Consolidated Balance Sheets (Parenthetical) (USD $) In Millions, except Share data, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Statement of Financial Position [Abstract]
Allowances, accounts and notes receivable	$ 9.5	$ 11.3
Accumulated depreciation	$ 580.3	$ 554.0
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	25,000,000	25,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	87,170,197	86,938,004
Treasury stock, shares	36,885,101	36,093,966