Contingencies (Details Textuals) (USD $) In Millions, unless otherwise specified	6 Months Ended	3 Months Ended		12 Months Ended
	Mar. 31, 2015 claim	Mar. 31, 2015	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2009
Loss Contingencies [Line Items]
Environmental accrual balance	$ 16	$ 16			$ 19
Discounted amount environmental accrual for ongoing operations maintenance and monitoring	8	8
Undiscounted amount environmental accrual for ongoing operations maintenance and monitoring	9	9
Rockwell Asbestos
Loss Contingencies [Line Items]
Environmental accrual balance	50	50			50
Number of pending claims	3,000	3,000			2,800
Obligation period for asbestos personal injury claims	10 years
Estimated insurance recoveries	11	11			11
Pending and future claims	48	48			48
Maremont Asbestos
Loss Contingencies [Line Items]
Environmental accrual balance	75	75			76
Number of pending claims	5,600	5,600			5,700
Obligation period for asbestos personal injury claims	10 years
Estimated insurance recoveries	45	45			49
Pending and future claims	73	73			73
Insurance Receivables | Rockwell Asbestos
Loss Contingencies [Line Items]
Estimated insurance recoveries	8	8			8
Rockwell Asbestos
Loss Contingencies [Line Items]
Range of possible loss, minimum	48	48
Range of possible loss, maximum	62	62
Superfund Sites
Loss Contingencies [Line Items]
Number of Superfund environmental sites	9	9
Environmental costs reasonably possible	17	17
Environmental accrual balance	2	2			2
Non-Superfund Sites
Loss Contingencies [Line Items]
Environmental costs reasonably possible	32	32
Environmental accrual balance	14	14			17
Maremont Asbestos
Loss Contingencies [Line Items]
Obligation period for asbestos personal injury claims	10 years
Range of possible loss, minimum	73	73
Range of possible loss, maximum	105	105
Indemnity Obligations
Loss Contingencies [Line Items]
Guarantee obligations recorded	13	13			14	28
Body Systems
Loss Contingencies [Line Items]
Increased liability					6
Indemnity obligations liability					2
Gain related to litigation settlement		6
MSSC
Loss Contingencies [Line Items]
Indemnity obligations liability	2	2			5
Potential Product Performance Issue
Loss Contingencies [Line Items]
Range of possible loss, minimum			12	12
Range of possible loss, maximum	3	3	20	20	3
Loss contingency accrual, provision				12
Non-cash cost recovery			5
Low Range
Loss Contingencies [Line Items]
Site contingency, accrual, discount rate	0.50%	0.50%
High Range
Loss Contingencies [Line Items]
Site contingency, accrual, discount rate	2.50%	2.50%
Tax Years 2008 Through 2014 | Value Added Tax
Loss Contingencies [Line Items]
Increased liability	$ 9	$ 9			$ 11