Accumulated Other Comprehensive Income - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Accumulated Other Comprehensive Income (Loss) [Line Items]
Income tax provision (benefit)	$ 88	$ 95
Income tax provision (benefit) for cash flow hedges	0	2
Benefit Plans Adjustments [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Income tax provision (benefit)	(5)	(8)
Unrealized Losses on Cash Flow Hedges [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Income tax provision (benefit)	$ (1)	$ (1)