Financial Derivatives (Gains (Losses) on Derivatives Not Designated As Hedging) (Details) - Not Designated as Hedging Instrument - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Derivative [Line Items]
Total gains (losses) from derivatives not designated as hedging instruments	$ (260)	$ (85)	$ 176
Mortgage Banking | Interest rate contracts:
Derivative [Line Items]
Total gains (losses) from derivatives not designated as hedging instruments	(70)	(671)	(78)
Customer-related Contracts
Derivative [Line Items]
Total gains (losses) from derivatives not designated as hedging instruments	205	331	284
Customer-related Contracts | Interest rate contracts:
Derivative [Line Items]
Total gains (losses) from derivatives not designated as hedging instruments	(15)	220	149
Customer-related Contracts | Foreign exchange contracts and other
Derivative [Line Items]
Total gains (losses) from derivatives not designated as hedging instruments	220	111	135
Other Risk Management Activity | Foreign exchange contracts and other
Derivative [Line Items]
Total gains (losses) from derivatives not designated as hedging instruments	$ (395)	$ 255	$ (30)