Commitments and Contingencies - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2013 United Airlines, Inc. Employee	Mar. 31, 2013 Floating Rate Debt	Mar. 31, 2013 Notes payable, fixed interest rates of 4.00% to 12.00% (weighted average rate of 6.96% as of December 31, 2012), payable through 2024	Mar. 31, 2013 Loans And Leases From Non U S Entities	Mar. 31, 2013 Tax-exempt special facilities revenue bonds	Mar. 31, 2013 Capital Addition Purchase Commitments United Airlines, Inc. AirCraft	Mar. 31, 2013 Capital Addition Purchase Commitments Boeing 737 AirCraft	Mar. 31, 2013 Capital Addition Purchase Commitments Boeing 737 United Airlines, Inc. AirCraft	Mar. 31, 2013 Capital Addition Purchase Commitments 787 Boeing AirCraft AirCraft	Mar. 31, 2013 Capital Addition Purchase Commitments 787 Boeing AirCraft United Airlines, Inc. AirCraft	Mar. 31, 2013 Capital Addition Purchase Commitments Airbus A350XWB aircraft United Airlines, Inc. AirCraft	Mar. 31, 2013 Capital Addition Purchase Commitments Boeing 737-900ER AirCraft AirCraft	Mar. 31, 2013 Capital Addition Purchase Commitments Boeing 737-900ER AirCraft United Airlines, Inc. AirCraft	Mar. 27, 2013 Revolving Credit Facility	Mar. 31, 2013 Minimum Tax-exempt special facilities revenue bonds	Mar. 31, 2013 Minimum Capital Addition Purchase Commitments United Airlines, Inc.	Mar. 31, 2013 Minimum Capital Addition Purchase Commitments Boeing 737	Mar. 31, 2013 Maximum Y	Mar. 31, 2013 Maximum Loans And Leases From Non U S Entities Y	Mar. 31, 2013 Maximum Tax-exempt special facilities revenue bonds	Mar. 31, 2013 Maximum Capital Addition Purchase Commitments United Airlines, Inc.	Mar. 31, 2013 Maximum Capital Addition Purchase Commitments Boeing 737
Commitments and Contingencies [Line Items]
Number of new aircraft committed to purchase							149	100	75		49	25
Number of new aircraft under purchase rights and options								100
New aircraft, scheduled delivery date																		2018				2020	2022
New aircraft, scheduled delivery date																	Apr. 01, 2013
Number of aircraft delivered														6
Number of aircraft expected to be delivered											2			18
Number of aircraft under financing arrangement expected to be delivered										1			14
Number of aircraft under financing arrangement delivered													6
Number of aircraft under financing arrangement expected to be delivered during the reminder of 2013													8
Guarantor obligations, maximum exposure						$ 1,900,000,000
Operating leases obligations						1,700,000,000
Capital leases obligations						190,000,000
Debt instrument, maturity year																2015					2038
Debt instrument principal amount			2,100,000,000	327,000,000	2,400,000,000
Debt instrument, remaining terms (years)																			9	8
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%