Shareholders' Equity - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions				3 Months Ended		9 Months Ended
	May 10, 2019	Nov. 09, 2018	May 04, 2018	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Oct. 31, 2019	Aug. 31, 2018	Jul. 31, 2016
Equity, Class of Treasury Stock [Line Items]
Interest and other expenses (income), net				$ 12.2	$ 11.8	$ (46.1)	$ 38.4
Dividends declared (in dollars per share)	$ 1.09	$ 1.01	$ 1.01
Dividends paid date	Jun. 14, 2019	Dec. 14, 2018	Jun. 15, 2018
Dividends record date	Jun. 03, 2019	Dec. 03, 2018	Jun. 01, 2018
Total cost of shares repurchased						$ 152.0	$ 299.2
Common Stock Repurchase 2019 Authorization
Equity, Class of Treasury Stock [Line Items]
Shares authorized to be repurchased (in shares)								6,000,000.0
Shares remaining authorized for repurchase (in shares)				6,000,000.0		6,000,000.0
Common Stock Repurchase 2018 Authorization
Equity, Class of Treasury Stock [Line Items]
Shares authorized to be repurchased (in shares)					300,000		300,000		6,000,000.0
Shares repurchased during period (in shares)						1,800,000
Shares remaining authorized for repurchase (in shares)				1,300,000		1,300,000
2016 Authorization
Equity, Class of Treasury Stock [Line Items]
Shares authorized to be repurchased (in shares)					2,800,000		2,800,000			6,000,000.0
Shares repurchased during period (in shares)							3,100,000
Shares remaining authorized for repurchase (in shares)				0		0
Non-Controlling Interests
Equity, Class of Treasury Stock [Line Items]
Interest and other expenses (income), net				$ 0.2	$ 1.3	$ 1.3	$ 3.5