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Revenue - Contract Costs, Assets and Liabilities (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Disaggregation of Revenue [Line Items]    
Contract liabilities $ 30.7 $ 32.4
Contract with Customer, Liability, Revenue Recognized $ 32.4 $ 26.4