Accrued Litigation for Both Covered and Non-Covered Litigation (Detail) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Jun. 30, 2012		Jun. 30, 2011
Loss Contingency Accrual [Roll Forward]
Beginning Balance	$ 425		$ 697
Provision for settled matters	4,098
Reclassification of settled matters		[1]	12	[1]
Interest accretion on settled matters	1		9
Payments on settled matters	(140)		(212)
Ending Balance	4,384		512
Settled [Member]
Loss Contingency Accrual [Roll Forward]
Provision for settled matters			6
Unsettled [Member]
Loss Contingency Accrual [Roll Forward]
Provision for settled matters

[1] Reclassification of amount previously recorded in accrued liabilities.