BUSINESS ACQUISITIONS - Narrative (Details) - USD ($) $ in Millions		12 Months Ended
	Oct. 01, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Business Acquisition [Line Items]
Goodwill recognized		$ 3,692	$ 3,367	$ 3,813
Acquired finite-lived intangible assets, useful life		7 years 7 months 6 days
Trade name
Business Acquisition [Line Items]
Acquired finite-lived intangible assets, useful life		10 years 3 months 18 days
Supply Chain  Solutions
Business Acquisition [Line Items]
Goodwill recognized		$ 2,442	2,230	2,682
U.S. Domestic Package
Business Acquisition [Line Items]
Goodwill recognized		$ 847	$ 715	$ 715
Roadie, Inc.
Business Acquisition [Line Items]
Goodwill recognized	$ 375
Intangible assets acquired	231
Roadie, Inc. | Technology
Business Acquisition [Line Items]
Intangible assets acquired	$ 145
Acquired finite-lived intangible assets, useful life	8 years
Roadie, Inc. | Trade name
Business Acquisition [Line Items]
Intangible assets acquired	$ 67
Acquired finite-lived intangible assets, useful life	10 years
Roadie, Inc. | Other Intangible Assets
Business Acquisition [Line Items]
Intangible assets acquired	$ 19
Acquired finite-lived intangible assets, useful life	8 years
Roadie, Inc. | Supply Chain  Solutions
Business Acquisition [Line Items]
Goodwill recognized	$ 243
Roadie, Inc. | U.S. Domestic Package
Business Acquisition [Line Items]
Goodwill recognized	$ 132