Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Statement of Comprehensive Income [Abstract]
Net income	$ 404	$ 156
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments	62	90
Realized and unrealized losses on derivatives	(42)	(17)
Pension and postretirement plans	(1)	(1)
Other comprehensive income	19	72
Total comprehensive income	423	228
Comprehensive income attributable to noncontrolling interests:
Net income	30	38
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments	1	31
Realized and unrealized losses on derivatives	(4)	(6)
Other comprehensive income (loss)	(3)	25
Comprehensive income attributable to noncontrolling interests	27	63
Comprehensive income attributable to Johnson Controls	$ 396	$ 165