Consolidated Balance Sheets (Parenthetical) (USD $) In Millions, except Per Share data, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Preferred stock, no par value
Preferred stock, shares authorized	25.0	25.0
Preferred stock, issued
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	450.0	450.0
Common stock, shares issued	197.9	197.9
Treasury stock, shares	68.6	64.5