Debt - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	1 Months Ended	9 Months Ended		6 Months Ended		9 Months Ended		12 Months Ended	9 Months Ended				9 Months Ended		1 Months Ended
	Aug. 31, 2012	Sep. 30, 2012	Sep. 30, 2011	Jun. 30, 2012 UAL 8% Contingent Senior Notes	Jun. 30, 2011 UAL 8% Contingent Senior Notes	Sep. 30, 2012 UAL 8% Contingent Senior Notes	Sep. 30, 2011 UAL 8% Contingent Senior Notes	Dec. 31, 2011 UAL 8% Contingent Senior Notes	Sep. 30, 2012 Continental Airlines Inc	Sep. 30, 2011 Continental Airlines Inc	Oct. 31, 2012 Continental Airlines Inc Class A Pass Through Certificates Subsequent Event	Oct. 31, 2012 Continental Airlines Inc Class B Pass Through Certificates Subsequent Event	Sep. 30, 2012 Continental Airlines Inc Class A Pass Through Certificates and Class B Pass Through Certificates	Mar. 31, 2012 Continental Airlines Inc Class A Pass Through Certificates and Class B Pass Through Certificates	Oct. 31, 2012 Continental Airlines Inc Class A Pass Through Certificates and Class B Pass Through Certificates Subsequent Event
Debt Instrument [Line Items]
Aggregate principal amount trusts issued											$ 712	$ 132		$ 892
Proceeds from issuance of long-term debt		86	142						86	142			577		844
Debt instrument stated interest rate											4.00%	5.50%
UAL's obligation to issue notes to the PBGC, principal						500
Debt instrument convertible effective interest rate				8.00%	8.00%	8.00%	8.00%	8.00%
Issuance of senior notes equal tranches				62.5				62.5
Number of tranches issued				1	1			2
Present value of obligation recorded as liability				48	49			88
Special facility revenue bonds	101
Defeasance funds	$ 100