Components of Accumulated Other Comprehensive Income (loss), Net of Tax (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended								9 Months Ended	3 Months Ended		12 Months Ended		3 Months Ended	12 Months Ended						9 Months Ended	3 Months Ended	12 Months Ended		3 Months Ended	12 Months Ended						9 Months Ended	3 Months Ended	12 Months Ended		3 Months Ended			3 Months Ended				3 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 United Air Lines Inc	Dec. 31, 2011 United Air Lines Inc	Dec. 31, 2010 United Air Lines Inc	Dec. 31, 2012 Continental Airlines Inc	Dec. 31, 2011 Continental Airlines Inc	Sep. 30, 2010 Continental Airlines Inc Predecessor	Dec. 31, 2010 Continental Airlines Inc Successor		Dec. 31, 2012 Continental Airlines Inc Successor	Dec. 31, 2011 Continental Airlines Inc Successor	Dec. 31, 2010 Continental Airlines Inc Successor Accumulated Other Comprehensive Income (Loss)	Dec. 31, 2012 Accumulated Defined Benefit Plans Adjustment	Dec. 31, 2011 Accumulated Defined Benefit Plans Adjustment	Dec. 31, 2010 Accumulated Defined Benefit Plans Adjustment	Dec. 31, 2012 Accumulated Defined Benefit Plans Adjustment United Air Lines Inc	Dec. 31, 2011 Accumulated Defined Benefit Plans Adjustment United Air Lines Inc	Dec. 31, 2010 Accumulated Defined Benefit Plans Adjustment United Air Lines Inc	Sep. 30, 2010 Accumulated Defined Benefit Plans Adjustment Continental Airlines Inc Predecessor	Dec. 31, 2010 Accumulated Defined Benefit Plans Adjustment Continental Airlines Inc Successor	Dec. 31, 2012 Accumulated Defined Benefit Plans Adjustment Continental Airlines Inc Successor	Dec. 31, 2011 Accumulated Defined Benefit Plans Adjustment Continental Airlines Inc Successor	Dec. 31, 2010 Accumulated Defined Benefit Plans Adjustment Continental Airlines Inc Successor Accumulated Other Comprehensive Income (Loss)	Dec. 31, 2012 Accumulated Net Unrealized Investment Gain (Loss)	Dec. 31, 2011 Accumulated Net Unrealized Investment Gain (Loss)	Dec. 31, 2010 Accumulated Net Unrealized Investment Gain (Loss)	Dec. 31, 2012 Accumulated Net Unrealized Investment Gain (Loss) United Air Lines Inc	Dec. 31, 2011 Accumulated Net Unrealized Investment Gain (Loss) United Air Lines Inc	Dec. 31, 2010 Accumulated Net Unrealized Investment Gain (Loss) United Air Lines Inc	Sep. 30, 2010 Accumulated Net Unrealized Investment Gain (Loss) Continental Airlines Inc Predecessor	Dec. 31, 2010 Accumulated Net Unrealized Investment Gain (Loss) Continental Airlines Inc Successor	Dec. 31, 2012 Accumulated Net Unrealized Investment Gain (Loss) Continental Airlines Inc Successor	Dec. 31, 2011 Accumulated Net Unrealized Investment Gain (Loss) Continental Airlines Inc Successor	Dec. 31, 2010 Accumulated Net Unrealized Investment Gain (Loss) Continental Airlines Inc Successor Accumulated Other Comprehensive Income (Loss)	Sep. 30, 2010 Accumulated Tax on Other Comprehensive Income Continental Airlines Inc Predecessor	Dec. 31, 2009 Accumulated Tax on Other Comprehensive Income Continental Airlines Inc Predecessor	Dec. 31, 2010 Accumulated Tax on Other Comprehensive Income Continental Airlines Inc Successor		Dec. 31, 2012 Accumulated Tax on Other Comprehensive Income Continental Airlines Inc Successor	Dec. 31, 2011 Accumulated Tax on Other Comprehensive Income Continental Airlines Inc Successor	Dec. 31, 2010 Accumulated Tax on Other Comprehensive Income Continental Airlines Inc Successor Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income [Line Items]
Continental-Successor Company Elimination of accumulated other comprehensive income in connection with the Merger										$ (1,162)				$ 1,092											$ 1,193											$ (23)							$ (78)
Beginning Balance	(417)	387	35	(128)	91	35	(821)	(297)	(1,185)			(297)	290		(312)	152	57	(62)	(91)	57	(1,275)		(250)	243		(105)	235	(22)	(66)	182	(22)	12		(41)	53		78	78			(6)	(6)
Derivative financial instruments:
Reclassification of gains(losses) into earnings	141	(503)	68	76	(417)	84			24	(16)		65	(86)													141	(503)	68	76	(417)	84	24	(16)	65	(86)
Change in fair value of derivatives	(51)	163	168	(23)	172	101			(13)	67		(28)	(9)													(51)	163	168	(23)	172	101	(13)	67	(28)	(9)
Change in fair value of other financial instruments	11		21	7	(3)	19				2		5	1													11		21	7	(3)	19		2	5	1
Employee benefit plans:
Reclassification of unrecognized net actuarial gains(losses) into earnings	17	(24)	(12)	(5)	(2)	(12)			62			22	(22)		17	(24)	(12)	(5)	(2)	(12)	62		22	(22)
Reclassification of prior service cost into earnings									23												23
Current year actuarial gains(losses)	(747)	(440)	107	(159)	31	(136)			(3)	243		(588)	(471)		(747)	(440)	107	(159)	31	(136)	(3)	243	(588)	(471)
Income tax expense on other comprehensive income										(6)	[1]																												(6)	[1]
Ending Balance	$ (1,046)	$ (417)	$ 387	$ (232)	$ (128)	$ 91	$ (821)	$ (297)	$ (1,092)	$ 290		$ (821)	$ (297)		$ (1,042)	$ (312)	$ 152	$ (226)	$ (62)	$ (91)	$ (1,193)	$ 243	$ (816)	$ (250)		$ (4)	$ (105)	$ 235	$ (6)	$ (66)	$ 182	$ 23	$ 53	$ 1	$ (41)		$ 78	$ 78	$ (6)		$ (6)	$ (6)

[1] Taxes on other comprehensive income did not impact Continental's net deferred tax position due to an offsetting tax benefit on the loss from continuing operations as described in Note 8.