Share-Based Compensation Plans - Additional Information (Detail) (USD $) In Millions, except Share data in Thousands, unless otherwise specified	1 Months Ended		3 Months Ended	12 Months Ended																		1 Months Ended	12 Months Ended						1 Months Ended	12 Months Ended						1 Months Ended	12 Months Ended			9 Months Ended	12 Months Ended		9 Months Ended						3 Months Ended	12 Months Ended
	Sep. 30, 2010	May 31, 2010	Dec. 31, 2010	Dec. 31, 2012 D		Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2012 Stock Options		Dec. 31, 2011 Stock Options		Dec. 31, 2010 Stock Options		Dec. 31, 2012 Stock Options Minimum	Dec. 31, 2012 Stock Options Maximum	Dec. 31, 2012 Restricted Stock and Restricted Stock Units	Dec. 31, 2011 Restricted Stock and Restricted Stock Units	Dec. 31, 2010 Restricted Stock and Restricted Stock Units	Dec. 31, 2012 Profit Based RSU Awards	Feb. 29, 2012 Restricted Stock	Dec. 31, 2012 Restricted Stock		Dec. 31, 2011 Restricted Stock		Dec. 31, 2010 Restricted Stock		Feb. 29, 2012 Restricted Stock Units	Dec. 31, 2012 Restricted Stock Units		Dec. 31, 2011 Restricted Stock Units		Dec. 31, 2010 Restricted Stock Units		Feb. 29, 2012 Performance Shares	Dec. 31, 2012 Continental Airlines Inc Restricted Stock Units	Dec. 31, 2011 Continental Airlines Inc Restricted Stock Units	Dec. 31, 2010 Continental Airlines Inc Restricted Stock Units	Sep. 30, 2010 Continental Airlines Inc Predecessor	Dec. 31, 2012 Continental Airlines Inc Predecessor	Dec. 31, 2010 Continental Airlines Inc Predecessor	Sep. 30, 2010 Continental Airlines Inc Predecessor Pilot Supplemental Option Plan Twenty Zero Five	Sep. 30, 2010 Continental Airlines Inc Predecessor Broad Based Employee Stock Option Plan Twenty Zero Five	Sep. 30, 2010 Continental Airlines Inc Predecessor Minimum Pilot Supplemental Option Plan Twenty Zero Five	Sep. 30, 2010 Continental Airlines Inc Predecessor Maximum Pilot Supplemental Option Plan Twenty Zero Five	Sep. 30, 2010 Continental Airlines Inc Predecessor Employee Stock Option	Sep. 30, 2010 Continental Airlines Inc Predecessor Non Employee Director Stock Option	Dec. 31, 2010 United Air Lines Inc	Dec. 31, 2012 United Air Lines Inc	Dec. 31, 2011 United Air Lines Inc	Dec. 31, 2010 United Air Lines Inc	Dec. 31, 2012 United Air Lines Inc Restricted Stock Units	Dec. 31, 2011 United Air Lines Inc Restricted Stock Units	Dec. 31, 2010 United Air Lines Inc Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of days used to compute performance period average closing price of restricted stock units				20
Share-Based Compensation, award granted																						500	545		536		212		600	1,986		3,655		1,395		1,300
Share-Based Compensation, vesting period																3 years	4 years					3 years							3 years							3 years					3 years		3 years	3 years			4 years
Share-Based Compensation, vesting date																																				Dec. 31, 2014
Equity awards conversion rate																																									1.05
Equity awards fair value																		$ 27	$ 7	$ 33																					$ 78
Equity awards payment percentage																																									150.00%
Closing price of common stock	$ 23.66	$ 22.33																																							$ 23.48
Cash settlements for restricted stock unit			19																											35		57		84			19	51	36										18				16	6	48
Stock options, contractual term, years										10 years																																		6 years	6 years	8 years	5 years	10 years
Dividend yield				0.00%																																					0.00%
Liability due to PBRSUs converted to fixed cash equivalent																														57							15																42
Share-based compensation expense				$ 57	[1],[2]	$ 54	[1],[2]	$ 117	[1],[2]	$ 1	[1],[2]	$ 5	[1],[2]	$ 7	[1],[2]								$ 13	[1],[2]	$ 12	[1],[2]	$ 6	[1],[2]		$ 37	[1],[2]	$ 18	[1],[2]	$ 20	[1],[2]					$ 57										$ 32	$ 28	$ 63
Employee profit sharing annual incremental period																					3 years

[1] All compensation cost is recorded to Salaries and related costs, with the exception of $9 million, $17 million and $70 million in 2012, 2011 and 2010, respectively, that was recorded in integration and Merger-related costs as a component of special charges, respectively.

[2] United recorded $32 million, $28 million and $63 million of compensation cost related to UAL's share-based plans during 2012, 2011 and 2010, respectively. These amounts included $5 million, $7 million and $24 million that were classified as integration and Merger-related costs as a component of special charges during 2012, 2011 and 2010, respectively. Continental Successor recorded $25 million, $26 million and $54 million of compensation cost related to UAL's share-based plans during 2012, 2011 and 2010, respectively. These amounts included $4 million, $10 million and $46 million that were classified as integration and Merger-related costs as a component of special charges during 2012, 2011 and 2010, respectively.