Fair Value (Nonrecurring Fair Value Measurements) (Details) - Fair Value, Nonrecurring - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024	Dec. 31, 2024
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 639		$ 853
Gains (Losses)	(95)	$ (73)
Level 3 | Nonaccrual loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	557		629
Gains (Losses)	(83)	(60)
Level 3 | Equity investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	35		198
Gains (Losses)	(6)	(10)
Level 3 | Loans held for sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	36		0
Gains (Losses)	(4)	0
Level 3 | OREO and foreclosed assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	4		8
Gains (Losses)	0	0
Level 3 | Long-lived assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	7		$ 18
Gains (Losses)	(2)	$ (3)
Level 2 | Loans held for sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 36