Benefit Plans - Weighted Average Assumptions Determining Pension Plan (Detail) - Pension Plans	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
United States
Net Cost
Discount rate	5.62%	2.89%	2.80%
Expected return on plan assets	7.25%	6.25%	6.25%
Rate of compensation increase	4.51%	4.31%	4.30%
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	4.00%	4.00%	4.00%
Benefit Obligation
Discount rate	6.01%	5.62%	2.89%
Rate of compensation increase	4.00%	4.51%	4.31%
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	4.00%	4.00%	4.00%
Foreign Plans
Net Cost
Discount rate	4.26%	1.75%	1.44%
Expected return on plan assets	5.02%	4.84%	4.92%
Rate of compensation increase	2.86%	2.63%	2.20%
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	1.98%	2.02%	1.95%
Benefit Obligation
Discount rate	4.62%	4.26%	1.75%
Rate of compensation increase	2.86%	2.86%	2.63%
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	2.21%	1.98%	2.02%