Condensed Consolidated Balance Sheets (Parenthetical) (Unaudited) (USD $)	3 Months Ended
	Mar. 31, 2013	Dec. 31, 2012
Statement of Financial Position [Abstract]
Preferred stock par value	$ 50	$ 50
Preferred stock dividend rate, per-dollar dividend	4.00%
Preference Stock No Par Value
Preference stock dividend rate, in dollars per share	$ 2.12	$ 2.12
Common stock, par value	$ 1	$ 1
Common stock, shares authorized	480,000,000	480,000,000
Common stock, shares issued	323,337,912	323,337,912
Treasury stock, shares	121,867,606,000	122,453,865,000