Organization and Summary of Significant Accounting Policies - Schedule of Carrying Amounts and Classifications of Assets and Liabilities for Consolidated VIEs (Details) - USD ($) $ in Millions	Dec. 31, 2023	Sep. 30, 2023
Variable Interest Entity [Line Items]
Current assets	$ 4,074	$ 4,316
Total assets	9,297	9,424
Current liabilities	3,548	3,738
Noncurrent liabilities	3,076	3,083
VIEs
Variable Interest Entity [Line Items]
Current assets	237	265
Noncurrent assets	112	121
Total assets	349	386
Current liabilities	172	228
Noncurrent liabilities	12	13
Total liabilities	$ 184	$ 241