Derivatives and Hedging Activities - Schedule of Derivative Instrument Cash Flow Hedge Earning Recognized by Income Statement Location (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Derivatives, Fair Value [Line Items]
Net Gains (Losses) Recognized in OCI	$ (78)	$ (467)	$ (359)	$ (360)
Realized gains (losses) (pre-tax) reclassified from AOCI into net income	(200)	(246)	(415)	(461)
Interest income – loans | Interest rate | Cash Flow Hedges
Derivatives, Fair Value [Line Items]
Net Gains (Losses) Recognized in OCI	(78)	(465)	(361)	(356)
Realized gains (losses) (pre-tax) reclassified from AOCI into net income	(199)	(245)	(415)	(460)
Interest expense — Long-term debt | Interest rate | Cash Flow Hedges
Derivatives, Fair Value [Line Items]
Net Gains (Losses) Recognized in OCI	0	(4)	1	(5)
Realized gains (losses) (pre-tax) reclassified from AOCI into net income	(1)	(1)	(1)	(1)
Investment banking and debt placement fees | Interest rate | Cash Flow Hedges
Derivatives, Fair Value [Line Items]
Net Gains (Losses) Recognized in OCI	0	2	1	1
Realized gains (losses) (pre-tax) reclassified from AOCI into net income	$ 0	$ 0	$ 1	$ 0