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Share Capital (Share Capital) (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2019 | Dec. 31, 2018
Reconciliation of number of shares outstanding [abstract] |  |
Beginning balance | $ 2,602.3 |
Shares issued through: |  |
Cancellation of unexchanged post-amalgamation shares (in shares) | (119,237) |
Ending balance | $ 2,695.3 | $ 2,602.3
Issued capital [member] |  |
Reconciliation of number of shares outstanding [abstract] |  |
Number of shares outstanding | 391,250,203.000 | 389,101,550.000
Beginning balance | $ 3,705.2 | $ 3,691.7
Shares issued through: |  |
Share-based compensation plans (in shares) | 1,555,989 | 1,984,698
Share-based compensation plans | $ 9.5 | $ 12.9
Exercise of warrants (in shares) | 45 | 163,955
Exercise of warrants | $ 0.0 | $ 0.6
Shares repurchased and cancelled (in shares) | (2,748,352) |
Shares repurchased and cancelled (i) | $ (26.1) |
Flow-through share financing (in shares) | 1,132,169 |
Flow-through share financing | $ 5.9 |
Cancellation of unexchanged post-amalgamation shares | $ (1.2) | $ 0.0
Number of shares outstanding | 391,070,817.000 | 391,250,203.000
Ending balance | $ 3,693.3 | $ 3,705.2

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