Business Segment Information (Reconciliation of Segment Operating Income to Consolidated Results) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2026	Mar. 31, 2025	Mar. 31, 2026	Mar. 31, 2025
Segment Reporting Information [Line Items]
Operating income (loss)	$ 752.7	$ (2,328.0)	$ 1,487.2	$ (1,684.4)
Business and asset actions	0.0	(2,927.9)	(22.0)	(2,927.9)
Shareholder activism-related costs	0.0	(31.4)	0.0	(61.3)
Equity affiliates' income	179.4	145.5	351.6	296.1
Interest expense	49.5	42.2	104.0	84.8
Other non-operating income (expense), net	0.9	(18.6)	(0.5)	20.3
Income (Loss) Before Taxes	883.5	(2,243.3)	1,734.3	(1,452.8)
Operating Segments
Segment Reporting Information [Line Items]
Operating income (loss)	752.7	631.3	1,509.2	1,304.8
Equity affiliates' income	179.4	152.3	351.6	302.9
Segment Reconciling Items
Segment Reporting Information [Line Items]
Business and asset actions	0.0	(2,927.9)	(22.0)	(2,927.9)
Shareholder activism-related costs	$ 0.0	$ (31.4)	$ 0.0	$ (61.3)