Income Taxes - Schedule of Effective Income Tax Rate Reconciliation (Details)	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
Effective Tax Rate Reconciliation
Statutory tax rate	21.00%	21.00%	21.00%
State and local income taxes	(0.10%)	0.20%	1.50%
Non-United States taxes	(3.80%)	(4.20%)	(4.70%)
Repatriation of foreign earnings	1.00%	0.90%	0.90%
Foreign-derived intangible income	(1.50%)	(0.70%)	(0.60%)
Settlements with taxing authorities and tax refund claims	0.60%	(1.20%)	0.30%
Change in valuation allowance	3.60%	0.50%	4.10%
Share-based compensation	(1.10%)	(0.20%)	(0.60%)
Research and development tax credit	(2.90%)	(2.00%)	(1.30%)
Other	1.50%	(0.50%)	(0.10%)
Effective income tax rate	18.30%	13.80%	20.50%
Effective income tax rate reconciliation, change in deferred tax assets valuation allowance and nondeductible goodwill impairment losses, percent	3.60%		4.10%