Earnings Per Share - Schedule of Basic and Diluted Earnings Per Share (Details) - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Numerator
Net income (controlling interest)	$ 122.5	$ 104.0
Interest expense on convertible securities, net of taxes	3.8	3.8
Net income (controlling interest), as adjusted	$ 126.3	$ 107.8
Denominator
Average shares outstanding—basic (in shares)	56.7	54.0
Effect of dilutive instruments:
Stock options and restricted stock (in shares)	0.3	0.4
Junior convertible securities (in shares)	2.2	2.2
Average shares outstanding—diluted (in shares)	59.2	56.6