Investments

As of March 31, 2018 and December 31, 2017, the estimated fair value of our short-term and long-term investments classified as available-for-sale was as follows:



	March 31, 2018
	Gross Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
	(In millions)
Short-term investments⁽¹⁾⁽²⁾:
Corporate debt securities	$	2,340	$	—	$	(4	)	$	2,336
Government and agency securities	495		—		(1		)	494
Long-term investments⁽¹⁾:
Corporate debt securities	1,324		1		(16		)	1,309
Government and agency securities	88		—		—			88
Total⁽¹⁾⁽²⁾	$	4,247	$	1	$	(21	)	$	4,227

⁽¹⁾Excludes short-term restricted cash of $81 million that we intend to use to support our global sabbatical program and a counterparty guarantee, and long-term restricted cash of $2 million.

⁽²⁾Excludes time deposits of $199 million, which are not considered available-for-sale securities.



	December 31, 2017
	Gross Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
	(In millions)
Short-term investments⁽¹⁾⁽²⁾:
Corporate debt securities	$	2,092	$	1	$	(1	)	$	2,092
Government and agency securities	210		—		—			210
Long-term investments⁽¹⁾:
Corporate debt securities	1,769		2		(7		)	1,764
Government and agency securities	98		—		—			98
Total⁽¹⁾⁽²⁾	$	4,169	$	3	$	(8	)	$	4,164

⁽¹⁾Excludes short-term restricted cash of $79 million that we intend to use to support our global sabbatical program and a counterparty guarantee, and long-term restricted cash of $2 million.

⁽²⁾Excludes time deposits of $163 million, which are not considered available-for-sale securities.

We elected to account for foreign denominated available-for-sale investments held in our Luxembourg banking subsidiary under the fair value option. Election of the fair value option allows us to recognize any gains and losses from fair value changes on such investments in other income (expense), net on the condensed consolidated statement of income to offset certain foreign exchange gains and losses on our foreign denominated customer liabilities. As of March 31, 2018 and December 31, 2017, the estimated fair value of our investments included within short-term investments and long-term investments under the fair value option was $317 million and $277 million, respectively. In the three months ended March 31, 2018 and 2017, $8 million and $6 million, respectively, of net gains from fair value changes were recognized in other income (expense), net on the condensed consolidated statement of income.

The aggregate fair value of short-term and long-term investments in an unrealized loss position was $3.4 billion as of March 31, 2018 and $2.8 billion as of December 31, 2017, of which $206 million and $207 million, respectively, was in a continuous unrealized loss position for greater than 12 months. The aggregate gross unrealized loss on our short-term and long-term investments was not material as of March 31, 2018 and December 31, 2017. We believe the decline in value is due to temporary market conditions and expect to recover the entire amortized cost basis of the securities. We neither intend nor anticipate the need to sell the securities before recovery. We will continue to monitor the performance of the investment portfolio and assess market and interest rate risk when evaluating whether other-than-temporary impairment exists. Amounts reclassified to earnings from unrealized gains and losses were not material for the three months ended March 31, 2018 and 2017.

The estimated fair values of our short-term and long-term investments classified as available-for-sale by date of contractual maturity at March 31, 2018 were as follows:



	March 31, 2018
	(In millions)
One year or less	$	2,830
One year through two years	823
Two years through three years	344
Three years through four years	171
Four years through five years	49
Greater than five years	10
Total	$	4,227

Other Investments

We have equity investments which consist primarily of minority equity interests in companies that are not publicly traded and are reported in long-term investments on our condensed consolidated balance sheet. Our equity investments totaled $88 million as of March 31, 2018 and December 31, 2017.