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Summary of Significant Accounting Policies - Summary of Allowance for Credit Losses (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Accounts Receivable, Allowance for Credit Loss [Roll Forward]      
Beginning balance $ 71.9 $ 47.6  
Amounts accrued 35.8 29.3 $ 31.3
Write-offs charged against the allowance (45.0) (5.0)  
Ending balance 71.6 71.9 $ 47.6
Cumulative Effect, Period of Adoption, Adjustment      
Accounts Receivable, Allowance for Credit Loss [Roll Forward]      
Beginning balance 8.9    
Ending balance   8.9  
Cumulative Effect, Period of Adoption, Adjusted Balance      
Accounts Receivable, Allowance for Credit Loss [Roll Forward]      
Beginning balance $ 80.8    
Ending balance   $ 80.8