Consolidated Balance Sheets (Parenthetical) - USD ($) shares in Millions, $ in Millions	Dec. 31, 2023	Sep. 30, 2023
Statement of Financial Position [Abstract]
Allowance for doubtful accounts receivable	$ 112	$ 100
Common stock, par value (in dollars per share)	$ 0.50	$ 0.50
Common stock, shares authorized (in shares)	1,200.0	1,200.0
Common stock, shares issued (in shares)	953.4	953.4
Common stock, shares outstanding (in shares)	571.7	572.0
Treasury stock, shares (in shares)	381.7	381.4