Equity and Noncontrolling Interests - Equity Attributable to Johnson Controls, Inc. and Noncontrolling Interests (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2016	Mar. 31, 2015
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance			$ 10,376
Beginning balance			163
Beginning balance			10,539
Net income (loss) attributable to Johnson Controls, Inc.	$ (530)	$ 529	(80)	$ 1,036
Foreign currency translation adjustments	203	(504)	26	(855)
Realized and unrealized gains (losses) on derivatives	5	7	2	(3)
Pension and postretirement plans	0	0	0	(3)
Other comprehensive income (loss)	208	(497)	28	(861)
Comprehensive income (loss) attributable to Johnson Controls, Inc.	(351)	54	(62)	197
Comprehensive income attributable to noncontrolling interests	90	6	111	45
Total comprehensive income (loss)	(261)	60	49	242
Ending balance	9,984	10,583	9,984	10,583
Ending balance	898	199	898	199
Ending balance	10,882	10,782	10,882	10,782
Equity Attributable to Johnson Controls, Inc
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	10,506	10,823	10,376	11,311
Net income (loss) attributable to Johnson Controls, Inc.	(530)	529	(80)	1,036
Foreign currency translation adjustments	175	(481)	15	(832)
Realized and unrealized gains (losses) on derivatives	4	6	3	(4)
Pension and postretirement plans			0	(3)
Other comprehensive income (loss)	179	(475)	18	(839)
Comprehensive income (loss) attributable to Johnson Controls, Inc.	(351)	54	(62)	197
Cash dividends - common stock	(189)	(170)	(377)	(342)
Dividends attributable to noncontrolling interests	0	0	0	0
Repurchases of common stock	0	(210)	0	(810)
Change In Noncontrolling Interest Share	0	0	0	0
Other, including options exercised	18	86	47	227
Ending balance	9,984	10,583	9,984	10,583
Nonredeemable Noncontrolling Interest [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Change In Noncontrolling Interest Share	73	69	691	69
Total Equity Excluding Redeemable Noncontrolling Interest [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Change In Noncontrolling Interest Share	73	69	691	69
Equity Attributable to Noncontrolling Interest
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	931	263	163	251
Income attributable to noncontrolling interests	50	16	70	36
Foreign currency translation adjustments	18	(3)	9	(3)
Realized and unrealized gains (losses) on derivatives	1	0	1	0
Pension and postretirement plans			0	0
Other comprehensive income (loss)	19	(3)	10	(3)
Comprehensive income attributable to noncontrolling interests	69	13	80	33
Cash dividends - common stock	0	0	0	0
Dividends attributable to noncontrolling interests	(29)	(8)	(36)	(16)
Repurchases of common stock	0	0	0	0
Other, including options exercised	0	0	0	0
Ending balance	898	199	898	199
Total Equity
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	11,437	11,086	10,539	11,562
Net income	(480)	545	(10)	1,072
Foreign currency translation adjustments	193	(484)	24	(835)
Realized and unrealized gains (losses) on derivatives	5	6	4	(4)
Pension and postretirement plans			0	(3)
Other comprehensive income (loss)	198	(478)	28	(842)
Total comprehensive income (loss)	(282)	67	18	230
Cash dividends - common stock	(189)	(170)	(377)	(342)
Dividends attributable to noncontrolling interests	(29)	(8)	(36)	(16)
Repurchases of common stock	0	(210)	0	(810)
Other, including options exercised	18	86	47	227
Ending balance	$ 10,882	$ 10,782	$ 10,882	$ 10,782