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, 2024	Mar. 31, 2023
Derivative [Line Items]
Derivative instruments not designated as hedging instruments gain (loss), net	$ 15	$ 88
Mortgage Banking | Interest Rate Contracts
Derivative [Line Items]
Derivative instruments not designated as hedging instruments gain (loss), net	(123)	107
Customer Contracts
Derivative [Line Items]
Derivative instruments not designated as hedging instruments gain (loss), net	13	58
Customer Contracts | Interest Rate Contracts
Derivative [Line Items]
Derivative instruments not designated as hedging instruments gain (loss), net	(16)	2
Customer Contracts | Foreign exchange contracts and other
Derivative [Line Items]
Derivative instruments not designated as hedging instruments gain (loss), net	29	56
Other Risk Management Activity | Foreign exchange contracts and other
Derivative [Line Items]
Derivative instruments not designated as hedging instruments gain (loss), net	$ 125	$ (77)