INVESTMENTS (Tables)

12 Months Ended

Dec. 31, 2018

Investments, Debt and Equity Securities [Abstract]

Schedule of Investments in Debt Securities

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



	December 31, 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	$	20.0	$	—	$	—		$	20.0	$	382.9	$	—	$	—		$	382.9
Commercial paper	—		—		—			—		1.4		—		—			1.4
U.S. government and agency securities	—		—		—			—		3.9		—		—			3.9
	$	20.0	$	—	$	—		$	20.0	$	388.2	$	—	$	—		$	388.2

Available-for-sale
Bank time deposits	$	—	$	—	$	—		$	—	$	0.5	$	—	$	—		$	0.5
Commercial paper	56.7		—		—			56.7		40.3		—		—			40.3
U.S. government and agency securities	79.7		0.2		(0.7		)	79.2		69.4		—		(0.7		)	68.7
Foreign government bonds	1.7		—		—			1.7		3.0		—		—			3.0
Asset-backed securities	110.6		0.1		(0.5		)	110.2		121.2		—		(0.4		)	120.8
Corporate debt securities	459.8		0.1		(4.3		)	455.6		446.5		0.8		(1.8		)	445.5
Municipal securities	2.8		—		—			2.8		4.4		—		—			4.4
	$	711.3	$	0.4	$	(5.5	)	$	706.2	$	685.3	$	0.8	$	(2.9	)	$	683.2

Schedule of Cost and Fair Value of Investments in Debt Securities, by Contractual Maturity

The cost and fair value of investments in debt securities, by contractual maturity, as of December 31, 2018 were as follows:



	Held-to-Maturity				Available-for-Sale
	Cost		Fair Value		Cost		Fair Value
	(in millions)
Due in 1 year or less	$	20.0	$	20.0	$	223.2	$	222.4
Due after 1 year through 5 years	—		—		385.6		381.7
Instruments not due at a single maturity date	—		—		102.5		102.1
	$	20.0	$	20.0	$	711.3	$	706.2

Gross Unrealized Losses and Fair Values for Investments in Unrealized Loss Position

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



	December 31, 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
U.S. government and agency securities	$	0.7	$	(0.1	)	$	56.5	$	(0.6	)	$	57.2	$	(0.7	)
Asset-backed securities	4.0		0.1			61.3		(0.6		)	65.3		(0.5		)
Corporate debt securities	177.4		(1.1		)	203.7		(3.2		)	381.1		(4.3		)
	$	182.1	$	(1.1	)	$	321.5	$	(4.4	)	$	503.6	$	(5.5	)



	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
U.S. government and agency securities	$	31.5	$	(0.2	)	$	37.1	$	(0.5	)	$	68.6	$	(0.7	)
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		)
	$	375.6	$	(1.7	)	$	119.5	$	(1.2	)	$	495.1	$	(2.9	)

Schedule of Investments in Unconsolidated Affiliates

Investments in these unconsolidated affiliates are recorded in "Long-term Investments" on the consolidated balance sheets, and are as follows:



	December 31,
	2018			2017
	(in millions)
Equity method investments
Cost	$	9.1		$	9.2
Equity in losses	(4.7		)	(5.1		)
Carrying value of equity method investments	4.4			4.1
Equity securities
Carrying value of non-marketable equity securities	18.1			10.7
Total investments in unconsolidated affiliates	$	22.5		$	14.8