Employee Benefit Plans - Net Periodic Defined Benefit Pension Costs (Detail) - Pension Benefits [Member] - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
U.S. Defined Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost		$ 1	$ 1	$ 1
Interest cost	$ 1	1	3	4
Expected return on plan assets	(1)	(2)	(3)	(7)
Net periodic benefit (credit) cost			1	(2)
Foreign Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	2	4	5
Interest cost	1	1	3	4
Expected return on plan assets	(2)	(2)	(7)	(8)
Amortization of prior service costs (credit)		2		2
Amortization of actual / actuarial loss	1	1	2	2
Settlement and curtailment gain				(6)
Net periodic benefit (credit) cost	$ 1	$ 4	$ 2	$ (1)