Cash Flow Hedge [Abstract]

No definition available.

Name:	jci_CashFlowHedgeAbstract
Namespace Prefix:	jci_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- References

No definition available.

+ Details

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

- Definition

Amount of realized and unrealized gain (loss) of derivative instruments not designated or qualifying as hedging instruments.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4CC
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL109998890-113959

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5624171-113959

+ Details

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

- Definition

The amount of net gains or losses on foreign currency cash flow hedges reclassified during the period to earnings from accumulated other comprehensive income upon the hedged transaction affecting earnings.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5624171-113959

+ Details

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

- Definition

Amount before tax of increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=114867106&loc=d3e637-108580

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 30
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=109978405&loc=d3e80720-113993

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 10A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=114867106&loc=SL7669646-108580

+ Details

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

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_ForeignExchangeContractMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IncomeStatementLocationAxis=us-gaap_CostOfSalesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IncomeStatementLocationAxis=jci_NetFinancingChargesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IncomeStatementLocationAxis=us-gaap_SegmentDiscontinuedOperationsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_EquitySwapMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IncomeStatementLocationAxis=us-gaap_SellingGeneralAndAdministrativeExpensesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis=us-gaap_NetInvestmentHedgingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis=us-gaap_CashFlowHedgingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_CommodityContractMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Derivative Instruments and Hedging Activities - Location and Amount of Gains and Losses on Derivative Instruments and Related Hedge Items (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Gain (Loss) Recognized in Income, Derivative not Recognized as Hedge	$ (16)	$ (34)	$ 11	$ (40)
Foreign Currency Exchange Derivatives \| Cost of Sales
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Gain (Loss) Recognized in Income, Derivative not Recognized as Hedge	(3)	(4)	(9)	(5)
Foreign Currency Exchange Derivatives \| Net Financing Charges
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Gain (Loss) Recognized in Income, Derivative not Recognized as Hedge	(18)	(32)	(42)	(29)
Foreign Currency Exchange Derivatives \| Discontinued Operations
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Gain (Loss) Recognized in Income, Derivative not Recognized as Hedge	(2)	5	52	4
Equity swap \| Selling, General And Administrative
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Gain (Loss) Recognized in Income, Derivative not Recognized as Hedge	7	(3)	10	(10)
Net Investment Hedging [Member]
Cash Flow Hedges Derivative Instruments at Fair Value, Net [Abstract]
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax	(36)	165	48	29
Cash Flow Hedging
Cash Flow Hedges Derivative Instruments at Fair Value, Net [Abstract]
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax	(7)	6	5	9
Amount of Gain (Loss) Reclassified from AOCI into Income	1	4	(9)	13
Cash Flow Hedging \| Foreign Currency Exchange Derivatives
Cash Flow Hedges Derivative Instruments at Fair Value, Net [Abstract]
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax	(2)	6	7	7
Cash Flow Hedging \| Foreign Currency Exchange Derivatives \| Cost of Sales
Cash Flow Hedges Derivative Instruments at Fair Value, Net [Abstract]
Amount of Gain (Loss) Reclassified from AOCI into Income	2	1	4	0
Cash Flow Hedging \| Foreign Currency Exchange Derivatives \| Discontinued Operations
Cash Flow Hedges Derivative Instruments at Fair Value, Net [Abstract]
Amount of Gain (Loss) Reclassified from AOCI into Income	0	1	0	2
Cash Flow Hedging \| Commodity Derivatives
Cash Flow Hedges Derivative Instruments at Fair Value, Net [Abstract]
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax	(5)	0	(2)	2
Cash Flow Hedging \| Commodity Derivatives \| Cost of Sales
Cash Flow Hedges Derivative Instruments at Fair Value, Net [Abstract]
Amount of Gain (Loss) Reclassified from AOCI into Income	0	0	(3)	3
Cash Flow Hedging \| Commodity Derivatives \| Discontinued Operations
Cash Flow Hedges Derivative Instruments at Fair Value, Net [Abstract]
Amount of Gain (Loss) Reclassified from AOCI into Income	$ (1)	$ 2	$ (10)	$ 8