Consolidated Balance Sheets (unaudited) (Parenthetical) (USD $) In Millions, except Per Share data	Sep. 30, 2011	Dec. 31, 2010
Shareholders' Equity
Preferred stock, par value per share (in dollars per share)	$ 1.00	$ 1.00
Preferred stock, shares authorized (in shares)	4	4
Common stock, par value per share (in dollars per share)	$ 3.333	$ 3.333
Common stock, shares authorized (in shares)	250	250
Common stock, shares issued (in shares)	196	195
Treasury stock, shares (in shares)	19	19