Equity Method Investments (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]
Equity method investments	$ 47.5		$ 47.5		$ 34.1
Income (Loss) from Equity Method Investments	(5.6)	$ (27.5)	(9.7)	$ (120.9)
Middlemount Mine
Schedule of Equity Method Investments [Line Items]
Equity method investments	40.2		40.2		27.1
Income (Loss) from Equity Method Investments	8.2	28.4	14.9	123.6
R3 Renewables
Schedule of Equity Method Investments [Line Items]
Equity method investments	7.3		7.3		$ 7.0
Income (Loss) from Equity Method Investments	$ (2.6)	$ (0.9)	$ (5.2)	$ (2.7)