Investments (Tables)

6 Months Ended

Jun. 30, 2020

Investments [Abstract]

Fair value of short and long-term investments classified as available for sale

The following tables summarize the unrealized gains and losses and estimated fair value of our investments classified as available-for-sale (in millions):

	June 30, 2020
	Gross Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Short-term investments:
Restricted cash	$	19	$	—	$	—	$	19
Corporate debt securities	3,866		3		—		3,869
Government and agency securities	409		—		—		409
	$	4,294	$	3	$	—	$	4,297
Long-term investments:
Corporate debt securities	530		5		(1)		534
	$	530	$	5	$	(1)	$	534

	December 31, 2019
	Gross Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Short-term investments:
Restricted cash	$	21	$	—	$	—	$	21
Corporate debt securities	1,653		1		—		1,654
Government and agency securities	175		—		—		175
	$	1,849	$	1	$	—	$	1,850
Long-term investments:
Corporate debt securities	957		4		—		961
	$	957	$	4	$	—	$	961

Estimated fair values of short and long-term investments classified by date of contractual maturity

The estimated fair values of our short-term and long-term investments classified as available-for-sale by date of contractual maturity as of June 30, 2020 are as follows (in millions):  

	June 30, 2020
One year or less (including restricted cash of $19)	$	4,297
One year through two years	335
Two years through three years	199
	$	4,831

Schedule of equity method investments

The following table provides a summary of our equity investments (in millions):

	June 30, 2020		December 31, 2019
Equity investments without readily determinable fair values	$	291	$	337
Equity investments under the equity method of accounting	7		7
Total equity investments	$	298	$	344

Schedule of equity securities without readily determinable fair value

The following table summarizes the change in total carrying value during the three and six months ended June 30, 2020 and 2019 related to equity investments without readily determinable fair values still held (in millions):

	Three Months Ended June 30,				Six Months Ended June 30,
	2020		2019		2020		2019
Carrying value, beginning of period	$	326	$	137	$	337	$	137
Downward adjustments for observable price changes and impairment	(40)		—		(40)		—
Foreign currency translation and other	5		(1)		(6)		(1)
Carrying value, end of period	$	291	$	136	$	291	$	136