Consolidated Statements of Income - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019		Mar. 31, 2018
Net sales		$ 5,779	$ 5,630	$ 11,243		$ 10,935
Cost of sales		3,935	3,806	7,674		7,413
Gross profit		1,844	1,824	3,569		3,522
Selling, general and administrative expenses		(1,458)	(1,490)	(2,896)		(2,809)
Restructuring and impairment costs		0	0	0		(154)
Net financing charges		(98)	(107)	(183)		(209)
Equity income		33	27	75		74
Income from continuing operations before income taxes		321	254	565		424
Income tax provision		47	36	155		253
Income from continuing operations		274	218	410		171
Income from discontinued operations, net of tax (Note 4)		284	265	547		583
Net income		558	483	957		754
Income from continuing operations attributable to noncontrolling interests		34	34	63		62
Income from discontinued operations attributable to noncontrolling interests		9	11	24		24
Net income attributable to Johnson Controls		515	438	870		668
Amounts attributable to Johnson Controls ordinary shareholders
Income from continuing operations		240	184	347		109
Income from discontinued operations		$ 275	$ 254	$ 523		$ 559
Earnings per share
Basic earnings per share from continuing operations		$ 0.27	$ 0.20	$ 0.38		$ 0.12
Basic earnings per share from discontinued operations		0.30	0.27	0.57		0.60
Basic earnings per share		0.57	0.47	0.95	[1]	0.72	[1]
Diluted earnings per share from continuing operations		0.26	0.20	0.38		0.12
Diluted earnings per share from discontinued operations		0.30	0.27	0.57		0.60
Diluted earnings per share	[1]	$ 0.57	$ 0.47	$ 0.95		$ 0.72
Products and Systems [Member]
Net sales		$ 4,240	$ 4,151	$ 8,162		$ 7,967
Cost of sales		3,029	2,968	5,853		5,758
Services [Member]
Net sales		1,539	1,479	3,081		2,968
Cost of sales		$ 906	$ 838	$ 1,821		$ 1,655

[1] Certain items do not sum due to rounding.