Annual report pursuant to Section 13 and 15(d)

COMPANY-SPONSORED EMPLOYEE BENEFIT PLANS - Additional Information (Details)

v3.25.0.1
COMPANY-SPONSORED EMPLOYEE BENEFIT PLANS - Additional Information (Details) - USD ($)
 1 Months Ended 12 Months Ended
Jan. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Defined Benefit Plan Disclosure [Line Items]        
Curtailments and settlements of benefit obligations       $ 34,000,000
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Settlement and Curtailment Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]       Investment income (expense) and other
Curtailment of benefit obligation, after tax       $ 24,000,000
Health care cost trends, initial annual rate increase   7.50%    
Health care cost trends, an ultimate trend rate   4.50%    
Employer contributions   $ 1,524,000,000 $ 1,393,000,000 $ 2,342,000,000
Actuarial gain (loss)   2,500,000,000 (2,400,000,000)  
Defined benefit plan, actuarial gain (loss), discount rates   $ 2,800,000,000 $ (2,300,000,000)  
Service cost discount rate   5.85% 5.40% 5.77%
Defined benefit plan, actuarial loss, demographic and assumption changes   $ 300,000,000 $ 100,000,000  
Common stock held in plan assets (in shares)   0 0  
Hedge funds        
Defined Benefit Plan Disclosure [Line Items]        
Unfunded commitments to limited partnerships   $ 0    
Private Equity and Real Estate        
Defined Benefit Plan Disclosure [Line Items]        
Unfunded commitments to limited partnerships   2,700,000,000    
Employee Defined Contribution Plans        
Defined Benefit Plan Disclosure [Line Items]        
Contributions charged to expense   161,000,000 $ 161,000,000 $ 153,000,000
UPS 401(k) Savings Plan        
Defined Benefit Plan Disclosure [Line Items]        
Contributions charged to expense   359,000,000 380,000,000 83,000,000
Transition contributions   108,000,000 128,000,000 0
Defined Contribution Money Purchase Plans        
Defined Benefit Plan Disclosure [Line Items]        
Contributions charged to expense   135,000,000 132,000,000 $ 119,000,000
Pension Benefits        
Defined Benefit Plan Disclosure [Line Items]        
Accumulated benefit obligation for pension plans   48,000,000,000.0 49,200,000,000  
Employer contributions   37,000,000 35,000,000  
Postemployment Retirement Benefits        
Defined Benefit Plan Disclosure [Line Items]        
Accumulated benefit obligation for pension plans   1,900,000,000 2,000,000,000.0  
Postretirement Medical Benefits        
Defined Benefit Plan Disclosure [Line Items]        
Employer contributions   $ 264,000,000 $ 51,000,000  
Minimum        
Defined Benefit Plan Disclosure [Line Items]        
Postretirement medical plans service minimum eligibility year   10 years    
Postretirement medical plans service minimum eligibility age   55 years    
Duration for unfunded commitments to be contributed   3 years    
Minimum | Private Equity and Real Estate        
Defined Benefit Plan Disclosure [Line Items]        
Redemption notice period, lower limit   10 years    
Minimum | UPS 401(k) Savings Plan        
Defined Benefit Plan Disclosure [Line Items]        
Employer contribution, percent of eligible compensation   5.00% 3.00%  
Minimum | UPS 401(k) Savings Plan | Subsequent Event        
Defined Benefit Plan Disclosure [Line Items]        
Employer contribution, percent of eligible compensation 3.00%      
Maximum        
Defined Benefit Plan Disclosure [Line Items]        
Duration for unfunded commitments to be contributed   6 years    
Maximum | Private Equity and Real Estate        
Defined Benefit Plan Disclosure [Line Items]        
Redemption notice period, upper limit   15 years    
Maximum | UPS 401(k) Savings Plan        
Defined Benefit Plan Disclosure [Line Items]        
Employer contribution, percent of eligible compensation   8.00% 8.00%