Pension and Postretirement Plans - Components of Net Periodic Benefit Cost (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2013	Mar. 31, 2012
U.S. Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 22	$ 17	$ 45	$ 34
Interest cost	37	37	75	75
Expected return on plan assets	(58)	(52)	(116)	(106)
Amortization of prior service credit	1	1	1	1
Net periodic benefit cost (credit)	2	3	5	4
Non-U.S. Pension
Defined Benefit Plan Disclosure [Line Items]
Service cost	9	8	19	17
Interest cost	16	18	32	36
Expected return on plan assets	(17)	(19)	(35)	(37)
Amortization of prior service credit	(1)	(1)	(1)	(1)
Curtailment gain	(2)	0	(26)	0
Net periodic benefit cost (credit)	5	6	(11)	15
Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	2	1	3	2
Interest cost	2	4	5	7
Expected return on plan assets	(3)	(3)	(6)	(6)
Amortization of prior service credit	(5)	(5)	(9)	(9)
Net periodic benefit cost (credit)	$ (4)	$ (3)	$ (7)	$ (6)