Restructuring - Restructuring Activities and Related Reserves (Detail) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Jun. 30, 2016	Jun. 30, 2016
Restructuring Cost And Reserve [Line Items]
Reserve balance	$ 13	$ 9
Charges (credit)	2	45
Costs charged against assets		(30)
Cash (paid) received	(9)	(18)
Reserve balance	6	6
Severance and Employee Benefits [Member]
Restructuring Cost And Reserve [Line Items]
Reserve balance	11	5
Charges (credit)		26
Cash (paid) received	(7)	(27)
Reserve balance	4	4
Environmental Remediation [Member]
Restructuring Cost And Reserve [Line Items]
Reserve balance	2	2
Charges (credit)	1	1
Cash (paid) received	(1)	(1)
Reserve balance	2	2
Asset Sales [Member]
Restructuring Cost And Reserve [Line Items]
Charges (credit)		(9)
Costs charged against assets		(7)
Cash (paid) received		16
Asset Impairment and Accelerated Depreciation [Member]
Restructuring Cost And Reserve [Line Items]
Charges (credit)		23
Costs charged against assets		(23)
Other [Member]
Restructuring Cost And Reserve [Line Items]
Reserve balance		2
Charges (credit)	1	4
Cash (paid) received	$ (1)	$ (6)