Debt - Additional Information (Detail) (USD $) Share data in Millions, unless otherwise specified	6 Months Ended		0 Months Ended		0 Months Ended			0 Months Ended	1 Months Ended	3 Months Ended			3 Months Ended	6 Months Ended	1 Months Ended	2 Months Ended	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Mar. 27, 2013 Term Loan Facility	Jun. 30, 2014 Term Loan Facility	Mar. 27, 2013 Revolving Credit Facility	Jun. 30, 2014 Revolving Credit Facility	Jun. 30, 2014 Interest Rate Floor Term Loan Facility	Mar. 27, 2013 LIBOR Term Loan Facility	Jun. 30, 2014 LIBOR Term Loan Facility	Mar. 31, 2014 6% Convertible Senior Notes	Jun. 30, 2014 6% Convertible Senior Notes	Jan. 17, 2014 8% notes due 2024	Jun. 30, 2014 4.5% Convertible Notes Due 2015	Jun. 30, 2014 United Airlines, Inc.	Jun. 30, 2011 United Airlines, Inc. Unsecured Debt	Feb. 20, 2014 United Airlines, Inc. Unsecured Debt	Jun. 30, 2014 United Airlines, Inc. Unsecured Debt
Debt Instrument [Line Items]
Debt purchased and retired													$ 28,000,000
Outstanding balance of debt instrument											58,000,000		202,000,000
Debt instrument stated interest rate							0.75%			6.00%			4.50%		4.50%		4.50%
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								46,000,000				156,000,000		156,000,000	156,000,000
Debt instrument maturity year										2029			2015				2021
Aggregate principal amount of debt redeemed												400,000,000
Repurchased debt															570,000,000
Aggregate principal amount															726,000,000
Debt instrument conversion rate																30.6419	30.6419
Credit Agreement			900,000,000		1,000,000,000
Debt instrument maturity date			Apr. 01, 2019		Apr. 01, 2018
Available under revolving credit facility						1,000,000,000
Credit agreement refinanced				$ 893,000,000
Debt instrument, basis spread on variable rate								3.00%	2.75%