Retirement Plans - Schedule of Net Periodic Benefit Cost (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Retirement Benefits [Abstract]
Service cost	$ 1	$ 2	$ 4	$ 4
Interest cost	4	4	14	13
Expected return on plan assets	(3)	(3)	(9)	(9)
Net actuarial and settlement/curtailment (gain) loss	0	0	0	8
Net periodic benefit cost	$ 2	$ 3	$ 9	$ 16