Commitments and Contingencies (Detail) $ in Millions	3 Months Ended	12 Months Ended
	Sep. 30, 2017 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)
Loss Contingencies [Line Items]
Reserves for environmental liabilities	$ 51	$ 51	$ 51
Accrued Environmental Loss Contingencies, Current	10	10
Accrued Environmental Loss Contingencies, Noncurrent	41	41
Conditional asset retirement obligations	61	61	74
Estimated asbestos related net liability on a discounted basis	181	181	148
Liability for Asbestos and Environmental Claims, Gross	573	573	548
Restricted Cash and Investments	392	392	400
Restricted Cash and Cash Equivalents	31	31	88
Insurance Recoveries		101	120
Insurable liabilities	445	445	422
Insurance Settlements Receivable	46	46
Insurance Settlements Receivable, Current	31	31
Insurance Settlements Receivable, Noncurrent	$ 15	$ 15	21
Arbitration award against the Company	50
Accrued interest while arbitration award remains outstanding	9.56%
Class actions lawsuits against the Company		12
Other possible individual product liability claims		490
Asbestos Issue [Member]
Loss Contingencies [Line Items]
Restricted Cash and Cash Equivalents	$ 22	$ 22	16
Restricted Investments	269	$ 269	264
Selling, general and administrative
Loss Contingencies [Line Items]
Arbitration award against the Company		50
Other current liabilities
Loss Contingencies [Line Items]
Liability for Asbestos and Environmental Claims, Gross	48	$ 48	35
Insurable liabilities	122	122	60
Accrued Compensation and Benefits [Member]
Loss Contingencies [Line Items]
Insurable liabilities	22	22	28
Other Noncurrent Liabilities [Member]
Loss Contingencies [Line Items]
Liability for Asbestos and Environmental Claims, Gross	525	525	513
Insurable liabilities	301	301	334
Other current assets
Loss Contingencies [Line Items]
Restricted Cash and Investments	53	53	41
Other noncurrent assets
Loss Contingencies [Line Items]
Restricted Cash and Investments	$ 339	$ 339	$ 359