Discontinued Operations Discontinued Operations - Additional Information (Details) $ in Millions	3 Months Ended				9 Months Ended
	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Jun. 30, 2014 USD ($)	Mar. 31, 2014 USD ($)	Jun. 30, 2015 USD ($)	Jun. 30, 2014 USD ($)
Discontinued Operations - Additional Information [Line Items]
Gain (loss) on business divestitures - net	$ 0		$ (95)		$ 0	$ (86)
U.S. federal statutory income tax rate	35.00%		35.00%		35.00%	35.00%
Global Workplace Solutions
Discontinued Operations - Additional Information [Line Items]
Ongoing Strategic Relationship		10 years
Transaction costs, divestiture related	$ 22				$ 39
Repatriation of Foreign Earnings	$ 335	$ 67
Automotive Experience Electronics
Discontinued Operations - Additional Information [Line Items]
Repatriation of Foreign Earnings				$ 180
Discontinued Operations
Discontinued Operations - Additional Information [Line Items]
Discontinued operation, gain (loss) on divestiture			$ (80)
Impairment of Long-Lived Assets to be Disposed of			43
Transaction costs, divestiture related			27
Severance Costs			10
Electronics
Discontinued Operations - Additional Information [Line Items]
Tangible and Intangible Asset Impairment Charges			43
Global Workplace Solutions | Brookfield Johnson Controls
Discontinued Operations - Additional Information [Line Items]
Number Of Joint Ventures Divested		2			2
Discontinued operation, gain (loss) on divestiture		$ 200			$ 200
Global Workplace Solutions | 2004 Divestiture
Discontinued Operations - Additional Information [Line Items]
Gain (loss) on business divestitures - net			$ (25)			$ (25)