Financial Instruments (Details 2) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Summary of Contractual Maturities: Available-for-Sale Securities
Due in one year or less, amortized cost	$ 2,151.5	$ 1,483.3
Due in one year or less, estimated fair value	2,143.1	1,473.5
Due after one year through five years, amortized cost	965.8	703.7
Due after one year through five years, estimated fair value	962.2	694.4
Due after five years, amortized cost	16.6	12.1
Due after five years, estimated fair value	16.0	11.3
Marketable debt securities	3,121.3	2,179.2
Amortized Cost	$ 3,133.9	$ 2,199.1