Earnings (loss) Per Share - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	2 Months Ended	3 Months Ended
	Feb. 20, 2014	Mar. 31, 2014	Jun. 30, 2011
Computation Of Earnings Per Share Line Items
Aggregate principal amount of convertible senior notes exchanged		$ 202
United Airlines, Inc.
Computation Of Earnings Per Share Line Items
Aggregate principal amount of convertible senior notes exchanged		156
United Airlines, Inc. | Unsecured Debt
Computation Of Earnings Per Share Line Items
Common stock issued in exchange for convertible notes	5	5
Aggregate principal amount of convertible senior notes exchanged	156	156
Debt instrument, maturity date		2021
Debt instrument stated interest rate		4.50%	4.50%
Debt instrument conversion rate	30.6419	30.6419
6% Convertible Senior Notes
Computation Of Earnings Per Share Line Items
Common stock issued in exchange for convertible notes		5
Aggregate principal amount of convertible senior notes exchanged		$ 46
Debt instrument effective interest rate		6.00%
Debt instrument, maturity date		2029