New Accounting Standards Recently Adopted Accounting Pronouncements (Details) $ in Millions	3 Months Ended
Dec. 31, 2017 USD ($)
Accounting Policies [Abstract]
Deferred tax asset from stock options exercised and restricted stock vestings	$ 179

Deferred tax asset from stock options exercised and restricted stock vestings on a modified retrospective basis through a cumulative-effect adjustment to retained earnings.

No definition available.

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