Property, Equipment and Technology, Net - Summary of Property, Equipment and Technology, Net (Detail) - USD ($) $ in Millions	Sep. 30, 2020	Sep. 30, 2019
Property, Plant and Equipment [Line Items]
Total property, equipment and technology	$ 7,161	$ 6,570
Accumulated depreciation and amortization	(4,424)	(3,875)
Property, equipment and technology, net	2,737	2,695
Land
Property, Plant and Equipment [Line Items]
Total property, equipment and technology	71	71
Buildings and building improvements
Property, Plant and Equipment [Line Items]
Total property, equipment and technology	1,007	965
Furniture, equipment and leasehold improvements
Property, Plant and Equipment [Line Items]
Total property, equipment and technology	1,997	1,913
Construction-in-progress
Property, Plant and Equipment [Line Items]
Total property, equipment and technology	163	180
Technology
Property, Plant and Equipment [Line Items]
Total property, equipment and technology	$ 3,923	$ 3,441