Computation of Earnings Per Share (Detail) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended			9 Months Ended	12 Months Ended						9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended									9 Months Ended	12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Sep. 30, 2010 Continental Airlines Inc Predecessor	Dec. 31, 2012 UAL 6% Senior Convertible Notes	Dec. 31, 2011 UAL 6% Senior Convertible Notes	Dec. 31, 2010 UAL 6% Senior Convertible Notes	Dec. 31, 2012 Continental 4.5% Convertible Notes	Dec. 31, 2011 Continental 4.5% Convertible Notes	Dec. 31, 2010 Continental 4.5% Convertible Notes	Sep. 30, 2010 Continental 4.5% Convertible Notes Continental Airlines Inc Predecessor	Dec. 31, 2010 Continental 5% Convertible Notes	Sep. 30, 2010 Continental 5% Convertible Notes Continental Airlines Inc Predecessor	Dec. 31, 2012 UAL 4.5% Senior Limited-Subordination Convertible Notes	Dec. 31, 2011 UAL 4.5% Senior Limited-Subordination Convertible Notes	Dec. 31, 2010 UAL 4.5% Senior Limited-Subordination Convertible Notes	Dec. 31, 2012 Stock Options	Dec. 31, 2011 Stock Options	Dec. 31, 2010 Stock Options	Dec. 31, 2012 Continental 6% Convertible Junior Subordinated Debentures	Dec. 31, 2011 Continental 6% Convertible Junior Subordinated Debentures	Dec. 31, 2010 Continental 6% Convertible Junior Subordinated Debentures	Sep. 30, 2010 Continental 6% Convertible Junior Subordinated Debentures Continental Airlines Inc Predecessor	Dec. 31, 2012 Restricted Stock	Dec. 31, 2011 Restricted Stock	Dec. 31, 2010 UAL 5% Senior Convertible Notes
Basic earnings (loss) per share:
Net income (loss)	$ (620)	$ 6	$ 339	$ (448)	$ (138)	$ 653	$ 538	$ (213)	$ (723)	$ 840	$ 253	$ 441
Less: Income allocable to participating securities										(3)	(1)
Earnings (loss) available to common stockholders									(723)	837	252	441
Basic weighted-average shares outstanding									331	329	207	140
Earnings (loss) per share, basic	$ (1.87)	$ 0.02	$ 1.02	$ (1.36)	$ (0.42)	$ 1.97	$ 1.63	$ (0.65)	$ (2.18)	$ 2.54	$ 1.22	$ 3.16
Diluted earnings (loss) per share:
Earnings (loss) available to common stockholders									(723)	837	252	441
Effect of convertible notes on diluted earnings per share, amount														18	18		9	2	7	1	10										10
Earnings (loss) available to common stockholders including the effect of dilutive securities									$ (723)	$ 864	$ 273	$ 468
Basic weighted-average shares outstanding									331	329	207	140
Effect of convertible notes on diluted earnings per share, shares														40	40		12	3	12	1	9										4
Effect of employee stock options										2	2	2
Diluted weighted-average shares outstanding									331	383	253	167
Earnings (loss) per share, diluted	$ (1.87)	$ 0.02	$ 0.89	$ (1.36)	$ (0.42)	$ 1.69	$ 1.39	$ (0.65)	$ (2.18)	$ 2.26	$ 1.08	$ 2.81
Potentially dilutive shares excluded from diluted per share amounts:
Potentially dilutive shares excluded from diluted per share amounts									66	21	35		40			12						5	11	22	4	5	9	4	4	1		1	1	3