CONDENSED CONSOLIDATED BALANCE SHEETS (unaudited) (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2022	Sep. 30, 2021	Mar. 31, 2021
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 70	$ 53	$ 52
Accumulated depreciation	$ 4,117	$ 3,950	$ 3,869
Preferred Stock, shares authorized (in shares)	5,000,000	5,000,000	5,000,000
Preferred Stock, shares issued (in shares)	220,000	220,000	0
Common Stock, shares authorized (in shares)	450,000,000	450,000,000	450,000,000
Common Stock, shares issued (in shares)	210,127,957	209,843,296	209,636,619