CONSOLIDATED CONDENSED BALANCE SHEETS (Parenthetical) (USD $) In Millions, except Per Share data, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Statement Of Financial Position [Abstract]
Common stock, shares authorized	250.0	250.0
Common stock, par value	$ 1	$ 1
Common stock, shares issued	104.0	104.0
Common stock, shares outstanding	91.2	92.1
Unvested restricted common stock included in shares issued and outstanding		0.2