MARKETABLE SECURITIES AND NON-CURRENT INVESTMENTS (Tables)

12 Months Ended

Dec. 31, 2023

Investments, Debt and Equity Securities [Abstract]

Summary of Marketable Securities

The following is a summary of marketable securities classified as trading and available-for-sale as of December 31, 2023 and 2022 (in millions):

	Cost		Unrealized Gains		Unrealized Losses		Estimated Fair Value
2023
Current trading marketable securities:
Equity securities	$	4	$	—	$	—	$	4
Total trading marketable securities	4		—		—		4
Current available-for-sale marketable securities:
U.S. government and agency debt securities	963		2		(4)		961
Mortgage and asset-backed debt securities	3		—		—		3
Corporate debt securities	1,891		4		(4)		1,891
U.S. state and local municipal debt securities	—		—		—		—
Non-U.S. government debt securities	7		—		—		7
Total available-for-sale marketable securities	2,864		6		(8)		2,862
Total current marketable securities	$	2,868	$	6	$	(8)	$	2,866
	Cost		Unrealized Gains		Unrealized Losses		Estimated Fair Value
2022
Current trading marketable securities:
Equity securities	$	2	$	—	$	—	$	2
Total trading marketable securities	2		—		—		2
Current available-for-sale marketable securities:
U.S. government and agency debt securities	355		—		(8)		347
Mortgage and asset-backed debt securities	9		—		—		9
Corporate debt securities	1,472		—		(6)		1,466
U.S. state and local municipal debt securities	4		—		—		4
Non-U.S. government debt securities	165		—		—		165
Total available-for-sale marketable securities	2,005		—		(14)		1,991
Total current marketable securities	$	2,007	$	—	$	(14)	$	1,993

Schedule of Unrealized Loss on Marketable Securities

The following table presents the age of gross unrealized losses and fair value by investment category for all securities in a loss position as of December 31, 2023 (in millions):

	Less Than 12 Months				12 Months or More				Total
	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
U.S. government and agency debt securities	$	508	$	(1)	$	191	$	(3)	$	699	$	(4)
Corporate debt securities	751		(2)		475		(2)		1,226		(4)
Total marketable securities	$	1,259	$	(3)	$	666	$	(5)	$	1,925	$	(8)

Amortized Cost and Estimated Fair Value of Marketable Securities by Contractual Maturity

The amortized cost and estimated fair value of marketable securities as of December 31, 2023 by contractual maturity are shown below (in millions). Actual maturities may differ from contractual maturities because the issuers of the securities may have the right to prepay obligations with or without prepayment penalties. 

	Cost		Estimated Fair Value
Due in one year or less	$	1,346	$	1,343
Due after one year through three years	1,513		1,514
Due after three years through five years	5		5
Due after five years	—		—
	2,864		2,862
Equity securities	4		4
	$	2,868	$	2,866

Investments Measured at Fair Value on a Recurring Basis

The following table presents information about our investments measured at fair value on a recurring basis as of December 31, 2023 and 2022, and indicates the fair value hierarchy of the valuation techniques utilized to determine such fair value (in millions):

	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
2023
Marketable Securities:
U.S. government and agency debt securities	$	961	$	—	$	—	$	961
Mortgage and asset-backed debt securities	—		3		—		3
Corporate debt securities	—		1,891		—		1,891
U.S. state and local municipal debt securities	—		—		—		—
Equity securities	—		4		—		4
Non-U.S. government debt securities	—		7		—		7
Total marketable securities	961		1,905		—		2,866
Other non-current investments(1)	—		19		—		19
Total	$	961	$	1,924	$	—	$	2,885
(1)Represents a variable life insurance policy funding benefits for the UPS Excess Coordinating Benefit Plan.
	Quoted Prices in Active Markets  for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
2022
Marketable Securities:
U.S. government and agency debt securities	$	279	$	68	$	—	$	347
Mortgage and asset-backed debt securities	—		9		—		9
Corporate debt securities	—		1,466		—		1,466
U.S. state and local municipal debt securities	—		4		—		4
Equity securities	—		2		—		2
Non-U.S. government debt securities	—		165		—		165
Total marketable securities	279		1,714		—		1,993
Other non-current investments(1)	—		18		—		18
Total	$	279	$	1,732	$	—	$	2,011
(1)Represents a variable life insurance policy funding benefits for the UPS Excess Coordinating Benefit Plan.