XML 65 R53.htm IDEA: XBRL DOCUMENT v3.22.0.1
Marketable Investment Securities - Cash, Cash Equivalents, and Maturities of Debt Securities Classified as Available-For-Sale Securities (Details) - USD ($)
$ in Millions
Dec. 31, 2021
Dec. 31, 2020
Amortized cost    
Cash and cash equivalents $ 258.4 $ 117.0
Available-for-sale, Due within one year 80.3  
Available-for-sale, Due after one year through five years 60.2  
Available-for-sale, Due after five years 0.0  
Total, Amortized cost 398.9 170.9
Estimated fair value    
Cash and cash equivalents 258.4 117.0
Available-for-sale, Due within one year 80.4  
Available-for-sale, Due after one year through five years 60.0  
Available-for-sale, Due after five years 0.0  
Total, Estimated fair value 398.8 171.7
Cash    
Amortized cost    
Cash and cash equivalents 195.2 47.9
Estimated fair value    
Cash and cash equivalents 195.2 47.9
Cash equivalents    
Amortized cost    
Cash and cash equivalents 63.2 69.1
Estimated fair value    
Cash and cash equivalents $ 63.2 $ 69.1