Pension and Postretirement Plans - Components of Net Periodic Benefit Cost (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Defined Benefit Plan Disclosure [Line Items]
Net actuarial (gain) loss	$ 87	$ (49)	$ 104	$ (252)
Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0	0	1
Interest cost	0	0	1	1
Expected return on plan assets	(3)	(2)	(7)	(6)
Amortization of prior service credit	(1)	(1)	(3)	(3)
Net periodic benefit cost (credit)	(4)	(3)	(9)	(7)
UNITED STATES | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest cost	17	14	38	36
Expected return on plan assets	(37)	(42)	(119)	(126)
Net actuarial (gain) loss	106	(49)	124	(252)
Settlement(Gain) Loss	2	(1)	3	(5)
Net periodic benefit cost (credit)	88	(78)	46	(347)
Foreign Plan [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	5	7	16	20
Interest cost	10	8	30	24
Expected return on plan assets	(20)	(29)	(62)	(84)
Amortization of prior service credit	0	1	0	1
Net actuarial (gain) loss	(19)	0	(20)	0
Settlement(Gain) Loss	(1)	0	7	0
Net periodic benefit cost (credit)	$ (25)	$ (13)	$ (29)	$ (39)