Commitments and Contingencies - Narrative (Details)	12 Months Ended
	Dec. 31, 2022 USD ($) employee technician option aircraft	Jul. 21, 2022 aircraft
Commitments and Contingencies [Line Items]
Loss contingency, loss in period	$ 94,000,000
Aggregate balance	$ 1,115,000,000
Number of call options to purchase regional jet aircraft | option	255
A321neo
Commitments and Contingencies [Line Items]
Number of aircrafts expected to take delivery that are delayed | aircraft		8
Boeing 737 Max
Commitments and Contingencies [Line Items]
Number of aircrafts expected to take delivery that are delayed | aircraft	37
B-737-Max
Commitments and Contingencies [Line Items]
Number of aircrafts expected to take delivery that are delayed | aircraft		6
United Airlines, Inc.
Commitments and Contingencies [Line Items]
Number of employees | employee	92,800
Percentage of employees represented by various U.S. labor organizations	84.00%
Labor negotiations, length of contract extension	2 years
Number of technicians | technician	8,000
Bargaining on successor agreement, term	1 year
United Airlines, Inc. | Surety Bonds
Commitments and Contingencies [Line Items]
Contingent liabilities based on participation	$ 377,000,000
Tax-Exempt Special Facilities Revenue Bonds
Commitments and Contingencies [Line Items]
Guarantor obligations, maximum exposure	2,000,000,000
Tax-Exempt Special Facilities Revenue Bonds | Indirect Guarantee of Indebtedness
Commitments and Contingencies [Line Items]
Guarantor obligations, maximum exposure	400,000,000
Contingent liabilities based on participation	2,500,000,000
Aircraft Mortgage Debt
Commitments and Contingencies [Line Items]
Guarantor obligations, maximum exposure	92,000,000
Floating Rate Debt
Commitments and Contingencies [Line Items]
Aggregate principal amount	$ 12,900,000,000
Debt instrument, remaining terms	12 years
Loans And Leases From Non U S Entities
Commitments and Contingencies [Line Items]
Debt instrument, remaining terms	12 years
Aggregate balance	$ 9,800,000,000