Product Warranties - Changes in Carrying Amount of Product Warranty liability (Detail) - USD ($) $ in Millions		9 Months Ended
		Jun. 30, 2017	Jun. 30, 2016
Product Warranties Disclosures [Abstract]
Warranties transferred to liabilities held for sale		$ 13
Movement in Standard Product Warranty Accrual [Roll Forward]
Balance at beginning of period		374	$ 288
Accruals for warranties issued during the period		221	230
Accruals from acquisition and divestitures (1)	[1]	2	53
Accruals related to pre-existing warranties		(5)	(7)
Settlements made (in cash or in kind) during the period		(199)	(220)
Currency translation		(1)	2
Balance at end of period		$ 392	$ 346

[1] 1) The nine months ended June 30, 2017 includes $13 million of product warranties transferred to liabilities held for sale on the consolidated statements of financial position. Refer to Note 5, "Discontinued Operations," of the notes to consolidated financial statements for further information regarding the Company's disposal groups classified as held for sale.