Fair Value - Changes in FV under the FV Option (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair value gains (losses), net (less than for 3 months ended June 30, 2026)	$ (76)	$ 211	$ 45	$ 334
Loans
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair value gains (losses), net (less than for 3 months ended June 30, 2026)	1	36	(22)	161
Long-term Debt
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair value gains (losses), net (less than for 3 months ended June 30, 2026)	$ 32	$ (68)	$ 119	$ (379)

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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