Goodwill and Intangible Assets, net - Other Intangible Assets (Details) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Other Intangible Assets [Line Items]
Finite-lived intangible assets, gross	$ 1,049.8	$ 613.4
Total intangible assets	1,103.5	667.2
Accumulated Amortization	(256.2)	(206.8)
Tradenames and other
Other Intangible Assets [Line Items]
Indefinite-lived intangible assets (excluding goodwill)	53.7	53.8
Patents, tradenames and trademarks
Other Intangible Assets [Line Items]
Finite-lived intangible assets, gross	204.9	151.4
Accumulated Amortization	(56.5)	(50.1)
Customer/agent relationships and other
Other Intangible Assets [Line Items]
Finite-lived intangible assets, gross	844.9	462.0
Accumulated Amortization	$ (199.7)	$ (156.7)