Business Segment Information (Reconciliation of Equity Affiliates' Income) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Segment Reporting Information [Line Items]
Tax reform repatriation - equity method investment				$ (32.5)
Equity affiliates' income	$ 56.4	$ 58.1	$ 155.5	115.6
Segment Reconciling Items
Segment Reporting Information [Line Items]
Tax reform repatriation - equity method investment	0.0	0.0	0.0	(32.5)
Segment Total
Segment Reporting Information [Line Items]
Equity affiliates' income	$ 56.4	$ 58.1	$ 155.5	$ 148.1