Stockholders' Equity (Components of Stockholders' Equity) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance as of December 31, 2015			$ 2,543.2
Other comprehensive income (loss)	$ 17.3	$ (125.6)	127.5	$ (173.3)
Balance as of September 30, 2016	2,693.9		2,693.9
Common Stock Held In Treasury And Employee Benefit Trust
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance as of December 31, 2015			(1,614.8)
Purchases of treasury stock			(50.6)
Reissuances of treasury stock			21.7
Net purchases of common stock for employee benefit trust			0.2
Balance as of September 30, 2016	(1,643.5)		(1,643.5)
Capital in Excess of Par Value of Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance as of December 31, 2015			759.0
Excess tax benefits on stock-based payment arrangements			0.2
Taxes withheld on issuance of stock-based awards			(8.6)
Reissuances of treasury stock			(21.7)
Net purchases of common stock for employee benefit trust			(0.8)
Stock-based compensation (Note 15)			36.0
Balance as of September 30, 2016	764.1		764.1
Accumulated Other Comprehensive Income (Loss)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance as of December 31, 2015			(872.7)
Other comprehensive income (loss)			127.5
Balance as of September 30, 2016	$ (745.2)		$ (745.2)