Financial Instruments and Fair Value Measurements - Additional Information (Detail) (USD $) In Millions, unless otherwise specified					6 Months Ended						6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013 6% convertible junior subordinated debentures due 2030	Jun. 30, 2013 Four Point Five Percent Convertible Notes Due Two Thousand Fifteen	Jun. 30, 2013 Auction Rate Securities	Jun. 30, 2013 Auction Rate Securities Minimum	Jun. 30, 2013 Auction Rate Securities Maximum	Jun. 30, 2013 EETC	Jun. 30, 2013 United Airlines, Inc.	Jun. 30, 2012 United Airlines, Inc.	Jun. 30, 2013 United Airlines, Inc. Auction Rate Securities Minimum	Jun. 30, 2013 United Airlines, Inc. Auction Rate Securities Maximum	Jun. 30, 2013 United Airlines, Inc. EETC	Jun. 30, 2013 United Airlines, Inc. Asset-backed Securities Minimum	Jun. 30, 2013 United Airlines, Inc. Asset-backed Securities Maximum	Jun. 30, 2013 United Airlines, Inc. Corporate Debt Minimum	Jun. 30, 2013 United Airlines, Inc. Corporate Debt Maximum
Fair Value [Line Items]
Available for sale investment, maturity date													2019
Available for sale investment, maturity year											1 year	33 years		1 year	42 years	1 year	22 years
Aggregate principal amount issued					$ 125
Available for sale investment, interest rates reset interval					28 days	7 days	35 days
Investment securities, unrealized gains (losses)								$ 3
Debt instrument convertible stated interest rate	8.00%	8.00%	6.00%	4.50%					8.00%	8.00%
Debt instrument maturity year			2030	2015