Employee Benefit Plans - Change in Projected Benefit Obligations and Change in Plan Assets (Detail) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Change in Plan Assets:
Fair value of plan assets at beginning of year	$ 217
Fair value of plan assets at end of year	135	$ 217
Pension Benefits [Member] | U.S. Defined Benefit Plans [Member]
Change in Benefit Obligations:
Benefit obligation at beginning of year	3	99
Service cost			$ 1
Interest cost			4
(Gain) loss from changes in actuarial assumptions and plan experience	(1)	(1)
Benefits paid		(3)
Settlements or curtailments		$ (92)
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Settlement and Curtailment Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]		Other income (expense)
Benefit obligation at end of year	2	$ 3	99
Change in Plan Assets:
Fair value of plan assets at beginning of year		96
Actual return on plan assets		1
Benefits paid		(3)
Settlements or curtailments		(92)
Other		(2)
Fair value of plan assets at end of year			96
Funded status	(2)	(3)
Recognized asset (liability)	(2)	(3)
Pension Benefits [Member] | Foreign Plans [Member]
Change in Benefit Obligations:
Benefit obligation at beginning of year	221	231
Service cost	4	6	5
Interest cost	$ 4	$ 3	3
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Excluding Service Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]	Other income (expense)	Other income (expense)
Plan participants’ contribution	$ 1	$ 1
Foreign currency exchange rate changes	(27)	6
(Gain) loss from changes in actuarial assumptions and plan experience	(43)	(11)
Benefits paid	(9)	(8)
Settlements or curtailments	$ (2)	$ (8)
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Settlement and Curtailment Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Other income (expense)	Other income (expense)
Divestiture of a business	$ (16)
Other		$ 1
Benefit obligation at end of year	133	221	231
Change in Plan Assets:
Fair value of plan assets at beginning of year	217	204
Actual return on plan assets	(35)	14
Employer contribution	5	7
Plan participants’ contribution	1	1
Foreign currency exchange rate changes	(24)	7
Benefits paid	(9)	(8)
Settlements or curtailments	(2)	(8)
Divestiture of a business	(18)
Fair value of plan assets at end of year	135	217	204
Funded status	2	(4)
Recognized asset (liability)	2	(4)
Postretirement Benefits [Member] | U.S. Defined Benefit Plans [Member]
Change in Benefit Obligations:
Benefit obligation at beginning of year	25	27
Interest cost			1
(Gain) loss from changes in actuarial assumptions and plan experience	(4)
Benefits paid	(3)	(2)
Settlements or curtailments	$ (2)
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Settlement and Curtailment Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Other income (expense)
Benefit obligation at end of year	$ 16	25	27
Change in Plan Assets:
Employer contribution	5	2
Benefits paid	(3)	(2)
Settlements or curtailments	(2)
Funded status	(16)	(25)
Recognized asset (liability)	(16)	(25)
Postretirement Benefits [Member] | Foreign Plans [Member]
Change in Benefit Obligations:
Benefit obligation at beginning of year	19	20
Interest cost	$ 1	$ 1
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Excluding Service Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]	Other income (expense)	Other income (expense)
Foreign currency exchange rate changes	$ (2)	$ 1
(Gain) loss from changes in actuarial assumptions and plan experience	(5)	(2)
Benefits paid		(1)
Benefit obligation at end of year	13	19	$ 20
Change in Plan Assets:
Employer contribution		1
Benefits paid		(1)
Funded status	(13)	(19)
Recognized asset (liability)	$ (13)	$ (19)