v3.26.1
Share Capital (Share Capital) (Details) - USD ($)
$ in Millions
 3 Months Ended 12 Months Ended
Jun. 30, 2024
Dec. 31, 2025
Dec. 31, 2024
Reconciliation of number of shares outstanding [abstract]      
Beginning balance   $ 3,584.2  
Shares issued through:      
Shares repurchased and cancelled (in shares) (451,990)    
Repurchase and cancellation of common shares (Note 19)   (38.8) $ 0.0
Exercise of Manitou warrants (in shares)     88,308
Ending balance   $ 4,445.8 $ 3,584.2
Issued capital [member]      
Reconciliation of number of shares outstanding [abstract]      
Number of shares outstanding   420,365,051 396,956,984
Beginning balance   $ 4,138.5 $ 3,738.6
Shares issued through:      
Share-based employment compensation plans (in shares)   411,984 1,006,149
Share-based compensation plans   $ 4.5 $ 8.6
Shares repurchased and cancelled (in shares)   1,326,929  
Repurchase and cancellation of common shares (Note 19)   $ (13.1) $ 0.0
Flow-through share financing (in shares)     451,990
Flow-through share financing   $ 0.0 $ 6.5
Dividend reinvestment plan and share purchase plan (in shares)   90,767 349,088
Shares issued during period, value, DRIP   $ 2.6 $ 5.8
Shares issued through share purchase plan (in shares)   252,730 401,537
ESPP (iv)   $ 6.6 $ 6.3
Exercise of Manitou warrants (in shares)   67,141  
Exercise of Orford warrants and stock options   $ 1.5 1.4
Shares repurchased and cancelled (i)   $ 0.0 $ (2.1)
Cancellation of unexchanged shares (in shares)     (220,745)
Number of shares outstanding   419,860,744 420,365,051
Ending balance   $ 4,140.6 $ 4,138.5
Issued capital [member] | Argonaut Transaction      
Shares issued through:      
Shares repurchased and cancelled (in shares)     20,423,051
Increase (decrease) through acquisition of subsidiary, equity     $ 360.1
Issuance of shares related to Argonaut Gold Inc. ("Argonaut") acquisition (Note 6)   $ 0.0 $ 360.1
Issued capital [member] | Orford Mining Corp.      
Shares issued through:      
Shares repurchased and cancelled (in shares)     908,689
Repurchase and cancellation of common shares (Note 19)     $ 13.3