v3.25.2
EMPLOYEE BENEFIT PLANS - Additional Information (Details)
$ in Millions
 6 Months Ended
Jun. 30, 2025
USD ($)
building
employee
Dec. 31, 2024
USD ($)
Defined Benefit Plan Disclosure [Line Items]    
Multiemployer plans, payment term 37 years  
National Master Agreement and Various Supplemental Agreements    
Defined Benefit Plan Disclosure [Line Items]    
Number of employees covered | employee 300,000  
Teamsters    
Defined Benefit Plan Disclosure [Line Items]    
Number of employees covered | employee 11,000  
Independent Pilots Association    
Defined Benefit Plan Disclosure [Line Items]    
Number of employees covered | employee 3,300  
Teamsters Local 2727    
Defined Benefit Plan Disclosure [Line Items]    
Number of employees covered | employee 1,900  
International Association Of Machinists And Aerospace Workers    
Defined Benefit Plan Disclosure [Line Items]    
Number of employees covered | employee 3,000  
Other current liabilities    
Defined Benefit Plan Disclosure [Line Items]    
Withdrawal liability   $ 19
Defined Benefit Pension Plan    
Defined Benefit Plan Disclosure [Line Items]    
Multi-employer plans, withdrawal obligation, fair value $ 654 651
Defined Benefit Pension Plan | Long term debt    
Defined Benefit Plan Disclosure [Line Items]    
Multiemployer plans, withdrawal obligation, present value 799 804
Defined Benefit Pension Plan | Other current liabilities    
Defined Benefit Plan Disclosure [Line Items]    
Multiemployer plans, withdrawal obligation, present value 9 $ 9
U.S | Defined Benefit Pension Plan    
Defined Benefit Plan Disclosure [Line Items]    
Amount contributed to company- sponsored benefit plans 765  
Estimated future employer contributions to defined benefit plan, current fiscal year 410  
U.S | U.S. Postretirement Medical Benefits    
Defined Benefit Plan Disclosure [Line Items]    
Amount contributed to company- sponsored benefit plans 156  
Estimated future employer contributions to defined benefit plan, current fiscal year $ 22  
Facility Closing    
Defined Benefit Plan Disclosure [Line Items]    
Number of buildings closed | building 74  
Number of buildings permanently closed | building 68