Unaudited Condensed Consolidated Statement Of Shareholders' Equity (USD $) In Millions, except Share data	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Treasury Stock [Member]
BALANCE, at Dec. 31, 2010	$ 2,078.9	$ 1.6	$ 2.0	$ 2,365.2	$ (289.9)
BALANCE, shares at Dec. 31, 2010		163,562,149
Net income	212.0			212.0
Repurchases of common stock	(367.0)				(367.0)
Stock-based compensation expense	15.7		15.7
Shares awarded under stock-based compensation plans, including income tax benefit of $19.0	85.3		0.3		85.0
BALANCE, at Sep. 30, 2011	$ 2,024.9	$ 1.6	$ 18.0	$ 2,577.2	$ (571.9)
BALANCE, shares at Sep. 30, 2011		163,562,149