Commitments and Contingencies - Additional Information (Detail) - USD ($)	3 Months Ended			12 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Loss Contingencies [Line Items]
Raw material purchased				$ 258,000,000	$ 466,000,000	$ 441,000,000
Long term purchase commitment related to information technology				$ 14,000,000
Purchase agreement period				5 years
Charges for environmental expense				$ 1,000,000	1,000,000	6,000,000
Settlement amount				4,000,000	10,000,000	3,000,000
Respirator Liabilities [Member]
Loss Contingencies [Line Items]
Respirator reserve			$ 35,000,000	24,000,000	35,000,000
Respirator charge			20,000,000
Respirator liability				$ 65,200,000
Settlement amount	$ 32,600,000
Description of pending claims				The Company paid $32.6 million of this settlement in the third quarter of fiscal 2020.  The remaining $32.6 million is included in Accounts payable and accrued liabilities on the Consolidated Balance Sheets as of September 30, 2020 and was paid by the Company in the first quarter of fiscal 2021.
Respirator Liabilities [Member] | Accounts Payable and Accrued Liabilities [Member]
Loss Contingencies [Line Items]
Settlement amount				$ 32,600,000
Respirator Liabilities [Member] | Selling and Administrative Expenses [Member]
Loss Contingencies [Line Items]
Respirator charge				3,000,000
Respirator Liabilities [Member] | Selling and Administrative Expenses [Member]
Loss Contingencies [Line Items]
Respirator charge		$ 50,000,000			20,000,000	10,000,000
Environmental Matters [Member]
Loss Contingencies [Line Items]
Reserved for environmental matters			13,000,000	7,000,000	13,000,000
Reserve for environmental matters included in accrued expenses			9,000,000	3,000,000	9,000,000
Reserve for environmental matters included in other liabilities			4,000,000	4,000,000	4,000,000
Cash payments for environmental reserves				7,000,000	2,000,000	3,000,000
Environmental Matters [Member] | Operating and Maintenance Component [Member]
Loss Contingencies [Line Items]
Reserved for environmental matters				4,000,000
Per Accident for Auto [Member]
Loss Contingencies [Line Items]
Self-insured liability				500,000
Per Occurrence for All Other [Member]
Loss Contingencies [Line Items]
Self-insured liability				2,000,000
Per Accident for U.S. Workers' Compensation [Member]
Loss Contingencies [Line Items]
Self-insured liability				1,000,000
Maximum [Member]
Loss Contingencies [Line Items]
Retention for medical costs per person per annum				250,000
Charges related to value added tax matters				$ 30,000,000
Minimum [Member] | Respirator Liabilities [Member]
Loss Contingencies [Line Items]
Periods of pending claim				10 years
Non-Controlling Interests [Member]
Loss Contingencies [Line Items]
Raw material purchased				$ 81,000,000	156,000,000	$ 156,000,000
Accounts payable and accrued liabilities			$ 20,000,000	$ 12,000,000	$ 20,000,000