XML 101 R62.htm IDEA: XBRL DOCUMENT v3.24.0.1
Pension, Postretirement And Other Employee Benefit Plans - Narrative (Details)
3 Months Ended 12 Months Ended
Mar. 31, 2021
USD ($)
Dec. 31, 2023
USD ($)
plan
Dec. 31, 2022
USD ($)
Dec. 31, 2021
USD ($)
Schedule Of Defined Benefit Plans And Defined Contribution Plans Disclosures [Line Items]        
Number of defined benefit pension plans | plan   2    
Profit sharing and payroll tax expense   $ 681,000,000 $ 133,000,000 $ 0
IAM National Pension Plan        
Schedule Of Defined Benefit Plans And Defined Contribution Plans Disclosures [Line Items]        
Multi-employer plan contributions     533,000,000  
United Airlines, Inc.        
Schedule Of Defined Benefit Plans And Defined Contribution Plans Disclosures [Line Items]        
Expense for defined contribution plans   $ 960,000,000 756,000,000 651,000,000
Minimum        
Schedule Of Defined Benefit Plans And Defined Contribution Plans Disclosures [Line Items]        
Percentage of pre-tax earnings paid for profit sharing plan   5.00%    
Minimum | United Airlines, Inc.        
Schedule Of Defined Benefit Plans And Defined Contribution Plans Disclosures [Line Items]        
Employer contribution percentage   1.00%    
Maximum        
Schedule Of Defined Benefit Plans And Defined Contribution Plans Disclosures [Line Items]        
Percentage of pre-tax earnings paid for profit sharing plan   20.00%    
Maximum | United Airlines, Inc.        
Schedule Of Defined Benefit Plans And Defined Contribution Plans Disclosures [Line Items]        
Employer contribution percentage   16.00%    
Other Postretirement Benefits        
Schedule Of Defined Benefit Plans And Defined Contribution Plans Disclosures [Line Items]        
Special termination benefits   $ 0 $ 0 (31,000,000)
Defined benefit plan, expected future employer contributions, next fiscal year   $ 104,000,000    
Employee Separation | Voluntary Separation Leave Programs        
Schedule Of Defined Benefit Plans And Defined Contribution Plans Disclosures [Line Items]        
Special termination benefits       31,000,000
Employee Separation | Voluntary Separation Leave Programs | Full-Time Employees        
Schedule Of Defined Benefit Plans And Defined Contribution Plans Disclosures [Line Items]        
Restructuring programs, one-time contribution per employee $ 125,000     125,000
Employee Separation | Voluntary Separation Leave Programs | Part-Time Employees        
Schedule Of Defined Benefit Plans And Defined Contribution Plans Disclosures [Line Items]        
Restructuring programs, one-time contribution per employee $ 75,000     $ 75,000