Consolidated Balance Sheets (Parenthetical) (USD $)	Dec. 31, 2012	Dec. 31, 2011
Statement of Financial Position [Abstract]
Common stock, par value	$ 5	$ 5
Common stock, authorized shares	325,000,000	325,000,000
Common stock, issued shares	228,164,824	228,164,824
Shares in treasury	39,889,610	30,831,076