Consolidated Statements of Shareholders' Equity Attributable to Johnson Controls Ordinary Shareholders Consolidated Statements of Shareholders' Equity Attributable to Johnson Controls Ordinary Shareholders - USD ($) $ in Millions	Total	Cumulative Effect, Period of Adoption, Adjustment	Ordinary Shares	Ordinary Shares Cumulative Effect, Period of Adoption, Adjustment	Capital in excess of par value	Capital in excess of par value Cumulative Effect, Period of Adoption, Adjustment	Retained Earnings	Retained Earnings Cumulative Effect, Period of Adoption, Adjustment	Treasury Stock, at Cost	Treasury Stock, at Cost Cumulative Effect, Period of Adoption, Adjustment	Accumulated Other Comprehensive Loss	Accumulated Other Comprehensive Loss Cumulative Effect, Period of Adoption, Adjustment	Power Solutions	Power Solutions Ordinary Shares	Power Solutions Capital in excess of par value	Power Solutions Retained Earnings	Power Solutions Treasury Stock, at Cost	Power Solutions Accumulated Other Comprehensive Loss
Adoption of ASU	$ 21,164		$ 10		$ 16,549		$ 6,604		$ (1,053)		$ (946)
Adoption of ASU | Adoption of ASC 606		$ (45)		$ 0		$ 0		$ (45)		$ 0		$ 0
Adoption of ASU | Adoption of ASU 2016-01		0		0		0		8		0		(8)
Adoption of ASU | Adoption of ASU 2016-16		(546)		0		0		(546)		0		0
Beginning balance at Sep. 30, 2018	21,164		10		16,549		6,604		(1,053)		(946)
Beginning balance (Adoption of ASC 606) at Sep. 30, 2018		(45)		0		0		(45)		0		0
Beginning balance (Adoption of ASU 2016-01) at Sep. 30, 2018		0		0		0		8		0		(8)
Beginning balance (Adoption of ASU 2016-16) at Sep. 30, 2018		(546)		0		0		(546)		0		0
Comprehensive income (loss)	4,969		0		0		5,062		0		(93)
Cash dividends - ordinary shares	(683)		0		0		(683)		0		0
Repurchases and retirements of ordinary shares	(5,122)		(1)		0		(4,034)		(1,087)		0
Divestiture of Power Solutions													$ 483	$ 0	$ 0	$ 0	$ 0	$ 483
Adoption of ASU	20,363		9		16,720		6,366		(2,168)		(564)
Adoption of ASU | Adoption of ASC 606		(45)		0		0		(45)		0		0
Adoption of ASU | Adoption of ASU 2016-01		0		0		0		8		0		(8)
Adoption of ASU | Adoption of ASU 2016-16		(546)		0		0		(546)		0		0
Other, including options exercised	143		0		171		0		(28)		0
Ending balance at Jun. 30, 2019	20,363		9		16,720		6,366		(2,168)		(564)
Adoption of ASU	20,036		10		16,640		6,416		(2,078)		(952)
Beginning balance at Mar. 31, 2019	20,036		10		16,640		6,416		(2,078)		(952)
Comprehensive income (loss)	4,097		0		0		4,192		0		(95)
Cash dividends - ordinary shares	(208)		0		0		(208)		0		0
Repurchases and retirements of ordinary shares	(4,122)		(1)		0		(4,034)		(87)		0
Divestiture of Power Solutions													$ 483	$ 0	$ 0	$ 0	$ 0	$ 483
Adoption of ASU	20,036		10		16,640		6,416		(2,078)		(952)
Other, including options exercised	77		0		80		0		(3)		0
Ending balance at Jun. 30, 2019	20,363		9		16,720		6,366		(2,168)		(564)
Adoption of ASU	20,363		9		16,720		6,366		(2,168)		(564)
Adoption of ASU	19,766		8		16,812		4,827		(1,086)		(795)
Adoption of ASU | Adoption of ASC 842		(5)		0		0		(5)		0		0
Beginning balance at Sep. 30, 2019	19,766		8		16,812		4,827		(1,086)		(795)
Beginning balance (Adoption of ASC 842) at Sep. 30, 2019		(5)		0		0		(5)		0		0
Comprehensive income (loss)	42		0		0		190		0		(148)
Cash dividends - ordinary shares	(590)		0		0		(590)		0		0
Repurchases and retirements of ordinary shares	(1,467)		0		0		(1,467)		0		0
Adoption of ASU	17,805		8		16,904		2,955		(1,119)		(943)
Adoption of ASU | Adoption of ASC 842		$ (5)		$ 0		$ 0		$ (5)		$ 0		$ 0
Other, including options exercised	59		0		92		0		(33)		0
Ending balance at Jun. 30, 2020	17,805		8		16,904		2,955		(1,119)		(943)
Adoption of ASU	18,084		8		16,883		3,332		(1,118)		(1,021)
Beginning balance at Mar. 31, 2020	18,084		8		16,883		3,332		(1,118)		(1,021)
Comprehensive income (loss)	(104)		0		0		(182)		0		78
Cash dividends - ordinary shares	(195)		0		0		(195)		0		0
Adoption of ASU	17,805		8		16,904		2,955		(1,119)		(943)
Other, including options exercised	20		0		21		0		(1)		0
Ending balance at Jun. 30, 2020	17,805		8		16,904		2,955		(1,119)		(943)
Adoption of ASU	$ 17,805		$ 8		$ 16,904		$ 2,955		$ (1,119)		$ (943)