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
	Mar. 31, 2025	Mar. 31, 2024
Derivative [Line Items]
Derivative instruments not designated as hedging instruments gain (loss), net	$ (42)	$ 15
Mortgage Banking | Interest rate contracts
Derivative [Line Items]
Derivative instruments not designated as hedging instruments gain (loss), net	85	(123)
Customer Contracts
Derivative [Line Items]
Derivative instruments not designated as hedging instruments gain (loss), net	47	13
Customer Contracts | Interest rate contracts
Derivative [Line Items]
Derivative instruments not designated as hedging instruments gain (loss), net	(21)	(16)
Customer Contracts | Foreign exchange contracts and other
Derivative [Line Items]
Derivative instruments not designated as hedging instruments gain (loss), net	68	29
Other Risk Management Activity | Foreign exchange contracts and other
Derivative [Line Items]
Derivative instruments not designated as hedging instruments gain (loss), net	$ (174)	$ 125