Shareholders' Equity - Changes in Certain Components of Shareholders' Equity (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended							12 Months Ended										12 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2012 Common Stock Issued at Par Value [Member]	Sep. 30, 2011 Common Stock Issued at Par Value [Member]	Sep. 30, 2010 Common Stock Issued at Par Value [Member]	Sep. 30, 2009 Common Stock Issued at Par Value [Member]	Sep. 30, 2012 Capital in Excess of Par Value [Member]	Sep. 30, 2011 Capital in Excess of Par Value [Member]	Sep. 30, 2010 Capital in Excess of Par Value [Member]	Sep. 30, 2012 Retained Earnings [Member]	Sep. 30, 2011 Retained Earnings [Member]	Sep. 30, 2010 Retained Earnings [Member]	Sep. 30, 2012 Deferred Compensation [Member]	Sep. 30, 2011 Deferred Compensation [Member]	Sep. 30, 2010 Deferred Compensation [Member]	Sep. 30, 2009 Deferred Compensation [Member]	Sep. 30, 2012 Treasury Stock [Member]	Sep. 30, 2011 Treasury Stock [Member]	Sep. 30, 2010 Treasury Stock [Member]
Balance	$ 4,828,175			$ 332,662	$ 332,662	$ 332,662	$ 332,662	$ 1,793,160	$ 1,624,768	$ 1,485,674	$ 9,633,584	$ 8,724,228	$ 7,752,831	$ 18,917	$ 18,875	$ 17,164	$ 17,906	$ (6,280,106)	$ (4,806,333)	$ (4,073,699)
Balance, Shares																		(117,844,159)	(102,845,609)	(95,579,970)
Net Income	1,169,927	1,270,994	1,317,610								1,169,927	1,270,994	1,317,610
Common ($1.48, $1.60 and $1.80 per share for the year ended 2010,2011,2012 respectively)											(368,133)	(361,638)	(346,213)
Share-based compensation plans, net								38,540	95,227	59,866								10,856	27,939	16,624
Share-based compensation plans, net, Shares																		1,972,763	3,432,415	2,758,391
Share-based compensation								88,335	73,165	79,228
Common stock held in trusts, net														42	1,711	(742)		(42)	(1,711)	742
Common stock held in trusts, net, Shares																		65,764	3,316	34,790
Repurchase of common stock																		(1,500,000)	(1,500,001)	(750,000)
Repurchase of common stock, Shares																		(19,945,407)	(18,434,281)	(10,058,820)
Balance	$ 4,135,889	$ 4,828,175		$ 332,662	$ 332,662	$ 332,662	$ 332,662	$ 1,920,035	$ 1,793,160	$ 1,624,768	$ 10,435,378	$ 9,633,584	$ 8,724,228	$ 18,917	$ 18,875	$ 17,164	$ 17,906	$ (7,769,292)	$ (6,280,106)	$ (4,806,333)
Balance, Shares																		(135,751,039)	(117,844,159)	(102,845,609)