Consolidated Balance Sheets (Parenthetical) (USD $) In Millions, except Share data	Jun. 30, 2011	Sep. 30, 2010
Consolidated Balance Sheets
Allowance for doubtful accounts receivable, current	$ 108	$ 98
Preferred stock, par value per share	$ 2.5	$ 2.5
Preferred stock, shares authorized	5,400,000	5,400,000
Preferred stock, shares issued	0	0
Common stock, par value per share	$ 0.5	$ 0.5
Common stock, shares authorized	1,200,000,000	1,200,000,000
Common stock, shares issued	953,354,012	953,354,012
Common stock, shares outstanding	746,860,009	752,690,806
Treasury stock, shares	206,494,003	200,663,206