INVESTMENTS

Debt Securities

Investments in debt securities at the end of each period were as follows (in millions):



	June 30, 2018									December 31, 2017
Held-to-maturity	Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value		Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Bank time deposits	$	45.7	$	—	$	—		$	45.7	$	382.9	$	—	$	—			$	382.9
Commercial paper	—		—		—			—		1.4		—		—				1.4
U.S. government and agency securities	3.0		—		—			3.0		3.9		—		—				3.9
Total	$	48.7	$	—	$	—		$	48.7	$	388.2	$	—	$	—			$	388.2

Available-for-sale
Bank time deposits	$	0.5	$	—	$	—		$	0.5	$	0.5	$	—	$	—			$	0.5
Commercial paper	18.6		—		—			18.6		40.3		—		—				40.3
U.S. government and agency securities	69.5		—		(0.9		)	68.6		69.4		—		(0.7		)		68.7
Foreign government bonds	3.0		—		—			3.0		3.0		—		—				3.0
Asset-backed securities	96.8		0.1		(1.0		)	95.9		121.2		—		(0.4		)		120.8
Corporate debt securities	390.2		0.6		(4.3		)	386.5		446.5		0.8		(1.8		)		445.5
Municipal securities	4.4		—		—			4.4		4.4		—		—				4.4
Total	$	583.0	$	0.7	$	(6.2	)	$	577.5	$	685.3	$	0.8	$	(2.9	)		$	683.2

The cost and fair value of investments in debt securities, by contractual maturity, as of June 30, 2018 were as follows:



	Held-to-Maturity				Available-for-Sale
	Cost		Fair Value		Cost		Fair Value
	(in millions)
Due in 1 year or less	$	45.7	$	45.7	$	129.3	$	128.7
Due after 1 year through 5 years	—		—		361.7		357.6
Instruments not due at a single maturity date	3.0		3.0		92.0		91.2
	$	48.7	$	48.7	$	583.0	$	577.5

Actual maturities may differ from the contractual maturities due to call or prepayment rights.

The following tables present gross unrealized losses and fair values for those investments that were in an unrealized loss position as of June 30, 2018 and December 31, 2017, aggregated by investment category and the length of time that individual securities have been in a continuous loss position (in millions):



	June 30, 2018
	Less than 12 Months					12 Months or Greater					Total
	Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses
Commercial paper	$	24.6	$	—		$	—	$	—		$	24.6	$	—
U.S. government and agency securities	31.3		(0.4		)	37.0		(0.5		)	68.3		(0.9		)
Foreign government bonds	3.0		—			—		—			3.0		—
Asset-backed securities	73.7		(0.8		)	16.1		(0.2		)	89.8		(1.0		)
Corporate debt securities	217.1		(3.4		)	51.9		(0.9		)	269.0		(4.3		)
Municipal securities	4.3		—			—		—			4.3		—
	$	354.0	$	(4.6	)	$	105.0	$	(1.6	)	$	459.0	$	(6.2	)



	December 31, 2017
	Less than 12 Months					12 Months or Greater					Total
	Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses
Commercial paper	$	2.4	$	—		$	—	$	—		$	2.4	$	—
U.S. government and agency securities	31.5		(0.2		)	37.1		(0.5		)	68.6		(0.7		)
Foreign government bonds	3.0		—			—		—			3.0		—
Asset-backed securities	90.8		(0.3		)	23.2		(0.1		)	114.0		(0.4		)
Corporate debt securities	253.3		(1.2		)	59.2		(0.6		)	312.5		(1.8		)
Municipal securities	4.3		—			—		—			4.3		—
	$	385.3	$	(1.7	)	$	119.5	$	(1.2	)	$	504.8	$	(2.9	)

Investments in Unconsolidated Affiliates

The Company has a number of equity investments in privately and publicly held companies. Investments in these unconsolidated affiliates are recorded in "Long-term Investments" on the consolidated condensed balance sheets, and are as follows:



	June 30, 2018			December 31, 2017
	(in millions)
Equity method investments
Cost	9.5			9.2
Equity in losses	(5.4		)	(5.1		)
Carrying value of equity method investments	4.1			4.1
Equity securities
Carrying value of non-marketable equity securities	14.5			10.7
Total investments in unconsolidated affiliates	$	18.6		$	14.8

Non-marketable equity securities consist of investments in privately held companies without readily determinable fair values, and are reported at cost minus impairment, if any, plus or minus changes resulting from observable price changes in orderly transactions for the identical or similar investment of the same issuer. During the three and six months ended June 30, 2018, the Company recorded $1.7 million of upward adjustments to the carrying value based on observable price changes, and $1.8 million of downward adjustments due to impairment.

During the three and six months ended June 30, 2018, the gross realized gains or losses from sales of available-for-sale investments were not material.