Consolidated Balance Sheets (Parenthetical) (USD $) In Millions, except Share data, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Redeemable convertible preferred stock, liquidation preference	$ 50	$ 50
Redeemable convertible preferred stock, shares outstanding	76,002	76,002
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares issued	49,693,532	49,697,763
Common stock, shares outstanding	49,693,532	49,697,763
Treasury stock, shares	8,738,094	8,758,267
Allowance for Doubtful Accounts [Member]
Allowances for receivables	$ 34.3	$ 17.2