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Equity Method Investment in ARO - Schedule of Related Parties (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2023
Sep. 30, 2022
Sep. 30, 2023
Sep. 30, 2022
Dec. 31, 2022
Schedule of Equity Method Investments [Line Items]          
Amounts receivable (1) $ 17.6   $ 17.6   $ 12.0
Contract liabilities(2) 13.1   13.1   16.7
Accounts payable(2) 54.9   54.9   43.2
Carrying value 275.2   275.2   254.0
Non-cash amortization (1)(2)     21.2 $ 37.8  
ARO          
Schedule of Equity Method Investments [Line Items]          
Principal amount 402.7   402.7   402.7
Discount (127.5)   (127.5)   (148.7)
Carrying value 275.2   275.2   254.0
Interest receivable 22.8   22.8   $ 0.0
Interest income 7.7 $ 2.8 22.8 8.6  
Non-cash amortization (1)(2) 7.2 22.4 21.2 37.8  
Total interest income on the Notes Receivable from ARO $ 14.9 $ 25.2 $ 44.0 $ 46.4