INVESTMENTS (Tables)

9 Months Ended

Sep. 30, 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):

	September 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	$	190.0	$	—	$	—		$	190.0	$	382.9	$	—	$	—			$	382.9
Commercial paper	—		—		—			—		1.4		—		—				1.4
U.S. government and agency securities	—		—		—			—		3.9		—		—				3.9
Total	$	190.0	$	—	$	—		$	190.0	$	388.2	$	—	$	—			$	388.2
Available-for-sale
Bank time deposits	$	—	$	—	$	—		$	—	$	0.5	$	—	$	—			$	0.5
Commercial paper	21.2		—		—			21.2		40.3		—		—				40.3
U.S. government and agency securities	82.2		—		(0.9		)	81.3		69.4		—		(0.7		)		68.7
Foreign government bonds	1.7		—		—			1.7		3.0		—		—				3.0
Asset-backed securities	94.1		—		(0.7		)	93.4		121.2		—		(0.4		)		120.8
Corporate debt securities	403.8		0.9		(3.9		)	400.8		446.5		0.8		(1.8		)		445.5
Municipal securities	2.8		—		—			2.8		4.4		—		—				4.4
Total	$	605.8	$	0.9	$	(5.5	)	$	601.2	$	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 September 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	$	190.0	$	190.0	$	145.2	$	144.4
Due after 1 year through 5 years	—		—		372.0		368.9
Due after 5 years through 10 years	—		—		1.0		1.0
Instruments not due at a single maturity date	—		—		87.6		86.9
	$	190.0	$	190.0	$	605.8	$	601.2

Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value

The following tables present gross unrealized losses and fair values for those investments that were in an unrealized loss position as of September 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):

	September 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	$	7.5	$	—		$	—	$	—		$	7.5	$	—
U.S. government and agency securities	122.0		(0.3		)	41.3		(0.6		)	163.3		(0.9		)
Foreign government bonds	1.7		—			—		—			1.7		—
Asset-backed securities	39.0		(0.2		)	43.1		(0.5		)	82.1		(0.7		)
Corporate debt securities	158.8		(2.0		)	98.6		(1.9		)	257.4		(3.9		)
Municipal securities	2.8		—			—		—			2.8		—
	$	331.8	$	(2.5	)	$	183.0	$	(3.0	)	$	514.8	$	(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
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	)

Schedule of Investments in Unconsolidated Affiliates

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

	September 30, 2018			December 31, 2017
	(in millions)
Equity method investments
Cost	$	9.5		$	9.2
Equity in losses	(5.1		)	(5.1		)
Carrying value of equity method investments	4.4			4.1
Equity securities
Carrying value of non-marketable equity securities	17.8			10.7
Total investments in unconsolidated affiliates	$	22.2		$	14.8