Shareholders' Equity - Components of Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Components of Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Foreign currency translation	$ (248.8)	$ (289.1)
Translation gain on net investment hedge, net of income taxes of $7.9 and $11.2, respectively	19.1	24.8
Translation gain (loss) on net investment hedge, tax	7.9	11.2
Translation loss on long-term intercompany loans	(130.2)	(133.7)
Unrealized gain on investments, net of income taxes of $4.7 and $4.2, respectively	21.0	18.6
Unrealized gain (loss) on investments, tax	4.7	4.2
Defined Benefit Plan Disclosure [Line Items]
Accumulated other comprehensive loss	(385.4)	(426.1)
Defined benefit pension plans, net of income taxes of $(27.7) and $(27.8), respectively
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plans	(50.1)	(50.4)
Defined benefit plans, taxes	(27.7)	(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	3.6	3.7
Defined benefit plans, taxes	$ 2.0	$ 2.1