Commitments and Contingencies - Narrative (Details) technician in Thousands, $ in Millions	3 Months Ended
	Mar. 31, 2023 USD ($) employee aircraft technician	Jun. 30, 2023 aircraft	Apr. 30, 2023 employee
Commitments and Contingencies [Line Items]
Remaining term of debt	12 years
International Association Of Machinists National Pension Plan | Subsequent Event
Commitments and Contingencies [Line Items]
Number of employees | employee			30,000
United Airlines, Inc.
Commitments and Contingencies [Line Items]
Number of employees | employee	96,300
Percentage of employees represented by various U.S. labor organizations	84.00%
Number of technicians | technician	8
Bargaining on successor agreement, term	1 year
Tax-Exempt Special Facilities Revenue Bonds
Commitments and Contingencies [Line Items]
Aggregate principal amount of guarantee | $	$ 2,000
Aircraft Mortgage Debt
Commitments and Contingencies [Line Items]
Aggregate principal amount of guarantee | $	88
Floating Rate Debt
Commitments and Contingencies [Line Items]
Debt | $	$ 12,900
Loans and Leases from Non-U.S. Entities
Commitments and Contingencies [Line Items]
Remaining term of debt	12 years
Aggregate balance | $	$ 9,700
A321neo
Commitments and Contingencies [Line Items]
Number of aircraft expected to take delivery that are delayed, current year	8
Number of additional aircrafts expected to take delivery that are delayed, next fiscal year	10
737 MAX
Commitments and Contingencies [Line Items]
Number of aircraft expected to take delivery that are delayed	11
Number of aircraft expected to take delivery that are delayed, current year	37
Number of additional aircrafts expected to take delivery that are delayed, next fiscal year	30
737 MAX | Forecast
Commitments and Contingencies [Line Items]
Number of aircraft expected to take delivery that are delayed, current year		6