Segment Information - Financial Information Related to Company's Reportable Segments (Detail) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2019	Mar. 31, 2018
Segment Reporting Information [Line Items]
Net sales	$ 5,779	$ 5,630		$ 11,243	$ 10,935
Segment EBITA	664	615		1,247	1,271
Corporate expenses	(167)	(162)		(303)	(300)
Amortization of intangible assets	(98)	(92)		(195)	(184)
Restructuring and impairment costs	0	0	$ (154)	0	(154)
Equity Securities, FV-NI, Unrealized Gain (Loss) Restricted	20	0		(1)
Net mark-to-market adjustments on pension plans				(1)	0
Net financing charges	(98)	(107)		(183)	(209)
Income from continuing operations before income taxes	321	254		565	424
Building Solutions North America
Segment Reporting Information [Line Items]
Net sales	2,187			4,303
Building Solutions EMEA/LA
Segment Reporting Information [Line Items]
Net sales	878			1,785
Building Solutions Asia Pacific
Segment Reporting Information [Line Items]
Net sales	628			1,241
Global Products
Segment Reporting Information [Line Items]
Net sales	2,086			3,914
Building Technologies & Solutions \| Building Solutions North America
Segment Reporting Information [Line Items]
Net sales	2,187	2,097		4,303	4,109
Segment EBITA	257	239		507	466
Building Technologies & Solutions \| Building Solutions EMEA/LA
Segment Reporting Information [Line Items]
Net sales	878	907		1,785	1,822
Segment EBITA	80	77		157	146
Building Technologies & Solutions \| Building Solutions Asia Pacific
Segment Reporting Information [Line Items]
Net sales	628	586		1,241	1,183
Segment EBITA	76	71		142	145
Building Technologies & Solutions \| Global Products
Segment Reporting Information [Line Items]
Net sales	2,086	2,040		3,914	3,821
Segment EBITA	$ 251	$ 228		$ 441	$ 514

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General expenses recorded at the Corporate segment.

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Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

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