Derivatives and Hedging Activities - Schedule of Derivative Instrument Cash Flow Hedge Earning Recognized by Income Statement Location (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Derivatives, Fair Value [Line Items]
Net Gains (Losses) Recognized in OCI	$ (281)	$ (107)
Realized gains (losses) (pre-tax) reclassified from AOCI into net income	(215)	(216)
Interest income – loans | Interest rate | Cash Flow Hedges
Derivatives, Fair Value [Line Items]
Net Gains (Losses) Recognized in OCI	(283)	109
Realized gains (losses) (pre-tax) reclassified from AOCI into net income	(216)	(215)
Interest expense — Long-term debt | Interest rate | Cash Flow Hedges
Derivatives, Fair Value [Line Items]
Net Gains (Losses) Recognized in OCI	1	(1)
Realized gains (losses) (pre-tax) reclassified from AOCI into net income	0	(1)
Investment banking and debt placement fees | Interest rate | Cash Flow Hedges
Derivatives, Fair Value [Line Items]
Net Gains (Losses) Recognized in OCI	1	(1)
Realized gains (losses) (pre-tax) reclassified from AOCI into net income	$ 1	$ 0