Fair Value - Changes in FV under the FV Option (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair value gains (losses)	$ 795	$ 292	$ 1,403	$ 1,301
Loans
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair value gains (losses)	(117)	(209)	(95)	(587)
Long-term debt:
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair value gains (losses)	$ 406	$ 787	$ 356	$ 2,400