Accumulated Other Comprehensive Income (Loss) - (Detail) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at September 30, 2015	$ (1,738)
Other comprehensive income before reclassifications, net of taxes	(116)
Amounts reclassified into income, net of taxes	15
Balance at December 31, 2015	(1,840)
Foreign Currency Translation Adjustments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at September 30, 2015	(961)
Other comprehensive income before reclassifications, net of taxes	(116)
Amounts reclassified into income, net of taxes	0
Balance at December 31, 2015	(1,077)
Benefit Plans Adjustments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at September 30, 2015	(741)
Other comprehensive income before reclassifications, net of taxes	0
Amounts reclassified into income, net of taxes	12	$ 11
Balance at December 31, 2015	(729)
Unrealized Losses on Cash Flow Hedges
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at September 30, 2015	(36)
Other comprehensive income before reclassifications, net of taxes	0	(8)
Amounts reclassified into income, net of taxes	3	$ 1
Balance at December 31, 2015	$ (33)