One-Time Adjustment to Decrease Frequent Flyer Deferred Revenue and Increase Special Revenue (Detail) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2011
Special Charges [Line Items]
Special revenue item	$ 107
United Continental Holdings Inc
Special Charges [Line Items]
Special revenue item	107
United Air Lines Inc
Special Charges [Line Items]
Special revenue item	88
Continental Airlines Inc
Special Charges [Line Items]
Special revenue item	$ 19