Annual report [Section 13 and 15(d), not S-K Item 405]

COMPANY-SPONSORED EMPLOYEE BENEFIT PLANS - Narrative (Details)

v3.25.4
COMPANY-SPONSORED EMPLOYEE BENEFIT PLANS - Narrative (Details) - USD ($)
 1 Months Ended 12 Months Ended
Jan. 31, 2025
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Defined Benefit Plan Disclosure [Line Items]          
Health care cost trends, initial annual rate increase   8.00%      
Health care cost trends, an ultimate trend rate   4.50%      
Employer contributions   $ 1,361,000,000 $ 1,524,000,000 $ 1,393,000,000  
Actuarial gain (loss)   (700,000,000) 2,500,000,000    
Defined benefit plan, actuarial gain (loss), discount rates   $ 300,000,000 $ (2,800,000,000)    
Service cost discount rate   5.79% 5.85% 5.40%  
Defined benefit plan, actuarial loss, demographic and assumption changes   $ 400,000,000 $ 300,000,000    
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   2,500,000,000      
Employee Defined Contribution Plans          
Defined Benefit Plan Disclosure [Line Items]          
Contributions charged to expense   137,000,000 $ 161,000,000 $ 161,000,000  
UPS 401(k) Savings Plan          
Defined Benefit Plan Disclosure [Line Items]          
Contributions charged to expense   342,000,000 359,000,000 380,000,000  
Transition contributions   99,000,000 108,000,000 128,000,000  
Defined Contribution Money Purchase Plans          
Defined Benefit Plan Disclosure [Line Items]          
Contributions charged to expense   143,000,000 135,000,000 $ 132,000,000  
Pension Benefits          
Defined Benefit Plan Disclosure [Line Items]          
Accumulated benefit obligation for pension plans   50,000,000,000.0 48,000,000,000.0    
Employer contributions   39,000,000 37,000,000    
Postemployment Retirement Benefits          
Defined Benefit Plan Disclosure [Line Items]          
Accumulated benefit obligation for pension plans   1,800,000,000 1,900,000,000    
Postretirement Medical Benefits          
Defined Benefit Plan Disclosure [Line Items]          
Employer contributions   $ 179,000,000 $ 264,000,000    
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      
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 3.00%     5.00% 3.00%
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%