Employee Benefit Plans - Defined Benefit Pension Plans Weighted-Average Asset Allocations (Detail)	Sep. 30, 2019	Sep. 30, 2018
U.S. Defined Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Equity securities		40.00%
Debt securities	68.00%	60.00%
Cash and other securities	32.00%
Total	100.00%	100.00%
Foreign Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Equity securities	39.00%	39.00%
Debt securities	50.00%	53.00%
Cash and other securities	11.00%	8.00%
Total	100.00%	100.00%