Cash Equivalents and Investments

Investments in Available-for-Sale Debt Securities

The following table summarizes the Company's unrealized gains and losses and fair value of investments designated as available-for-sale debt securities as of March 31, 2019 and December 31, 2018 (in millions):



	As of March 31, 2019									As of December 31, 2018
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value		Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
Fixed income securities:
Asset-backed securities	$	30.4	$	—	$	(0.1	)	$	30.3	$	46.8	$	—	$	(0.3	)	$	46.5
Certificates of deposit	95.4		—		—			95.4		152.9		—		—			152.9
Commercial paper	377.5		—		—			377.5		393.6		—		—			393.6
Corporate debt securities	363.3		—		(1.3		)	362.0		416.1		—		(3.1		)	413.0
Foreign government debt securities	38.4		—		(0.1		)	38.3		20.0		—		(0.1		)	19.9
Time deposits	84.2		—		—			84.2		278.6		—		—			278.6
U.S. government agency securities	25.7		—		(0.1		)	25.6		87.2		—		(0.2		)	87.0
U.S. government securities	746.6		0.1		(0.3		)	746.4		811.8		—		(0.5		)	811.3
Total fixed income securities	1,761.5		0.1		(1.9		)	1,759.7		2,207.0		—		(4.2		)	2,202.8
Privately-held debt and redeemable preferred stock securities	14.6		37.4		—			52.0		16.6		37.4		—			54.0
Total available-for-sale debt securities	$	1,776.1	$	37.5	$	(1.9	)	$	1,811.7	$	2,223.6	$	37.4	$	(4.2	)	$	2,256.8

Reported as:
Cash equivalents	$	414.4	$	—	$	—		$	414.4	$	936.5	$	—	$	—		$	936.5
Short-term investments	1,226.7		0.1		(1.2		)	1,225.6		1,069.2		—		(1.9		)	1,067.3
Long-term investments	120.4		—		(0.7		)	119.7		201.3		—		(2.3		)	199.0
Other long-term assets	14.6		37.4		—			52.0		16.6		37.4		—			54.0
Total	$	1,776.1	$	37.5	$	(1.9	)	$	1,811.7	$	2,223.6	$	37.4	$	(4.2	)	$	2,256.8

The following table presents the contractual maturities of the Company's total fixed income securities as of March 31, 2019 (in millions):



	Amortized Cost		Estimated Fair Value
Due in less than one year	$	1,641.1	$	1,640.0
Due between one and five years	120.4		119.7
Total	$	1,761.5	$	1,759.7

The following tables present the Company's total fixed income securities that were in an unrealized loss position as of March 31, 2019 and December 31, 2018 (in millions):



	As of March 31, 2019
	Less than 12 Months				12 Months or Greater					Total
	Fair Value		Unrealized Loss		Fair Value		Unrealized Loss			Fair Value		Unrealized Loss
Fixed income securities:
Asset-backed securities	$	0.2	$	—	$	27.7	$	(0.1	)	$	27.9	$	(0.1	)
Corporate debt securities	47.3		—		278.1		(1.3		)	325.4		(1.3		)
Foreign government debt securities	5.5		—		17.3		(0.1		)	22.8		(0.1		)
U.S. government agency securities	—		—		23.6		(0.1		)	23.6		(0.1		)
U.S. government securities	312.0		—		46.4		(0.3		)	358.4		(0.3		)
Total fixed income securities	$	365.0	$	—	$	393.1	$	(1.9	)	$	758.1	$	(1.9	)



	As of December 31, 2018
	Less than 12 Months					12 Months or Greater					Total
	Fair Value		Unrealized Loss			Fair Value		Unrealized Loss			Fair Value		Unrealized Loss
Fixed income securities:
Asset-backed securities	$	3.1	$	—		$	43.0	$	(0.3	)	$	46.1	$	(0.3	)
Corporate debt securities	72.6		(0.1		)	330.7		(3.0		)	403.3		(3.1		)
Foreign government debt securities	1.5		—			18.4		(0.1		)	19.9		(0.1		)
U.S. government agency securities	2.0		—			45.2		(0.2		)	47.2		(0.2		)
U.S. government securities	344.0		—			63.5		(0.5		)	407.5		(0.5		)
Total fixed income securities	$	423.2	$	(0.1	)	$	500.8	$	(4.1	)	$	924.0	$	(4.2	)

For available-for-sale debt securities that have unrealized losses, the Company assesses impairment by evaluating various factors, including whether (i) it has the intention to sell any of these investments and (ii) whether it is more likely than not that it will be required to sell any of these investments before recovery of the entire amortized cost basis. As of March 31, 2019, the Company had 382 investments in unrealized loss positions. The gross unrealized losses related to these investments were primarily due to changes in market interest rates. The Company anticipates that it will recover the entire amortized cost basis of such available-for-sale debt securities and has determined that no other-than-temporary impairments associated with credit losses were required to be recognized during the three months ended March 31, 2019 and March 31, 2018.

During the three months ended March 31, 2019 and March 31, 2018, there were no material gross realized gains or losses from available-for-sale debt securities.

Investments in Equity Securities

The following table presents the Company's investments in equity securities as of March 31, 2019 and December 31, 2018 (in millions):



	As of
	March 31, 2019		December 31, 2018
Equity investments with readily determinable fair value
Money market funds⁽¹⁾	$	836.7	$	996.9
Mutual funds⁽²⁾	26.2		24.3
Publicly-traded equity securities	1.8		2.8
Equity investments without readily determinable fair value	42.1		36.4
Total equity securities	$	906.8	$	1,060.4

Reported as:
Cash equivalents	$	825.1	$	985.3
Short-term investments	1.8		2.8
Prepaid expenses and other current assets	11.2		10.9
Other long-term assets	68.7		61.4
Total	$	906.8	$	1,060.4

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⁽¹⁾	Balance includes $11.6 million and $11.6 million in restricted investments measured at fair value, related to the Company's acquisition-related escrow accounts as of March 31, 2019 and December 31, 2018, respectively.


⁽²⁾	Balance relates to restricted investments measured at fair value related to the Company's Deferred Compensation Plan.

For the three months ended March 31, 2019 and March 31, 2018, there were no material unrealized gains or losses recognized for equity investments.

Restricted Cash and Investments

As of March 31, 2019, the carrying value of restricted cash and investments was $55.3 million, of which $28.8 million was included in prepaid expenses and other current assets and $26.5 million was included in other long-term assets on the Condensed Consolidated Balance Sheet.

The following table provides a reconciliation of cash, cash equivalents, and restricted cash included in the Condensed Consolidated Balance Sheets as of March 31, 2019 and December 31, 2018 (in millions):



	As of
	March 31, 2019		December 31, 2018
Cash and cash equivalents	$	2,155.6	$	2,489.0
Restricted cash included in Prepaid expenses and other current assets	17.5		16.8
Total cash, cash equivalents, and restricted cash	$	2,173.1	$	2,505.8