Fair Value - Changes in FV under the FV Option (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair value gains (losses), net	$ 630	$ 13	$ 675	$ 347
Loans
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair value gains (losses), net	(370)	87	(392)	248
Long-term Debt
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair value gains (losses), net	$ 730	$ (203)	$ 849	$ (582)