Asset Retirement Obligations (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at beginning of period	$ 728.2	$ 752.3
Liabilities settled or disposed	(72.4)	(38.4)
Accretion expense	54.9	56.0
Revisions to estimates	9.1	(41.7)
Balance at end of period	719.8	728.2
Less: Current portion (included in “Accounts payable and accrued expenses”)	65.0	77.7
Asset retirement obligations	654.8	650.5
Balance at end of period — active locations	511.8	471.8
Balance at end of period — closed or inactive locations	208.0	256.4
Surety bonds and bank guarantees outstanding to secure reclamation obligations or activities	1,294.7	1,451.9
Letters of credit in support of reclamation obligations or activities	$ 323.0	$ 315.0
Maximum
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Life of mine	20 years
Minimum
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Life of mine	3 years
LOM 3 Years or Less
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Credit adjusted risk free interest rates	7.89%	9.16%
LOM Greater than 20 Years
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Credit adjusted risk free interest rates	10.12%	12.74%