Business Segment Information (Reconciliation of Operating Income) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Segment Reporting Information [Line Items]
Operating income (loss)	$ 790.6	$ 737.6	$ (893.8)	$ 2,041.7
Business and asset actions	(24.1)	0.0	(2,952.0)	(57.0)
Shareholder activism costs	(25.0)	0.0	(86.3)	0.0
Gain on sale of business	67.3	0.0	67.3	0.0
Operating Segments
Segment Reporting Information [Line Items]
Operating income (loss)	741.1	737.6	2,045.9	2,098.7
Segment Reconciling Items
Segment Reporting Information [Line Items]
Business and asset actions	(24.1)	0.0	(2,952.0)	(57.0)
Shareholder activism costs	(25.0)	0.0	(86.3)	0.0
Gain on sale of business	67.3	0.0	67.3	0.0
Gain on sale of other assets	$ 31.3	$ 0.0	$ 31.3	$ 0.0