Consolidated Balance Sheets (Unaudited) (Parenthetical) (USD $)	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2012
SHAREHOLDERS' EQUITY
Common stock, par value (in dollars per share)	$ 2.50	$ 2.50	$ 2.50
Common stock, shares authorized (in shares)	500,000,000	500,000,000	500,000,000
Common stock, shares issued (in shares)	95,174,441	94,549,867	94,436,177