Consolidated Balance Sheets (Parenthetical) (USD $)	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2011
Common stock, par value	$ 1.00	$ 1.00	$ 1.00
Common stock, shares authorized	1,000,000,000	1,000,000,000	1,000,000,000
Common stock, shares issued	441,400,000	441,400,000	441,400,000
Treasury stock, shares	98,600,000	104,400,000	101,800,000