XML 149 R119.htm IDEA: XBRL DOCUMENT v3.8.0.1
Capital Structure - Preferred Stock (Details) - USD ($)
$ in Millions
12 Months Ended
Jun. 13, 2016
May 24, 2016
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Capital Structure            
Redemption of shares (as percentage) 100.00% 100.00%        
Preferred shares repurchased   $ 344.5        
Repurchase of outstanding shares     $ 0.0 $ 226.0 $ 0.0  
Gain on redemption of preferred shares     0.0 78.0 0.0  
Carrying value of preferred stock at time of redemption     $ 0.0 $ 0.0 $ 302.0 $ 291.0
Convertible Preferred Stock            
Capital Structure            
Preferred stock, dividend rate (as percent)   2.822% 2.822% 2.822% 2.822%  
Repurchase of outstanding shares $ 226.0          
Gain on redemption of preferred shares 78.0          
Carrying value of preferred stock at time of redemption $ 304.0