Summary of Significant Accounting Policies Accounting Policies (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Sep. 30, 2014 Segment	Sep. 30, 2013	Sep. 30, 2012
Financial Statement Details [Line Items]
Maturity period to be considered cash equivalents	3 months
Restricted cash and cash equivalents	$ 4	$ 32
Engineering and research and development costs to be reimbursed	265	259
Expected reimbursement period of less than one year	1 year
Expected reimbursement period beyond one year	1 year
Molds, dies and other tools costs capitalized within property, plant and equipment	96	99
Molds, dies and other tools costs to be reimbursed	151	297
Costs and earnings in excess of billings related to contracts	507	503
Billing in excess of costs and earnings on uncompleted contracts	363	250
Timing of the first deliverable to the last delivery	Approximately four to twelve months
Research activities costs relating to product development and improvement, net of customer reimbursements	792	791	834
Customer reimbursements included in research activities costs	352	347	426
Foreign currency transaction gains (losses)	$ (8)	$ (25)	$ 12
Number of reportable segments	7
Minimum
Financial Statement Details [Line Items]
Duration of extended warranty arrangements	1 year
Maximum
Financial Statement Details [Line Items]
Duration of extended warranty arrangements	5 years
Building And Improvements | Minimum
Financial Statement Details [Line Items]
Estimated useful lives	3 years
Building And Improvements | Maximum
Financial Statement Details [Line Items]
Estimated useful lives	40 years
Machinery and Equipment | Minimum
Financial Statement Details [Line Items]
Estimated useful lives	3 years
Machinery and Equipment | Maximum
Financial Statement Details [Line Items]
Estimated useful lives	15 years
Prior To Reorganization | Building Efficiency
Financial Statement Details [Line Items]
Number of reportable segments	5
After Reorganization | Building Efficiency
Financial Statement Details [Line Items]
Number of reportable segments	4