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Commitments and Contingencies - Restricted Cash and Marketable Securities (Details) - USD ($)
$ in Millions
Jun. 30, 2022
Dec. 31, 2021
Jun. 30, 2021
Dec. 31, 2020
Restricted Cash and Marketable Securities [Abstract]        
Financing proceeds $ 2.0 $ 12.4    
Capping, closure and post-closure obligations 38.3 42.4    
Insurance 81.2 84.2    
Total restricted cash and marketable securities $ 121.5 $ 139.0 $ 151.0 $ 149.1