INVESTMENTS (Tables)

9 Months Ended

Sep. 30, 2020

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, 2020									December 31, 2019
Held-to-maturity	Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value		Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Bank time deposits	$	—	$	—	$	—		$	—	$	100.2	$	—	$	—			$	100.2
Available-for-sale
Bank time deposits	$	33.3	$	—	$	—		$	33.3	$	13.1	$	—	$	—			$	13.1
Commercial paper	60.1		—		—			60.1		34.3		—		—				34.3
U.S. government and agency securities	130.3		2.5		—			132.8		113.2		0.6		—				113.8
Foreign government bonds	1.7		—		—			1.7		1.7		—		—				1.7
Asset-backed securities	135.3		1.9		—			137.2		141.2		0.6		(0.1		)		141.7
Corporate debt securities	465.0		7.0		(0.1		)	471.9		487.0		2.3		(0.1		)		489.2
Total	$	825.7	$	11.4	$	(0.1	)	$	837.0	$	790.5	$	3.5	$	(0.2	)		$	793.8

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, 2020, were as follows:

	Available-for-Sale
	Cost		Fair Value
	(in millions)
Due in 1 year or less	$	270.2	$	271.3
Due after 1 year through 5 years	407.6		415.2
Instruments not due at a single maturity date	147.9		150.5
	$	825.7	$	837.0

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, 2020 and December 31, 2019, aggregated by investment category and the length of time that individual securities have been in a continuous loss position (in millions):

	September 30, 2020
	Less than 12 Months					12 Months or Greater				Total
	Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses
Corporate debt securities	$	28.5	$	(0.1	)	$	—	$	—	$	28.5	$	(0.1	)

	December 31, 2019
	Less than 12 Months					12 Months or Greater				Total
	Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses
Asset-backed securities	$	73.4	$	(0.1	)	$	—	$	—	$	73.4	$	(0.1	)
Corporate debt securities	81.4		(0.1		)	—		—		81.4		(0.1		)
	$	154.8	$	(0.2	)	$	—	$	—	$	154.8	$	(0.2	)

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, 2020			December 31, 2019
	(in millions)
Equity method investments
Cost	$	10.1		$	10.7
Equity in losses	(4.6		)	(4.5		)
Carrying value of equity method investments	5.5			6.2
Equity securities
Carrying value of non-marketable equity securities	27.8			23.1
Total investments in unconsolidated affiliates	$	33.3		$	29.3