REVENUE RECOGNITION - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Disaggregation of Revenue [Line Items]
Revenue	$ 21,221	$ 21,818	$ 42,767	$ 43,524
Supply Chain Solutions
Disaggregation of Revenue [Line Items]
Revenue	2,653	3,247	5,366	6,431
U.S \| U.S. Domestic Package
Disaggregation of Revenue [Line Items]
Revenue	14,083	14,201	28,543	28,467
International \| International Package
Disaggregation of Revenue [Line Items]
Revenue	4,485	4,370	8,858	8,626
Next Day Air \| U.S \| U.S. Domestic Package
Disaggregation of Revenue [Line Items]
Revenue	2,293	2,309	4,654	4,625
Deferred \| U.S \| U.S. Domestic Package
Disaggregation of Revenue [Line Items]
Revenue	1,024	1,107	2,073	2,263
Ground \| U.S \| U.S. Domestic Package
Disaggregation of Revenue [Line Items]
Revenue	10,484	10,703	21,193	21,465
Cargo and Other \| U.S \| U.S. Domestic Package
Disaggregation of Revenue [Line Items]
Revenue	282	82	623	114
Cargo and Other \| International \| International Package
Disaggregation of Revenue [Line Items]
Revenue	171	163	329	311
Domestic \| International \| International Package
Disaggregation of Revenue [Line Items]
Revenue	830	770	1,601	1,528
Export \| International \| International Package
Disaggregation of Revenue [Line Items]
Revenue	3,484	3,437	6,928	6,787
Forwarding \| Supply Chain Solutions
Disaggregation of Revenue [Line Items]
Revenue	732	1,315	1,458	2,595
Logistics \| Supply Chain Solutions
Disaggregation of Revenue [Line Items]
Revenue	1,476	1,546	3,048	3,088
Other \| Supply Chain Solutions
Disaggregation of Revenue [Line Items]
Revenue	$ 445	$ 386	$ 860	$ 748