
	June 30, 2020		December 31, 2019
	(in millions)
Short-term investments:
Equity investment security	$	27	$	26
Held-to-maturity investment securities	130		287
Time deposits ⁽¹⁾	3		466
Total short-term investments	$	160	$	779


Long-term investments:
Equity and cost method investments	$	38	$	17
Time deposits ⁽¹⁾	391		—
Total long-term investments	$	429	$	17

(1)As of June 30, 2020, $391 million in restricted time deposits were classified as long-term. As of December 31, 2019, $414 million in restricted time deposits were classified as short-term. See Note 8.

Our equity investment security is a U.S. dollar denominated investment in an open-ended mutual fund. Realized and unrealized gains and losses were immaterial for the three and six months ended June 30, 2020 and 2019.

Our held-to-maturity investment securities consist of Indian rupee denominated investments primarily in commercial paper, international corporate bonds and government debt securities. Our investment guidelines are to purchase securities that are investment grade at the time of acquisition. The basis for the measurement of fair value of our held-to-maturity investments is Level 2 in the fair value hierarchy.

The amortized cost, gross unrealized gains and losses and fair value of held-to-maturity investment securities at June 30, 2020 were as follows:



	Amortized Cost		Unrealized Gains		Unrealized Losses		Fair Value
	(in millions)
Short-term investments, due within one year:
Corporate and other debt securities	$	56	$	—	$	—	$	56
Commercial paper	74		1		—		75
Total short-term held-to-maturity investments	$	130	$	1	$	—	$	131

The amortized cost, gross unrealized gains and losses and fair value of held-to-maturity investment securities at December 31, 2019 were as follows:



	Amortized Cost		Unrealized Gains		Unrealized Losses		Fair Value
	(in millions)
Short-term investments, due within one year:
Corporate and other debt securities	$	101	$	—	$	—	$	101
Commercial paper	186		—		—		186
Total short-term held-to-maturity investments	$	287	$	—	$	—	$	287

As of June 30, 2020, there were no held-to-maturity investment securities in an unrealized loss position. As of December 31, 2019, commercial paper in the amount of $70 million and corporate and other debt securities in the amount of $42 million

were in an unrealized loss position. The total unrealized loss was less than $1 million and none of the securities had been in an unrealized loss position for longer than 12 months.

We monitor the credit ratings of the securities in our portfolio on an ongoing basis and evaluate the need for an allowance for expected credit losses. The securities in our portfolio are highly rated and short-term in nature. Historically, we have not had any impairment losses on our portfolio. As of June 30, 2020, our corporate and other debt securities were rated AAA and our commercial paper were rated A-1+ by CRISIL, an Indian subsidiary of S&P Global.

During the six months ended June 30, 2020 and the year ended December 31, 2019, there were no transfers of investments between our available-for-sale and held-to-maturity investment portfolios.

During 2020, we acquired a $26 million equity method investment in the technology sector. As of June 30, 2020 and December 31, 2019, we had equity method investments of $34 million and $9 million, respectively and cost method investments of $4 million and $8 million, respectively.