Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Sep. 30, 2016	Sep. 30, 2015
Allowance for doubtful accounts receivables	$ 92	$ 89
Common stock, par value per share	$ 0.50	$ 0.50
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	642,796,490	654,608,521
Treasury stock, shares	310,557,522	298,745,491