Fair Value of Assets and Liabilities - Gains/(losses) on Nonrecurring Fair Value Measurements (Details) - Non Recurring - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net gains/(losses), loans and leases	$ (31)	$ (19)	$ (56)	$ (23)
Net gains/(losses), other assets	0	(1)	0	(1)
Gains (losses) on financial assets measured on non-recurring basis	(32)	(21)	(57)	(26)
SBAs
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net gains/(losses), loans held for sale - SBAs and USDA	$ (1)	$ (1)	$ (1)	$ (2)