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

UNITED PARCEL SERVICE INC 10-Q