Benefit Plans (Detail) - Pension Plans - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 25	$ 24
Interest cost	39	35
Expected return on plan assets	(42)	(38)
Amortization of prior service credit	(1)	(2)
Amortization of loss	16	17
Net pension cost	$ 37	$ 36