Income Tax Expense by Fiscal Year (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Current:
U.S. federal	$ 568	$ 1,376	$ 1,365
State and local	(58)	165	311
Non-U.S.	239	214	168
Total current taxes	749	1,755	1,844
Deferred:
U.S. federal	1,401	(1,276)	160
State and local	114	(415)	(2)
Non-U.S.	13	1	8
Total deferred taxes	1,528	(1,690)	166
Income tax provision	$ 2,277	$ 65	$ 2,010