PROPERTY AND EQUIPMENT, NET (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 1,294	$ 1,188
Less: Accumulated depreciation and amortization	(759)	(661)
Total property and equipment, net	535	527
Land
Property, Plant and Equipment [Line Items]
Total property and equipment	29	29
Software, including development in progress
Property, Plant and Equipment [Line Items]
Total property and equipment	565	490
Amortization expense	54	49	$ 44
Buildings, building components, leasehold and land improvements
Property, Plant and Equipment [Line Items]
Total property and equipment	406	391
Furniture, fixtures and equipment
Property, Plant and Equipment [Line Items]
Total property and equipment	294	278
Property, Plant and Equipment
Property, Plant and Equipment [Line Items]
Depreciation expense	$ 52	$ 48	$ 41