Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents (Details) - USD ($) $ in Millions	Dec. 31, 2023	Sep. 30, 2023	Dec. 31, 2022	Sep. 30, 2022
Restricted Cash and Cash Equivalents Items [Line Items]
Cash and cash equivalents	$ 13,591	$ 16,286
Cash, cash equivalents, restricted cash and restricted cash equivalents	19,636	21,990	$ 18,383	$ 20,377
U.S. litigation escrow
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash and restricted cash equivalents:	1,616	1,764
Customer collateral
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash and restricted cash equivalents:	3,164	3,005
Prepaid expenses and other current assets
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash and restricted cash equivalents:	$ 1,265	$ 935