Segment Data - Revenues to Unaffiliated Customers and Long-lived Assets Including Property, Plant and Equipment (Detail) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	$ 3,059	$ 3,120	$ 2,051	$ 2,051	$ 2,202	$ 2,157	$ 2,072	$ 2,015	$ 10,282	$ 8,446	$ 8,054
Long-Lived Assets	20,774				6,317				20,774	6,317	6,276
Corporate
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-Lived Assets	332				340				332	340	350
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									5,069	3,417	3,353
Long-Lived Assets	15,513				3,126				15,513	3,126	3,251
Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									2,434	2,383	2,189
Long-Lived Assets	3,876				1,790				3,876	1,790	1,649
Greater Asia
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									1,545	1,437	1,344
Long-Lived Assets	569				555				569	555	519
Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									1,234	1,210	1,168
Long-Lived Assets	$ 484				$ 505				$ 484	$ 505	$ 505