Consolidated Balance Sheets (Parenthetical) - USD ($) shares in Millions, $ in Millions	Dec. 31, 2020	Sep. 30, 2020
Statement of Financial Position [Abstract]
Allowance for doubtful accounts receivable	$ 140	$ 138
Common stock, par value per share	$ 0.50	$ 0.50
Common stock, shares authorized	1,200.0	1,200.0
Common stock, shares issued	953.4	953.4
Common stock, shares outstanding	599.8	598.0
Treasury stock, shares	353.6	355.4

Amount of allowance for credit loss on accounts receivable, classified as current.

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Number of common and preferred shares that were previously issued and that were repurchased by the issuing entity and held in treasury on the financial statement date. This stock has no voting rights and receives no dividends.

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