Income Taxes (Deferred Tax Assets and Liabilities - Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024
Income Tax Disclosures [Line Items]
Business and asset actions, including equity affiliate income	$ 3,700.0
Valuation allowance	(506.3)	$ (158.4)
Federal foreign income tax credits	10.8
Cumulative undistributed earnings	9,800.0
U.S. Income and foreign withholding taxes estimate	923.1
Foreign Loss Carryforwards
Income Tax Disclosures [Line Items]
Valuation allowance	(44.6)
Foreign Capital Losses
Income Tax Disclosures [Line Items]
Valuation allowance	(55.3)
Other Charges from Business and Asset Actions
Income Tax Disclosures [Line Items]
Valuation allowance	(392.0)
Foreign
Income Tax Disclosures [Line Items]
Tax credit carryforwards	16.2
Operating loss carryforwards	371.1
Operating loss carryforwards not subject to expiration	$ 202.8