Property, Equipment and Technology, Net (Detail) - USD ($) $ in Millions	Sep. 30, 2017	Sep. 30, 2016
Property, Plant and Equipment [Line Items]
Total property, equipment and technology	$ 5,143	$ 4,798
Accumulated depreciation and amortization	(2,890)	(2,648)
Property, equipment and technology, net	2,253	2,150
Land
Property, Plant and Equipment [Line Items]
Total property, equipment and technology	72	74
Buildings and building improvements
Property, Plant and Equipment [Line Items]
Total property, equipment and technology	865	839
Furniture, equipment and leasehold improvements
Property, Plant and Equipment [Line Items]
Total property, equipment and technology	1,534	1,382
Construction-in-progress
Property, Plant and Equipment [Line Items]
Total property, equipment and technology	139	125
Technology
Property, Plant and Equipment [Line Items]
Total property, equipment and technology	$ 2,533	$ 2,378