Fair Value (Nonrecurring Fair Value Measurements) (Details) - Fair Value, Nonrecurring - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nonrecurring Assets - Fair Value	$ 628		$ 802
Nonrecurring Assets - Gains (Losses)	(73)	$ (89)
Level 3 | Nonaccrual loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nonrecurring Assets - Fair Value	602		578
Nonrecurring Assets - Gains (Losses)	(60)	(79)
Level 3 | Equity investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nonrecurring Assets - Fair Value	10		203
Nonrecurring Assets - Gains (Losses)	(10)	(5)
Level 3 | OREO and foreclosed assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nonrecurring Assets - Fair Value	7		12
Nonrecurring Assets - Gains (Losses)
Level 3 | Long-lived assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nonrecurring Assets - Fair Value	9		9
Nonrecurring Assets - Gains (Losses)	$ (3)	$ (5)
Level 1 | Equity investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nonrecurring Assets - Fair Value			$ 30