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Other Long-term Liabilities - Schedule of Other Long-term Liabilities (Details) - USD ($)
$ in Millions
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Other Liabilities Noncurrent [Abstract]      
Deferred revenue $ 168.5 $ 172.0 $ 175.5
Asset retirement obligations 68.3 66.3 $ 55.5
Operating lease liabilities 46.2 47.2  
Other liabilities 26.1 20.1  
Total long-term liabilities $ 309.1 $ 305.6