Derivative Instruments and Hedging Activities (Derivatives Not Designated as Hedges) (Details) - Derivatives not designated as hedging instruments - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Derivative Instruments, Gain (Loss) [Line Items]
Other Noninterest Income/(Expense)	$ 14	$ 9
Customer-facing interest rate derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Other Noninterest Income/(Expense)	6	1
Other interest rate derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Other Noninterest Income/(Expense)	1	1
Foreign exchange derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Other Noninterest Income/(Expense)	7	7
Purchased credit derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Other Noninterest Income/(Expense)	$ 0	$ 0