United Parcel Service, Inc. Annual report pursuant to Section 13 and 15(d)

QUARTERLY INFORMATION (unaudited) - Transformation and Other Costs (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018
Interim Period, Costs Not Allocable [Line Items]
Legal Contingencies and Expenses	$ 97	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0
Defined Benefit Plan Mark-to-Market Charges	2,387	0	0	0	1,627	0	0	0
Transformation Strategy - Employee Benefits
Interim Period, Costs Not Allocable [Line Items]
Transformation cost	17	41	2	106	0	70	192	0
Transformation Strategy - Other Costs
Interim Period, Costs Not Allocable [Line Items]
Transformation cost	31	22	19	17	0	27	71	0
U.S. Domestic Package
Interim Period, Costs Not Allocable [Line Items]
Transformation cost	133	26	18	28	0	39	196	0
International Package
Interim Period, Costs Not Allocable [Line Items]
Transformation cost	10	26	2	84	0	40	36	0
Supply Chain & Freight
Interim Period, Costs Not Allocable [Line Items]
Transformation cost	$ 2	$ 11	$ 1	$ 11	$ 0	$ 18	$ 31	$ 0