Benefit Plans - Weighted Average Assumptions Determining Pension Plan (Parenthetical) (Detail)	0 Months Ended		1 Months Ended		12 Months Ended
	Nov. 30, 2011	Sep. 30, 2011	Nov. 30, 2011 U.S. Plans [Member]	Sep. 30, 2011 U.S. Plans [Member]	Sep. 30, 2014 U.S. Plans [Member]	Sep. 30, 2013 U.S. Plans [Member]	Sep. 30, 2012 U.S. Plans [Member]	Sep. 30, 2014 Other Postretirement Benefits [Member]	Sep. 30, 2013 Other Postretirement Benefits [Member]	Sep. 30, 2014 Postemployment Benefit Plan [Member]	Sep. 30, 2013 Postemployment Benefit Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	5.10%	4.90%	5.10%	4.90%	4.95%	3.90%	4.90%
Discount rates					4.15%	4.95%	3.90%	3.85%	4.40%	3.75%	4.00%