Leases - Schedule of Operating Lease Right of Use Assets and Operating Lease Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2023	Sep. 30, 2023
Leases [Abstract]
Operating lease right-of-use assets	$ 245	$ 241
Operating lease liabilities - current	81	77
Operating lease liabilities - noncurrent	163	163
Present value of lease liabilities	$ 244	$ 240
Weighted average remaining lease term:
Operating leases	5 years	5 years
Weighted average discount rate:
Operating leases	6.50%	6.10%
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Other noncurrent assets	Other noncurrent assets
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Other current liabilities	Other current liabilities
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Other Liabilities, Noncurrent	Other Liabilities, Noncurrent