Derivatives and Hedging Activities - Schedule of Derivative Instrument Cash Flow Hedge Earning Recognized by Income Statement Location (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Derivatives, Fair Value [Line Items]
Net Gains (Losses) Recognized in OCI	$ (30)	$ 405	$ 332	$ 46
Net Gains (Losses) Reclassified From OCI Into Income	(98)	(187)	(283)	(602)
Interest income – loans | Interest rate | Cash Flow Hedges
Derivatives, Fair Value [Line Items]
Net Gains (Losses) Recognized in OCI	(30)	410	333	49
Net Gains (Losses) Reclassified From OCI Into Income	(98)	(184)	(281)	(599)
Interest expense — Long-term debt | Interest rate | Cash Flow Hedges
Derivatives, Fair Value [Line Items]
Net Gains (Losses) Recognized in OCI	0	0	(1)	1
Net Gains (Losses) Reclassified From OCI Into Income	0	0	(2)	(1)
Investment banking and debt placement fees | Interest rate | Cash Flow Hedges
Derivatives, Fair Value [Line Items]
Net Gains (Losses) Recognized in OCI	0	(5)	0	(4)
Net Gains (Losses) Reclassified From OCI Into Income	$ 0	$ (3)	$ 0	$ (2)