Cash Equivalents and Investments - Maturities of Fixed Income Securities (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Amortized Cost
Amortized Cost	$ 437.8	$ 821.1
Estimated Fair Value
Total	465.7	857.1
Fixed income securities
Amortized Cost
Due in less than one year	276.5
Due between one and five years	145.8
Amortized Cost	422.3	811.5
Estimated Fair Value
Due in less than one year	273.2
Due between one and five years	139.6
Total	$ 412.8	$ 810.1

Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in second through fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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