Benefit Plans (Detail) - Pension Plans - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 22	$ 24	$ 69	$ 71
Interest cost	34	35	108	103
Expected return on plan assets	(37)	(38)	(117)	(112)
Amortization of prior service credit	(1)	(2)	(3)	(5)
Amortization of loss	14	17	44	49
Curtailment/settlement gain	0	(14)	0	(13)
Net pension cost	$ 32	$ 22	$ 101	$ 92