Commitments and Contingencies - Additional Information (Detail) (USD $)	1 Months Ended	9 Months Ended	12 Months Ended			1 Months Ended
	Apr. 30, 2013	Sep. 30, 2013	Dec. 31, 2012 Aircraft	Sep. 30, 2013 United Airlines, Inc. Employee	Sep. 30, 2013 Tax-exempt special facilities revenue bonds	Apr. 30, 2013 Embraer EMB175 aircraft Aircraft	Sep. 30, 2013 Floating Rate Debt	Sep. 30, 2013 Fixed Rate Debt	Sep. 30, 2013 Loans And Leases From Non U S Entities	Sep. 30, 2013 Capital Addition Purchase Commitments Boeing 737-900ER AirCraft Aircraft	Sep. 30, 2013 Capital Addition Purchase Commitments Boeing 737-900ER AirCraft United Airlines, Inc. Aircraft	Sep. 30, 2013 Capital Addition Purchase Commitments Boeing 787-8 United Airlines, Inc. Aircraft	Sep. 30, 2013 Capital Addition Purchase Commitments Embraer EMB175 aircraft United Airlines, Inc. Aircraft	Sep. 30, 2013 Capital Addition Purchase Commitments Boeing 737 MAX 9 Aircraft United Airlines, Inc. Aircraft	Sep. 30, 2013 Capital Addition Purchase Commitments EETC Boeing 737-900ER AirCraft Aircraft	Sep. 30, 2013 Capital Addition Purchase Commitments EETC Boeing 787-8 Aircraft	Sep. 30, 2013 Capital Addition Purchase Commitments Notes Payable to Banks Boeing 737-900ER AirCraft Aircraft	Oct. 23, 2013 Capital Addition Purchase Commitments Subsequent Event Boeing 737 MAX 9 Aircraft United Airlines, Inc. Aircraft	Sep. 30, 2013 Revolving Credit Facility	Mar. 27, 2013 Revolving Credit Facility	Sep. 30, 2013 Maximum Y	Sep. 30, 2013 Maximum Tax-exempt special facilities revenue bonds	Apr. 30, 2013 Maximum Embraer EMB175 aircraft	Sep. 30, 2013 Maximum Loans And Leases From Non U S Entities Y	Sep. 30, 2013 Maximum Capital Addition Purchase Commitments United Airlines, Inc.	Sep. 30, 2013 Minimum Tax-exempt special facilities revenue bonds	Apr. 30, 2013 Minimum Embraer EMB175 aircraft	Sep. 30, 2013 Minimum Capital Addition Purchase Commitments United Airlines, Inc.
Commitments and Contingencies [Line Items]
New aircraft, scheduled delivery date																							2015		2025		2014	2013
Number of aircraft expected to be delivered											6	1
Number of new aircraft committed to purchase						30							30	100				100
Number of aircraft under financing arrangement expected to be delivered															18	1	1
Number of aircraft under financing arrangement expected to be delivered during the reminder of 2013										5
Number of aircraft to be operated			133			30
Lease extension signed with the Port Authority of New York and New Jersey	20 years
Commitment to invest an additional amount in facility upgrades	$ 150,000,000
Guarantor obligations, maximum exposure					1,900,000,000
Operating leases obligations					1,600,000,000
Capital leases obligations					262,000,000
Debt instrument, maturity year																						2038				2015
Debt instrument principal amount							2,000,000,000	296,000,000	2,300,000,000
Debt instrument, remaining terms (years)																					12			12
Borrowing capacity under revolving credit facility																				1,000,000,000
Capacity available under the revolving credit facility																			$ 1,000,000,000
Number of employees				88,000
Percentage of employees represented by various U.S. labor organizations		80.00%