XML 93 R74.htm IDEA: XBRL DOCUMENT v3.6.0.2
Fair Value Measurements - Summary of Financial Liabilities not Carried at Fair Value (Details) - Level 2 - USD ($)
$ in Millions
Dec. 31, 2016
Dec. 31, 2015
Carrying Amount    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Senior notes $ 945.1 $ 944.6
Convertible securities 307.5 305.2
Fair Value    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Senior notes 936.0 966.3
Convertible securities $ 466.9 $ 483.6