Employee Benefit Plans - Defined Benefit Pension Plans Weighted-Average Asset Allocations (Detail)	Sep. 30, 2021	Sep. 30, 2020
U.S. Defined Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Debt securities		95.00%
Cash and other securities		5.00%
Total		100.00%
Foreign Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Equity securities	21.00%	39.00%
Debt securities	73.00%	50.00%
Real estate	2.00%	6.00%
Cash and other securities	4.00%	5.00%
Total	100.00%	100.00%