Accumulated Other Comprehensive Income - Schedule of Accumulated Other Comprehensive Income (Loss) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive (loss) income, beginning balance			$ (516)
Other comprehensive income before reclassifications			30
Amounts reclassified into income			29
Accumulated other comprehensive (loss) income, ending balance	(457)		(457)
Foreign Currency Translation Adjustments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive (loss) income, beginning balance			74
Other comprehensive income before reclassifications			3
Accumulated other comprehensive (loss) income, ending balance	77		77
Benefit Plans Adjustments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive (loss) income, beginning balance			(558)
Other comprehensive income before reclassifications			27
Amounts reclassified into income	8	14	25	41
Accumulated other comprehensive (loss) income, ending balance	(506)		(506)
Unrealized Losses on Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive (loss) income, beginning balance			(31)
Amounts reclassified into income	1	1	4	4
Accumulated other comprehensive (loss) income, ending balance	$ (28)		$ (28)