Pension and Other Postretirement Benefits - Weighted Average Actuarial Assumptions (Detail)	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
U.S. Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate for benefit obligation: Pension	5.52%	2.98%	2.88%
Discount rate for net periodic benefit cost: Pension	2.98%	2.88%	3.27%
Expected long-term rate of return on plan assets	6.50%	6.50%	7.00%
Non-U.S. Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate for benefit obligation: Pension	5.00%	2.10%	1.60%
Discount rate for net periodic benefit cost: Pension	2.10%	1.60%	1.80%
Expected long-term rate of return on plan assets	3.50%	3.50%	3.00%
Rate of increase in compensation levels for:
Benefit obligation	2.50%	2.50%	2.50%
Net periodic benefit cost	2.50%	2.50%	2.50%