Accumulated Other Comprehensive Income (Loss) - (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at September 30, 2015			$ (1,738)
Other comprehensive income (loss) before reclassifications, net of taxes			89
Amounts reclassified into income, net of taxes			45
Balance at June 30, 2016	$ (1,605)		(1,605)
Foreign Currency Translation
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at September 30, 2015			(961)
Other comprehensive income (loss) before reclassifications, net of taxes			101
Amounts reclassified into income, net of taxes			0
Balance at June 30, 2016	(861)		(861)
Benefit Plans
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at September 30, 2015			(741)
Other comprehensive income (loss) before reclassifications, net of taxes			0
Amounts reclassified into income, net of taxes	12	$ 11	36	$ 33
Balance at June 30, 2016	(705)		(705)
Cash Flow Hedges
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at September 30, 2015			(36)
Other comprehensive income (loss) before reclassifications, net of taxes			(12)
Amounts reclassified into income, net of taxes	3	$ 2	9	$ 4
Balance at June 30, 2016	$ (39)		$ (39)