Benefit Plans (Detail) - Pension Plans - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 24	$ 38	$ 71	$ 106
Interest cost	35	21	103	59
Expected return on plan assets	(38)	(52)	(112)	(146)
Amortization of prior service credit	(2)	(4)	(5)	(12)
Amortization of loss	17	17	49	48
Curtailment/settlement (gain) loss	(14)	(1)	(13)	5
Net pension cost	$ 22	$ 19	$ 92	$ 61