Restructuring Charges - Narrative (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 97.4	$ 0.0	$ 0.0
Restructuring charges, net of tax	$ 73.1
Restructuring charges, per diluted share (in USD per share)	$ 0.64
Expected restructuring charges	$ 97.4
Payments	27.7
Cost of sales
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 31.5
Restructuring Charges, Statement of Income or Comprehensive Income [Extensible Enumeration]	Cost of Goods and Services Sold
Selling, general and administrative expenses
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 65.9
Restructuring Charges, Statement of Income or Comprehensive Income [Extensible Enumeration]	Selling, General and Administrative Expense
Severance Benefits
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 92.3
Payments	22.6
Strategic Advisory Services
Restructuring Cost and Reserve [Line Items]
Restructuring charges	5.1
Payments	$ 5.1