Goodwill and Other Intangible Assets Changes in Carrying Amount of Goodwill (Details) - USD ($)	3 Months Ended		12 Months Ended
	Jun. 30, 2016	Sep. 30, 2014	Sep. 30, 2016	Sep. 30, 2015
Goodwill [Roll Forward]
Goodwill, Beginning Balance			$ 6,824,000,000	$ 7,127,000,000
Business Acquisitions			258,000,000	43,000,000
Business Divestitures			(19,000,000)	(29,000,000)
Impairments			0	0
Currency Translation and Other			38,000,000	(317,000,000)
Goodwill, Ending Balance		$ 7,127,000,000	7,101,000,000	6,824,000,000
Building Efficiency
Goodwill [Roll Forward]
Business Acquisitions			0
Business Divestitures			(3,000,000)
Currency Translation and Other			(1,000,000)
Goodwill, Ending Balance			1,697,000,000
Power Solutions
Goodwill [Roll Forward]
Goodwill, Beginning Balance			1,082,000,000	1,142,000,000
Business Acquisitions			0	0
Business Divestitures			0	0
Currency Translation and Other			4,000,000	(60,000,000)
Goodwill, Ending Balance		1,142,000,000	1,086,000,000	1,082,000,000
Building Efficiency Systems and Service North America [Member]
Goodwill [Roll Forward]
Business Divestitures	$ (3,000,000)
Building Efficiency Systems and Service North America [Member] | Building Efficiency
Goodwill [Roll Forward]
Goodwill, Beginning Balance			978,000,000	982,000,000
Business Acquisitions			0	0
Business Divestitures			(3,000,000)	(2,000,000)
Currency Translation and Other			0	(2,000,000)
Goodwill, Ending Balance		982,000,000	975,000,000	978,000,000
Building Efficiency Products North America [Member] | Building Efficiency
Goodwill [Roll Forward]
Goodwill, Beginning Balance			1,701,000,000	1,688,000,000
Business Acquisitions				34,000,000
Business Divestitures				(14,000,000)
Currency Translation and Other				(7,000,000)
Goodwill, Ending Balance		1,688,000,000		1,701,000,000
Building Efficiency Asia | Building Efficiency
Goodwill [Roll Forward]
Goodwill, Beginning Balance			389,000,000	414,000,000
Business Acquisitions			253,000,000	0
Business Divestitures			0	0
Currency Translation and Other			15,000,000	(25,000,000)
Goodwill, Ending Balance		414,000,000	657,000,000	389,000,000
Building Efficiency Other | Building Efficiency
Goodwill [Roll Forward]
Goodwill, Beginning Balance			310,000,000	345,000,000
Business Acquisitions			5,000,000	0
Business Divestitures			(13,000,000)	0
Impairments		(47,000,000)
Currency Translation and Other			(1,000,000)	(35,000,000)
Goodwill, Ending Balance		345,000,000	301,000,000	310,000,000
Seating | Automotive Experience
Goodwill [Roll Forward]
Goodwill, Beginning Balance			2,364,000,000	2,556,000,000
Business Acquisitions			0	0
Business Divestitures			0	(4,000,000)
Currency Translation and Other			21,000,000	(188,000,000)
Goodwill, Ending Balance		2,556,000,000	2,385,000,000	2,364,000,000
Interiors | Automotive Experience
Goodwill [Roll Forward]
Goodwill, Beginning Balance			$ 0	0
Business Acquisitions				9,000,000
Business Divestitures				(9,000,000)
Currency Translation and Other				0
Goodwill, Ending Balance		$ 0		$ 0