Consolidated Balance Sheets (Parenthetical) (USD $) In Millions, except Per Share data, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Allowance for doubtful accounts	$ 2.4	$ 2.4
Common stock, par value	$ 1	$ 1
Common stock, shares authorized	90.0	90.0
Common stock, shares issued	63.4	63.4
Treasury stock, shares	1.0	1.0