Cash Dividends (Details) - $ / shares						3 Months Ended		9 Months Ended
	Jun. 06, 2018	Jun. 01, 2018	Mar. 07, 2018	Mar. 01, 2018	Dec. 05, 2017	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Cash Dividends
Cash dividends declared, per share (in dollars per share)	$ 0.71		$ 0.70		$ 0.70	$ 0.71	$ 0.70	$ 2.11	$ 2.10
Cash dividend paid, per share (in dollars per share)		$ 0.70		$ 0.70