Significant Restructuring and Impairment Costs (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended					12 Months Ended
	Sep. 30, 2013 Employees Plant	Jun. 30, 2013	Mar. 31, 2013	Sep. 30, 2012	Jun. 30, 2012	Sep. 30, 2013 Employees Plant	Sep. 30, 2012	Sep. 30, 2011
Restructuring Cost and Reserve [Line Items]
Restructuring and impairment costs	$ 758	$ 143	$ 84	$ 245	$ 52	$ 985	$ 297	$ 0
Number of employees to be severed						16,700
Number of employees severed	6,300					6,300
Plants to be closed	21					21
Plants closed	5					5
Automotive Experience
Restructuring Cost and Reserve [Line Items]
Number of employees to be severed						9,500
Plants to be closed	17					17
Building Efficiency
Restructuring Cost and Reserve [Line Items]
Number of employees to be severed						6,200
Plants to be closed	2					2
Power Solutions
Restructuring Cost and Reserve [Line Items]
Restructuring and impairment costs						$ (36)	$ (37)
Number of employees to be severed						1,000
Plants to be closed	2					2