Marketable Securities (Tables)

12 Months Ended

Dec. 31, 2022

Investments, Debt and Equity Securities [Abstract]

Available-for-sale debt securities

The following tables summarize the Company's investments in available-for-sale debt securities:

(In millions)	Amortized		Unrealized				Fair
As of December 31, 2022	Cost Basis		Gains		Losses		Value
Corporate bonds	$	6,975.5	$	—	$	(291.1)	$	6,684.4
U.S. government and government agency obligations	2,945.4		0.9		(6.9)		2,939.4
Sovereign bonds	67.1		—		(3.0)		64.1
Commercial paper	121.1		—		—		121.1
Certificates of deposit	182.1		—		(0.1)		182.0
Asset-backed securities	28.9		—		(1.7)		27.2
	$	10,320.1	$	0.9	$	(302.8)	$	10,018.2
As of December 31, 2021
Corporate bonds	$	7,518.4	$	10.2	$	(40.9)	$	7,487.7
U.S. government and government agency obligations	109.0		0.3		(0.8)		108.5
Sovereign bonds	64.4		0.3		(0.3)		64.4
Commercial paper	439.7		—		(0.1)		439.6
Certificates of deposit	255.2		—		(0.1)		255.1
Asset-backed securities	42.0		—		(0.1)		41.9
	$	8,428.7	$	10.8	$	(42.3)	$	8,397.2

Marketable securities, based on contractual maturity dates

The fair values of available-for-sale debt securities by contractual maturity consist of the following:

	As of December 31,
(In millions)	2022		2021
Maturities within one year	$	4,636.4	$	2,809.1
Maturities after one year through five years	5,381.4		5,588.1
Maturities after five years	0.4		—
	$	10,018.2	$	8,397.2

Fair value and unrealized losses of marketable securities

The following table shows the fair value of the Company's available-for-sale debt securities that have unrealized losses, aggregated by investment category and length of time that the individual securities have been in a continuous loss position.

	Less than 12 Months				12 Months or Greater				Total
(In millions) As of December 31, 2022	Fair Value		Unrealized Loss		Fair Value		Unrealized Loss		Fair Value		Unrealized Loss
Corporate bonds	$	2,445.4	$	(73.1)	$	4,200.4	$	(218.0)	$	6,645.8	$	(291.1)
U.S. government and government agency obligations	785.2		(2.0)		71.0		(4.9)		856.2		(6.9)
Sovereign bonds	18.6		(1.1)		45.6		(1.9)		64.2		(3.0)
Certificates of deposit	40.2		(0.1)		—		—		40.2		(0.1)
Asset-backed securities	11.5		(0.6)		15.2		(1.1)		26.7		(1.7)
	$	3,300.9	$	(76.9)	$	4,332.2	$	(225.9)	$	7,633.1	$	(302.8)
As of December 31, 2021
Corporate bonds	$	5,889.3	$	(40.9)	$	—	$	—	$	5,889.3	$	(40.9)
U.S. government and government agency obligations	90.0		(0.8)		—		—		90.0		(0.8)
Sovereign bonds	37.0		(0.3)		—		—		37.0		(0.3)
Commercial paper	295.7		(0.1)		—		—		295.7		(0.1)
Certificates of deposit	169.4		(0.1)		—		—		169.4		(0.1)
Asset-backed securities	34.9		(0.1)		—		—		34.9		(0.1)
	$	6,516.3	$	(42.3)	$	—	$	—	$	6,516.3	$	(42.3)