Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents - Schedule of Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents (Details) - USD ($) $ in Millions	Jun. 30, 2024	Sep. 30, 2023	Jun. 30, 2023	Sep. 30, 2022
Restricted Cash and Cash Equivalents Items [Line Items]
Cash and cash equivalents	$ 12,947	$ 16,286
Cash, cash equivalents, restricted cash and restricted cash equivalents	19,276	21,990	$ 21,039	$ 20,377
U.S. litigation escrow
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash and restricted cash equivalents:	1,596	1,764
Customer collateral
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash and restricted cash equivalents:	3,472	3,005
Prepaid expenses and other current assets
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash and restricted cash equivalents:	$ 1,261	$ 935