Shareholders' Equity - Components of Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Components of Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Foreign currency translation	$ (155.0)	$ (289.1)
Translation (loss) gain on net investment hedge, net of income taxes of $(10.5) and $11.2, respectively	(13.9)	24.8
Translation gain (loss) on net investment hedge, tax	(10.5)	11.2
Translation loss on long-term intercompany loans	(131.4)	(133.7)
Unrealized gain on investments, net of income taxes of $4.8 and $4.2, respectively	21.6	18.6
Unrealized gain (loss) on investments, tax	4.8	4.2
Defined Benefit Plan Disclosure [Line Items]
Accumulated other comprehensive loss	(324.7)	(426.1)
Defined benefit pension plans, net of income taxes of $(27.5) and $(27.8), respectively
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plans	(49.5)	(50.4)
Defined benefit plans, taxes	(27.5)	(27.8)
Retiree health care plan, net of income taxes of $2.0 and $2.1, respectively
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plans	3.5	3.7
Defined benefit plans, taxes	$ 2.0	$ 2.1