Earnings Per Share - Additional Information (Detail) (USD $) Share data in Millions, unless otherwise specified	6 Months Ended			6 Months Ended	2 Months Ended	6 Months Ended		3 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jul. 24, 2014 Subsequent Event	Jun. 30, 2014 United Airlines, Inc.	Feb. 20, 2014 United Airlines, Inc. Unsecured Debt	Jun. 30, 2014 United Airlines, Inc. Unsecured Debt	Jun. 30, 2011 United Airlines, Inc. Unsecured Debt	Mar. 31, 2014 6% Convertible Senior Notes	Jun. 30, 2014 4.5% Convertible Notes Due 2015
Computation Of Earnings Per Share Line Items
Debt purchased and retired									$ 28,000,000
Debt instrument convertible stated interest rate						4.50%	4.50%	6.00%	4.50%
Debt instrument maturity year						2021		2029	2015
Common stock issued in exchange for convertible notes					5	5		5
Aggregate principal amount of convertible senior notes exchanged	202,000,000	189,000,000		156,000,000	156,000,000	156,000,000		46,000,000
Debt instrument conversion rate					30.6419	30.6419
Share repurchase program authorized amount	1,000,000,000
Agreement to repurchase through an accelerated share share repurchase program			$ 200,000,000