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, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Derivative [Line Items]
Derivative instruments not designated as hedging instruments gain (loss), net	$ 21	$ (238)	$ 164	$ (280)
Mortgage Banking \| Interest rate contracts
Derivative [Line Items]
Derivative instruments not designated as hedging instruments gain (loss), net	(32)	34	(50)	119
Customer Contracts
Derivative [Line Items]
Derivative instruments not designated as hedging instruments gain (loss), net	53	115	138	162
Customer Contracts \| Interest rate contracts
Derivative [Line Items]
Derivative instruments not designated as hedging instruments gain (loss), net	3	6	32	(15)
Customer Contracts \| Foreign exchange contracts and other
Derivative [Line Items]
Derivative instruments not designated as hedging instruments gain (loss), net	50	109	106	177
Other Risk Management Activity \| Foreign exchange contracts and other
Derivative [Line Items]
Derivative instruments not designated as hedging instruments gain (loss), net	$ 0	$ (387)	$ 76	$ (561)