CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Millions	Sep. 30, 2020	Sep. 30, 2019
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 42	$ 32
Common stock, shares authorized (in shares)	450,000,000	450,000,000
Common stock, shares issued (in shares)	209,514,044	209,304,129