Employee Benefit Plans - Net Periodic Defined Benefit Pension and Other Postretirement Benefit Costs (Detail) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Pension Benefits [Member] | U.S. Defined Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost			$ 1
Interest cost			4
Expected return on plan assets			$ (3)
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Expected Return (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]			Other income (expense)
Settlements or Curtailments cost		$ 4	$ 3
Net periodic (benefit) cost		4	5
Pension Benefits [Member] | Foreign Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 4	6	5
Interest cost	4	3	3
Expected return on plan assets	$ (6)	$ (10)	$ (9)
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Expected Return (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Other income (expense)	Other income (expense)	Other income (expense)
Amortization of net losses	$ 1	$ 3	$ 3
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Amortization of Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Other income (expense)	Other income (expense)	Other income (expense)
Settlements or Curtailments cost		$ 1	$ 1
Other		2
Net periodic (benefit) cost	$ 3	5	3
Postretirement Benefits [Member] | U.S. Defined Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest cost			1
Amortization of net losses			$ (1)
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Amortization of Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]			Other income (expense)
Settlements or Curtailments cost	(1)
Net periodic (benefit) cost	(1)
Postretirement Benefits [Member] | Foreign Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest cost	1	1
Amortization of net losses			$ 1
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Amortization of Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]			Other income (expense)
Net periodic (benefit) cost	$ 1	$ 1	$ 1