Consolidated Balance Sheets (Parenthetical) - USD ($) shares in Millions, $ in Millions	Dec. 31, 2024	Sep. 30, 2024
Statement of Financial Position [Abstract]
Allowance for doubtful accounts receivable	$ 124	$ 121
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)	563.9	570.2
Treasury stock, shares (in shares)	389.5	383.2