XML 68 R55.htm IDEA: XBRL DOCUMENT v3.8.0.1
Share-Based Compensation - Summary of Share-Based Compensation (Details) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2017
Sep. 30, 2016
Sep. 30, 2017
Sep. 30, 2016
Dec. 31, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]          
Share-based compensation $ 10.3 $ 10.7 $ 30.0 $ 30.7  
Tax benefit 4.0 $ 4.1 11.5 $ 11.8  
Compensation expense related to share-based compensation $ 73.8   $ 73.8   $ 66.4
Weighted average period over which compensation expense will be recognized     3 years