Income Taxes - Effective Tax Rate-Business and Asset Actions (Details) $ in Millions	3 Months Ended	9 Months Ended
	Jun. 30, 2025 USD ($)	Jun. 30, 2025 USD ($)
Income Tax Disclosure [Abstract]
Business and asset actions, including equity affiliate income		$ 2,958.8
Restructuring charges tax benefit	$ 649.3
Cost to establish reserves for uncertain tax positions	22.5
Effective income tax rate reconciliation, foreign derived income, amount	15.2
Valuation allowance against deferred tax assets	$ 41.8	$ 41.8