Marketable Securities and Equity Investments - Available-for-Sale Debt Securities at Fair Value (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Debt Securities, Available-for-sale [Line Items]
Debt Securities	$ 5,642.8	$ 3,977.1
Cash and cash equivalents
Debt Securities, Available-for-sale [Line Items]
Debt Securities	5,372.9	3,478.1
Marketable securities
Debt Securities, Available-for-sale [Line Items]
Debt Securities	157.7	499.0
Other assets
Debt Securities, Available-for-sale [Line Items]
Debt Securities	$ 112.2	$ 0.0