Segment Information - Financial Information Related to Company's Reportable Segments (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended	6 Months Ended
Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2015	Mar. 31, 2014
Segment Reporting Information [Line Items]
Net sales	$ 9,198us-gaap_SalesRevenueNet	$ 9,467us-gaap_SalesRevenueNet	$ 18,822us-gaap_SalesRevenueNet	$ 18,964us-gaap_SalesRevenueNet
Segment Income	680jci_SegmentIncomeLoss	593jci_SegmentIncomeLoss	1,386jci_SegmentIncomeLoss	1,214jci_SegmentIncomeLoss
Net financing charges	(69)jci_NetFinancingCharges	(56)jci_NetFinancingCharges	(140)jci_NetFinancingCharges	(111)jci_NetFinancingCharges
Income from continuing operations before income taxes	611	537	1,246	1,103
Building Efficiency
Segment Reporting Information [Line Items]
Net sales	2,377	2,280	4,874	4,584
Segment Income	166	127	323	252
Building Efficiency \| North America Systems and Service
Segment Reporting Information [Line Items]
Net sales	1,019	1,024	2,036	2,015
Segment Income	107	100	186	166
Building Efficiency \| Building Efficiency Asia
Segment Reporting Information [Line Items]
Net sales	422	449	916	959
Segment Income	49	54	119	129
Building Efficiency \| Building Efficiency Other
Segment Reporting Information [Line Items]
Net sales	936	807	1,922	1,610
Segment Income	10	(27)	18	(43)
Automotive Experience
Segment Reporting Information [Line Items]
Net sales	5,233	5,623	10,516	11,044
Segment Income	250	232	484	422
Automotive Experience \| Seating
Segment Reporting Information [Line Items]
Net sales	4,141	4,514	8,276	8,793
Segment Income	229	229	430	399
Automotive Experience \| Interiors
Segment Reporting Information [Line Items]
Net sales	1,092	1,109	2,240	2,251
Segment Income	21	3	54	23
Power Solutions
Segment Reporting Information [Line Items]
Net sales	1,588	1,564	3,432	3,336
Segment Income	$ 264	$ 234	$ 579	$ 540

Net financing charges includes interest expense, interest income, bank fees and amortization of debt issuance costs.

No definition available.

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Namespace Prefix:	jci_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of income or loss from continuing operations for the reportable segment before income taxes and noncontrolling interests, excluding net financing charges, significant restructuring and impairment costs, and net mark-to-market adjustments on pension and postretirement plans.

+ References

No definition available.

+ Details

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Namespace Prefix:	jci_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

This element represents the income or loss from continuing operations attributable to the economic entity which may also be defined as revenue less expenses from ongoing operations, after income or loss from equity method investments, but before income taxes, extraordinary items, and noncontrolling interest.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 940

-SubTopic 20

-Section 25

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=35710027&loc=d3e41242-110953

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section S99

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 10

-Article 5

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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- Definition

Total revenue from sale of goods and services rendered during the reporting period, in the normal course of business, reduced by sales returns and allowances, and sales discounts.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1)

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Article 5

+ Details

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Balance Type:	credit
Period Type:	duration

- Details

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- Details

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- Details

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- Details

Name:	jci_PrimaryBusinessInformationByPrimaryBusinessAxis=jci_PowerSolutionsMember
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