Accounting for Derivative Instruments and Hedging Activities - Offsetting of Derivatives by Counterparty Master Agreement Level and Collateral Received (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024
Offsetting of Derivatives by Counterparty Master Agreement Level and Collateral Received or Paid
Gross Amounts of Recognized Assets / Liabilities	$ 397	$ 992
Derivative Instruments	0	0
Cash Collateral (Held) / Posted	(78)	(107)
Net Amount	319	885
Interest rate contracts
Offsetting of Derivatives by Counterparty Master Agreement Level and Collateral Received or Paid
Derivative Assets	0	9
Derivative Instruments		(3)
Cash Collateral (Held)/Posted		0
Net Amount		6
Derivative liabilities	(4)	(3)
Derivative Instruments	0	3
Cash Collateral (Held)/Posted	0	0
Net Amount	(4)	0
Gross Amounts of Recognized Assets / Liabilities		6
Derivative Instruments		0
Cash Collateral (Held) / Posted		0
Net Amount		6
Foreign exchange contract
Offsetting of Derivatives by Counterparty Master Agreement Level and Collateral Received or Paid
Derivative Assets	3	22
Derivative Instruments	(2)	(1)
Cash Collateral (Held)/Posted	0	0
Net Amount	1	21
Derivative liabilities	(3)	(1)
Derivative Instruments	2	1
Cash Collateral (Held)/Posted	0	0
Net Amount	(1)	0
Gross Amounts of Recognized Assets / Liabilities	0	21
Derivative Instruments	0	0
Cash Collateral (Held) / Posted	0	0
Net Amount	0	21
Commodity contracts
Offsetting of Derivatives by Counterparty Master Agreement Level and Collateral Received or Paid
Derivative Assets	3,754	4,365
Derivative Instruments	(2,724)	(2,992)
Cash Collateral (Held)/Posted	(215)	(168)
Net Amount	815	1,205
Derivative liabilities	(3,070)	(3,197)
Derivative Instruments	2,724	2,992
Cash Collateral (Held)/Posted	137	61
Net Amount	(209)	(144)
Gross Amounts of Recognized Assets / Liabilities	684	1,168
Derivative Instruments	0	0
Cash Collateral (Held) / Posted	(78)	(107)
Net Amount	606	1,061
Consumer Financing Program
Offsetting of Derivatives by Counterparty Master Agreement Level and Collateral Received or Paid
Derivative Assets		(203)
Derivative Instruments		0
Cash Collateral (Held)/Posted		0
Net Amount		(203)
Derivative liabilities	(283)	$ (203)
Derivative Instruments	0
Cash Collateral (Held)/Posted	0
Net Amount	$ (283)