INVESTMENTS (Tables)

6 Months Ended

Jun. 30, 2021

Investments, Debt and Equity Securities [Abstract]

Investments by Major Security Type

The following table summarizes, by major security type, the Company's investments at June 30, 2021 (in millions): 

	Cost		Gross Unrealized Gains /Upward Adjustments		Gross Unrealized Losses /Downward Adjustments		Carrying  Value
Short-term investments:
Debt securities:
Trip.com Group convertible debt securities	$	500	$	1	$	—	$	501
Long-term investments:
Investments in private companies:
Debt securities	$	200	$	126	$	—	$	326
Equity securities	66		—		—		66
Other long-term investments:
Debt securities:
Trip.com Group convertible debt securities	25		—		(1)		24
Equity securities	963		3,040		(100)		3,903
Total	$	1,254	$	3,166	$	(101)	$	4,319

The following table summarizes, by major security type, the Company's investments at December 31, 2020 (in millions):

	Cost		Gross Unrealized Gains/Upward Adjustments		Gross Unrealized Losses/Downward Adjustments		Carrying  Value
Short-term investments:
Debt securities:
Trip.com Group convertible debt securities	$	500	$	1	$	—	$	501
Long-term investments:
Investments in private companies:
Debt securities	$	200	$	—	$	—	$	200
Equity securities	552		3		(100)		455
Other long-term investments:
Debt securities:
Trip.com Group convertible debt securities	25		—		(1)		24
Equity securities	463		2,617		—		3,080
Total	$	1,240	$	2,620	$	(101)	$	3,759