Financial Derivatives (Gains (Losses) on Derivatives Not Designated As Hedging Instruments under GAAP) (Details) - Not Designated as Hedging Instrument - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Derivative [Line Items]
Derivative instruments not designated as hedging instruments gain (loss), net	$ (238)	$ (113)	$ (280)	$ (98)
Mortgage Banking \| Interest rate contracts
Derivative [Line Items]
Derivative instruments not designated as hedging instruments gain (loss), net	34	(45)	119	(168)
Customer Contracts
Derivative [Line Items]
Derivative instruments not designated as hedging instruments gain (loss), net	115	25	162	38
Customer Contracts \| Interest rate contracts
Derivative [Line Items]
Derivative instruments not designated as hedging instruments gain (loss), net	6	(21)	(15)	(37)
Customer Contracts \| Foreign exchange contracts and other
Derivative [Line Items]
Derivative instruments not designated as hedging instruments gain (loss), net	109	46	177	75
Other Risk Management Activity \| Foreign exchange contracts and other
Derivative [Line Items]
Derivative instruments not designated as hedging instruments gain (loss), net	$ (387)	$ (93)	$ (561)	$ 32