Commitments and Contingencies - Additional Information (Detail)	3 Months Ended	6 Months Ended	12 Months Ended
	Sep. 30, 2017 USD ($)	Mar. 31, 2018 USD ($)	Sep. 30, 2017 USD ($)
Loss Contingencies [Line Items]
Estimated asbestos related net liability on a discounted basis	$ 181,000,000	$ 174,000,000	$ 181,000,000
Reserves for environmental liabilities	51,000,000	47,000,000	51,000,000
Conditional asset retirement obligations	61,000,000	65,000,000	61,000,000
Accrued Environmental Loss Contingencies, Current		12,000,000
Accrued Environmental Loss Contingencies, Noncurrent		35,000,000
Liability for Asbestos and Environmental Claims, Gross	573,000,000	555,000,000	573,000,000
Restricted Cash and Investments	392,000,000	381,000,000	392,000,000
Restricted Cash and Cash Equivalents	31,000,000	21,000,000	31,000,000
Insurance Recoveries		95,000,000	101,000,000
Insurable liabilities	445,000,000	439,000,000	445,000,000
Insurance Settlements Receivable, Current	31,000,000	6,000,000	31,000,000
Insurance Settlements Receivable	46,000,000	21,000,000	46,000,000
Insurance Settlements Receivable, Noncurrent	15,000,000	$ 15,000,000	15,000,000
Arbitration award to plaintiff	$ 50,000,000
Accrued interest while arbitration award remains outstanding	9.56%
Class actions lawsuits against the Company		15
Other possible individual product liability claims		540
Asbestos Issue [Member]
Loss Contingencies [Line Items]
Restricted Cash and Cash Equivalents	$ 22,000,000	$ 12,000,000	22,000,000
Restricted Investments	269,000,000	274,000,000	269,000,000
Selling, General And Administrative
Loss Contingencies [Line Items]
Arbitration award to plaintiff	50,000,000
Accrued Compensation and Benefits [Member]
Loss Contingencies [Line Items]
Insurable liabilities	22,000,000	22,000,000	22,000,000
Other Current Assets
Loss Contingencies [Line Items]
Restricted Cash and Investments	53,000,000	57,000,000	53,000,000
Other Noncurrent Assets
Loss Contingencies [Line Items]
Restricted Cash and Investments	339,000,000	324,000,000	339,000,000
Other Noncurrent Liabilities [Member]
Loss Contingencies [Line Items]
Liability for Asbestos and Environmental Claims, Gross	525,000,000	501,000,000	525,000,000
Insurable liabilities	301,000,000	336,000,000	301,000,000
Other Current Liabilities
Loss Contingencies [Line Items]
Liability for Asbestos and Environmental Claims, Gross	48,000,000	54,000,000	48,000,000
Insurable liabilities	$ 122,000,000	$ 81,000,000	$ 122,000,000
PENNSYLVANIA
Loss Contingencies [Line Items]
Loss Contingency, Number of Plaintiffs		2
NEW YORK
Loss Contingencies [Line Items]
Loss Contingency, Number of Plaintiffs		32
COLORADO
Loss Contingencies [Line Items]
Loss Contingency, Number of Plaintiffs		90