CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (Parenthetical) - $ / shares	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Statement Of Stockholders Equity [Abstract]
Dividends declared on common stock (in dollars per share)	$ 2.37	$ 2.25	$ 2.10
Dividends declared on preferred stock (in dollars per depositary share)	$ 0.344