Consolidated Statements of Comprehensive Income (Unaudited) (Parenthetical) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Other comprehensive income:
Income tax expense (benefit) on translation adjustments on net investment hedge	$ (3.3)	$ (12.0)
Income tax expense (benefit) on unrealized gain (loss) on investments	0.5	(0.1)
Income tax expense (benefit) on defined benefit pension plans and retiree health care plan	$ 0.0	$ (0.3)