Employee Benefit Plans - Defined Benefit Pension Plans Weighted-Average Asset Allocations (Detail)		Sep. 30, 2018	Sep. 30, 2017
U.S. Defined Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Equity securities		40.00%	48.00%
Debt securities		60.00%	5.00%
Cash and other securities	[1]		47.00%
Total		100.00%	100.00%
Foreign Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Equity securities		39.00%	39.00%
Debt securities		53.00%	53.00%
Cash and other securities	[1]	8.00%	8.00%
Total		100.00%	100.00%

[1] Prior to year-end 2017, within the U.S. defined benefit pension plan, the Company transitioned the majority of its fixed income assets held in a mutual fund investment to a separately managed account. This transition process temporarily resulted in a larger percentage of the assets being held in cash or cash equivalents on September 30, 2017.