Segment Information - Financial Information Related to Company's Reportable Segments (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Segment Reporting Information [Line Items]
Net sales	$ 10,666us-gaap_SalesRevenueNet	$ 10,574us-gaap_SalesRevenueNet
Segment Income	748jci_SegmentIncomeLoss	650jci_SegmentIncomeLoss
Net financing charges	(71)jci_NetFinancingCharges	(55)jci_NetFinancingCharges
Income from continuing operations before income taxes	677	595
Building Efficiency
Segment Reporting Information [Line Items]
Net sales	3,539	3,381
Segment Income	187	146
Building Efficiency \| North America Systems and Service
Segment Reporting Information [Line Items]
Net sales	1,017	991
Segment Income	81	67
Building Efficiency \| Global Workplace Solutions
Segment Reporting Information [Line Items]
Net sales	1,042	1,077
Segment Income	26	18
Building Efficiency \| Building Efficiency Asia
Segment Reporting Information [Line Items]
Net sales	494	510
Segment Income	71	76
Building Efficiency \| Building Efficiency Other
Segment Reporting Information [Line Items]
Net sales	986	803
Segment Income	9	(15)
Automotive Experience
Segment Reporting Information [Line Items]
Net sales	5,283	5,421
Segment Income	243	197
Automotive Experience \| Seating
Segment Reporting Information [Line Items]
Net sales	4,135	4,279
Segment Income	208	175
Automotive Experience \| Interiors
Segment Reporting Information [Line Items]
Net sales	1,148	1,142
Segment Income	35	22
Power Solutions
Segment Reporting Information [Line Items]
Net sales	1,844	1,772
Segment Income	$ 318	$ 307

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

No definition available.

Name:	jci_NetFinancingCharges
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

Name:	jci_SegmentIncomeLoss
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

Name:	us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- 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

Name:	us-gaap_SalesRevenueNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	us-gaap_SegmentReportingInformationLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	jci_PrimaryBusinessInformationByPrimaryBusinessAxis=jci_AutomotiveExperienceMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	jci_PrimaryBusinessInformationByPrimaryBusinessAxis=jci_BuildingEfficiencyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	jci_PrimaryBusinessInformationByPrimaryBusinessAxis=jci_PowerSolutionsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: