SEGMENT AND GEOGRAPHIC INFORMATION - Revenue by Product Type (Detail) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenue from External Customer [Line Items]
Revenue	$ 24,896	$ 21,238	$ 20,459	$ 18,035	$ 20,568	$ 18,318	$ 18,048	$ 17,160	$ 84,628	$ 74,094	$ 71,861
U.S. Domestic Package | Operating Segments
Revenue from External Customer [Line Items]
Revenue									53,499	46,493
International Package | Operating Segments
Revenue from External Customer [Line Items]
Revenue									15,945	14,220
Supply Chain & Freight | Operating Segments
Revenue from External Customer [Line Items]
Revenue									15,184	13,381	13,826
Other
Revenue from External Customer [Line Items]
Revenue									987	814	794
Freight
Revenue from External Customer [Line Items]
Revenue									3,149	3,265	3,218
Logistics
Revenue from External Customer [Line Items]
Revenue									4,073	3,435	3,234
Forwarding
Revenue from External Customer [Line Items]
Revenue									6,975	5,867	6,580
United States
Revenue from External Customer [Line Items]
Revenue									66,580	58,699	56,115
United States | U.S. Domestic Package | Operating Segments
Revenue from External Customer [Line Items]
Revenue									53,499	46,493	43,593
United States | Ground
Revenue from External Customer [Line Items]
Revenue									39,312	32,834	31,223
United States | Deferred
Revenue from External Customer [Line Items]
Revenue									5,665	5,180	4,752
United States | Next Day Air
Revenue from External Customer [Line Items]
Revenue									8,522	8,479	7,618
International Package
Revenue from External Customer [Line Items]
Revenue									18,048	15,395	15,746
International Package | International Package | Operating Segments
Revenue from External Customer [Line Items]
Revenue									15,945	14,220	14,442
International Package | Cargo & Other
Revenue from External Customer [Line Items]
Revenue									626	547	595
International Package | Export
Revenue from External Customer [Line Items]
Revenue									12,159	10,837	10,973
International Package | Domestic
Revenue from External Customer [Line Items]
Revenue									$ 3,160	$ 2,836	$ 2,874