XML 145 R120.htm IDEA: XBRL DOCUMENT v3.8.0.1
Share-based payment plans - Expenses (Details) - USD ($)
$ in Millions
3 Months Ended 12 Months Ended
Jun. 30, 2016
Dec. 31, 2017
Dec. 31, 2016
Share-based payment plans      
Executive compensation settlement $ 11.9   $ 11.9
Accelerated vesting of share-based payment awards   $ 33.1  
Total share-based compensation expense   57.9 14.7
Cash-settled SARs      
Share-based payment plans      
Cash settled share based compensation expense   12.2 (5.2)
Equity-settled SARs      
Share-based payment plans      
Equity settled share based compensation expense   7.8 6.9
Cash-settled DSUs      
Share-based payment plans      
Equity settled share based compensation expense   0.9 0.4
Equity-settled DSUs      
Share-based payment plans      
Equity settled share based compensation expense   2.9  
Share matching program      
Share-based payment plans      
Share-based compensation expense excluding settlements, cash and equity-settled transactions   0.3 0.1
Employee Share Purchase Plan      
Share-based payment plans      
Share-based compensation expense excluding settlements, cash and equity-settled transactions   $ 0.7 $ 0.6