XML 108 R85.htm IDEA: XBRL DOCUMENT v3.22.0.1
Financial Instruments and Risk Management (Market Price Risk) (Details)
$ in Millions
 12 Months Ended
Dec. 31, 2021
USD ($)
Dec. 31, 2020
USD ($)
$ / oz
Disclosure of detailed information about hedged items [line items]    
Unrealized gains $ 0.4 $ 0.7
Market risk [member]    
Disclosure of detailed information about hedged items [line items]    
Potential percentage change in value 1000.00%  
Impact on other comprehensive income $ 2.4 4.3
Gold Options [Member] | Market risk [member]    
Disclosure of detailed information about hedged items [line items]    
Potential percentage change in value 10.00%  
Impact on pre-tax earnings $ 81.2 $ 73.8
Bottom of range [member] | Gold Options [Member] | Market risk [member]    
Disclosure of detailed information about hedged items [line items]    
Average realized price per ounce | $ / oz   1,684
Top of range [member] | Gold Options [Member] | Market risk [member]    
Disclosure of detailed information about hedged items [line items]    
Average realized price per ounce | $ / oz   1,943