Fair Value - Changes in FV under the FV Option (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair value gains (losses)	$ 480	$ 784
Loans
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair value gains (losses)	(191)	25
Long-term debt
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair value gains (losses)	$ 1,100	$ 373