Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Statement of Comprehensive Income [Abstract]
Net income	$ 1,122	$ 443	$ 1,452	$ 914
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments	(72)	(356)	28	(286)
Realized and unrealized gains (losses) on derivatives	4	(22)	7	(5)
Pension and postretirement plans	(1)	0	(2)	(2)
Other comprehensive income (loss)	(69)	(378)	33	(293)
Total comprehensive income	1,053	65	1,485	621
Comprehensive income attributable to noncontrolling interests:
Net income	73	64	152	143
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments	(47)	(58)	(5)	(66)
Realized and unrealized gains (losses) on derivatives	2	(3)	(3)	1
Other comprehensive loss	(45)	(61)	(8)	(65)
Comprehensive income attributable to noncontrolling interests	28	3	144	78
Comprehensive income attributable to Johnson Controls	$ 1,025	$ 62	$ 1,341	$ 543