Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2022

Fair Value Disclosures [Abstract]

Schedule of assets measured at fair value on a recurring basis

The table below summarizes the Company's assets which are measured at fair value on a recurring basis. The following fair value hierarchy is used to classify assets, based on inputs to valuation techniques utilized to measure fair value:

•Level 1 - Quoted prices in active markets for identical assets

•Level 2 - Significant other observable inputs, such as quoted market prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active, or model-based valuations in which significant inputs used are observable

•Level 3 - Significant other unobservable inputs

(In millions)			Fair Value Measurements at Reporting Date
As of December 31, 2022	Fair Value		Level 1		Level 2
Available-for-sale debt securities:
Corporate bonds	$	6,684.4	$	—	$	6,684.4
U.S. government and government agency obligations	2,939.4		—		2,939.4
Sovereign bonds	64.1		—		64.1
Commercial paper	121.1		—		121.1
Certificates of deposit	182.0		—		182.0
Asset-backed securities	27.2		—		27.2
Equity securities (unrestricted)	24.6		24.6		—
Equity securities (restricted)	1,185.4		1,185.4		—
	$	11,228.2	$	1,210.0	$	10,018.2
As of December 31, 2021
Available-for-sale debt securities:
Corporate bonds	$	7,487.7	$	—	$	7,487.7
U.S. government and government agency obligations	108.5		—		108.5
Sovereign bonds	64.4		—		64.4
Commercial paper	439.6		—		439.6
Certificates of deposit	255.1		—		255.1
Asset-backed securities	41.9		—		41.9
Equity securities (unrestricted)	58.4		58.4		—
Equity securities (restricted)	1,191.5		1,191.5		—
	$	9,647.1	$	1,249.9	$	8,397.2