuel Expense) (Effective Portion)	(141)	503
Amount of Gain (Loss) Recognized in Income (Nonoperating Expense) (Ineffective Portion)	(1)	(59)
Aircraft Fuel Gain (Loss)				(35)
Nonoperating Income (Expense)			38
Total Gain (Loss)			$ 38	$ (35)

The effective portion of net gain (loss) reclassified from accumulated other comprehensive income into income on derivative instruments designated and qualifying as hedging instruments.

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The portion of gains and losses (net) on derivative instruments designated and qualifying as hedging instruments representing (a) the amount of the hedge ineffectiveness and (b) the amount, if any, excluded from the assessment of hedge effectiveness.

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- Definition

The amount of net gains and losses recognized in income during the period on derivative instruments designated and qualifying as hedging instruments in fair value hedges and related hedged items designated and qualifying in fair value hedges, on derivative instruments designated and qualifying as hedging instruments in cash flow hedges, and on derivative instruments not designated as hedging instruments.

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- Definition

The effective portion of gains and losses (net) on derivative instruments designated and qualifying as hedging instruments that was recognized in other comprehensive income during the current period.

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